File indexing completed on 2024-04-28 03:54:48

 /*
     xcf.cpp: A Qt 5 plug-in for reading GIMP XCF image files
     SPDX-FileCopyrightText: 2001 lignum Computing Inc. <allen@lignumcomputing.com>
     SPDX-FileCopyrightText: 2004 Melchior FRANZ <mfranz@kde.org>
 
     SPDX-License-Identifier: LGPL-2.1-or-later
 */
 
 #include "util_p.h"
 #include "xcf_p.h"
 
 #include <QColorSpace>
 #include <QDebug>
 #include <QIODevice>
 #include <QImage>
 #include <QImageReader>
 #include <QList>
 #include <QLoggingCategory>
 #include <QPainter>
 #include <QStack>
 #include <QtEndian>
 
 #ifndef XCF_QT5_SUPPORT
 // Float images are not supported by Qt 5 and can be disabled in QT 6 to reduce memory usage.
 // Unfortunately enabling/disabling this define results in slightly different images, so leave the default if possible.
 #define USE_FLOAT_IMAGES // default uncommented
 
 // Let's set a "reasonable" maximum size
 #define MAX_IMAGE_WIDTH 300000
 #define MAX_IMAGE_HEIGHT 300000
 #else
 // While it is possible to have images larger than 32767 pixels, QPainter seems unable to go beyond this threshold using Qt 5.
 #define MAX_IMAGE_WIDTH 32767
 #define MAX_IMAGE_HEIGHT 32767
 #endif
 
 #ifdef USE_FLOAT_IMAGES
 #include <qrgbafloat.h>
 #endif
 
 #include <stdlib.h>
 #include <string.h>
 
 #include "gimp_p.h"
 
 Q_DECLARE_LOGGING_CATEGORY(XCFPLUGIN)
 Q_LOGGING_CATEGORY(XCFPLUGIN, "kf.imageformats.plugins.xcf", QtWarningMsg)
 
 //#define DISABLE_TILE_PROFILE // default commented (comment to use the conversion as intended by Martin)
 #define DISABLE_IMAGE_PROFILE // default uncommented (comment to use the conversion as intended by Martin)
 #define DISABLE_TILE_PROFILE_CONV // default uncommented (comment to use the conversion as intended by Martin)
 #define DISABLE_IMAGE_PROFILE_CONV // default uncommented (comment to use the conversion as intended by Martin)
 
 const float INCHESPERMETER = (100.0f / 2.54f);
 
 namespace
 {
 struct RandomTable {
     // From glibc
     static constexpr int rand_r(unsigned int *seed)
     {
         unsigned int next = *seed;
         int result = 0;
 
         next *= 1103515245;
         next += 12345;
         result = (unsigned int)(next / 65536) % 2048;
 
         next *= 1103515245;
         next += 12345;
         result <<= 10;
         result ^= (unsigned int)(next / 65536) % 1024;
 
         next *= 1103515245;
         next += 12345;
         result <<= 10;
         result ^= (unsigned int)(next / 65536) % 1024;
 
         *seed = next;
 
         return result;
     }
 
     constexpr RandomTable()
         : values{}
     {
         unsigned int next = RANDOM_SEED;
 
         for (int i = 0; i < RANDOM_TABLE_SIZE; i++) {
             values[i] = rand_r(&next);
         }
 
         for (int i = 0; i < RANDOM_TABLE_SIZE; i++) {
             int tmp{};
             int swap = i + rand_r(&next) % (RANDOM_TABLE_SIZE - i);
             tmp = values[i];
             values[i] = values[swap];
             values[swap] = tmp;
         }
     }
 
     int values[RANDOM_TABLE_SIZE]{};
 };
 } // namespace {
 
 /*!
  * Each layer in an XCF file is stored as a matrix of
  * 64-pixel by 64-pixel images. The GIMP has a sophisticated
  * method of handling very large images as well as implementing
  * parallel processing on a tile-by-tile basis. Here, though,
  * we just read them in en-masse and store them in a matrix.
  */
 typedef QList<QList<QImage>> Tiles;
 
 class XCFImageFormat
 {
     Q_GADGET
 public:
     //! Properties which can be stored in an XCF file.
     enum PropType {
         PROP_END = 0,
         PROP_COLORMAP = 1,
         PROP_ACTIVE_LAYER = 2,
         PROP_ACTIVE_CHANNEL = 3,
         PROP_SELECTION = 4,
         PROP_FLOATING_SELECTION = 5,
         PROP_OPACITY = 6,
         PROP_MODE = 7,
         PROP_VISIBLE = 8,
         PROP_LINKED = 9,
         PROP_LOCK_ALPHA = 10,
         PROP_APPLY_MASK = 11,
         PROP_EDIT_MASK = 12,
         PROP_SHOW_MASK = 13,
         PROP_SHOW_MASKED = 14,
         PROP_OFFSETS = 15,
         PROP_COLOR = 16,
         PROP_COMPRESSION = 17,
         PROP_GUIDES = 18,
         PROP_RESOLUTION = 19,
         PROP_TATTOO = 20,
         PROP_PARASITES = 21,
         PROP_UNIT = 22,
         PROP_PATHS = 23,
         PROP_USER_UNIT = 24,
         PROP_VECTORS = 25,
         PROP_TEXT_LAYER_FLAGS = 26,
         PROP_OLD_SAMPLE_POINTS = 27,
         PROP_LOCK_CONTENT = 28,
         PROP_GROUP_ITEM = 29,
         PROP_ITEM_PATH = 30,
         PROP_GROUP_ITEM_FLAGS = 31,
         PROP_LOCK_POSITION = 32,
         PROP_FLOAT_OPACITY = 33,
         PROP_COLOR_TAG = 34,
         PROP_COMPOSITE_MODE = 35,
         PROP_COMPOSITE_SPACE = 36,
         PROP_BLEND_SPACE = 37,
         PROP_FLOAT_COLOR = 38,
         PROP_SAMPLE_POINTS = 39,
         MAX_SUPPORTED_PROPTYPE, // should always be at the end so its value is last + 1
     };
     Q_ENUM(PropType)
 
     //! Compression type used in layer tiles.
     enum XcfCompressionType : qint8 {
         COMPRESS_INVALID = -1, /* our own */
         COMPRESS_NONE = 0,
         COMPRESS_RLE = 1,
         COMPRESS_ZLIB = 2, /* unused */
         COMPRESS_FRACTAL = 3, /* unused */
     };
     Q_ENUM(XcfCompressionType)
 
     enum LayerModeType : quint32 {
         GIMP_LAYER_MODE_NORMAL_LEGACY,
         GIMP_LAYER_MODE_DISSOLVE,
         GIMP_LAYER_MODE_BEHIND_LEGACY,
         GIMP_LAYER_MODE_MULTIPLY_LEGACY,
         GIMP_LAYER_MODE_SCREEN_LEGACY,
         GIMP_LAYER_MODE_OVERLAY_LEGACY,
         GIMP_LAYER_MODE_DIFFERENCE_LEGACY,
         GIMP_LAYER_MODE_ADDITION_LEGACY,
         GIMP_LAYER_MODE_SUBTRACT_LEGACY,
         GIMP_LAYER_MODE_DARKEN_ONLY_LEGACY,
         GIMP_LAYER_MODE_LIGHTEN_ONLY_LEGACY,
         GIMP_LAYER_MODE_HSV_HUE_LEGACY,
         GIMP_LAYER_MODE_HSV_SATURATION_LEGACY,
         GIMP_LAYER_MODE_HSL_COLOR_LEGACY,
         GIMP_LAYER_MODE_HSV_VALUE_LEGACY,
         GIMP_LAYER_MODE_DIVIDE_LEGACY,
         GIMP_LAYER_MODE_DODGE_LEGACY,
         GIMP_LAYER_MODE_BURN_LEGACY,
         GIMP_LAYER_MODE_HARDLIGHT_LEGACY,
         GIMP_LAYER_MODE_SOFTLIGHT_LEGACY,
         GIMP_LAYER_MODE_GRAIN_EXTRACT_LEGACY,
         GIMP_LAYER_MODE_GRAIN_MERGE_LEGACY,
         GIMP_LAYER_MODE_COLOR_ERASE_LEGACY,
         GIMP_LAYER_MODE_OVERLAY,
         GIMP_LAYER_MODE_LCH_HUE,
         GIMP_LAYER_MODE_LCH_CHROMA,
         GIMP_LAYER_MODE_LCH_COLOR,
         GIMP_LAYER_MODE_LCH_LIGHTNESS,
         GIMP_LAYER_MODE_NORMAL,
         GIMP_LAYER_MODE_BEHIND,
         GIMP_LAYER_MODE_MULTIPLY,
         GIMP_LAYER_MODE_SCREEN,
         GIMP_LAYER_MODE_DIFFERENCE,
         GIMP_LAYER_MODE_ADDITION,
         GIMP_LAYER_MODE_SUBTRACT,
         GIMP_LAYER_MODE_DARKEN_ONLY,
         GIMP_LAYER_MODE_LIGHTEN_ONLY,
         GIMP_LAYER_MODE_HSV_HUE,
         GIMP_LAYER_MODE_HSV_SATURATION,
         GIMP_LAYER_MODE_HSL_COLOR,
         GIMP_LAYER_MODE_HSV_VALUE,
         GIMP_LAYER_MODE_DIVIDE,
         GIMP_LAYER_MODE_DODGE,
         GIMP_LAYER_MODE_BURN,
         GIMP_LAYER_MODE_HARDLIGHT,
         GIMP_LAYER_MODE_SOFTLIGHT,
         GIMP_LAYER_MODE_GRAIN_EXTRACT,
         GIMP_LAYER_MODE_GRAIN_MERGE,
         GIMP_LAYER_MODE_VIVID_LIGHT,
         GIMP_LAYER_MODE_PIN_LIGHT,
         GIMP_LAYER_MODE_LINEAR_LIGHT,
         GIMP_LAYER_MODE_HARD_MIX,
         GIMP_LAYER_MODE_EXCLUSION,
         GIMP_LAYER_MODE_LINEAR_BURN,
         GIMP_LAYER_MODE_LUMA_DARKEN_ONLY,
         GIMP_LAYER_MODE_LUMA_LIGHTEN_ONLY,
         GIMP_LAYER_MODE_LUMINANCE,
         GIMP_LAYER_MODE_COLOR_ERASE,
         GIMP_LAYER_MODE_ERASE,
         GIMP_LAYER_MODE_MERGE,
         GIMP_LAYER_MODE_SPLIT,
         GIMP_LAYER_MODE_PASS_THROUGH,
         GIMP_LAYER_MODE_COUNT,
     };
     Q_ENUM(LayerModeType)
 
     //! Type of individual layers in an XCF file.
     enum GimpImageType : qint32 {
         RGB_GIMAGE,
         RGBA_GIMAGE,
         GRAY_GIMAGE,
         GRAYA_GIMAGE,
         INDEXED_GIMAGE,
         INDEXEDA_GIMAGE,
     };
     Q_ENUM(GimpImageType)
 
     //! Type of individual layers in an XCF file.
     enum GimpColorSpace : qint32 {
         AutoColorSpace,
         RgbLinearSpace,
         RgbPerceptualSpace,
         LabSpace,
     };
     Q_ENUM(GimpColorSpace);
 
     //! Mode to use when compositing layer
     enum GimpCompositeMode : qint32 {
         CompositeAuto,
         CompositeUnion,
         CompositeClipBackdrop,
         CompositeClipLayer,
         CompositeIntersect,
     };
     Q_ENUM(GimpCompositeMode);
 
     enum GimpPrecision : qint32 {
         GIMP_PRECISION_U8_LINEAR = 100, /*< desc="8-bit linear integer"         >*/
         GIMP_PRECISION_U8_NON_LINEAR = 150, /*< desc="8-bit non-linear integer"          >*/
         GIMP_PRECISION_U8_PERCEPTUAL = 175, /*< desc="8-bit perceptual integer"          >*/
         GIMP_PRECISION_U16_LINEAR = 200, /*< desc="16-bit linear integer"        >*/
         GIMP_PRECISION_U16_NON_LINEAR = 250, /*< desc="16-bit non-linear integer"         >*/
         GIMP_PRECISION_U16_PERCEPTUAL = 275, /*< desc="16-bit perceptual integer"         >*/
         GIMP_PRECISION_U32_LINEAR = 300, /*< desc="32-bit linear integer"        >*/
         GIMP_PRECISION_U32_NON_LINEAR = 350, /*< desc="32-bit non-linear integer"         >*/
         GIMP_PRECISION_U32_PERCEPTUAL = 375, /*< desc="32-bit perceptual integer"         >*/
         GIMP_PRECISION_HALF_LINEAR = 500, /*< desc="16-bit linear floating point" >*/
         GIMP_PRECISION_HALF_NON_LINEAR = 550, /*< desc="16-bit non-linear floating point"  >*/
         GIMP_PRECISION_HALF_PERCEPTUAL = 575, /*< desc="16-bit perceptual floating point"  >*/
         GIMP_PRECISION_FLOAT_LINEAR = 600, /*< desc="32-bit linear floating point" >*/
         GIMP_PRECISION_FLOAT_NON_LINEAR = 650, /*< desc="32-bit non-linear floating point"  >*/
         GIMP_PRECISION_FLOAT_PERCEPTUAL = 675, /*< desc="32-bit perceptual floating point"  >*/
         GIMP_PRECISION_DOUBLE_LINEAR = 700, /*< desc="64-bit linear floating point" >*/
         GIMP_PRECISION_DOUBLE_NON_LINEAR = 750, /*< desc="64-bit non-linear floating point"  >*/
         GIMP_PRECISION_DOUBLE_PERCEPTUAL = 775, /*< desc="64-bit perceptual floating point"  >*/
     };
     Q_ENUM(GimpPrecision);
 
     XCFImageFormat();
     bool readXCF(QIODevice *device, QImage *image);
 
     /*!
      * Each GIMP image is composed of one or more layers. A layer can
      * be one of any three basic types: RGB, grayscale or indexed. With an
      * optional alpha channel, there are six possible types altogether.
      *
      * Note: there is only ever one instance of this structure. The
      * layer info is discarded after it is merged into the final QImage.
      */
     class Layer
     {
     public:
         quint32 width; //!< Width of the layer
         quint32 height; //!< Height of the layer
         GimpImageType type; //!< Type of the layer (GimpImageType)
         char *name; //!< Name of the layer
         qint64 hierarchy_offset; //!< File position of Tile hierarchy
         qint64 mask_offset; //!< File position of mask image
 
         uint nrows; //!< Number of rows of tiles (y direction)
         uint ncols; //!< Number of columns of tiles (x direction)
 
         Tiles image_tiles; //!< The basic image
         //! For Grayscale and Indexed images, the alpha channel is stored
         //! separately (in this data structure, anyway).
         Tiles alpha_tiles;
         Tiles mask_tiles; //!< The layer mask (optional)
 
         //! Additional information about a layer mask.
         struct {
             quint32 opacity;
             float opacityFloat = 1.f;
             quint32 visible;
             quint32 show_masked;
             uchar red, green, blue;
             float redF, greenF, blueF; // Floats should override
             quint32 tattoo;
         } mask_channel;
 
         XcfCompressionType compression = COMPRESS_INVALID; //!< tile compression method (CompressionType)
 
         bool active; //!< Is this layer the active layer?
         quint32 opacity = 255; //!< The opacity of the layer
         float opacityFloat = 1.f; //!< The opacity of the layer, but floating point (both are set)
         quint32 visible = 1; //!< Is the layer visible?
         quint32 linked; //!< Is this layer linked (geometrically)
         quint32 preserve_transparency; //!< Preserve alpha when drawing on layer?
         quint32 apply_mask = 9; //!< Apply the layer mask? Use 9 as "uninitilized". Spec says "If the property does not appear for a layer which has a layer
                                 //!< mask, it defaults to true (1).
                                 //   Robust readers should force this to false if the layer has no layer mask.
         quint32 edit_mask; //!< Is the layer mask the being edited?
         quint32 show_mask; //!< Show the layer mask rather than the image?
         qint32 x_offset = 0; //!< x offset of the layer relative to the image
         qint32 y_offset = 0; //!< y offset of the layer relative to the image
         LayerModeType mode = GIMP_LAYER_MODE_NORMAL_LEGACY; //!< Combining mode of layer (LayerModeEffects)
         quint32 tattoo; //!< (unique identifier?)
         GimpColorSpace blendSpace = RgbLinearSpace; //!< What colorspace to use when blending
         GimpColorSpace compositeSpace = RgbLinearSpace; //!< What colorspace to use when compositing
         GimpCompositeMode compositeMode = CompositeUnion; //!< How to composite layer (union, clip, etc.)
 
         //! As each tile is read from the file, it is buffered here.
 #ifdef USE_FLOAT_IMAGES
         uchar tile[quint64(TILE_WIDTH * TILE_HEIGHT * sizeof(QRgbaFloat32) * 1.5)];
 #else
         uchar tile[quint64(TILE_WIDTH * TILE_HEIGHT * sizeof(QRgba64) * 1.5)];
 #endif
 
         //! The data from tile buffer is copied to the Tile by this
         //! method.  Depending on the type of the tile (RGB, Grayscale,
         //! Indexed) and use (image or mask), the bytes in the buffer are
         //! copied in different ways.
         bool (*assignBytes)(Layer &layer, uint i, uint j, const GimpPrecision &precision);
 
         Layer(void)
             : name(nullptr)
         {
         }
         ~Layer(void)
         {
             delete[] name;
         }
 
         Layer(const Layer &) = delete;
         Layer &operator=(const Layer &) = delete;
 
         QImage::Format qimageFormat(const GimpPrecision precision, uint num_colors = 0, bool legacyMode = false) const
         {
             int bpc = bytesPerChannel(precision);
 #ifdef USE_FLOAT_IMAGES
             bool float16 = !legacyMode && precision >= GIMP_PRECISION_HALF_LINEAR && precision <= GIMP_PRECISION_HALF_PERCEPTUAL;
             bool float32 = !legacyMode && precision >= GIMP_PRECISION_FLOAT_LINEAR && precision <= GIMP_PRECISION_FLOAT_PERCEPTUAL;
 #endif
 
             if (legacyMode) {
                 bpc = std::min(bpc, 1);
             }
 
             switch (type) {
             case RGB_GIMAGE:
                 if (opacity == OPAQUE_OPACITY) {
 #ifdef USE_FLOAT_IMAGES
                     if (float16) {
                         return QImage::Format_RGBX16FPx4;
                     }
                     if (float32) {
                         return QImage::QImage::Format_RGBX32FPx4;
                     }
 #endif
 
                     if (bpc == 1) {
                         return QImage::Format_RGBX8888;
                     } else if (bpc == 2 || bpc == 4) {
                         return QImage::Format_RGBX64;
                     } else {
                         qCDebug(XCFPLUGIN) << "Layer has invalid bpc" << bpc << precision;
                         return QImage::Format_Invalid;
                     }
                 }
                 Q_FALLTHROUGH();
             case RGBA_GIMAGE:
 #ifdef USE_FLOAT_IMAGES
                 if (float16) {
                     return QImage::Format_RGBA16FPx4;
                 }
                 if (float32) {
                     return QImage::QImage::Format_RGBA32FPx4;
                 }
 #endif
                 if (bpc == 1) {
                     return QImage::Format_RGBA8888;
                 } else if (bpc == 2 || bpc == 4) {
                     return QImage::Format_RGBA64;
                 } else {
                     qCDebug(XCFPLUGIN) << "Layer has invalid bpc" << bpc;
                     return QImage::Format_Invalid;
                 }
                 break;
 
             case GRAY_GIMAGE:
                 if (opacity == OPAQUE_OPACITY) {
                     return QImage::Format_Indexed8;
                 } // else, fall through to 32-bit representation
                 Q_FALLTHROUGH();
             case GRAYA_GIMAGE:
                 return QImage::Format_RGBA8888;
                 break;
 
             case INDEXED_GIMAGE:
                 // As noted in the table above, there are quite a few combinations
                 // which are possible with indexed images, depending on the
                 // presence of transparency (note: not translucency, which is not
                 // supported by The GIMP for indexed images) and the number of
                 // individual colors.
 
