File indexing completed on 2024-05-12 15:56:55

 /*
  *  SPDX-FileCopyrightText: 2014 Dmitry Kazakov <dimula73@gmail.com>
  *
  *  SPDX-License-Identifier: GPL-2.0-or-later
  */
 
 #ifndef __KIS_ACS_PIXEL_CACHE_RENDERER_H
 #define __KIS_ACS_PIXEL_CACHE_RENDERER_H
 
 #include "KoColorSpace.h"
 #include "kis_paint_device.h"
 #include "kis_iterator_ng.h"
 #include "kis_display_color_converter.h"
 
 
 namespace Acs {
 
     class PixelCacheRenderer {
     public:
         /**
          * \p Sampler class must provide one method:
          *     - KoColor Sampler::colorAt(float x, float y);
          *
          * How to handle High DPI:
          *  - sampleRect - is in device independent pixels coordinates space
          *     (amount of space on the widget)
          *  - devicePixelRatioF - the amount of UI scaling
          *  - pixelCache and realPixelCache gets the size of
          *     sampleRect.size()*devicePixelRatioF
          *     and sets the device pixel ratio,
          *     and color samplers need to take it into account.
          *  That way you can paint on the cache the same way you'd paint on a low dpi display
          *    and then just use painter->drawImage() and it works.
          */
         template <class Sampler>
         static void render(Sampler *sampler,
                            const KisDisplayColorConverter *converter,
                            const QRect &sampleRect,
                            KisPaintDeviceSP &realPixelCache,
                            QImage &pixelCache,
                            QPoint &pixelCacheOffset,
                            qreal devicePixelRatioF)
             {
                 const KoColorSpace *cacheColorSpace = converter->paintingColorSpace();
                 const int pixelSize = cacheColorSpace->pixelSize();
 
                 if (!realPixelCache || realPixelCache->colorSpace() != cacheColorSpace) {
                     realPixelCache = new KisPaintDevice(cacheColorSpace);
                 }
 
                 KoColor color;
 
                 QRect sampleRectHighDPI = QRect(sampleRect.topLeft(), sampleRect.size()*devicePixelRatioF);
                 KisSequentialIterator it(realPixelCache, sampleRectHighDPI);
 
                 while (it.nextPixel()) {
                     color = sampler->colorAt(it.x()/devicePixelRatioF, it.y()/devicePixelRatioF);
                     memcpy(it.rawData(), color.data(), pixelSize);
                 }
 
 
                 // NOTE: toQImage() function of the converter copies exactBounds() only!
                 pixelCache = converter->toQImage(realPixelCache);
                 pixelCache.setDevicePixelRatio(devicePixelRatioF);
                 pixelCacheOffset = realPixelCache->exactBounds().topLeft()/devicePixelRatioF - sampleRect.topLeft();
         }
     };
 }
 
 #endif /* __KIS_ACS_PIXEL_CACHE_RENDERER_H */