                 // Note: Qt treats a bitmap with a Black and White color palette
                 // as a mask, so only the "on" bits are drawn, regardless of the
                 // order color table entries. Otherwise (i.e., at least one of the
                 // color table entries is not black or white), it obeys the one-
                 // or two-color palette. Have to ask about this...
 
                 if (num_colors == 1 || num_colors == 2) {
                     return QImage::Format_MonoLSB;
                 } else {
                     return QImage::Format_Indexed8;
                 }
                 break;
 
             case INDEXEDA_GIMAGE:
                 if (num_colors == 1) {
                     return QImage::Format_MonoLSB;
                 } else {
                     return QImage::Format_Indexed8;
                 }
             }
             qCWarning(XCFPLUGIN) << "Unhandled layer mode" << XCFImageFormat::LayerModeType(type);
             return QImage::Format_Invalid;
         }
     };
 
     /*!
      * The in-memory representation of the XCF Image. It contains a few
      * metadata items, but is mostly a container for the layer information.
      */
     class XCFImage
     {
     public:
         struct Header {
             GimpPrecision precision = GIMP_PRECISION_U8_LINEAR; //!< Default precision (GimpPrecision)
             quint32 width; //!< width of the XCF image
             quint32 height; //!< height of the XCF image
             qint32 type; //!< type of the XCF image (GimpImageBaseType)
         } header;
 
         XcfCompressionType compression = COMPRESS_RLE; //!< tile compression method (CompressionType)
         float x_resolution = -1; //!< x resolution in dots per inch
         float y_resolution = -1; //!< y resolution in dots per inch
         qint32 tattoo; //!< (unique identifier?)
         quint32 unit; //!< Units of The GIMP (inch, mm, pica, etc...)
         qint32 num_colors = 0; //!< number of colors in an indexed image
         QList<QRgb> palette; //!< indexed image color palette
 
         int num_layers; //!< number of layers
         Layer layer; //!< most recently read layer
 
         bool initialized; //!< Is the QImage initialized?
         QImage image; //!< final QImage
 
         QHash<QString,QByteArray> parasites;    //!< parasites data
 
         XCFImage(void)
             : initialized(false)
         {
         }
 
         QImage::Format qimageFormat() const
         {
             return layer.qimageFormat(header.precision, num_colors, true);
         }
 
         uint bytesPerChannel() const
         {
             return XCFImageFormat::bytesPerChannel(header.precision);
         }
     };
 
 private:
     static qint64 readOffsetPtr(QDataStream &stream)
     {
         if (stream.version() >= 11) {
             qint64 ret;
             stream >> ret;
             return ret;
         } else {
             quint32 ret;
             stream >> ret;
             return ret;
         }
     }
 
     //! In layer DISSOLVE mode, a random number is chosen to compare to a
     //! pixel's alpha. If the alpha is greater than the random number, the
     //! pixel is drawn. This table merely contains the random number seeds
     //! for each ROW of an image. Therefore, the random numbers chosen
     //! are consistent from run to run.
     static int random_table[RANDOM_TABLE_SIZE];
     static bool random_table_initialized;
 
     static constexpr RandomTable randomTable{};
 
     //! This table is used as a shared grayscale ramp to be set on grayscale
     //! images. This is because Qt does not differentiate between indexed and
     //! grayscale images.
     static QList<QRgb> grayTable;
 
     //! This table provides the add_pixel saturation values (i.e. 250 + 250 = 255).
     // static int add_lut[256][256]; - this is so lame waste of 256k of memory
     static int add_lut(int, int);
 
     //! The bottom-most layer is copied into the final QImage by this
     //! routine.
     typedef void (*PixelCopyOperation)(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n);
 
     //! Higher layers are merged into the final QImage by this routine.
     typedef bool (*PixelMergeOperation)(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n);
 
     static bool modeAffectsSourceAlpha(const quint32 type);
 
     bool loadImageProperties(QDataStream &xcf_io, XCFImage &image);
     bool loadProperty(QDataStream &xcf_io, PropType &type, QByteArray &bytes, quint32 &rawType);
     bool loadLayer(QDataStream &xcf_io, XCFImage &xcf_image);
     bool loadLayerProperties(QDataStream &xcf_io, Layer &layer);
     bool composeTiles(XCFImage &xcf_image);
     void setGrayPalette(QImage &image);
     void setPalette(XCFImage &xcf_image, QImage &image);
     void setImageParasites(const XCFImage &xcf_image, QImage &image);
     static bool assignImageBytes(Layer &layer, uint i, uint j, const GimpPrecision &precision);
     bool loadHierarchy(QDataStream &xcf_io, Layer &layer, const GimpPrecision precision);
     bool loadLevel(QDataStream &xcf_io, Layer &layer, qint32 bpp, const GimpPrecision precision);
     static bool assignMaskBytes(Layer &layer, uint i, uint j, const GimpPrecision &precision);
     bool loadMask(QDataStream &xcf_io, Layer &layer, const GimpPrecision precision);
     bool loadChannelProperties(QDataStream &xcf_io, Layer &layer);
     bool initializeImage(XCFImage &xcf_image);
     bool loadTileRLE(QDataStream &xcf_io, uchar *tile, int size, int data_length, qint32 bpp, qint64 *bytesParsed);
 
     static void copyLayerToImage(XCFImage &xcf_image);
     static void copyRGBToRGB(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n);
     static void copyGrayToGray(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n);
     static void copyGrayToRGB(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n);
     static void copyGrayAToRGB(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n);
     static void copyIndexedToIndexed(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n);
     static void copyIndexedAToIndexed(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n);
     static void copyIndexedAToRGB(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n);
 
     static void mergeLayerIntoImage(XCFImage &xcf_image);
     static bool mergeRGBToRGB(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n);
     static bool mergeGrayToGray(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n);
     static bool mergeGrayAToGray(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n);
     static bool mergeGrayToRGB(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n);
     static bool mergeGrayAToRGB(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n);
     static bool mergeIndexedToIndexed(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n);
     static bool mergeIndexedAToIndexed(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n);
     static bool mergeIndexedAToRGB(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n);
 
     static void initializeRandomTable();
     static void dissolveRGBPixels(QImage &image, int x, int y);
     static void dissolveAlphaPixels(QImage &image, int x, int y);
 
     static uint bytesPerChannel(const GimpPrecision precision)
     {
         switch (precision) {
         case GIMP_PRECISION_U8_LINEAR:
         case GIMP_PRECISION_U8_NON_LINEAR:
         case GIMP_PRECISION_U8_PERCEPTUAL:
             return 1;
             break;
         case GIMP_PRECISION_U16_LINEAR:
         case GIMP_PRECISION_U16_NON_LINEAR:
         case GIMP_PRECISION_U16_PERCEPTUAL:
         case GIMP_PRECISION_HALF_LINEAR:
         case GIMP_PRECISION_HALF_NON_LINEAR:
         case GIMP_PRECISION_HALF_PERCEPTUAL:
             return 2;
             break;
 
         case GIMP_PRECISION_U32_LINEAR:
         case GIMP_PRECISION_U32_NON_LINEAR:
         case GIMP_PRECISION_U32_PERCEPTUAL:
         case GIMP_PRECISION_FLOAT_LINEAR:
         case GIMP_PRECISION_FLOAT_NON_LINEAR:
         case GIMP_PRECISION_FLOAT_PERCEPTUAL:
             return 4;
             break;
         case GIMP_PRECISION_DOUBLE_LINEAR:
         case GIMP_PRECISION_DOUBLE_NON_LINEAR:
         case GIMP_PRECISION_DOUBLE_PERCEPTUAL:
             return 8;
             break;
 
         default:
             qCDebug(XCFPLUGIN) << "Layer has invalid precision" << precision;
             return 0;
         }
     }
 
 public:
     static bool readXCFHeader(QDataStream &ds, XCFImage::Header *header);
 };
 
 int XCFImageFormat::random_table[RANDOM_TABLE_SIZE];
 bool XCFImageFormat::random_table_initialized;
 
 constexpr RandomTable XCFImageFormat::randomTable;
 
 QList<QRgb> XCFImageFormat::grayTable;
 
 bool XCFImageFormat::modeAffectsSourceAlpha(const quint32 type)
 {
     switch (type) {
     case GIMP_LAYER_MODE_NORMAL_LEGACY:
     case GIMP_LAYER_MODE_DISSOLVE:
     case GIMP_LAYER_MODE_BEHIND_LEGACY:
         return true;
 
     case GIMP_LAYER_MODE_MULTIPLY_LEGACY:
     case GIMP_LAYER_MODE_SCREEN_LEGACY:
     case GIMP_LAYER_MODE_OVERLAY_LEGACY:
     case GIMP_LAYER_MODE_DIFFERENCE_LEGACY:
     case GIMP_LAYER_MODE_ADDITION_LEGACY:
     case GIMP_LAYER_MODE_SUBTRACT_LEGACY:
     case GIMP_LAYER_MODE_DARKEN_ONLY_LEGACY:
     case GIMP_LAYER_MODE_LIGHTEN_ONLY_LEGACY:
     case GIMP_LAYER_MODE_HSV_HUE_LEGACY:
     case GIMP_LAYER_MODE_HSV_SATURATION_LEGACY:
     case GIMP_LAYER_MODE_HSL_COLOR_LEGACY:
     case GIMP_LAYER_MODE_HSV_VALUE_LEGACY:
     case GIMP_LAYER_MODE_DIVIDE_LEGACY:
     case GIMP_LAYER_MODE_DODGE_LEGACY:
     case GIMP_LAYER_MODE_BURN_LEGACY:
     case GIMP_LAYER_MODE_HARDLIGHT_LEGACY:
     case GIMP_LAYER_MODE_SOFTLIGHT_LEGACY:
     case GIMP_LAYER_MODE_GRAIN_EXTRACT_LEGACY:
     case GIMP_LAYER_MODE_GRAIN_MERGE_LEGACY:
         return false;
 
     case GIMP_LAYER_MODE_COLOR_ERASE_LEGACY:
     case GIMP_LAYER_MODE_OVERLAY:
     case GIMP_LAYER_MODE_LCH_HUE:
     case GIMP_LAYER_MODE_LCH_CHROMA:
     case GIMP_LAYER_MODE_LCH_COLOR:
     case GIMP_LAYER_MODE_LCH_LIGHTNESS:
         return false;
 
     case GIMP_LAYER_MODE_NORMAL:
         return true;
 
     case GIMP_LAYER_MODE_BEHIND:
     case GIMP_LAYER_MODE_MULTIPLY:
     case GIMP_LAYER_MODE_SCREEN:
     case GIMP_LAYER_MODE_DIFFERENCE:
     case GIMP_LAYER_MODE_ADDITION:
     case GIMP_LAYER_MODE_SUBTRACT:
     case GIMP_LAYER_MODE_DARKEN_ONLY:
     case GIMP_LAYER_MODE_LIGHTEN_ONLY:
     case GIMP_LAYER_MODE_HSV_HUE:
     case GIMP_LAYER_MODE_HSV_SATURATION:
     case GIMP_LAYER_MODE_HSL_COLOR:
     case GIMP_LAYER_MODE_HSV_VALUE:
     case GIMP_LAYER_MODE_DIVIDE:
     case GIMP_LAYER_MODE_DODGE:
     case GIMP_LAYER_MODE_BURN:
     case GIMP_LAYER_MODE_HARDLIGHT:
     case GIMP_LAYER_MODE_SOFTLIGHT:
     case GIMP_LAYER_MODE_GRAIN_EXTRACT:
     case GIMP_LAYER_MODE_GRAIN_MERGE:
     case GIMP_LAYER_MODE_VIVID_LIGHT:
     case GIMP_LAYER_MODE_PIN_LIGHT:
     case GIMP_LAYER_MODE_LINEAR_LIGHT:
     case GIMP_LAYER_MODE_HARD_MIX:
     case GIMP_LAYER_MODE_EXCLUSION:
     case GIMP_LAYER_MODE_LINEAR_BURN:
     case GIMP_LAYER_MODE_LUMA_DARKEN_ONLY:
     case GIMP_LAYER_MODE_LUMA_LIGHTEN_ONLY:
     case GIMP_LAYER_MODE_LUMINANCE:
     case GIMP_LAYER_MODE_COLOR_ERASE:
     case GIMP_LAYER_MODE_ERASE:
     case GIMP_LAYER_MODE_MERGE:
     case GIMP_LAYER_MODE_SPLIT:
     case GIMP_LAYER_MODE_PASS_THROUGH:
         return false;
 
     default:
         qCWarning(XCFPLUGIN) << "Unhandled layer mode" << XCFImageFormat::LayerModeType(type);
         return false;
     }
 }
 
 //! Change a QRgb value's alpha only.
 inline QRgb qRgba(const QRgb rgb, int a)
 {
     return ((a & 0xff) << 24 | (rgb & RGB_MASK));
 }
 
 /*!
  * The constructor for the XCF image loader.
  */
 XCFImageFormat::XCFImageFormat()
 {
     static_assert(sizeof(QRgb) == 4, "the code assumes sizeof(QRgb) == 4, if that's not your case, help us fix it :)");
 }
 
 /*!
  * This initializes the tables used in the layer dissolving routines.
  */
 void XCFImageFormat::initializeRandomTable()
 {
     // From GIMP "paint_funcs.c" v1.2
     srand(RANDOM_SEED);
 
     for (int i = 0; i < RANDOM_TABLE_SIZE; i++) {
         random_table[i] = rand();
     }
 
     for (int i = 0; i < RANDOM_TABLE_SIZE; i++) {
         int tmp;
         int swap = i + rand() % (RANDOM_TABLE_SIZE - i);
         tmp = random_table[i];
         random_table[i] = random_table[swap];
         random_table[swap] = tmp;
     }
 }
 
 inline int XCFImageFormat::add_lut(int a, int b)
 {
     return qMin(a + b, 255);
 }
 
 bool XCFImageFormat::readXCFHeader(QDataStream &xcf_io, XCFImage::Header *header)
 {
     QByteArray tag(14, '\0');
 
     if (xcf_io.readRawData(tag.data(), tag.size()) != tag.size()) {
         qCDebug(XCFPLUGIN) << "XCF: read failure on header tag";
         return false;
     }
     if (!tag.startsWith("gimp xcf") || !tag.endsWith('\0')) {
         qCDebug(XCFPLUGIN) << "XCF: read called on non-XCF file";
         return false;
     }
 
     // Remove null terminator
     tag.chop(1);
 
     if (tag.right(4) == "file") {
         xcf_io.setVersion(0);
     } else {
         // Version 1 and onwards use the format "gimp xcf v###" instead of "gimp xcf file"
         bool ok;
         xcf_io.setVersion(tag.right(3).toInt(&ok));
         if (!ok) {
             qCDebug(XCFPLUGIN) << "Failed to parse version" << tag;
             return false;
         }
     }
     qCDebug(XCFPLUGIN) << "version" << xcf_io.version();
 
     if (xcf_io.version() > 12) {
         qCDebug(XCFPLUGIN) << "Unsupported version" << xcf_io.version();
         return false;
     }
 
     xcf_io >> header->width >> header->height >> header->type;
 
     if (xcf_io.version() >= 4) {
         int precision;
         xcf_io >> precision;
         qCDebug(XCFPLUGIN) << "Precision" << GimpPrecision(precision);
         if (xcf_io.version() < 7) {
             switch (precision) {
             case 0:
                 precision = GIMP_PRECISION_U8_NON_LINEAR;
                 break;
             case 1:
                 precision = GIMP_PRECISION_U16_NON_LINEAR;
                 break;
             case 2:
                 precision = GIMP_PRECISION_U32_LINEAR;
                 break;
             case 3:
                 precision = GIMP_PRECISION_HALF_LINEAR;
                 break;
             case 4:
                 precision = GIMP_PRECISION_FLOAT_LINEAR;
                 break;
             default:
                 if (precision < GIMP_PRECISION_U8_LINEAR) {
                     qCWarning(XCFPLUGIN) << "Invalid precision read" << precision;
                     return false;
                 } else {
                     qCDebug(XCFPLUGIN) << "Unexpected precision" << precision << "in version" << xcf_io.version();
                 }
             }
         }
         header->precision = GimpPrecision(precision);
     }
     qCDebug(XCFPLUGIN) << "tag:" << tag << " height: " << header->width << " width: " << header->height << " type: " << header->type;
 
     if ((sizeof(void *) == 4 && qint64(header->width) * header->height > 16384 * 16384)) {
         qCWarning(XCFPLUGIN) << "On 32-bits programs the maximum image size is limited to" << 16384 << "x" << 16384 << "px";
         return false;
     }
 
     if (header->width > MAX_IMAGE_WIDTH || header->height > MAX_IMAGE_HEIGHT) {
         qCWarning(XCFPLUGIN) << "The maximum image size is limited to" << MAX_IMAGE_WIDTH << "x" << MAX_IMAGE_HEIGHT << "px";
         return false;
     }
 
     return true;
 }
 
 bool XCFImageFormat::readXCF(QIODevice *device, QImage *outImage)
 {
     XCFImage xcf_image;
     QDataStream xcf_io(device);
 
     if (!readXCFHeader(xcf_io, &xcf_image.header)) {
         return false;
     }
 
     if (!loadImageProperties(xcf_io, xcf_image)) {
         return false;
     }
 
     // The layers appear to be stored in top-to-bottom order. This is
     // the reverse of how a merged image must be computed. So, the layer
     // offsets are pushed onto a LIFO stack (thus, we don't have to load
     // all the data of all layers before beginning to construct the
     // merged image).
 
     QStack<qint64> layer_offsets;
 
     while (true) {
         const qint64 layer_offset = readOffsetPtr(xcf_io);
 
         if (layer_offset == 0) {
             break;
         }
 
         if (layer_offset < 0) {
             qCDebug(XCFPLUGIN) << "XCF: negative layer offset";
             return false;
         }
 
         layer_offsets.push(layer_offset);
     }
 
     xcf_image.num_layers = layer_offsets.size();
 
     if (layer_offsets.size() == 0) {
         qCDebug(XCFPLUGIN) << "XCF: no layers!";
         return false;
     }
     qCDebug(XCFPLUGIN) << xcf_image.num_layers << "layers";
 
     // Load each layer and add it to the image
     while (!layer_offsets.isEmpty()) {
         qint64 layer_offset = layer_offsets.pop();
 
         xcf_io.device()->seek(layer_offset);
 
         if (!loadLayer(xcf_io, xcf_image)) {
             return false;
         }
     }
 
     if (!xcf_image.initialized) {
         qCDebug(XCFPLUGIN) << "XCF: no visible layers!";
         return false;
     }
 
     // The image was created: now I can set metadata and ICC color profile inside it.
     setImageParasites(xcf_image, xcf_image.image);
 
     *outImage = xcf_image.image;
     return true;
 }
 
 /*!
  * An XCF file can contain an arbitrary number of properties associated
  * with the image (and layer and mask).
  * \param xcf_io the data stream connected to the XCF image
  * \param xcf_image XCF image data.
  * \return true if there were no I/O errors.
  */
 bool XCFImageFormat::loadImageProperties(QDataStream &xcf_io, XCFImage &xcf_image)
 {
     while (true) {
         PropType type;
         QByteArray bytes;
         quint32 rawType;
 
         if (!loadProperty(xcf_io, type, bytes, rawType)) {
             qCDebug(XCFPLUGIN) << "XCF: error loading global image properties";
             return false;
         }
 
         QDataStream property(bytes);
 
         switch (type) {
         case PROP_END:
             return true;
 
         case PROP_COMPRESSION:
             property >> xcf_image.compression;
             break;
 
         case PROP_RESOLUTION:
             property.setFloatingPointPrecision(QDataStream::SinglePrecision);
             property >> xcf_image.x_resolution >> xcf_image.y_resolution;
             break;
 
         case PROP_TATTOO:
             property >> xcf_image.tattoo;
             break;
 
         case PROP_PARASITES:
             while (!property.atEnd()) {
                 char *tag;
 #if QT_VERSION < QT_VERSION_CHECK(6, 7, 0)
                 quint32 size;
 #else
                 qsizetype size;
 #endif
 
                 property.readBytes(tag, size);
 
                 quint32 flags;
                 QByteArray data;
                 property >> flags >> data;
 
                 // WARNING: you cannot add metadata to QImage here because it can be null.
                 // Adding a metadata to a QImage when it is null, does nothing (metas are lost).
                 if (tag) // store metadata for future use
                     xcf_image.parasites.insert(QString::fromUtf8(tag), data);
 
                 delete[] tag;
             }
             break;
 
         case PROP_UNIT:
             property >> xcf_image.unit;
             break;
 
         case PROP_PATHS: // This property is ignored.
             break;
 
         case PROP_USER_UNIT: // This property is ignored.
             break;
 
         case PROP_COLORMAP:
             property >> xcf_image.num_colors;
             if (xcf_image.num_colors < 0 || xcf_image.num_colors > 65535) {
                 return false;
             }
 
             xcf_image.palette = QList<QRgb>();
             xcf_image.palette.reserve(xcf_image.num_colors);
 
             for (int i = 0; i < xcf_image.num_colors; i++) {
                 uchar r;
                 uchar g;
                 uchar b;
                 property >> r >> g >> b;
                 xcf_image.palette.push_back(qRgb(r, g, b));
             }
             break;
 
         default:
             qCDebug(XCFPLUGIN) << "XCF: unimplemented image property" << type << "(" << rawType << ")"
                                << ", size " << bytes.size();
             break;
         }
     }
 }
 
 /*!
  * Read a single property from the image file. The property type is returned
  * in type and the data is returned in bytes.
  * \param xcf the image file data stream.
  * \param type returns with the property type.
  * \param bytes returns with the property data.
  * \return true if there were no IO errors.  */
 bool XCFImageFormat::loadProperty(QDataStream &xcf_io, PropType &type, QByteArray &bytes, quint32 &rawType)
 {
     quint32 size;
 
     xcf_io >> rawType;
     if (rawType >= MAX_SUPPORTED_PROPTYPE) {
         type = MAX_SUPPORTED_PROPTYPE;
         // we don't support the property, but we still need to read from the device, assume it's like all the
         // non custom properties that is data_length + data
         xcf_io >> size;
         xcf_io.skipRawData(size);
         // return true because we don't really want to totally fail on an unsupported property since it may not be fatal
         return true;
     }
 
     type = PropType(rawType);
 
     char *data = nullptr;
 
     // The colormap property size is not the correct number of bytes:
     // The GIMP source xcf.c has size = 4 + ncolors, but it should be
     // 4 + 3 * ncolors
 
     if (type == PROP_COLORMAP) {
         xcf_io >> size;
         quint32 ncolors;
         xcf_io >> ncolors;
 
         size = 3 * ncolors + 4;
 
         if (size > 65535 || size < 4) {
             return false;
         }
 
         data = new char[size];
 
         // since we already read "ncolors" from the stream, we put that data back
         data[0] = 0;
         data[1] = 0;
         data[2] = ncolors >> 8;
         data[3] = ncolors & 255;
 
         // ... and read the remaining bytes from the stream
         xcf_io.readRawData(data + 4, size - 4);
     } else if (type == PROP_USER_UNIT) {
         // The USER UNIT property size is not correct. I'm not sure why, though.
         float factor;
         qint32 digits;
 
         xcf_io >> size >> factor >> digits;
 
         for (int i = 0; i < 5; i++) {
             char *unit_strings;
 
             xcf_io >> unit_strings;
 
             delete[] unit_strings;
 
             if (xcf_io.device()->atEnd()) {
                 qCDebug(XCFPLUGIN) << "XCF: read failure on property " << type;
                 return false;
             }
         }
 
         size = 0;
     } else {
         xcf_io >> size;
         if (size > 256000) {
             return false;
         }
         data = new char[size];
         const quint32 dataRead = xcf_io.readRawData(data, size);
         if (dataRead < size) {
             qCDebug(XCFPLUGIN) << "XCF: loadProperty read less data than expected" << size << dataRead;
             memset(&data[dataRead], 0, size - dataRead);
         }
     }
 
     if (size != 0 && data) {
         bytes = QByteArray(data, size);
     }
 
     delete[] data;
 
     return true;
 }
 
 /*!
  * Load a layer from the XCF file. The data stream must be positioned at
  * the beginning of the layer data.
  * \param xcf_io the image file data stream.
  * \param xcf_image contains the layer and the color table
  * (if the image is indexed).
  * \return true if there were no I/O errors.
  */
 bool XCFImageFormat::loadLayer(QDataStream &xcf_io, XCFImage &xcf_image)
 {
     Layer &layer(xcf_image.layer);
     delete[] layer.name;
 
     xcf_io >> layer.width >> layer.height >> layer.type >> layer.name;
 
     // Don't want to keep passing this around, dumb XCF format
     layer.compression = XcfCompressionType(xcf_image.compression);
 
     if (!loadLayerProperties(xcf_io, layer)) {
         return false;
     }
 
     qCDebug(XCFPLUGIN) << "layer: \"" << layer.name << "\", size: " << layer.width << " x " << layer.height << ", type: " << layer.type
                        << ", mode: " << layer.mode << ", opacity: " << layer.opacity << ", visible: " << layer.visible << ", offset: " << layer.x_offset << ", "
                        << layer.y_offset << ", compression" << layer.compression;
 
     // Skip reading the rest of it if it is not visible. Typically, when
     // you export an image from the The GIMP it flattens (or merges) only
     // the visible layers into the output image.
 
     if (layer.visible == 0) {
         return true;
     }
 
     // If there are any more layers, merge them into the final QImage.
 
     layer.hierarchy_offset = readOffsetPtr(xcf_io);
     layer.mask_offset = readOffsetPtr(xcf_io);
 
     if (layer.hierarchy_offset < 0) {
         qCDebug(XCFPLUGIN) << "XCF: negative layer hierarchy_offset";
         return false;
     }
 
     if (layer.mask_offset < 0) {
         qCDebug(XCFPLUGIN) << "XCF: negative layer mask_offset";
         return false;
     }
 
     // Allocate the individual tile QImages based on the size and type
     // of this layer.
 
     if (!composeTiles(xcf_image)) {
         return false;
     }
     xcf_io.device()->seek(layer.hierarchy_offset);
 
     // As tiles are loaded, they are copied into the layers tiles by
     // this routine. (loadMask(), below, uses a slightly different
     // version of assignBytes().)
 
     layer.assignBytes = assignImageBytes;
 
     if (!loadHierarchy(xcf_io, layer, xcf_image.header.precision)) {
         return false;
     }
 
     if (layer.mask_offset != 0) {
         // 9 means its not on the file. Spec says "If the property does not appear for a layer which has a layer mask, it defaults to true (1).
         if (layer.apply_mask == 9) {
             layer.apply_mask = 1;
         }
 
         xcf_io.device()->seek(layer.mask_offset);
 
         if (!loadMask(xcf_io, layer, xcf_image.header.precision)) {
             return false;
         }
     } else {
         // Spec says "Robust readers should force this to false if the layer has no layer mask."
         layer.apply_mask = 0;
     }
 
     // Now we should have enough information to initialize the final
     // QImage. The first visible layer determines the attributes
     // of the QImage.
 
     if (!xcf_image.initialized) {
         if (!initializeImage(xcf_image)) {
             return false;
         }
         copyLayerToImage(xcf_image);
         xcf_image.initialized = true;
     } else {
         const QColorSpace colorspaceBefore = xcf_image.image.colorSpace();
         mergeLayerIntoImage(xcf_image);
         if (xcf_image.image.colorSpace() != colorspaceBefore) {
             qCDebug(XCFPLUGIN) << "Converting color space back to" << colorspaceBefore << "after layer composition";
             xcf_image.image.convertToColorSpace(colorspaceBefore);
         }
     }
 
     return true;
 }
 
 /*!
  * An XCF file can contain an arbitrary number of properties associated
  * with a layer.
  * \param xcf_io the data stream connected to the XCF image.
  * \param layer layer to collect the properties.
  * \return true if there were no I/O errors.
  */
 bool XCFImageFormat::loadLayerProperties(QDataStream &xcf_io, Layer &layer)
 {
     while (true) {
         PropType type;
         QByteArray bytes;
         quint32 rawType;
 
         if (!loadProperty(xcf_io, type, bytes, rawType)) {
             qCDebug(XCFPLUGIN) << "XCF: error loading layer properties";
             return false;
         }
 
         QDataStream property(bytes);
 
         switch (type) {
         case PROP_END:
             return true;
 
         case PROP_ACTIVE_LAYER:
             layer.active = true;
             break;
 
         case PROP_OPACITY:
             property >> layer.opacity;
             layer.opacity = std::min(layer.opacity, 255u);
             break;
 
         case PROP_FLOAT_OPACITY:
             // For some reason QDataStream isn't able to read the float (tried
             // setting the endianness manually)
             if (bytes.size() == 4) {
                 layer.opacityFloat = qFromBigEndian(*reinterpret_cast<float *>(bytes.data()));
             } else {
                 qCDebug(XCFPLUGIN) << "XCF: Invalid data size for float:" << bytes.size();
             }
             break;
 
         case PROP_VISIBLE:
             property >> layer.visible;
             break;
 
         case PROP_LINKED:
             property >> layer.linked;
             break;
 
         case PROP_LOCK_ALPHA:
             property >> layer.preserve_transparency;
             break;
 
         case PROP_APPLY_MASK:
             property >> layer.apply_mask;
             break;
 
         case PROP_EDIT_MASK:
             property >> layer.edit_mask;
             break;
 
         case PROP_SHOW_MASK:
             property >> layer.show_mask;
             break;
 
         case PROP_OFFSETS:
             property >> layer.x_offset >> layer.y_offset;
             break;
 
         case PROP_MODE:
             property >> layer.mode;
             if (layer.mode >= GIMP_LAYER_MODE_COUNT) {
                 qCDebug(XCFPLUGIN) << "Found layer with unsupported mode" << LayerModeType(layer.mode) << "Defaulting to mode 0";
                 layer.mode = GIMP_LAYER_MODE_NORMAL_LEGACY;
             }
             break;
 
         case PROP_TATTOO:
             property >> layer.tattoo;
             break;
 
         case PROP_COMPOSITE_SPACE:
             property >> layer.compositeSpace;
             if (layer.compositeSpace < 0) {
                 layer.compositeSpace = GimpColorSpace(-layer.compositeSpace);
             }
             break;
 
         case PROP_COMPOSITE_MODE:
             property >> layer.compositeMode;
             if (layer.compositeMode < 0) {
                 layer.compositeMode = XCFImageFormat::GimpCompositeMode(-layer.compositeMode);
             }
             break;
 
         case PROP_BLEND_SPACE:
             property >> layer.blendSpace;
             if (layer.blendSpace) {
                 layer.blendSpace = GimpColorSpace(-layer.blendSpace);
             }
             break;
 
         // Just for organization in the UI, doesn't influence rendering
         case PROP_COLOR_TAG:
             break;
 
         // We don't support editing, so for now just ignore locking
         case PROP_LOCK_CONTENT:
         case PROP_LOCK_POSITION:
             break;
 
         default:
             qCDebug(XCFPLUGIN) << "XCF: unimplemented layer property " << type << "(" << rawType << ")"
                                << ", size " << bytes.size();
             break;
         }
     }
 }
 
 /*!
  * Compute the number of tiles in the current layer and allocate
  * QImage structures for each of them.
  * \param xcf_image contains the current layer.
  */
 bool XCFImageFormat::composeTiles(XCFImage &xcf_image)
 {
     Layer &layer(xcf_image.layer);
 
     layer.nrows = (layer.height + TILE_HEIGHT - 1) / TILE_HEIGHT;
     layer.ncols = (layer.width + TILE_WIDTH - 1) / TILE_WIDTH;
 
     qCDebug(XCFPLUGIN) << "IMAGE: height=" << xcf_image.header.height << ", width=" << xcf_image.header.width;
     qCDebug(XCFPLUGIN) << "LAYER: height=" << layer.height << ", width=" << layer.width;
     qCDebug(XCFPLUGIN) << "LAYER: rows=" << layer.nrows << ", columns=" << layer.ncols;
 
     // NOTE: starting from GIMP 2.10, images can be very large. The 32K limit for width and height is obsolete
     //       and it was changed to 300000 (the same as Photoshop Big image). This plugin was able to open an RGB
     //       image of 108000x40000 pixels saved with GIMP 2.10
     // SANITY CHECK: Catch corrupted XCF image file where the width or height
     //               of a tile is reported are bogus. See Bug# 234030.
     if ((sizeof(void *) == 4 && qint64(layer.width) * layer.height > 16384 * 16384)) {
         qCWarning(XCFPLUGIN) << "On 32-bits programs the maximum layer size is limited to" << 16384 << "x" << 16384 << "px";
         return false;
     }
     if (layer.width > MAX_IMAGE_WIDTH || layer.height > MAX_IMAGE_HEIGHT) {
         qCWarning(XCFPLUGIN) << "The maximum layer size is limited to" << MAX_IMAGE_WIDTH << "x" << MAX_IMAGE_HEIGHT << "px";
         return false;
     }
 
     // NOTE: A layer is a named rectangular area of pixels which has a definite position with respect to the canvas.
     //       It may extend beyond the canvas or (more commonly) only cover some of it.
     // SANITY CHECK: Avoid to load XCF with a layer grater than 10 times the final image
     if (qint64(layer.width) * layer.height / 10 > qint64(xcf_image.header.width) * xcf_image.header.height) {
         if (qint64(layer.width) * layer.height > 16384 * 16384) { // large layers only
             qCWarning(XCFPLUGIN) << "Euristic sanity check: the image may be corrupted!";
             return false;
         }
     }
 
 #ifndef XCF_QT5_SUPPORT
     // Qt 6 image allocation limit calculation: we have to check the limit here because the image is splitted in
     // tiles of 64x64 pixels. The required memory to build the image is at least doubled because tiles are loaded
     // and then the final image is created by copying the tiles inside it.
     // NOTE: on Windows to open a 10GiB image the plugin uses 28GiB of RAM
     qint64 channels = 1 + (layer.type == RGB_GIMAGE ? 2 : 0) + (layer.type == RGBA_GIMAGE ? 3 : 0);
     if (qint64(layer.width) * qint64(layer.height) * channels * 2ll / 1024ll / 1024ll > QImageReader::allocationLimit()) {
         qCDebug(XCFPLUGIN) << "Rejecting image as it exceeds the current allocation limit of" << QImageReader::allocationLimit() << "megabytes";
         return false;
     }
 #endif
 
     layer.image_tiles.resize(layer.nrows);
 
     if (layer.type == GRAYA_GIMAGE || layer.type == INDEXEDA_GIMAGE) {
         layer.alpha_tiles.resize(layer.nrows);
     }
 
     if (layer.mask_offset != 0) {
         layer.mask_tiles.resize(layer.nrows);
     }
 
     for (uint j = 0; j < layer.nrows; j++) {
         layer.image_tiles[j].resize(layer.ncols);
 
         if (layer.type == GRAYA_GIMAGE || layer.type == INDEXEDA_GIMAGE) {
             layer.alpha_tiles[j].resize(layer.ncols);
         }
 
         if (layer.mask_offset != 0) {
             layer.mask_tiles[j].resize(layer.ncols);
         }
     }
 
     const QImage::Format format = layer.qimageFormat(xcf_image.header.precision);
 
     for (uint j = 0; j < layer.nrows; j++) {
         for (uint i = 0; i < layer.ncols; i++) {
             uint tile_width = (i + 1) * TILE_WIDTH <= layer.width ? TILE_WIDTH : layer.width - i * TILE_WIDTH;
 
             uint tile_height = (j + 1) * TILE_HEIGHT <= layer.height ? TILE_HEIGHT : layer.height - j * TILE_HEIGHT;
 
             // Try to create the most appropriate QImage (each GIMP layer
             // type is treated slightly differently)
 
             switch (layer.type) {
             case RGB_GIMAGE:
             case RGBA_GIMAGE:
                 layer.image_tiles[j][i] = QImage(tile_width, tile_height, format);
                 if (layer.image_tiles[j][i].isNull()) {
                     return false;
                 }
                 layer.image_tiles[j][i].setColorCount(0);
                 break;
 
             case GRAY_GIMAGE:
                 layer.image_tiles[j][i] = QImage(tile_width, tile_height, QImage::Format_Indexed8);
                 if (layer.image_tiles[j][i].isNull()) {
                     return false;
                 }
                 layer.image_tiles[j][i].setColorCount(256);
                 setGrayPalette(layer.image_tiles[j][i]);
                 break;
 
             case GRAYA_GIMAGE:
                 layer.image_tiles[j][i] = QImage(tile_width, tile_height, QImage::Format_Indexed8);
                 layer.image_tiles[j][i].setColorCount(256);
                 if (layer.image_tiles[j][i].isNull()) {
                     return false;
                 }
                 setGrayPalette(layer.image_tiles[j][i]);
 
                 layer.alpha_tiles[j][i] = QImage(tile_width, tile_height, QImage::Format_Indexed8);
                 if (layer.alpha_tiles[j][i].isNull()) {
                     return false;
                 }
                 layer.alpha_tiles[j][i].setColorCount(256);
                 setGrayPalette(layer.alpha_tiles[j][i]);
                 break;
 
             case INDEXED_GIMAGE:
                 layer.image_tiles[j][i] = QImage(tile_width, tile_height, QImage::Format_Indexed8);
                 layer.image_tiles[j][i].setColorCount(xcf_image.num_colors);
                 if (layer.image_tiles[j][i].isNull()) {
                     return false;
                 }
                 setPalette(xcf_image, layer.image_tiles[j][i]);
                 break;
 
             case INDEXEDA_GIMAGE:
                 layer.image_tiles[j][i] = QImage(tile_width, tile_height, QImage::Format_Indexed8);
                 if (layer.image_tiles[j][i].isNull()) {
                     return false;
                 }
                 layer.image_tiles[j][i].setColorCount(xcf_image.num_colors);
                 setPalette(xcf_image, layer.image_tiles[j][i]);
 
                 layer.alpha_tiles[j][i] = QImage(tile_width, tile_height, QImage::Format_Indexed8);
                 if (layer.alpha_tiles[j][i].isNull()) {
                     return false;
                 }
                 layer.alpha_tiles[j][i].setColorCount(256);
                 setGrayPalette(layer.alpha_tiles[j][i]);
             }
             if (layer.type != GRAYA_GIMAGE && layer.image_tiles[j][i].format() != format) {
                 qCWarning(XCFPLUGIN) << "Selected wrong tile format" << layer.image_tiles[j][i].format() << "expected" << format;
                 return false;
             }
 
 #ifndef DISABLE_TILE_PROFILE
             switch (xcf_image.header.precision) {
             case XCFImageFormat::GIMP_PRECISION_HALF_LINEAR:
             case XCFImageFormat::GIMP_PRECISION_FLOAT_LINEAR:
             case XCFImageFormat::GIMP_PRECISION_DOUBLE_LINEAR:
             case XCFImageFormat::GIMP_PRECISION_U8_LINEAR:
             case XCFImageFormat::GIMP_PRECISION_U16_LINEAR:
             case XCFImageFormat::GIMP_PRECISION_U32_LINEAR:
                 layer.image_tiles[j][i].setColorSpace(QColorSpace::SRgbLinear);
                 break;
             case XCFImageFormat::GIMP_PRECISION_HALF_NON_LINEAR:
             case XCFImageFormat::GIMP_PRECISION_FLOAT_NON_LINEAR:
             case XCFImageFormat::GIMP_PRECISION_DOUBLE_NON_LINEAR:
             case XCFImageFormat::GIMP_PRECISION_U8_NON_LINEAR:
             case XCFImageFormat::GIMP_PRECISION_U16_NON_LINEAR:
             case XCFImageFormat::GIMP_PRECISION_U32_NON_LINEAR:
                 layer.image_tiles[j][i].setColorSpace(QColorSpace::SRgb);
                 break;
             case XCFImageFormat::GIMP_PRECISION_HALF_PERCEPTUAL:
             case XCFImageFormat::GIMP_PRECISION_FLOAT_PERCEPTUAL:
             case XCFImageFormat::GIMP_PRECISION_DOUBLE_PERCEPTUAL:
             case XCFImageFormat::GIMP_PRECISION_U8_PERCEPTUAL:
             case XCFImageFormat::GIMP_PRECISION_U16_PERCEPTUAL:
             case XCFImageFormat::GIMP_PRECISION_U32_PERCEPTUAL:
                 layer.image_tiles[j][i].setColorSpace(QColorSpace::SRgb);
                 break;
             }
 #endif
             if (layer.mask_offset != 0) {
                 layer.mask_tiles[j][i] = QImage(tile_width, tile_height, QImage::Format_Indexed8);
                 layer.mask_tiles[j][i].setColorCount(256);
                 if (layer.mask_tiles[j][i].isNull()) {
                     return false;
                 }
                 setGrayPalette(layer.mask_tiles[j][i]);
             }
         }
     }
     return true;
 }
 
 /*!
  * Apply a grayscale palette to the QImage. Note that Qt does not distinguish
  * between grayscale and indexed images. A grayscale image is just
  * an indexed image with a 256-color, grayscale palette.
  * \param image image to set to a grayscale palette.
  */
 void XCFImageFormat::setGrayPalette(QImage &image)
 {
     if (grayTable.isEmpty()) {
         grayTable.resize(256);
 
         for (int i = 0; i < 256; i++) {
             grayTable[i] = qRgb(i, i, i);
         }
     }
 
     image.setColorTable(grayTable);
 }
 
 /*!
  * Copy the indexed palette from the XCF image into the QImage.
  * \param xcf_image XCF image containing the palette read from the data stream.
  * \param image image to apply the palette to.
  */
 void XCFImageFormat::setPalette(XCFImage &xcf_image, QImage &image)
 {
     Q_ASSERT(xcf_image.num_colors == xcf_image.palette.size());
 
     image.setColorTable(xcf_image.palette);
 }
 
 /*!
  * Copy the parasites info to QImage.
  * \param xcf_image XCF image containing the parasites read from the data stream.
  * \param image image to apply the parasites data.
  * \note Some comment taken from https://gitlab.gnome.org/GNOME/gimp/-/blob/master/devel-docs/parasites.txt
  */
 void XCFImageFormat::setImageParasites(const XCFImage &xcf_image, QImage &image)
 {
     auto&& p = xcf_image.parasites;
     auto keys = p.keys();
     for (auto &&key : std::as_const(keys)) {
         auto value = p.value(key);
         if (value.isEmpty())
             continue;
 
         // "icc-profile" (IMAGE, PERSISTENT | UNDOABLE)
         //     This contains an ICC profile describing the color space the
         //     image was produced in. TIFF images stored in PhotoShop do
         //     oftentimes contain embedded profiles. An experimental color
         //     manager exists to use this parasite, and it will be used
         //     for interchange between TIFF and PNG (identical profiles)
         if (key == QStringLiteral("icc-profile")) {
             auto cs = QColorSpace::fromIccProfile(value);
             if (cs.isValid())
                 image.setColorSpace(cs);
             continue;
         }
 
         // "gimp-comment" (IMAGE, PERSISTENT)
         //    Standard GIF-style image comments.  This parasite should be
         //    human-readable text in UTF-8 encoding.  A trailing \0 might
         //    be included and is not part of the comment.  Note that image
         //    comments may also be present in the "gimp-metadata" parasite.
         if (key == QStringLiteral("gimp-comment")) {
             value.replace('\0', QByteArray());
             image.setText(QStringLiteral("Comment"), QString::fromUtf8(value));
             continue;
         }
 
         // "gimp-image-metadata"
         //     Saved by GIMP 2.10.30 but it is not mentioned in the specification.
         //     It is an XML block with the properties set using GIMP.
         if (key == QStringLiteral("gimp-image-metadata")) {
             // NOTE: I arbitrary defined the metadata "XML:org.gimp.xml" because it seems
             //       a GIMP proprietary XML format (no xmlns defined)
             value.replace('\0', QByteArray());
             image.setText(QStringLiteral("XML:org.gimp.xml"), QString::fromUtf8(value));
             continue;
         }
 
 #if 0   // Unable to generate it using latest GIMP version
         // "gimp-metadata" (IMAGE, PERSISTENT)
         //     The metadata associated with the image, serialized as one XMP
         //     packet.  This metadata includes the contents of any XMP, EXIF
         //     and IPTC blocks from the original image, as well as
         //     user-specified values such as image comment, copyright,
         //     license, etc.
         if (key == QStringLiteral("gimp-metadata")) {
             // NOTE: "XML:com.adobe.xmp" is the meta set by Qt reader when an
             //       XMP packet is found (e.g. when reading a PNG saved by Photoshop).
             //       I reused the same key because some programs could search for it.
             value.replace('\0', QByteArray());
             image.setText(QStringLiteral("XML:com.adobe.xmp"), QString::fromUtf8(value));
             continue;
         }
 #endif
     }
 
 #ifdef DISABLE_IMAGE_PROFILE
     // final colorspace checks
     if (!image.colorSpace().isValid()) {
         switch (xcf_image.header.precision) {
         case XCFImageFormat::GIMP_PRECISION_HALF_LINEAR:
         case XCFImageFormat::GIMP_PRECISION_FLOAT_LINEAR:
         case XCFImageFormat::GIMP_PRECISION_DOUBLE_LINEAR:
         case XCFImageFormat::GIMP_PRECISION_U8_LINEAR:
         case XCFImageFormat::GIMP_PRECISION_U16_LINEAR:
         case XCFImageFormat::GIMP_PRECISION_U32_LINEAR:
             image.setColorSpace(QColorSpace::SRgbLinear);
             break;
         default:
             image.setColorSpace(QColorSpace::SRgb);
             break;
         }
     }
 #endif
 }
 
 /*!
  * Copy the bytes from the tile buffer into the image tile QImage, taking into
  * account all the myriad different modes.
  * \param layer layer containing the tile buffer and the image tile matrix.
  * \param i column index of current tile.
  * \param j row index of current tile.
  */
 bool XCFImageFormat::assignImageBytes(Layer &layer, uint i, uint j, const GimpPrecision &precision)
 {
     QImage &image = layer.image_tiles[j][i];
 
     const uchar *tile = layer.tile;
     const int width = image.width();
     const int height = image.height();
     const int bytesPerLine = image.bytesPerLine();
     uchar *bits = image.bits();
 
     // Handle the special cases
     if (layer.type == GRAYA_GIMAGE || layer.type == GRAY_GIMAGE || layer.type == INDEXEDA_GIMAGE) {
         auto bpc = bytesPerChannel(precision);
         for (int y = 0; y < height; y++) {
             uchar *dataPtr = bits + y * bytesPerLine;
             uchar *alphaPtr = nullptr;
             if (!layer.alpha_tiles.isEmpty())
                 alphaPtr = layer.alpha_tiles[j][i].scanLine(y);
             if (bpc == 4) {
 #ifdef USE_FLOAT_IMAGES
                 if (precision < GimpPrecision::GIMP_PRECISION_HALF_LINEAR) {
                     for (int x = 0; x < width; x++) {
                         auto src = (const quint16 *)tile;
                         *dataPtr++ = qFromBigEndian<quint16>(src[0]) / 257;
                         if (alphaPtr) {
                             *alphaPtr++ = qFromBigEndian<quint16>(src[1]) / 257;
                             tile += sizeof(quint16) * 2;
                         } else {
                             tile += sizeof(quint16);
                         }
                     }
                 } else {
                     for (int x = 0; x < width; x++) {
                         auto src = (const float *)tile;
                         *dataPtr++ = qFromBigEndian<float>(src[0]) * 255;
                         if (alphaPtr) {
                             *alphaPtr++ = qFromBigEndian<float>(src[1]) * 255;
                             tile += sizeof(float) * 2;
                         } else {
                             tile += sizeof(float);
                         }
                     }
                 }
 #else
                 for (int x = 0; x < width; x++) {
                     auto src = (const quint16 *)tile;
                     *dataPtr++ = qFromBigEndian<quint16>(src[0]) / 257;
                     if (alphaPtr) {
                         *alphaPtr++ = qFromBigEndian<quint16>(src[1]) / 257;
                         tile += sizeof(quint16) * 2;
                     } else {
                         tile += sizeof(quint16);
                     }
                 }
 #endif
             } else if (bpc == 2) {
 #ifdef USE_FLOAT_IMAGES
                 if (precision < GimpPrecision::GIMP_PRECISION_HALF_LINEAR) {
                     for (int x = 0; x < width; x++) {
                         auto src = (const quint16 *)tile;
                         *dataPtr++ = qFromBigEndian<quint16>(src[0]) / 257;
                         if (alphaPtr)
                             *alphaPtr++ = qFromBigEndian<quint16>(src[1]) / 257;
                         tile += sizeof(QRgb);
                     }
                 } else {
                     for (int x = 0; x < width; x++) {
                         auto src = (const qfloat16 *)tile;
                         *dataPtr++ = qFromBigEndian<qfloat16>(src[0]) * 255;
                         if (alphaPtr)
                             *alphaPtr++ = qFromBigEndian<qfloat16>(src[1]) * 255;
                         tile += sizeof(QRgb);
                     }
                 }
 #else
                 for (int x = 0; x < width; x++) {
                     auto src = (const quint16 *)tile;
                     *dataPtr++ = qFromBigEndian<quint16>(src[0]) / 257;
                     if (alphaPtr)
                         *alphaPtr++ = qFromBigEndian<quint16>(src[1]) / 257;
                     tile += sizeof(QRgb);
                 }
 #endif
             } else {
                 for (int x = 0; x < width; x++) {
                     if (tile[0] < image.colorCount())
                         *dataPtr++ = tile[0];
                     if (alphaPtr)
                         *alphaPtr++ = tile[1];
                     tile += sizeof(QRgb);
                 }
             }
         }
         return true;
     }
 
     switch (image.format()) {
     case QImage::Format_RGBX8888:
         for (int y = 0; y < height; y++) {
             uchar *dataPtr = image.scanLine(y);
             for (int x = 0; x < width * 4; x += 4, tile += 4) {
                 dataPtr[x + 0] = tile[0];
                 dataPtr[x + 1] = tile[1];
                 dataPtr[x + 2] = tile[2];
                 dataPtr[x + 3] = 255;
             }
         }
         break;
     case QImage::Format_RGBA8888:
         for (int y = 0; y < height; y++) {
             const size_t bpl = width * 4;
             memcpy(image.scanLine(y), tile + y * bpl, bpl);
         }
         break;
     case QImage::Format_RGBX64:
         for (int y = 0; y < height; y++) {
             quint16 *dataPtr = (quint16 *)image.scanLine(y);
             const size_t bpl = width * sizeof(QRgba64);
             const quint16 *src = (const quint16 *)(tile + y * bpl);
             for (int x = 0; x < width * 4; x += 4) {
                 dataPtr[x + 0] = qFromBigEndian(src[x + 0]);
                 dataPtr[x + 1] = qFromBigEndian(src[x + 1]);
                 dataPtr[x + 2] = qFromBigEndian(src[x + 2]);
                 dataPtr[x + 3] = 65535;
             }
         }
         break;
 #ifdef USE_FLOAT_IMAGES
     case QImage::Format_RGBX16FPx4:
         for (int y = 0; y < height; y++) {
             qfloat16 *dataPtr = (qfloat16 *)image.scanLine(y);
             const qfloat16 *src = (const qfloat16 *)(tile + y * width * sizeof(QRgbaFloat16));
             for (int x = 0; x < width * 4; x += 4) {
                 dataPtr[x + 0] = qFromBigEndian(src[x + 0]);
                 dataPtr[x + 1] = qFromBigEndian(src[x + 1]);
                 dataPtr[x + 2] = qFromBigEndian(src[x + 2]);
                 dataPtr[x + 3] = qfloat16(1);
             }
         }
         break;
     case QImage::Format_RGBA16FPx4:
         static_assert(sizeof(QRgbaFloat16) == sizeof(QRgba64), "Different sizes for float and int 16 bit pixels");
 #endif
     case QImage::Format_RGBA64:
         for (int y = 0; y < height; y++) {
             const size_t bpl = width * sizeof(QRgba64);
             qFromBigEndian<qint16>(tile + y * bpl, width * 4, image.scanLine(y));
         }
         break;
 #ifdef USE_FLOAT_IMAGES
     case QImage::Format_RGBA32FPx4:
         for (int y = 0; y < height; y++) {
             const size_t bpl = width * sizeof(QRgbaFloat32);
             qFromBigEndian<qint32>(tile + y * bpl, width * 4, image.scanLine(y));
         }
         break;
     case QImage::Format_RGBX32FPx4:
         for (int y = 0; y < height; y++) {
             float *dataPtr = (float *)image.scanLine(y);
             const float *src = (const float *)(tile + y * width * sizeof(QRgbaFloat32));
             for (int x = 0; x < width * 4; x += 4) {
                 dataPtr[x + 0] = qFromBigEndian(src[x + 0]);
                 dataPtr[x + 1] = qFromBigEndian(src[x + 1]);
                 dataPtr[x + 2] = qFromBigEndian(src[x + 2]);
                 dataPtr[x + 3] = 1.f;
             }
         }
         break;
 #endif
     case QImage::Format_Indexed8:
         for (int y = 0; y < height; y++) {
             uchar *dataPtr = bits + y * bytesPerLine;
             for (int x = 0; x < width; x++) {
                 *dataPtr++ = tile[0];
                 tile += sizeof(QRgb);
             }
         }
         break;
     default:
         qCWarning(XCFPLUGIN) << "Unhandled image format" << image.format() << "and/or layer type" << layer.type;
         return false;
     }
 
     return true;
 }
 
 /*!
  * The GIMP stores images in a "mipmap"-like hierarchy. As far as the QImage
  * is concerned, however, only the top level (i.e., the full resolution image)
  * is used.
  * \param xcf_io the data stream connected to the XCF image.
  * \param layer the layer to collect the image.
  * \return true if there were no I/O errors.
  */
 bool XCFImageFormat::loadHierarchy(QDataStream &xcf_io, Layer &layer, const GimpPrecision precision)
 {
     qint32 width;
     qint32 height;
     quint32 bpp;
 
     xcf_io >> width >> height >> bpp;
     const qint64 offset = readOffsetPtr(xcf_io);
 
     qCDebug(XCFPLUGIN) << "width" << width << "height" << height << "bpp" << bpp << "offset" << offset;
 
     if (offset < 0) {
         qCDebug(XCFPLUGIN) << "XCF: negative hierarchy offset";
         return false;
     }
 
     const bool isMask = layer.assignBytes == assignMaskBytes;
 
     // make sure bpp is correct and complain if it is not
     switch (layer.type) {
     case RGB_GIMAGE:
         if (bpp != 3 * bytesPerChannel(precision)) {
             qCDebug(XCFPLUGIN) << "Found layer of type RGB but with bpp != 3" << bpp;
 
             if (!isMask) {
                 return false;
             }
         }
         break;
     case RGBA_GIMAGE:
         if (bpp != 4 * bytesPerChannel(precision)) {
             qCDebug(XCFPLUGIN) << "Found layer of type RGBA but with bpp != 4, got" << bpp << "bpp";
 
             if (!isMask) {
                 return false;
             }
         }
         break;
     case GRAY_GIMAGE:
         if (bpp != 1 * bytesPerChannel(precision)) {
             qCDebug(XCFPLUGIN) << "Found layer of type Gray but with bpp != 1" << bpp;
             return false;
         }
         break;
     case GRAYA_GIMAGE:
         if (bpp != 2 * bytesPerChannel(precision)) {
             qCDebug(XCFPLUGIN) << "Found layer of type Gray+Alpha but with bpp != 2" << bpp;
 
             if (!isMask) {
                 return false;
             }
         }
         break;
     case INDEXED_GIMAGE:
         if (bpp != 1 * bytesPerChannel(precision)) {
             qCDebug(XCFPLUGIN) << "Found layer of type Indexed but with bpp != 1" << bpp;
             return false;
         }
         break;
     case INDEXEDA_GIMAGE:
         if (bpp != 2 * bytesPerChannel(precision)) {
             qCDebug(XCFPLUGIN) << "Found layer of type Indexed+Alpha but with bpp != 2" << bpp;
 
             if (!isMask) {
                 return false;
             }
         }
         break;
     }
 
     if (bpp > 4 * bytesPerChannel(precision)) {
         qCDebug(XCFPLUGIN) << "bpp is" << bpp << "We don't support layers with bpp > 4";
         return false;
     }
 
     // GIMP stores images in a "mipmap"-like format (multiple levels of
     // increasingly lower resolution). Only the top level is used here,
     // however.
 
     quint32 junk;
     do {
         xcf_io >> junk;
 
         if (xcf_io.device()->atEnd()) {
             qCDebug(XCFPLUGIN) << "XCF: read failure on layer " << layer.name << " level offsets";
             return false;
         }
     } while (junk != 0);
 
     qint64 saved_pos = xcf_io.device()->pos();
 
     xcf_io.device()->seek(offset);
     if (!loadLevel(xcf_io, layer, bpp, precision)) {
         return false;
     }
 
     xcf_io.device()->seek(saved_pos);
     return true;
 }
 
 template<typename SourceFormat>
 static bool convertFloatTo16Bit(uchar *output, quint64 outputSize, uchar *input)
 {
     SourceFormat *source = (SourceFormat *)(input);
     for (quint64 offset = 0; offset < outputSize; offset++) {
         ((uint16_t *)output)[offset] = qToBigEndian(quint16(qBound(0., qFromBigEndian<SourceFormat>(source[offset]) * 65535. + 0.5, 65535.)));
     }
     return true;
 }
 
 /*!
  * Load one level of the image hierarchy (but only the top level is ever used).
  * \param xcf_io the data stream connected to the XCF image.
  * \param layer the layer to collect the image.
  * \param bpp the number of bytes in a pixel.
  * \return true if there were no I/O errors.
  * \sa loadTileRLE().
  */
 bool XCFImageFormat::loadLevel(QDataStream &xcf_io, Layer &layer, qint32 bpp, const GimpPrecision precision)
 {
     qint32 width;
     qint32 height;
 
     xcf_io >> width >> height;
     qint64 offset = readOffsetPtr(xcf_io);
 
     if (offset < 0) {
         qCDebug(XCFPLUGIN) << "XCF: negative level offset";
         return false;
     }
 
     if (offset == 0) {
         // offset 0 with rowsxcols != 0 is probably an error since it means we have tiles
         // without data but just clear the bits for now instead of returning false
         for (uint j = 0; j < layer.nrows; j++) {
             for (uint i = 0; i < layer.ncols; i++) {
                 layer.image_tiles[j][i].fill(Qt::transparent);
                 if (layer.type == GRAYA_GIMAGE || layer.type == INDEXEDA_GIMAGE) {
                     layer.alpha_tiles[j][i].fill(Qt::transparent);
                 }
             }
         }
         return true;
     }
 
     bool needConvert = true;
     switch (precision) {
 #ifdef USE_FLOAT_IMAGES
     case GIMP_PRECISION_HALF_LINEAR:
     case GIMP_PRECISION_HALF_NON_LINEAR:
     case GIMP_PRECISION_HALF_PERCEPTUAL:
     case GIMP_PRECISION_FLOAT_LINEAR:
     case GIMP_PRECISION_FLOAT_NON_LINEAR:
     case GIMP_PRECISION_FLOAT_PERCEPTUAL:
 #endif
     case GIMP_PRECISION_U8_LINEAR:
     case GIMP_PRECISION_U8_NON_LINEAR:
     case GIMP_PRECISION_U8_PERCEPTUAL:
     case GIMP_PRECISION_U16_LINEAR:
     case GIMP_PRECISION_U16_NON_LINEAR:
     case GIMP_PRECISION_U16_PERCEPTUAL:
         needConvert = false;
         break;
     default:
         break;
     }
 
     const uint blockSize = TILE_WIDTH * TILE_HEIGHT * bpp * 1.5;
 
     QList<uchar> buffer;
     if (needConvert) {
         buffer.resize(blockSize * (bpp == 2 ? 2 : 1));
     }
     for (uint j = 0; j < layer.nrows; j++) {
         for (uint i = 0; i < layer.ncols; i++) {
             if (offset == 0) {
                 qCDebug(XCFPLUGIN) << "XCF: incorrect number of tiles in layer " << layer.name;
                 return false;
             }
 
             qint64 saved_pos = xcf_io.device()->pos();
             qint64 offset2 = readOffsetPtr(xcf_io);
 
             if (offset2 < 0) {
                 qCDebug(XCFPLUGIN) << "XCF: negative level offset";
                 return false;
             }
 
             // Evidently, RLE can occasionally expand a tile instead of compressing it!
             if (offset2 == 0) {
                 offset2 = offset + blockSize;
             }
 
             xcf_io.device()->seek(offset);
             qint64 bytesParsed = 0;
 
             switch (layer.compression) {
             case COMPRESS_NONE: {
                 if (xcf_io.version() > 11 || size_t(bpp) > sizeof(QRgba64)) {
                     qCDebug(XCFPLUGIN) << "Component reading not supported yet";
                     return false;
                 }
                 const int data_size = bpp * TILE_WIDTH * TILE_HEIGHT;
                 if (data_size > int(blockSize)) {
                     qCDebug(XCFPLUGIN) << "Tile data too big, we can only fit" << sizeof(layer.tile) << "but need" << data_size;
                     return false;
                 }
                 int dataRead = xcf_io.readRawData(reinterpret_cast<char *>(layer.tile), data_size);
                 if (dataRead < data_size) {
                     qCDebug(XCFPLUGIN) << "short read, expected" << data_size << "got" << dataRead;
                     return false;
                 }
                 bytesParsed = dataRead;
                 break;
             }
             case COMPRESS_RLE: {
                 int size = layer.image_tiles[j][i].width() * layer.image_tiles[j][i].height();
                 const uint data_size = size * bpp;
                 if (needConvert) {
                     if (data_size >= unsigned(buffer.size())) {
                         qCDebug(XCFPLUGIN) << "Tile data too big, we can only fit" << buffer.size() << "but need" << data_size;
                         return false;
                     }
                 } else {
                     if (data_size > sizeof(layer.tile)) {
                         qCDebug(XCFPLUGIN) << "Tile data too big, we can only fit" << sizeof(layer.tile) << "but need" << data_size;
                         return false;
                     }
                     if (blockSize > sizeof(layer.tile)) {
                         qCWarning(XCFPLUGIN) << "Too small tiles" << sizeof(layer.tile) << "this image requires" << blockSize << sizeof(QRgba64) << bpp;
                         return false;
                     }
                 }
                 if (!loadTileRLE(xcf_io, needConvert ? buffer.data() : layer.tile, size, offset2 - offset, bpp, &bytesParsed)) {
                     qCDebug(XCFPLUGIN) << "Failed to read RLE";
                     return false;
                 }
                 break;
             }
             default:
                 qCDebug(XCFPLUGIN) << "Unhandled compression" << layer.compression;
                 return false;
             }
 
             if (needConvert) {
                 if (bytesParsed > buffer.size()) {
                     qCDebug(XCFPLUGIN) << "Invalid number of bytes parsed" << bytesParsed << buffer.size();
                     return false;
                 }
 
                 switch (precision) {
                 case GIMP_PRECISION_U32_LINEAR:
                 case GIMP_PRECISION_U32_NON_LINEAR:
                 case GIMP_PRECISION_U32_PERCEPTUAL: {
                     quint32 *source = (quint32 *)(buffer.data());
                     for (quint64 offset = 0, len = buffer.size() / sizeof(quint32); offset < len; ++offset) {
                         ((quint16 *)layer.tile)[offset] = qToBigEndian<quint16>(qFromBigEndian(source[offset]) / 65537);
                     }
                     break;
                 }
 #ifndef USE_FLOAT_IMAGES
                 case GIMP_PRECISION_HALF_LINEAR:
                 case GIMP_PRECISION_HALF_NON_LINEAR:
                 case GIMP_PRECISION_HALF_PERCEPTUAL:
                     convertFloatTo16Bit<qfloat16>(layer.tile, buffer.size() / sizeof(qfloat16), buffer.data());
                     break;
                 case GIMP_PRECISION_FLOAT_LINEAR:
                 case GIMP_PRECISION_FLOAT_NON_LINEAR:
                 case GIMP_PRECISION_FLOAT_PERCEPTUAL:
                     convertFloatTo16Bit<float>(layer.tile, buffer.size() / sizeof(float), buffer.data());
                     break;
                 case GIMP_PRECISION_DOUBLE_LINEAR:
                 case GIMP_PRECISION_DOUBLE_NON_LINEAR:
                 case GIMP_PRECISION_DOUBLE_PERCEPTUAL:
                     convertFloatTo16Bit<double>(layer.tile, buffer.size() / sizeof(double), buffer.data());
                     break;
 #else
                 case GIMP_PRECISION_DOUBLE_LINEAR:
                 case GIMP_PRECISION_DOUBLE_NON_LINEAR:
                 case GIMP_PRECISION_DOUBLE_PERCEPTUAL: {
                     double *source = (double *)(buffer.data());
                     for (quint64 offset = 0, len = buffer.size() / sizeof(double); offset < len; ++offset) {
                         ((float *)layer.tile)[offset] = qToBigEndian<float>(float(qFromBigEndian(source[offset])));
                     }
                     break;
                 }
 #endif
                 default:
                     qCWarning(XCFPLUGIN) << "Unsupported precision" << precision;
                     return false;
                 }
             }
 
             // The bytes in the layer tile are juggled differently depending on
             // the target QImage. The caller has set layer.assignBytes to the
             // appropriate routine.
             if (!layer.assignBytes(layer, i, j, precision)) {
                 return false;
             }
 
             xcf_io.device()->seek(saved_pos);
             offset = readOffsetPtr(xcf_io);
 
             if (offset < 0) {
                 qCDebug(XCFPLUGIN) << "XCF: negative level offset";
                 return false;
             }
         }
     }
 
     return true;
 }
 
 /*!
  * A layer can have a one channel image which is used as a mask.
  * \param xcf_io the data stream connected to the XCF image.
  * \param layer the layer to collect the mask image.
  * \return true if there were no I/O errors.
  */
 bool XCFImageFormat::loadMask(QDataStream &xcf_io, Layer &layer, const GimpPrecision precision)
 {
     qint32 width;
     qint32 height;
     char *name;
 
     xcf_io >> width >> height >> name;
 
     delete[] name;
 
     if (!loadChannelProperties(xcf_io, layer)) {
         return false;
     }
 
     const qint64 hierarchy_offset = readOffsetPtr(xcf_io);
 
     if (hierarchy_offset < 0) {
         qCDebug(XCFPLUGIN) << "XCF: negative mask hierarchy_offset";
         return false;
     }
 
     xcf_io.device()->seek(hierarchy_offset);
     layer.assignBytes = assignMaskBytes;
 
     if (!loadHierarchy(xcf_io, layer, precision)) {
         return false;
     }
 
     return true;
 }
 
 /*!
  * This is the routine for which all the other code is simply
  * infrastructure. Read the image bytes out of the file and
  * store them in the tile buffer. This is passed a full 32-bit deep
  * buffer, even if bpp is smaller. The caller can figure out what to
  * do with the bytes.
  *
  * The tile is stored in "channels", i.e. the red component of all
  * pixels, then the green component of all pixels, then blue then
  * alpha, or, for indexed images, the color indices of all pixels then
  * the alpha of all pixels.
  *
  * The data is compressed with "run length encoding". Some simple data
  * integrity checks are made.
  *
  * \param xcf_io the data stream connected to the XCF image.
  * \param tile the buffer to expand the RLE into.
  * \param image_size number of bytes expected to be in the image tile.
  * \param data_length number of bytes expected in the RLE.
  * \param bpp number of bytes per pixel.
  * \return true if there were no I/O errors and no obvious corruption of
  * the RLE data.
  */
 bool XCFImageFormat::loadTileRLE(QDataStream &xcf_io, uchar *tile, int image_size, int data_length, qint32 bpp, qint64 *bytesParsed)
 {
     uchar *data = tile;
 
     uchar *xcfdata;
     uchar *xcfodata;
     uchar *xcfdatalimit;
 
     int step = sizeof(QRgb);
     switch (bpp) {
     case 1:
     case 2:
     case 3:
     case 4:
         step = sizeof(QRgb);
         break;
     case 6:
     case 8:
         step = sizeof(QRgb) * 2;
         break;
     case 12:
     case 16:
         step = sizeof(QRgb) * 4;
         break;
     default:
         qCDebug(XCFPLUGIN) << "XCF: unhandled bit depth" << bpp;
         return false;
     }
 
     if (data_length < 0 || data_length > int(TILE_WIDTH * TILE_HEIGHT * step * 1.5)) {
         qCDebug(XCFPLUGIN) << "XCF: invalid tile data length" << data_length;
         return false;
     }
 
     xcfdata = xcfodata = new uchar[data_length];
 
     const int dataRead = xcf_io.readRawData((char *)xcfdata, data_length);
     if (dataRead <= 0) {
         delete[] xcfodata;
         qCDebug(XCFPLUGIN) << "XCF: read failure on tile" << dataRead;
         return false;
     }
 
     if (dataRead < data_length) {
         memset(&xcfdata[dataRead], 0, data_length - dataRead);
     }
 
     if (!xcf_io.device()->isOpen()) {
         delete[] xcfodata;
         qCDebug(XCFPLUGIN) << "XCF: read failure on tile";
         return false;
     }
 
     xcfdatalimit = &xcfodata[data_length - 1];
 
     for (int i = 0; i < bpp; ++i) {
         data = tile + i;
 
         int size = image_size;
 
         while (size > 0) {
             if (xcfdata > xcfdatalimit) {
                 goto bogus_rle;
             }
 
             uchar val = *xcfdata++;
             uint length = val;
 
             if (length >= 128) {
                 length = 255 - (length - 1);
                 if (length == 128) {
                     if (xcfdata >= xcfdatalimit) {
                         goto bogus_rle;
                     }
 
                     length = (*xcfdata << 8) + xcfdata[1];
 
                     xcfdata += 2;
                 }
 
                 size -= length;
 
                 if (size < 0) {
                     goto bogus_rle;
                 }
 
                 if (&xcfdata[length - 1] > xcfdatalimit) {
                     goto bogus_rle;
                 }
 
                 while (length-- > 0) {
                     *data = *xcfdata++;
                     data += step;
                 }
             } else {
                 length += 1;
                 if (length == 128) {
                     if (xcfdata >= xcfdatalimit) {
                         goto bogus_rle;
                     }
 
                     length = (*xcfdata << 8) + xcfdata[1];
                     xcfdata += 2;
                 }
 
                 size -= length;
 
                 if (size < 0) {
                     goto bogus_rle;
                 }
 
                 if (xcfdata > xcfdatalimit) {
                     goto bogus_rle;
                 }
 
                 qintptr totalLength = qintptr(data - tile) + length * step;
                 if (totalLength >= image_size * step * 1.5) {
                     qCDebug(XCFPLUGIN) << "Ran out of space when trying to unpack image, over:" << totalLength - image_size << totalLength << image_size
                                        << length;
                     goto bogus_rle;
                 }
 
                 val = *xcfdata++;
 
                 while (length-- > 0) {
                     *data = val;
                     data += step;
                 }
             }
         }
     }
     *bytesParsed = qintptr(data - tile);
 
     delete[] xcfodata;
     return true;
 
 bogus_rle:
 
     qCDebug(XCFPLUGIN) << "The run length encoding could not be decoded properly";
     delete[] xcfodata;
     return false;
 }
 
 /*!
  * An XCF file can contain an arbitrary number of properties associated
  * with a channel. Note that this routine only reads mask channel properties.
  * \param xcf_io the data stream connected to the XCF image.
  * \param layer layer containing the mask channel to collect the properties.
  * \return true if there were no I/O errors.
  */
 bool XCFImageFormat::loadChannelProperties(QDataStream &xcf_io, Layer &layer)
 {
     while (true) {
         PropType type;
         QByteArray bytes;
         quint32 rawType;
 
         if (!loadProperty(xcf_io, type, bytes, rawType)) {
             qCDebug(XCFPLUGIN) << "XCF: error loading channel properties";
             return false;
         }
 
         QDataStream property(bytes);
 
         switch (type) {
         case PROP_END:
             return true;
 
         case PROP_OPACITY:
             property >> layer.mask_channel.opacity;
             layer.mask_channel.opacity = std::min(layer.mask_channel.opacity, 255u);
             break;
 
         case PROP_FLOAT_OPACITY:
             // For some reason QDataStream isn't able to read the float (tried
             // setting the endianness manually)
             if (bytes.size() == 4) {
                 layer.mask_channel.opacityFloat = qFromBigEndian(*reinterpret_cast<float *>(bytes.data()));
             } else {
                 qCDebug(XCFPLUGIN) << "XCF: Invalid data size for float:" << bytes.size();
             }
             break;
 
         case PROP_VISIBLE:
             property >> layer.mask_channel.visible;
             break;
 
         case PROP_SHOW_MASKED:
             property >> layer.mask_channel.show_masked;
             break;
 
         case PROP_COLOR:
             property >> layer.mask_channel.red >> layer.mask_channel.green >> layer.mask_channel.blue;
             break;
 
         case PROP_FLOAT_COLOR:
             property >> layer.mask_channel.redF >> layer.mask_channel.greenF >> layer.mask_channel.blueF;
             break;
 
         case PROP_TATTOO:
             property >> layer.mask_channel.tattoo;
             break;
 
         // Only used in edit mode
         case PROP_LINKED:
             break;
 
         // Just for organization in the UI, doesn't influence rendering
         case PROP_COLOR_TAG:
             break;
 
         // We don't support editing, so for now just ignore locking
         case PROP_LOCK_CONTENT:
         case PROP_LOCK_POSITION:
             break;
 
         default:
             qCDebug(XCFPLUGIN) << "XCF: unimplemented channel property " << type << "(" << rawType << ")"
                                << ", size " << bytes.size();
             break;
         }
     }
 }
 
 /*!
  * Copy the bytes from the tile buffer into the mask tile QImage.
  * \param layer layer containing the tile buffer and the mask tile matrix.
  * \param i column index of current tile.
  * \param j row index of current tile.
  */
 bool XCFImageFormat::assignMaskBytes(Layer &layer, uint i, uint j, const GimpPrecision &precision)
 {
     QImage &image = layer.mask_tiles[j][i];
     if (image.depth() != 8) {
         qCWarning(XCFPLUGIN) << "invalid bytes per pixel, we only do 8 bit masks" << image.depth();
         return false;
     }
 
     uchar *tile = layer.tile;
     const int width = image.width();
     const int height = image.height();
     const int bytesPerLine = image.bytesPerLine();
     uchar *bits = image.bits();
     auto bpc = bytesPerChannel(precision);
 
     // mask management is a house of cards: the mask is always treated as 8 bit by the plugin
     // (I don't want to twist the code) so it needs a conversion here.
     // If previously converted the step is the type size, otherwise is the one set in loadTileRLE().
     for (int y = 0; y < height; y++) {
         uchar *dataPtr = bits + y * bytesPerLine;
 #ifdef USE_FLOAT_IMAGES
         if (bpc == 4) {
             if (precision < GimpPrecision::GIMP_PRECISION_HALF_LINEAR) {
                 for (int x = 0; x < width; x++) {
                     *dataPtr++ = qFromBigEndian<quint16>(*(const quint16 *)tile) / 257;
                     tile += sizeof(quint16); // was converted to 16 bits in loadLevel()
                 }
             } else {
                 for (int x = 0; x < width; x++) {
                     *dataPtr++ = qFromBigEndian<float>(*(const float *)tile) * 255;
                     tile += sizeof(QRgb); // yeah! see loadTileRLE()
                 }
             }
         } else if (bpc == 2) {
             // when not converted, the step of a
             if (precision < GimpPrecision::GIMP_PRECISION_HALF_LINEAR) {
                 for (int x = 0; x < width; x++) {
                     *dataPtr++ = qFromBigEndian<quint16>(*(const quint16 *)tile) / 257;
                     tile += sizeof(QRgb); // yeah! see loadTileRLE()
                 }
             } else {
                 for (int x = 0; x < width; x++) {
                     *dataPtr++ = qFromBigEndian<qfloat16>(*(const qfloat16 *)tile) * 255;
                     tile += sizeof(QRgb); // yeah! see loadTileRLE()
                 }
             }
         }
 #else
         if (bpc == 2) {
             for (int x = 0; x < width; x++) {
                 *dataPtr++ = qFromBigEndian<quint16>(*(const quint16 *)tile) / 257;
                 tile += sizeof(QRgb); // yeah! see loadTileRLE() / loadLevel()
             }
         } else if (bpc == 4) {
             for (int x = 0; x < width; x++) {
                 *dataPtr++ = qFromBigEndian<quint16>(*(const quint16 *)tile) / 257;
                 tile += sizeof(quint16); // was converted to 16 bits in loadLevel()
             }
         }
 #endif
         else {
             for (int x = 0; x < width; x++) {
                 *dataPtr++ = tile[0];
                 tile += sizeof(QRgb); // yeah! see loadTileRLE()
             }
         }
     }
 
     return true;
 }
 
 /*!
  * Construct the QImage which will eventually be returned to the QImage
  * loader.
  *
  * There are a couple of situations which require that the QImage is not
  * exactly the same as The GIMP's representation. The full table is:
  * \verbatim
  *  Grayscale  opaque      :  8 bpp indexed
  *  Grayscale  translucent : 32 bpp + alpha
  *  Indexed    opaque      :  1 bpp if num_colors <= 2
  *                         :  8 bpp indexed otherwise
  *  Indexed    translucent :  8 bpp indexed + alpha if num_colors < 256
  *                         : 32 bpp + alpha otherwise
  *  RGB        opaque      : 32 bpp
  *  RGBA       translucent : 32 bpp + alpha
  * \endverbatim
  * Whether the image is translucent or not is determined by the bottom layer's
  * alpha channel. However, even if the bottom layer lacks an alpha channel,
  * it can still have an opacity < 1. In this case, the QImage is promoted
  * to 32-bit. (Note this is different from the output from the GIMP image
  * exporter, which seems to ignore this attribute.)
  *
  * Independently, higher layers can be translucent, but the background of
  * the image will not show through if the bottom layer is opaque.
  *
  * For indexed images, translucency is an all or nothing effect.
  * \param xcf_image contains image info and bottom-most layer.
  */
 bool XCFImageFormat::initializeImage(XCFImage &xcf_image)
 {
     // (Aliases to make the code look a little better.)
     Layer &layer(xcf_image.layer);
     QImage &image(xcf_image.image);
 
     switch (layer.type) {
     case GRAY_GIMAGE:
         if (layer.opacity == OPAQUE_OPACITY) {
             image = imageAlloc(xcf_image.header.width, xcf_image.header.height, QImage::Format_Indexed8);
             image.setColorCount(256);
             if (image.isNull()) {
                 return false;
             }
             setGrayPalette(image);
             image.fill(255);
             break;
         } // else, fall through to 32-bit representation
         Q_FALLTHROUGH();
     case GRAYA_GIMAGE:
     case RGB_GIMAGE:
     case RGBA_GIMAGE:
         image = imageAlloc(xcf_image.header.width, xcf_image.header.height, xcf_image.qimageFormat());
         if (image.isNull()) {
             return false;
         }
         if (image.hasAlphaChannel()) {
             image.fill(Qt::transparent);
         } else {
             image.fill(Qt::white);
         }
         break;
 
     case INDEXED_GIMAGE:
         // As noted in the table above, there are quite a few combinations
         // which are possible with indexed images, depending on the
         // presence of transparency (note: not translucency, which is not
         // supported by The GIMP for indexed images) and the number of
         // individual colors.
 
         // Note: Qt treats a bitmap with a Black and White color palette
         // as a mask, so only the "on" bits are drawn, regardless of the
         // order color table entries. Otherwise (i.e., at least one of the
         // color table entries is not black or white), it obeys the one-
         // or two-color palette. Have to ask about this...
 
         if (xcf_image.num_colors <= 2) {
             image = imageAlloc(xcf_image.header.width, xcf_image.header.height, QImage::Format_MonoLSB);
             image.setColorCount(xcf_image.num_colors);
             if (image.isNull()) {
                 return false;
             }
             image.fill(0);
             setPalette(xcf_image, image);
         } else if (xcf_image.num_colors <= 256) {
             image = imageAlloc(xcf_image.header.width, xcf_image.header.height, QImage::Format_Indexed8);
             image.setColorCount(xcf_image.num_colors);
             if (image.isNull()) {
                 return false;
             }
             image.fill(0);
             setPalette(xcf_image, image);
         }
         break;
 
     case INDEXEDA_GIMAGE:
         if (xcf_image.num_colors == 1) {
             // Plenty(!) of room to add a transparent color
             xcf_image.num_colors++;
             xcf_image.palette.resize(xcf_image.num_colors);
             xcf_image.palette[1] = xcf_image.palette[0];
             xcf_image.palette[0] = qRgba(255, 255, 255, 0);
 
             image = imageAlloc(xcf_image.header.width, xcf_image.header.height, QImage::Format_MonoLSB);
             image.setColorCount(xcf_image.num_colors);
             if (image.isNull()) {
                 return false;
             }
             image.fill(0);
             setPalette(xcf_image, image);
         } else if (xcf_image.num_colors < 256) {
             // Plenty of room to add a transparent color
             xcf_image.num_colors++;
             xcf_image.palette.resize(xcf_image.num_colors);
             for (int c = xcf_image.num_colors - 1; c >= 1; c--) {
                 xcf_image.palette[c] = xcf_image.palette[c - 1];
             }
 
             xcf_image.palette[0] = qRgba(255, 255, 255, 0);
             image = imageAlloc(xcf_image.header.width, xcf_image.header.height, QImage::Format_Indexed8);
             image.setColorCount(xcf_image.num_colors);
             if (image.isNull()) {
                 return false;
             }
             image.fill(0);
             setPalette(xcf_image, image);
         } else {
             // No room for a transparent color, so this has to be promoted to
             // true color. (There is no equivalent PNG representation output
             // from The GIMP as of v1.2.)
             image = imageAlloc(xcf_image.header.width, xcf_image.header.height, QImage::Format_ARGB32);
             if (image.isNull()) {
                 return false;
             }
             image.fill(qRgba(255, 255, 255, 0));
         }
         break;
     }
     if (image.format() != xcf_image.qimageFormat()) {
         qCWarning(XCFPLUGIN) << "Selected wrong format:" << image.format() << "expected" << layer.qimageFormat(xcf_image.header.precision);
         return false;
     }
 
     // The final profile should be the one in the Parasite
     // NOTE: if not set here, the colorSpace is aet in setImageParasites() (if no one defined in the parasites)
 #ifndef DISABLE_IMAGE_PROFILE
     switch (xcf_image.header.precision) {
     case XCFImageFormat::GIMP_PRECISION_HALF_LINEAR:
     case XCFImageFormat::GIMP_PRECISION_FLOAT_LINEAR:
     case XCFImageFormat::GIMP_PRECISION_DOUBLE_LINEAR:
     case XCFImageFormat::GIMP_PRECISION_U8_LINEAR:
     case XCFImageFormat::GIMP_PRECISION_U16_LINEAR:
     case XCFImageFormat::GIMP_PRECISION_U32_LINEAR:
         image.setColorSpace(QColorSpace::SRgbLinear);
         break;
     case XCFImageFormat::GIMP_PRECISION_HALF_NON_LINEAR:
     case XCFImageFormat::GIMP_PRECISION_FLOAT_NON_LINEAR:
     case XCFImageFormat::GIMP_PRECISION_DOUBLE_NON_LINEAR:
     case XCFImageFormat::GIMP_PRECISION_U8_NON_LINEAR:
     case XCFImageFormat::GIMP_PRECISION_U16_NON_LINEAR:
     case XCFImageFormat::GIMP_PRECISION_U32_NON_LINEAR:
         image.setColorSpace(QColorSpace::SRgb);
         break;
     case XCFImageFormat::GIMP_PRECISION_HALF_PERCEPTUAL:
     case XCFImageFormat::GIMP_PRECISION_FLOAT_PERCEPTUAL:
     case XCFImageFormat::GIMP_PRECISION_DOUBLE_PERCEPTUAL:
     case XCFImageFormat::GIMP_PRECISION_U8_PERCEPTUAL:
     case XCFImageFormat::GIMP_PRECISION_U16_PERCEPTUAL:
     case XCFImageFormat::GIMP_PRECISION_U32_PERCEPTUAL:
         image.setColorSpace(QColorSpace::SRgb);
         break;
     }
 #endif
 
     if (xcf_image.x_resolution > 0 && xcf_image.y_resolution > 0) {
         const float dpmx = xcf_image.x_resolution * INCHESPERMETER;
         if (dpmx > float(std::numeric_limits<int>::max())) {
             return false;
         }
         const float dpmy = xcf_image.y_resolution * INCHESPERMETER;
         if (dpmy > float(std::numeric_limits<int>::max())) {
             return false;
         }
         image.setDotsPerMeterX((int)dpmx);
         image.setDotsPerMeterY((int)dpmy);
     }
     return true;
 }
 
 /*!
  * Copy a layer into an image, taking account of the manifold modes. The
  * contents of the image are replaced.
  * \param xcf_image contains the layer and image to be replaced.
  */
 void XCFImageFormat::copyLayerToImage(XCFImage &xcf_image)
 {
     Layer &layer(xcf_image.layer);
     QImage &image(xcf_image.image);
     PixelCopyOperation copy = nullptr;
 
     switch (layer.type) {
     case RGB_GIMAGE:
     case RGBA_GIMAGE:
         copy = copyRGBToRGB;
         break;
     case GRAY_GIMAGE:
         if (layer.opacity == OPAQUE_OPACITY) {
             copy = copyGrayToGray;
         } else {
             copy = copyGrayToRGB;
         }
         break;
     case GRAYA_GIMAGE:
         copy = copyGrayAToRGB;
         break;
     case INDEXED_GIMAGE:
         copy = copyIndexedToIndexed;
         break;
     case INDEXEDA_GIMAGE:
         if (xcf_image.image.depth() <= 8) {
             copy = copyIndexedAToIndexed;
         } else {
             copy = copyIndexedAToRGB;
         }
     }
 
     if (!copy) {
         return;
     }
 
     // For each tile...
 
     for (uint j = 0; j < layer.nrows; j++) {
         uint y = j * TILE_HEIGHT;
 
         for (uint i = 0; i < layer.ncols; i++) {
             uint x = i * TILE_WIDTH;
 
             // This seems the best place to apply the dissolve because it
             // depends on the global position of each tile's
             // pixels. Apparently it's the only mode which can apply to a
             // single layer.
 
             if (layer.mode == GIMP_LAYER_MODE_DISSOLVE) {
                 if (!random_table_initialized) {
                     initializeRandomTable();
                     random_table_initialized = true;
                 }
                 if (layer.type == RGBA_GIMAGE) {
                     dissolveRGBPixels(layer.image_tiles[j][i], x, y);
                 }
 
                 else if (layer.type == GRAYA_GIMAGE) {
                     dissolveAlphaPixels(layer.alpha_tiles[j][i], x, y);
                 }
             }
 
             // Shortcut for common case
             if (copy == copyRGBToRGB && layer.apply_mask != 1) {
                 QPainter painter(&image);
                 painter.setOpacity(layer.opacity / 255.0);
                 painter.setCompositionMode(QPainter::CompositionMode_Source);
                 if (x + layer.x_offset < MAX_IMAGE_WIDTH &&
                     y + layer.y_offset < MAX_IMAGE_HEIGHT) {
                     painter.drawImage(x + layer.x_offset, y + layer.y_offset, layer.image_tiles[j][i]);
                 }
                 continue;
             }
 
             for (int l = 0; l < layer.image_tiles[j][i].height(); l++) {
                 for (int k = 0; k < layer.image_tiles[j][i].width(); k++) {
                     int m = x + k + layer.x_offset;
                     int n = y + l + layer.y_offset;
 
                     if (m < 0 || m >= image.width() || n < 0 || n >= image.height()) {
                         continue;
                     }
 
                     (*copy)(layer, i, j, k, l, image, m, n);
                 }
             }
         }
     }
 }
 
 /*!
  * Copy an RGB pixel from the layer to the RGB image. Straight-forward.
  * The only thing this has to take account of is the opacity of the
  * layer. Evidently, the GIMP exporter itself does not actually do this.
  * \param layer source layer.
  * \param i x tile index.
  * \param j y tile index.
  * \param k x pixel index of tile i,j.
  * \param l y pixel index of tile i,j.
  * \param image destination image.
  * \param m x pixel of destination image.
  * \param n y pixel of destination image.
  */
 void XCFImageFormat::copyRGBToRGB(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n)
 {
     if (image.depth() == 32) {
         QRgb src = layer.image_tiles[j][i].pixel(k, l);
         uchar src_a = layer.opacity;
 
         if (layer.type == RGBA_GIMAGE) {
             src_a = INT_MULT(src_a, qAlpha(src));
         }
 
         // Apply the mask (if any)
 
         if (layer.apply_mask == 1 && layer.mask_tiles.size() > (int)j && layer.mask_tiles[j].size() > (int)i) {
             src_a = INT_MULT(src_a, layer.mask_tiles[j][i].pixelIndex(k, l));
         }
 
         image.setPixel(m, n, qRgba(src, src_a));
     } else if (image.depth() == 64) {
         QRgba64 src = layer.image_tiles[j][i].pixelColor(k, l).rgba64();
         quint16 src_a = layer.opacity;
 
         if (layer.type == RGBA_GIMAGE) {
             src_a = INT_MULT(src_a, qAlpha(src));
         }
 
         // Apply the mask (if any)
 
         if (layer.apply_mask == 1 && layer.mask_tiles.size() > (int)j && layer.mask_tiles[j].size() > (int)i) {
             src_a = INT_MULT(src_a, layer.mask_tiles[j][i].pixelIndex(k, l));
         }
         src.setAlpha(src_a);
 
         image.setPixel(m, n, src);
     }
 }
 
 /*!
  * Copy a Gray pixel from the layer to the Gray image. Straight-forward.
  * \param layer source layer.
  * \param i x tile index.
  * \param j y tile index.
  * \param k x pixel index of tile i,j.
  * \param l y pixel index of tile i,j.
  * \param image destination image.
  * \param m x pixel of destination image.
  * \param n y pixel of destination image.
  */
 void XCFImageFormat::copyGrayToGray(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n)
 {
     int src = layer.image_tiles[j][i].pixelIndex(k, l);
     image.setPixel(m, n, src);
 }
 
 /*!
  * Copy a Gray pixel from the layer to an RGB image. Straight-forward.
  * The only thing this has to take account of is the opacity of the
  * layer. Evidently, the GIMP exporter itself does not actually do this.
  * \param layer source layer.
  * \param i x tile index.
  * \param j y tile index.
  * \param k x pixel index of tile i,j.
  * \param l y pixel index of tile i,j.
  * \param image destination image.
  * \param m x pixel of destination image.
  * \param n y pixel of destination image.
  */
 void XCFImageFormat::copyGrayToRGB(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n)
 {
     QRgb src = layer.image_tiles[j][i].pixel(k, l);
     uchar src_a = layer.opacity;
     image.setPixel(m, n, qRgba(src, src_a));
 }
 
 /*!
  * Copy a GrayA pixel from the layer to an RGB image. Straight-forward.
  * The only thing this has to take account of is the opacity of the
  * layer. Evidently, the GIMP exporter itself does not actually do this.
  * \param layer source layer.
  * \param i x tile index.
  * \param j y tile index.
  * \param k x pixel index of tile i,j.
  * \param l y pixel index of tile i,j.
  * \param image destination image.
  * \param m x pixel of destination image.
  * \param n y pixel of destination image.
  */
 void XCFImageFormat::copyGrayAToRGB(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n)
 {
     QRgb src = layer.image_tiles[j][i].pixel(k, l);
     uchar src_a = layer.alpha_tiles[j][i].pixelIndex(k, l);
     src_a = INT_MULT(src_a, layer.opacity);
 
     // Apply the mask (if any)
 
     if (layer.apply_mask == 1 && layer.mask_tiles.size() > (int)j && layer.mask_tiles[j].size() > (int)i) {
         src_a = INT_MULT(src_a, layer.mask_tiles[j][i].pixelIndex(k, l));
     }
 
     image.setPixel(m, n, qRgba(src, src_a));
 }
 
 /*!
  * Copy an Indexed pixel from the layer to the Indexed image. Straight-forward.
  * \param layer source layer.
  * \param i x tile index.
  * \param j y tile index.
  * \param k x pixel index of tile i,j.
  * \param l y pixel index of tile i,j.
  * \param image destination image.
  * \param m x pixel of destination image.
  * \param n y pixel of destination image.
  */
 void XCFImageFormat::copyIndexedToIndexed(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n)
 {
     int src = layer.image_tiles[j][i].pixelIndex(k, l);
     image.setPixel(m, n, src);
 }
 
 /*!
  * Copy an IndexedA pixel from the layer to the Indexed image. Straight-forward.
  * \param layer source layer.
  * \param i x tile index.
  * \param j y tile index.
  * \param k x pixel index of tile i,j.
  * \param l y pixel index of tile i,j.
  * \param image destination image.
  * \param m x pixel of destination image.
  * \param n y pixel of destination image.
  */
 void XCFImageFormat::copyIndexedAToIndexed(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n)
 {
     uchar src = layer.image_tiles[j][i].pixelIndex(k, l);
     uchar src_a = layer.alpha_tiles[j][i].pixelIndex(k, l);
     src_a = INT_MULT(src_a, layer.opacity);
 
     if (layer.apply_mask == 1 && layer.mask_tiles.size() > (int)j && layer.mask_tiles[j].size() > (int)i) {
         src_a = INT_MULT(src_a, layer.mask_tiles[j][i].pixelIndex(k, l));
     }
 
     if (src_a > 127) {
         src++;
     } else {
         src = 0;
     }
 
     image.setPixel(m, n, src);
 }
 
 /*!
  * Copy an IndexedA pixel from the layer to an RGB image. Straight-forward.
  * The only thing this has to take account of is the opacity of the
  * layer. Evidently, the GIMP exporter itself does not actually do this.
  * \param layer source layer.
  * \param i x tile index.
  * \param j y tile index.
  * \param k x pixel index of tile i,j.
  * \param l y pixel index of tile i,j.
  * \param image destination image.
  * \param m x pixel of destination image.
  * \param n y pixel of destination image.
  */
 void XCFImageFormat::copyIndexedAToRGB(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n)
 {
     QRgb src = layer.image_tiles[j][i].pixel(k, l);
     uchar src_a = layer.alpha_tiles[j][i].pixelIndex(k, l);
     src_a = INT_MULT(src_a, layer.opacity);
 
     // Apply the mask (if any)
     if (layer.apply_mask == 1 && layer.mask_tiles.size() > (int)j && layer.mask_tiles[j].size() > (int)i) {
         src_a = INT_MULT(src_a, layer.mask_tiles[j][i].pixelIndex(k, l));
     }
 
     // This is what appears in the GIMP window
     if (src_a <= 127) {
         src_a = 0;
     } else {
         src_a = OPAQUE_OPACITY;
     }
 
     image.setPixel(m, n, qRgba(src, src_a));
 }
 
 /*!
  * Merge a layer into an image, taking account of the manifold modes.
  * \param xcf_image contains the layer and image to merge.
  */
 void XCFImageFormat::mergeLayerIntoImage(XCFImage &xcf_image)
 {
     Layer &layer(xcf_image.layer);
     QImage &image(xcf_image.image);
 
     PixelMergeOperation merge = nullptr;
 
     if (!layer.opacity) {
         return; // don't bother doing anything
     }
 
     if (layer.blendSpace == XCFImageFormat::AutoColorSpace) {
         qCDebug(XCFPLUGIN) << "Auto blend space, defaulting to RgbLinearSpace (same as Gimp when writing this)";
         layer.blendSpace = XCFImageFormat::RgbLinearSpace;
     }
 
     if (layer.blendSpace != XCFImageFormat::RgbLinearSpace) {
         qCDebug(XCFPLUGIN) << "Unimplemented blend color space" << layer.blendSpace;
     }
     qCDebug(XCFPLUGIN) << "Blend color space" << layer.blendSpace;
 
     if (layer.compositeSpace == XCFImageFormat::AutoColorSpace) {
         qCDebug(XCFPLUGIN) << "Auto composite space, defaulting to RgbLinearSpace (same as Gimp when writing this)";
         layer.compositeSpace = XCFImageFormat::RgbLinearSpace;
     }
 
     if (layer.compositeSpace != XCFImageFormat::RgbLinearSpace) {
         qCDebug(XCFPLUGIN) << "Unimplemented composite color space" << layer.compositeSpace;
     }
     if (layer.compositeMode != XCFImageFormat::CompositeUnion) {
         qCDebug(XCFPLUGIN) << "Unhandled composite mode" << layer.compositeMode;
     }
 
     switch (layer.type) {
     case RGB_GIMAGE:
     case RGBA_GIMAGE:
         merge = mergeRGBToRGB;
         break;
     case GRAY_GIMAGE:
         if (layer.opacity == OPAQUE_OPACITY) {
             merge = mergeGrayToGray;
         } else {
             merge = mergeGrayToRGB;
         }
         break;
     case GRAYA_GIMAGE:
         if (xcf_image.image.depth() <= 8) {
             merge = mergeGrayAToGray;
         } else {
             merge = mergeGrayAToRGB;
         }
         break;
     case INDEXED_GIMAGE:
         merge = mergeIndexedToIndexed;
         break;
     case INDEXEDA_GIMAGE:
         if (xcf_image.image.depth() <= 8) {
             merge = mergeIndexedAToIndexed;
         } else {
             merge = mergeIndexedAToRGB;
         }
     }
 
     if (!merge) {
         return;
     }
 
     if (merge == mergeRGBToRGB && layer.apply_mask != 1) {
         int painterMode = -1;
         switch (layer.mode) {
         case GIMP_LAYER_MODE_NORMAL:
         case GIMP_LAYER_MODE_NORMAL_LEGACY:
             painterMode = QPainter::CompositionMode_SourceOver;
             break;
         case GIMP_LAYER_MODE_MULTIPLY:
         case GIMP_LAYER_MODE_MULTIPLY_LEGACY:
             painterMode = QPainter::CompositionMode_Multiply;
             break;
         case GIMP_LAYER_MODE_SCREEN:
         case GIMP_LAYER_MODE_SCREEN_LEGACY:
             painterMode = QPainter::CompositionMode_Screen;
             break;
         case GIMP_LAYER_MODE_OVERLAY:
         case GIMP_LAYER_MODE_OVERLAY_LEGACY:
             painterMode = QPainter::CompositionMode_Overlay;
             break;
         case GIMP_LAYER_MODE_DIFFERENCE:
         case GIMP_LAYER_MODE_DIFFERENCE_LEGACY:
             painterMode = QPainter::CompositionMode_Difference;
             break;
         case GIMP_LAYER_MODE_DARKEN_ONLY:
         case GIMP_LAYER_MODE_DARKEN_ONLY_LEGACY:
             painterMode = QPainter::CompositionMode_Darken;
             break;
         case GIMP_LAYER_MODE_LIGHTEN_ONLY:
         case GIMP_LAYER_MODE_LIGHTEN_ONLY_LEGACY:
             painterMode = QPainter::CompositionMode_Lighten;
             break;
         case GIMP_LAYER_MODE_DODGE:
         case GIMP_LAYER_MODE_DODGE_LEGACY:
             painterMode = QPainter::CompositionMode_ColorDodge;
             break;
         case GIMP_LAYER_MODE_BURN:
         case GIMP_LAYER_MODE_BURN_LEGACY:
             painterMode = QPainter::CompositionMode_ColorBurn;
             break;
         case GIMP_LAYER_MODE_HARDLIGHT:
         case GIMP_LAYER_MODE_HARDLIGHT_LEGACY:
             painterMode = QPainter::CompositionMode_HardLight;
             break;
         case GIMP_LAYER_MODE_SOFTLIGHT:
         case GIMP_LAYER_MODE_SOFTLIGHT_LEGACY:
             painterMode = QPainter::CompositionMode_SoftLight;
             break;
         case GIMP_LAYER_MODE_ADDITION:
         case GIMP_LAYER_MODE_ADDITION_LEGACY:
             painterMode = QPainter::CompositionMode_Plus;
             break;
         case GIMP_LAYER_MODE_EXCLUSION:
             painterMode = QPainter::CompositionMode_Exclusion;
             break;
 
             // Not bothered to find what the QPainter equivalent is, or there is none
         case GIMP_LAYER_MODE_GRAIN_EXTRACT:
         case GIMP_LAYER_MODE_GRAIN_EXTRACT_LEGACY:
         case GIMP_LAYER_MODE_GRAIN_MERGE:
         case GIMP_LAYER_MODE_GRAIN_MERGE_LEGACY:
         case GIMP_LAYER_MODE_COLOR_ERASE:
         case GIMP_LAYER_MODE_COLOR_ERASE_LEGACY:
         case GIMP_LAYER_MODE_LCH_HUE:
         case GIMP_LAYER_MODE_LCH_CHROMA:
         case GIMP_LAYER_MODE_LCH_COLOR:
         case GIMP_LAYER_MODE_LCH_LIGHTNESS:
         case GIMP_LAYER_MODE_BEHIND:
         case GIMP_LAYER_MODE_BEHIND_LEGACY:
         case GIMP_LAYER_MODE_SUBTRACT:
         case GIMP_LAYER_MODE_SUBTRACT_LEGACY:
         case GIMP_LAYER_MODE_HSV_HUE:
         case GIMP_LAYER_MODE_HSV_SATURATION:
         case GIMP_LAYER_MODE_HSL_COLOR:
         case GIMP_LAYER_MODE_HSV_VALUE:
         case GIMP_LAYER_MODE_DIVIDE:
         case GIMP_LAYER_MODE_VIVID_LIGHT:
         case GIMP_LAYER_MODE_PIN_LIGHT:
         case GIMP_LAYER_MODE_LINEAR_LIGHT:
         case GIMP_LAYER_MODE_HARD_MIX:
         case GIMP_LAYER_MODE_LINEAR_BURN:
         case GIMP_LAYER_MODE_LUMA_DARKEN_ONLY:
         case GIMP_LAYER_MODE_LUMA_LIGHTEN_ONLY:
         case GIMP_LAYER_MODE_LUMINANCE:
         case GIMP_LAYER_MODE_ERASE:
         case GIMP_LAYER_MODE_MERGE:
         case GIMP_LAYER_MODE_SPLIT:
         case GIMP_LAYER_MODE_PASS_THROUGH:
         case GIMP_LAYER_MODE_HSV_HUE_LEGACY:
         case GIMP_LAYER_MODE_HSV_SATURATION_LEGACY:
         case GIMP_LAYER_MODE_HSL_COLOR_LEGACY:
         case GIMP_LAYER_MODE_HSV_VALUE_LEGACY:
         case GIMP_LAYER_MODE_DIVIDE_LEGACY:
             qCDebug(XCFPLUGIN) << "No QPainter equivalent to" << layer.mode;
             break;
 
             // Special
         case GIMP_LAYER_MODE_DISSOLVE:
         case GIMP_LAYER_MODE_COUNT:
             break;
         }
 
         if (painterMode != -1) {
             QPainter painter(&image);
             painter.setOpacity(layer.opacity / 255.0);
             painter.setCompositionMode(QPainter::CompositionMode(painterMode));
             qCDebug(XCFPLUGIN) << "Using QPainter for mode" << layer.mode;
 
             for (uint j = 0; j < layer.nrows; j++) {
                 uint y = j * TILE_HEIGHT;
 
                 for (uint i = 0; i < layer.ncols; i++) {
                     uint x = i * TILE_WIDTH;
 
                     QImage &tile = layer.image_tiles[j][i];
                     if (x + layer.x_offset < MAX_IMAGE_WIDTH &&
                         y + layer.y_offset < MAX_IMAGE_HEIGHT) {
                         painter.drawImage(x + layer.x_offset, y + layer.y_offset, tile);
                     }
                 }
             }
 
             return;
         }
     }
 
 #ifndef DISABLE_IMAGE_PROFILE_CONV // The final profile should be the one in the Parasite
     if (layer.compositeSpace == XCFImageFormat::RgbPerceptualSpace && image.colorSpace() != QColorSpace::SRgb) {
         qCDebug(XCFPLUGIN) << "Converting to composite color space" << layer.compositeSpace;
         image.convertToColorSpace(QColorSpace::SRgb);
     }
     if (layer.compositeSpace == XCFImageFormat::RgbLinearSpace && image.colorSpace() != QColorSpace::SRgbLinear) {
         qCDebug(XCFPLUGIN) << "Converting to composite color space" << layer.compositeSpace;
         image.convertToColorSpace(QColorSpace::SRgbLinear);
     }
 #endif
 
     for (uint j = 0; j < layer.nrows; j++) {
         uint y = j * TILE_HEIGHT;
 
         for (uint i = 0; i < layer.ncols; i++) {
             uint x = i * TILE_WIDTH;
 
             // This seems the best place to apply the dissolve because it
             // depends on the global position of each tile's
             // pixels. Apparently it's the only mode which can apply to a
             // single layer.
 
             if (layer.mode == GIMP_LAYER_MODE_DISSOLVE) {
                 if (!random_table_initialized) {
                     initializeRandomTable();
                     random_table_initialized = true;
                 }
                 if (layer.type == RGBA_GIMAGE) {
                     dissolveRGBPixels(layer.image_tiles[j][i], x, y);
                 }
 
                 else if (layer.type == GRAYA_GIMAGE) {
                     dissolveAlphaPixels(layer.alpha_tiles[j][i], x, y);
                 }
             }
 
             // Shortcut for common case
             if (merge == mergeRGBToRGB && layer.apply_mask != 1 && layer.mode == GIMP_LAYER_MODE_NORMAL_LEGACY) {
                 QPainter painter(&image);
                 painter.setOpacity(layer.opacity / 255.0);
                 painter.setCompositionMode(QPainter::CompositionMode_SourceOver);
                 if (x + layer.x_offset < MAX_IMAGE_WIDTH &&
                     y + layer.y_offset < MAX_IMAGE_HEIGHT) {
                     painter.drawImage(x + layer.x_offset, y + layer.y_offset, layer.image_tiles[j][i]);
                 }
                 continue;
             }
 
 #ifndef DISABLE_TILE_PROFILE_CONV // not sure about that: left as old plugin
             QImage &tile = layer.image_tiles[j][i];
             if (layer.compositeSpace == XCFImageFormat::RgbPerceptualSpace && tile.colorSpace() != QColorSpace::SRgb) {
                 tile.convertToColorSpace(QColorSpace::SRgb);
             }
             if (layer.compositeSpace == XCFImageFormat::RgbLinearSpace && tile.colorSpace() != QColorSpace::SRgbLinear) {
                 tile.convertToColorSpace(QColorSpace::SRgbLinear);
             }
 #endif
 
             for (int l = 0; l < layer.image_tiles[j][i].height(); l++) {
                 for (int k = 0; k < layer.image_tiles[j][i].width(); k++) {
                     int m = x + k + layer.x_offset;
                     int n = y + l + layer.y_offset;
 
                     if (m < 0 || m >= image.width() || n < 0 || n >= image.height()) {
                         continue;
                     }
 
                     if (!(*merge)(layer, i, j, k, l, image, m, n)) {
                         return;
                     }
                 }
             }
         }
     }
 }
 
 /*!
  * Merge an RGB pixel from the layer to the RGB image. Straight-forward.
  * The only thing this has to take account of is the opacity of the
  * layer. Evidently, the GIMP exporter itself does not actually do this.
  * \param layer source layer.
  * \param i x tile index.
  * \param j y tile index.
  * \param k x pixel index of tile i,j.
  * \param l y pixel index of tile i,j.
  * \param image destination image.
  * \param m x pixel of destination image.
  * \param n y pixel of destination image.
  */
 bool XCFImageFormat::mergeRGBToRGB(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n)
 {
     QRgb src = layer.image_tiles[j][i].pixel(k, l);
     QRgb dst = image.pixel(m, n);
 
     uchar src_r = qRed(src);
     uchar src_g = qGreen(src);
     uchar src_b = qBlue(src);
     uchar src_a = qAlpha(src);
 
     uchar dst_r = qRed(dst);
     uchar dst_g = qGreen(dst);
     uchar dst_b = qBlue(dst);
     uchar dst_a = qAlpha(dst);
 
     if (!src_a) {
         return false; // nothing to merge
     }
 
     switch (layer.mode) {
     case GIMP_LAYER_MODE_NORMAL:
     case GIMP_LAYER_MODE_NORMAL_LEGACY:
         break;
     case GIMP_LAYER_MODE_MULTIPLY:
     case GIMP_LAYER_MODE_MULTIPLY_LEGACY:
         src_r = INT_MULT(src_r, dst_r);
         src_g = INT_MULT(src_g, dst_g);
         src_b = INT_MULT(src_b, dst_b);
         src_a = qMin(src_a, dst_a);
         break;
     case GIMP_LAYER_MODE_DIVIDE:
     case GIMP_LAYER_MODE_DIVIDE_LEGACY:
         src_r = qMin((dst_r * 256) / (1 + src_r), 255);
         src_g = qMin((dst_g * 256) / (1 + src_g), 255);
         src_b = qMin((dst_b * 256) / (1 + src_b), 255);
         src_a = qMin(src_a, dst_a);
         break;
     case GIMP_LAYER_MODE_SCREEN:
     case GIMP_LAYER_MODE_SCREEN_LEGACY:
         src_r = 255 - INT_MULT(255 - dst_r, 255 - src_r);
         src_g = 255 - INT_MULT(255 - dst_g, 255 - src_g);
         src_b = 255 - INT_MULT(255 - dst_b, 255 - src_b);
         src_a = qMin(src_a, dst_a);
         break;
     case GIMP_LAYER_MODE_OVERLAY:
     case GIMP_LAYER_MODE_OVERLAY_LEGACY:
         src_r = INT_MULT(dst_r, dst_r + INT_MULT(2 * src_r, 255 - dst_r));
         src_g = INT_MULT(dst_g, dst_g + INT_MULT(2 * src_g, 255 - dst_g));
         src_b = INT_MULT(dst_b, dst_b + INT_MULT(2 * src_b, 255 - dst_b));
         src_a = qMin(src_a, dst_a);
         break;
     case GIMP_LAYER_MODE_DIFFERENCE:
     case GIMP_LAYER_MODE_DIFFERENCE_LEGACY:
         src_r = dst_r > src_r ? dst_r - src_r : src_r - dst_r;
         src_g = dst_g > src_g ? dst_g - src_g : src_g - dst_g;
         src_b = dst_b > src_b ? dst_b - src_b : src_b - dst_b;
         src_a = qMin(src_a, dst_a);
         break;
     case GIMP_LAYER_MODE_ADDITION:
     case GIMP_LAYER_MODE_ADDITION_LEGACY:
         src_r = add_lut(dst_r, src_r);
         src_g = add_lut(dst_g, src_g);
         src_b = add_lut(dst_b, src_b);
         src_a = qMin(src_a, dst_a);
         break;
     case GIMP_LAYER_MODE_SUBTRACT:
     case GIMP_LAYER_MODE_SUBTRACT_LEGACY:
         src_r = dst_r > src_r ? dst_r - src_r : 0;
         src_g = dst_g > src_g ? dst_g - src_g : 0;
         src_b = dst_b > src_b ? dst_b - src_b : 0;
         src_a = qMin(src_a, dst_a);
         break;
     case GIMP_LAYER_MODE_DARKEN_ONLY:
     case GIMP_LAYER_MODE_DARKEN_ONLY_LEGACY:
         src_r = dst_r < src_r ? dst_r : src_r;
         src_g = dst_g < src_g ? dst_g : src_g;
         src_b = dst_b < src_b ? dst_b : src_b;
         src_a = qMin(src_a, dst_a);
         break;
     case GIMP_LAYER_MODE_LIGHTEN_ONLY:
     case GIMP_LAYER_MODE_LIGHTEN_ONLY_LEGACY:
         src_r = dst_r < src_r ? src_r : dst_r;
         src_g = dst_g < src_g ? src_g : dst_g;
         src_b = dst_b < src_b ? src_b : dst_b;
         src_a = qMin(src_a, dst_a);
         break;
     case GIMP_LAYER_MODE_HSV_HUE:
     case GIMP_LAYER_MODE_HSV_HUE_LEGACY: {
         uchar new_r = dst_r;
         uchar new_g = dst_g;
         uchar new_b = dst_b;
 
         RGBTOHSV(src_r, src_g, src_b);
         RGBTOHSV(new_r, new_g, new_b);
 
         new_r = src_r;
 
         HSVTORGB(new_r, new_g, new_b);
 
         src_r = new_r;
         src_g = new_g;
         src_b = new_b;
         src_a = qMin(src_a, dst_a);
     } break;
     case GIMP_LAYER_MODE_HSV_SATURATION:
     case GIMP_LAYER_MODE_HSV_SATURATION_LEGACY: {
         uchar new_r = dst_r;
         uchar new_g = dst_g;
         uchar new_b = dst_b;
 
         RGBTOHSV(src_r, src_g, src_b);
         RGBTOHSV(new_r, new_g, new_b);
 
         new_g = src_g;
 
         HSVTORGB(new_r, new_g, new_b);
 
         src_r = new_r;
         src_g = new_g;
         src_b = new_b;
         src_a = qMin(src_a, dst_a);
     } break;
     case GIMP_LAYER_MODE_HSV_VALUE:
     case GIMP_LAYER_MODE_HSV_VALUE_LEGACY: {
         uchar new_r = dst_r;
         uchar new_g = dst_g;
         uchar new_b = dst_b;
 
         RGBTOHSV(src_r, src_g, src_b);
         RGBTOHSV(new_r, new_g, new_b);
 
         new_b = src_b;
 
         HSVTORGB(new_r, new_g, new_b);
 
         src_r = new_r;
         src_g = new_g;
         src_b = new_b;
         src_a = qMin(src_a, dst_a);
     } break;
     case GIMP_LAYER_MODE_HSL_COLOR:
     case GIMP_LAYER_MODE_HSL_COLOR_LEGACY: {
         uchar new_r = dst_r;
         uchar new_g = dst_g;
         uchar new_b = dst_b;
 
         RGBTOHLS(src_r, src_g, src_b);
         RGBTOHLS(new_r, new_g, new_b);
 
         new_r = src_r;
         new_b = src_b;
 
         HLSTORGB(new_r, new_g, new_b);
 
         src_r = new_r;
         src_g = new_g;
         src_b = new_b;
         src_a = qMin(src_a, dst_a);
     } break;
     case GIMP_LAYER_MODE_DODGE:
     case GIMP_LAYER_MODE_DODGE_LEGACY: {
         uint tmp;
 
         tmp = dst_r << 8;
         tmp /= 256 - src_r;
         src_r = (uchar)qMin(tmp, 255u);
 
         tmp = dst_g << 8;
         tmp /= 256 - src_g;
         src_g = (uchar)qMin(tmp, 255u);
 
         tmp = dst_b << 8;
         tmp /= 256 - src_b;
         src_b = (uchar)qMin(tmp, 255u);
 
         src_a = qMin(src_a, dst_a);
     } break;
     case GIMP_LAYER_MODE_BURN:
     case GIMP_LAYER_MODE_BURN_LEGACY: {
         uint tmp;
 
         tmp = (255 - dst_r) << 8;
         tmp /= src_r + 1;
         src_r = (uchar)qMin(tmp, 255u);
         src_r = 255 - src_r;
 
         tmp = (255 - dst_g) << 8;
         tmp /= src_g + 1;
         src_g = (uchar)qMin(tmp, 255u);
         src_g = 255 - src_g;
 
         tmp = (255 - dst_b) << 8;
         tmp /= src_b + 1;
         src_b = (uchar)qMin(tmp, 255u);
         src_b = 255 - src_b;
 
         src_a = qMin(src_a, dst_a);
     } break;
     case GIMP_LAYER_MODE_HARDLIGHT:
     case GIMP_LAYER_MODE_HARDLIGHT_LEGACY: {
         uint tmp;
         if (src_r > 128) {
             tmp = ((int)255 - dst_r) * ((int)255 - ((src_r - 128) << 1));
             src_r = (uchar)qMin(255 - (tmp >> 8), 255u);
         } else {
             tmp = (int)dst_r * ((int)src_r << 1);
             src_r = (uchar)qMin(tmp >> 8, 255u);
         }
 
         if (src_g > 128) {
             tmp = ((int)255 - dst_g) * ((int)255 - ((src_g - 128) << 1));
             src_g = (uchar)qMin(255 - (tmp >> 8), 255u);
         } else {
             tmp = (int)dst_g * ((int)src_g << 1);
             src_g = (uchar)qMin(tmp >> 8, 255u);
         }
 
         if (src_b > 128) {
             tmp = ((int)255 - dst_b) * ((int)255 - ((src_b - 128) << 1));
             src_b = (uchar)qMin(255 - (tmp >> 8), 255u);
         } else {
             tmp = (int)dst_b * ((int)src_b << 1);
             src_b = (uchar)qMin(tmp >> 8, 255u);
         }
         src_a = qMin(src_a, dst_a);
     } break;
     case GIMP_LAYER_MODE_SOFTLIGHT:
     case GIMP_LAYER_MODE_SOFTLIGHT_LEGACY: {
         uint tmpS;
         uint tmpM;
 
         tmpM = INT_MULT(dst_r, src_r);
         tmpS = 255 - INT_MULT((255 - dst_r), (255 - src_r));
         src_r = INT_MULT((255 - dst_r), tmpM) + INT_MULT(dst_r, tmpS);
 
         tmpM = INT_MULT(dst_g, src_g);
         tmpS = 255 - INT_MULT((255 - dst_g), (255 - src_g));
         src_g = INT_MULT((255 - dst_g), tmpM) + INT_MULT(dst_g, tmpS);
 
         tmpM = INT_MULT(dst_b, src_b);
         tmpS = 255 - INT_MULT((255 - dst_b), (255 - src_b));
         src_b = INT_MULT((255 - dst_b), tmpM) + INT_MULT(dst_b, tmpS);
 
         src_a = qMin(src_a, dst_a);
     } break;
     case GIMP_LAYER_MODE_GRAIN_EXTRACT:
     case GIMP_LAYER_MODE_GRAIN_EXTRACT_LEGACY: {
         int tmp;
 
         tmp = dst_r - src_r + 128;
         tmp = qMin(tmp, 255);
         tmp = qMax(tmp, 0);
         src_r = (uchar)tmp;
 
         tmp = dst_g - src_g + 128;
         tmp = qMin(tmp, 255);
         tmp = qMax(tmp, 0);
         src_g = (uchar)tmp;
 
         tmp = dst_b - src_b + 128;
         tmp = qMin(tmp, 255);
         tmp = qMax(tmp, 0);
         src_b = (uchar)tmp;
 
         src_a = qMin(src_a, dst_a);
     } break;
     case GIMP_LAYER_MODE_GRAIN_MERGE:
     case GIMP_LAYER_MODE_GRAIN_MERGE_LEGACY: {
         int tmp;
 
         tmp = dst_r + src_r - 128;
         tmp = qMin(tmp, 255);
         tmp = qMax(tmp, 0);
         src_r = (uchar)tmp;
 
         tmp = dst_g + src_g - 128;
         tmp = qMin(tmp, 255);
         tmp = qMax(tmp, 0);
         src_g = (uchar)tmp;
 
         tmp = dst_b + src_b - 128;
         tmp = qMin(tmp, 255);
         tmp = qMax(tmp, 0);
         src_b = (uchar)tmp;
 
         src_a = qMin(src_a, dst_a);
     } break;
     case GIMP_LAYER_MODE_LINEAR_LIGHT: {
         if (src_r <= 128) {
             src_r = qBound(0, dst_r + 2 * src_r - 255, 255);
         } else {
             src_r = qBound(0, dst_r + 2 * (src_r - 128), 255);
         }
         if (src_g <= 128) {
             src_g = qBound(0, dst_g + 2 * src_g - 255, 255);
         } else {
             src_g = qBound(0, dst_g + 2 * (src_g - 127), 255);
         }
         if (src_b <= 128) {
             src_b = qBound(0, dst_b + 2 * src_b - 255, 255);
         } else {
             src_b = qBound(0, dst_b + 2 * (src_b - 127), 255);
         }
     } break;
     case GIMP_LAYER_MODE_VIVID_LIGHT: {
         // From http://www.simplefilter.de/en/basics/mixmods.html
         float A[3];
         A[0] = src_r / 255.;
         A[1] = src_g / 255.;
         A[2] = src_b / 255.;
         float B[3];
         B[0] = dst_r / 255.;
         B[1] = dst_g / 255.;
         B[2] = dst_b / 255.;
         float C[3]{};
         for (int i = 0; i < 3; i++) {
             if (A[i] <= 0.5f) {
                 if (A[i] > 0.f) {
                     C[i] = 1.f - (1.f - B[i]) / (2.f * A[i]);
                 }
             } else {
                 if (A[i] < 1.f) {
                     C[i] = B[i] / (2.f * (1.f - A[i]));
                 }
             }
         }
         src_r = qBound(0.f, C[0] * 255.f, 255.f);
         src_g = qBound(0.f, C[1] * 255.f, 255.f);
         src_b = qBound(0.f, C[2] * 255.f, 255.f);
     } break;
     default:
         qCWarning(XCFPLUGIN) << "Unhandled mode" << layer.mode;
         return false;
     }
 
     src_a = INT_MULT(src_a, layer.opacity);
 
     // Apply the mask (if any)
 
     if (layer.apply_mask == 1 && layer.mask_tiles.size() > (int)j && layer.mask_tiles[j].size() > (int)i) {
         src_a = INT_MULT(src_a, layer.mask_tiles[j][i].pixelIndex(k, l));
     }
 
     uchar new_r;
     uchar new_g;
     uchar new_b;
     uchar new_a;
     new_a = dst_a + INT_MULT(OPAQUE_OPACITY - dst_a, src_a);
 
     const float src_ratio = new_a == 0 ? 1.0 : (float)src_a / new_a;
     float dst_ratio = 1.0 - src_ratio;
 
     new_r = (uchar)(src_ratio * src_r + dst_ratio * dst_r + EPSILON);
     new_g = (uchar)(src_ratio * src_g + dst_ratio * dst_g + EPSILON);
     new_b = (uchar)(src_ratio * src_b + dst_ratio * dst_b + EPSILON);
 
     if (!modeAffectsSourceAlpha(layer.mode)) {
         new_a = dst_a;
     }
 
     image.setPixel(m, n, qRgba(new_r, new_g, new_b, new_a));
     return true;
 }
 
 /*!
  * Merge a Gray pixel from the layer to the Gray image. Straight-forward.
  * \param layer source layer.
  * \param i x tile index.
  * \param j y tile index.
  * \param k x pixel index of tile i,j.
  * \param l y pixel index of tile i,j.
  * \param image destination image.
  * \param m x pixel of destination image.
  * \param n y pixel of destination image.
  */
 bool XCFImageFormat::mergeGrayToGray(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n)
 {
     int src = layer.image_tiles[j][i].pixelIndex(k, l);
     image.setPixel(m, n, src);
     return true;
 }
 
 /*!
  * Merge a GrayA pixel from the layer to the Gray image. Straight-forward.
  * \param layer source layer.
  * \param i x tile index.
  * \param j y tile index.
  * \param k x pixel index of tile i,j.
  * \param l y pixel index of tile i,j.
  * \param image destination image.
  * \param m x pixel of destination image.
  * \param n y pixel of destination image.
  */
 bool XCFImageFormat::mergeGrayAToGray(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n)
 {
     int src = qGray(layer.image_tiles[j][i].pixel(k, l));
     int dst = image.pixelIndex(m, n);
 
     uchar src_a = layer.alpha_tiles[j][i].pixelIndex(k, l);
 
     if (!src_a) {
         return false; // nothing to merge
     }
 
     switch (layer.mode) {
     case GIMP_LAYER_MODE_MULTIPLY:
     case GIMP_LAYER_MODE_MULTIPLY_LEGACY: {
         src = INT_MULT(src, dst);
     } break;
     case GIMP_LAYER_MODE_DIVIDE:
     case GIMP_LAYER_MODE_DIVIDE_LEGACY: {
         src = qMin((dst * 256) / (1 + src), 255);
     } break;
     case GIMP_LAYER_MODE_SCREEN:
     case GIMP_LAYER_MODE_SCREEN_LEGACY: {
         src = 255 - INT_MULT(255 - dst, 255 - src);
     } break;
     case GIMP_LAYER_MODE_OVERLAY:
     case GIMP_LAYER_MODE_OVERLAY_LEGACY: {
         src = INT_MULT(dst, dst + INT_MULT(2 * src, 255 - dst));
     } break;
     case GIMP_LAYER_MODE_DIFFERENCE:
     case GIMP_LAYER_MODE_DIFFERENCE_LEGACY: {
         src = dst > src ? dst - src : src - dst;
     } break;
     case GIMP_LAYER_MODE_ADDITION:
     case GIMP_LAYER_MODE_ADDITION_LEGACY: {
         src = add_lut(dst, src);
     } break;
     case GIMP_LAYER_MODE_SUBTRACT:
     case GIMP_LAYER_MODE_SUBTRACT_LEGACY: {
         src = dst > src ? dst - src : 0;
     } break;
     case GIMP_LAYER_MODE_DARKEN_ONLY:
     case GIMP_LAYER_MODE_DARKEN_ONLY_LEGACY: {
         src = dst < src ? dst : src;
     } break;
     case GIMP_LAYER_MODE_LIGHTEN_ONLY:
     case GIMP_LAYER_MODE_LIGHTEN_ONLY_LEGACY: {
         src = dst < src ? src : dst;
     } break;
     case GIMP_LAYER_MODE_DODGE:
     case GIMP_LAYER_MODE_DODGE_LEGACY: {
         uint tmp = dst << 8;
         tmp /= 256 - src;
         src = (uchar)qMin(tmp, 255u);
     } break;
     case GIMP_LAYER_MODE_BURN:
     case GIMP_LAYER_MODE_BURN_LEGACY: {
         uint tmp = (255 - dst) << 8;
         tmp /= src + 1;
         src = (uchar)qMin(tmp, 255u);
         src = 255 - src;
     } break;
     case GIMP_LAYER_MODE_HARDLIGHT:
     case GIMP_LAYER_MODE_HARDLIGHT_LEGACY: {
         uint tmp;
         if (src > 128) {
             tmp = ((int)255 - dst) * ((int)255 - ((src - 128) << 1));
             src = (uchar)qMin(255 - (tmp >> 8), 255u);
         } else {
             tmp = (int)dst * ((int)src << 1);
             src = (uchar)qMin(tmp >> 8, 255u);
         }
     } break;
     case GIMP_LAYER_MODE_SOFTLIGHT:
     case GIMP_LAYER_MODE_SOFTLIGHT_LEGACY: {
         uint tmpS;
         uint tmpM;
 
         tmpM = INT_MULT(dst, src);
         tmpS = 255 - INT_MULT((255 - dst), (255 - src));
         src = INT_MULT((255 - dst), tmpM) + INT_MULT(dst, tmpS);
 
     } break;
     case GIMP_LAYER_MODE_GRAIN_EXTRACT:
     case GIMP_LAYER_MODE_GRAIN_EXTRACT_LEGACY: {
         int tmp;
 
         tmp = dst - src + 128;
         tmp = qMin(tmp, 255);
         tmp = qMax(tmp, 0);
 
         src = (uchar)tmp;
     } break;
     case GIMP_LAYER_MODE_GRAIN_MERGE:
     case GIMP_LAYER_MODE_GRAIN_MERGE_LEGACY: {
         int tmp;
 
         tmp = dst + src - 128;
         tmp = qMin(tmp, 255);
         tmp = qMax(tmp, 0);
 
         src = (uchar)tmp;
     } break;
     default:
         qCWarning(XCFPLUGIN) << "Unhandled mode" << layer.mode;
         return false;
     }
 
     src_a = INT_MULT(src_a, layer.opacity);
 
     // Apply the mask (if any)
 
     if (layer.apply_mask == 1 && layer.mask_tiles.size() > (int)j && layer.mask_tiles[j].size() > (int)i) {
         src_a = INT_MULT(src_a, layer.mask_tiles[j][i].pixelIndex(k, l));
     }
 
     uchar new_a = OPAQUE_OPACITY;
 
     const float src_ratio = new_a == 0 ? 1.0 : (float)src_a / new_a;
     float dst_ratio = 1.0 - src_ratio;
 
     uchar new_g = (uchar)(src_ratio * src + dst_ratio * dst + EPSILON);
 
     image.setPixel(m, n, new_g);
     return true;
 }
 
 /*!
  * Merge a Gray pixel from the layer to an RGB image. Straight-forward.
  * The only thing this has to take account of is the opacity of the
  * layer. Evidently, the GIMP exporter itself does not actually do this.
  * \param layer source layer.
  * \param i x tile index.
  * \param j y tile index.
  * \param k x pixel index of tile i,j.
  * \param l y pixel index of tile i,j.
  * \param image destination image.
  * \param m x pixel of destination image.
  * \param n y pixel of destination image.
  */
 bool XCFImageFormat::mergeGrayToRGB(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n)
 {
     QRgb src = layer.image_tiles[j][i].pixel(k, l);
     uchar src_a = layer.opacity;
     image.setPixel(m, n, qRgba(src, src_a));
     return true;
 }
 
 /*!
  * Merge a GrayA pixel from the layer to an RGB image. Straight-forward.
  * The only thing this has to take account of is the opacity of the
  * layer. Evidently, the GIMP exporter itself does not actually do this.
  * \param layer source layer.
  * \param i x tile index.
  * \param j y tile index.
  * \param k x pixel index of tile i,j.
  * \param l y pixel index of tile i,j.
  * \param image destination image.
  * \param m x pixel of destination image.
  * \param n y pixel of destination image.
  */
 bool XCFImageFormat::mergeGrayAToRGB(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n)
 {
     int src = qGray(layer.image_tiles[j][i].pixel(k, l));
     int dst = qGray(image.pixel(m, n));
 
     uchar src_a = layer.alpha_tiles[j][i].pixelIndex(k, l);
     uchar dst_a = qAlpha(image.pixel(m, n));
 
     if (!src_a) {
         return false; // nothing to merge
     }
 
     switch (layer.mode) {
     case GIMP_LAYER_MODE_MULTIPLY:
     case GIMP_LAYER_MODE_MULTIPLY_LEGACY: {
         src = INT_MULT(src, dst);
         src_a = qMin(src_a, dst_a);
     } break;
     case GIMP_LAYER_MODE_DIVIDE:
     case GIMP_LAYER_MODE_DIVIDE_LEGACY: {
         src = qMin((dst * 256) / (1 + src), 255);
         src_a = qMin(src_a, dst_a);
     } break;
     case GIMP_LAYER_MODE_SCREEN:
     case GIMP_LAYER_MODE_SCREEN_LEGACY: {
         src = 255 - INT_MULT(255 - dst, 255 - src);
         src_a = qMin(src_a, dst_a);
     } break;
     case GIMP_LAYER_MODE_OVERLAY:
     case GIMP_LAYER_MODE_OVERLAY_LEGACY: {
         src = INT_MULT(dst, dst + INT_MULT(2 * src, 255 - dst));
         src_a = qMin(src_a, dst_a);
     } break;
     case GIMP_LAYER_MODE_DIFFERENCE:
     case GIMP_LAYER_MODE_DIFFERENCE_LEGACY: {
         src = dst > src ? dst - src : src - dst;
         src_a = qMin(src_a, dst_a);
     } break;
     case GIMP_LAYER_MODE_ADDITION:
     case GIMP_LAYER_MODE_ADDITION_LEGACY: {
         src = add_lut(dst, src);
         src_a = qMin(src_a, dst_a);
     } break;
     case GIMP_LAYER_MODE_SUBTRACT:
     case GIMP_LAYER_MODE_SUBTRACT_LEGACY: {
         src = dst > src ? dst - src : 0;
         src_a = qMin(src_a, dst_a);
     } break;
     case GIMP_LAYER_MODE_DARKEN_ONLY:
     case GIMP_LAYER_MODE_DARKEN_ONLY_LEGACY: {
         src = dst < src ? dst : src;
         src_a = qMin(src_a, dst_a);
     } break;
     case GIMP_LAYER_MODE_LIGHTEN_ONLY:
     case GIMP_LAYER_MODE_LIGHTEN_ONLY_LEGACY: {
         src = dst < src ? src : dst;
         src_a = qMin(src_a, dst_a);
     } break;
     case GIMP_LAYER_MODE_DODGE:
     case GIMP_LAYER_MODE_DODGE_LEGACY: {
         uint tmp = dst << 8;
         tmp /= 256 - src;
         src = (uchar)qMin(tmp, 255u);
         src_a = qMin(src_a, dst_a);
     } break;
     case GIMP_LAYER_MODE_BURN:
     case GIMP_LAYER_MODE_BURN_LEGACY: {
         uint tmp = (255 - dst) << 8;
         tmp /= src + 1;
         src = (uchar)qMin(tmp, 255u);
         src = 255 - src;
         src_a = qMin(src_a, dst_a);
     } break;
     case GIMP_LAYER_MODE_HARDLIGHT:
     case GIMP_LAYER_MODE_HARDLIGHT_LEGACY: {
         uint tmp;
         if (src > 128) {
             tmp = ((int)255 - dst) * ((int)255 - ((src - 128) << 1));
             src = (uchar)qMin(255 - (tmp >> 8), 255u);
         } else {
             tmp = (int)dst * ((int)src << 1);
             src = (uchar)qMin(tmp >> 8, 255u);
         }
         src_a = qMin(src_a, dst_a);
     } break;
     case GIMP_LAYER_MODE_SOFTLIGHT:
     case GIMP_LAYER_MODE_SOFTLIGHT_LEGACY: {
         uint tmpS;
         uint tmpM;
 
         tmpM = INT_MULT(dst, src);
         tmpS = 255 - INT_MULT((255 - dst), (255 - src));
         src = INT_MULT((255 - dst), tmpM) + INT_MULT(dst, tmpS);
 
         src_a = qMin(src_a, dst_a);
     } break;
     case GIMP_LAYER_MODE_GRAIN_EXTRACT:
     case GIMP_LAYER_MODE_GRAIN_EXTRACT_LEGACY: {
         int tmp;
 
         tmp = dst - src + 128;
         tmp = qMin(tmp, 255);
         tmp = qMax(tmp, 0);
 
         src = (uchar)tmp;
         src_a = qMin(src_a, dst_a);
     } break;
     case GIMP_LAYER_MODE_GRAIN_MERGE:
     case GIMP_LAYER_MODE_GRAIN_MERGE_LEGACY: {
         int tmp;
 
         tmp = dst + src - 128;
         tmp = qMin(tmp, 255);
         tmp = qMax(tmp, 0);
 
         src = (uchar)tmp;
         src_a = qMin(src_a, dst_a);
     } break;
     default:
         qCWarning(XCFPLUGIN) << "Unhandled mode" << layer.mode;
         return false;
     }
 
     src_a = INT_MULT(src_a, layer.opacity);
 
     // Apply the mask (if any)
     if (layer.apply_mask == 1 && layer.mask_tiles.size() > (int)j && layer.mask_tiles[j].size() > (int)i) {
         src_a = INT_MULT(src_a, layer.mask_tiles[j][i].pixelIndex(k, l));
     }
 
     uchar new_a = dst_a + INT_MULT(OPAQUE_OPACITY - dst_a, src_a);
 
     const float src_ratio = new_a == 0 ? 1.0 : (float)src_a / new_a;
     float dst_ratio = 1.0 - src_ratio;
 
     uchar new_g = (uchar)(src_ratio * src + dst_ratio * dst + EPSILON);
 
     if (!modeAffectsSourceAlpha(layer.mode)) {
         new_a = dst_a;
     }
 
     image.setPixel(m, n, qRgba(new_g, new_g, new_g, new_a));
     return true;
 }
 
 /*!
  * Merge an Indexed pixel from the layer to the Indexed image. Straight-forward.
  * \param layer source layer.
  * \param i x tile index.
  * \param j y tile index.
  * \param k x pixel index of tile i,j.
  * \param l y pixel index of tile i,j.
  * \param image destination image.
  * \param m x pixel of destination image.
  * \param n y pixel of destination image.
  */
 bool XCFImageFormat::mergeIndexedToIndexed(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n)
 {
     int src = layer.image_tiles[j][i].pixelIndex(k, l);
     image.setPixel(m, n, src);
     return true;
 }
 
 /*!
  * Merge an IndexedA pixel from the layer to the Indexed image. Straight-forward.
  * \param layer source layer.
  * \param i x tile index.
  * \param j y tile index.
  * \param k x pixel index of tile i,j.
  * \param l y pixel index of tile i,j.
  * \param image destination image.
  * \param m x pixel of destination image.
  * \param n y pixel of destination image.
  */
 bool XCFImageFormat::mergeIndexedAToIndexed(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n)
 {
     uchar src = layer.image_tiles[j][i].pixelIndex(k, l);
     uchar src_a = layer.alpha_tiles[j][i].pixelIndex(k, l);
     src_a = INT_MULT(src_a, layer.opacity);
 
     if (layer.apply_mask == 1 && layer.mask_tiles.size() > (int)j && layer.mask_tiles[j].size() > (int)i) {
         src_a = INT_MULT(src_a, layer.mask_tiles[j][i].pixelIndex(k, l));
     }
 
     if (src_a > 127) {
         src++;
         image.setPixel(m, n, src);
     }
     return true;
 }
 
 /*!
  * Merge an IndexedA pixel from the layer to an RGB image. Straight-forward.
  * The only thing this has to take account of is the opacity of the
  * layer. Evidently, the GIMP exporter itself does not actually do this.
  * \param layer source layer.
  * \param i x tile index.
  * \param j y tile index.
  * \param k x pixel index of tile i,j.
  * \param l y pixel index of tile i,j.
  * \param image destination image.
  * \param m x pixel of destination image.
  * \param n y pixel of destination image.
  */
 bool XCFImageFormat::mergeIndexedAToRGB(const Layer &layer, uint i, uint j, int k, int l, QImage &image, int m, int n)
 {
     QRgb src = layer.image_tiles[j][i].pixel(k, l);
     uchar src_a = layer.alpha_tiles[j][i].pixelIndex(k, l);
     src_a = INT_MULT(src_a, layer.opacity);
 
     // Apply the mask (if any)
     if (layer.apply_mask == 1 && layer.mask_tiles.size() > (int)j && layer.mask_tiles[j].size() > (int)i) {
         src_a = INT_MULT(src_a, layer.mask_tiles[j][i].pixelIndex(k, l));
     }
 
     // This is what appears in the GIMP window
     if (src_a <= 127) {
         src_a = 0;
     } else {
         src_a = OPAQUE_OPACITY;
     }
 
     image.setPixel(m, n, qRgba(src, src_a));
     return true;
 }
 
 /*!
  * Dissolving pixels: pick a random number between 0 and 255. If the pixel's
  * alpha is less than that, make it transparent.
  * \param image the image tile to dissolve.
  * \param x the global x position of the tile.
  * \param y the global y position of the tile.
  */
 void XCFImageFormat::dissolveRGBPixels(QImage &image, int x, int y)
 {
     // The apparently spurious rand() calls are to wind the random
     // numbers up to the same point for each tile.
 
     for (int l = 0; l < image.height(); l++) {
         unsigned int next = randomTable.values[(l + y) % RANDOM_TABLE_SIZE];
 
         for (int k = 0; k < x; k++) {
             RandomTable::rand_r(&next);
         }
 
         for (int k = 0; k < image.width(); k++) {
             int rand_val = RandomTable::rand_r(&next) & 0xff;
             QRgb pixel = image.pixel(k, l);
 
             if (rand_val > qAlpha(pixel)) {
                 image.setPixel(k, l, qRgba(pixel, 0));
             }
         }
     }
 }
 
 /*!
  * Dissolving pixels: pick a random number between 0 and 255. If the pixel's
  * alpha is less than that, make it transparent. This routine works for
  * the GRAYA and INDEXEDA image types where the pixel alpha's are stored
  * separately from the pixel themselves.
  * \param image the alpha tile to dissolve.
  * \param x the global x position of the tile.
  * \param y the global y position of the tile.
  */
 void XCFImageFormat::dissolveAlphaPixels(QImage &image, int x, int y)
 {
     // The apparently spurious rand() calls are to wind the random
     // numbers up to the same point for each tile.
 
     for (int l = 0; l < image.height(); l++) {
         unsigned int next = randomTable.values[(l + y) % RANDOM_TABLE_SIZE];
 
         for (int k = 0; k < x; k++) {
             RandomTable::rand_r(&next);
         }
 
         for (int k = 0; k < image.width(); k++) {
             int rand_val = RandomTable::rand_r(&next) & 0xff;
             uchar alpha = image.pixelIndex(k, l);
 
             if (rand_val > alpha) {
                 image.setPixel(k, l, 0);
             }
         }
     }
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 XCFHandler::XCFHandler()
 {
 }
 
 bool XCFHandler::canRead() const
 {
     if (canRead(device())) {
         setFormat("xcf");
         return true;
     }
     return false;
 }
 
 bool XCFHandler::read(QImage *image)
 {
     XCFImageFormat xcfif;
     return xcfif.readXCF(device(), image);
 }
 
 bool XCFHandler::write(const QImage &)
 {
     return false;
 }
 
 bool XCFHandler::supportsOption(ImageOption option) const
 {
     if (option == QImageIOHandler::Size)
         return true;
     return false;
 }
 
 QVariant XCFHandler::option(ImageOption option) const
 {
     QVariant v;
 
     if (option == QImageIOHandler::Size) {
         /*
          * The image structure always starts at offset 0 in the XCF file.
          * byte[9]     "gimp xcf " File type identification
          * byte[4]     version     XCF version
          *                          "file": version 0
          *                          "v001": version 1
          *                          "v002": version 2
          *                          "v003": version 3
          * byte        0            Zero marks the end of the version tag.
          * uint32      width        Width of canvas
          * uint32      height       Height of canvas
          */
         if (auto d = device()) {
             // transactions works on both random and sequential devices
             d->startTransaction();
             auto ba9 = d->read(9);      // "gimp xcf "
             auto ba5 = d->read(4+1);    // version + null terminator
             auto ba = d->read(8);       // width and height
             d->rollbackTransaction();
             if (ba9 == QByteArray("gimp xcf ") && ba5.size() == 5) {
                 QDataStream ds(ba);
                 quint32 width;
                 ds >> width;
                 quint32 height;
                 ds >> height;
                 if (ds.status() == QDataStream::Ok)
                     v = QVariant::fromValue(QSize(width, height));
             }
         }
     }
 
     return v;
 }
 
 bool XCFHandler::canRead(QIODevice *device)
 {
     if (!device) {
         qCDebug(XCFPLUGIN) << "XCFHandler::canRead() called with no device";
         return false;
     }
     if (device->isSequential()) {
         return false;
     }
 
     const qint64 oldPos = device->pos();
     if (!device->isSequential()) {
         QDataStream ds(device);
         XCFImageFormat::XCFImage::Header header;
         bool failed = !XCFImageFormat::readXCFHeader(ds, &header);
         ds.setDevice(nullptr);
         device->seek(oldPos);
         if (failed) {
             return false;
         }
 
         switch (header.precision) {
         case XCFImageFormat::GIMP_PRECISION_HALF_LINEAR:
         case XCFImageFormat::GIMP_PRECISION_HALF_NON_LINEAR:
         case XCFImageFormat::GIMP_PRECISION_HALF_PERCEPTUAL:
         case XCFImageFormat::GIMP_PRECISION_FLOAT_LINEAR:
         case XCFImageFormat::GIMP_PRECISION_FLOAT_NON_LINEAR:
         case XCFImageFormat::GIMP_PRECISION_FLOAT_PERCEPTUAL:
         case XCFImageFormat::GIMP_PRECISION_U8_LINEAR:
         case XCFImageFormat::GIMP_PRECISION_U8_NON_LINEAR:
         case XCFImageFormat::GIMP_PRECISION_U8_PERCEPTUAL:
         case XCFImageFormat::GIMP_PRECISION_U16_LINEAR:
         case XCFImageFormat::GIMP_PRECISION_U16_NON_LINEAR:
         case XCFImageFormat::GIMP_PRECISION_U16_PERCEPTUAL:
         case XCFImageFormat::GIMP_PRECISION_U32_LINEAR:
         case XCFImageFormat::GIMP_PRECISION_U32_NON_LINEAR:
         case XCFImageFormat::GIMP_PRECISION_U32_PERCEPTUAL:
             break;
         case XCFImageFormat::GIMP_PRECISION_DOUBLE_LINEAR:
         case XCFImageFormat::GIMP_PRECISION_DOUBLE_NON_LINEAR:
         case XCFImageFormat::GIMP_PRECISION_DOUBLE_PERCEPTUAL:
         default:
             qCDebug(XCFPLUGIN) << "unsupported precision" << header.precision;
             return false;
         }
 
         return true;
     }
 
     char head[8];
     qint64 readBytes = device->read(head, sizeof(head));
     if (readBytes != sizeof(head)) {
         if (device->isSequential()) {
             while (readBytes > 0) {
                 device->ungetChar(head[readBytes-- - 1]);
             }
         } else {
             device->seek(oldPos);
         }
         return false;
     }
 
     if (device->isSequential()) {
         while (readBytes > 0) {
             device->ungetChar(head[readBytes-- - 1]);
         }
     } else {
         device->seek(oldPos);
     }
 
     return qstrncmp(head, "gimp xcf", 8) == 0;
 }
 
 QImageIOPlugin::Capabilities XCFPlugin::capabilities(QIODevice *device, const QByteArray &format) const
 {
     if (format == "xcf") {
         return Capabilities(CanRead);
     }
     if (!format.isEmpty()) {
         return {};
     }
     if (!device->isOpen()) {
         return {};
     }
 
     Capabilities cap;
     if (device->isReadable() && XCFHandler::canRead(device)) {
         cap |= CanRead;
     }
     return cap;
 }
 
 QImageIOHandler *XCFPlugin::create(QIODevice *device, const QByteArray &format) const
 {
     QImageIOHandler *handler = new XCFHandler;
     handler->setDevice(device);
     handler->setFormat(format);
     return handler;
 }
 
 // Just so I can get enum values printed
 #include "xcf.moc"
 
 #include "moc_xcf_p.cpp"