File indexing completed on 2024-06-16 04:16:49

 /*
  * KDE. Krita Project.
  *
  * SPDX-FileCopyrightText: 2021 Deif Lou <ginoba@gmail.com>
  *
  * SPDX-License-Identifier: GPL-2.0-or-later
  */
 
 #include <algorithm>
 #include <limits>
 #include <cmath>
 
 #include "KisScreentoneScreentoneFunctions.h"
 #include "KisScreentoneGeneratorTemplate.h"
 
 KisScreentoneGeneratorTemplate::KisScreentoneGeneratorTemplate(const KisScreentoneGeneratorConfigurationSP config)
 {
     const int pattern = config->pattern();
     const int shape = config->shape();
     const int interpolation = config->interpolation();
 
     if (pattern == KisScreentonePatternType_Dots) {
         if (shape == KisScreentoneShapeType_RoundDots) {
             if (interpolation == KisScreentoneInterpolationType_Linear) {
                 KisScreentoneScreentoneFunctions::DotsRoundLinear screentoneFunction;
                 makeTemplate(config, screentoneFunction);
             } else if (interpolation == KisScreentoneInterpolationType_Sinusoidal) {
                 KisScreentoneScreentoneFunctions::DotsRoundSinusoidal screentoneFunction;
                 makeTemplate(config, screentoneFunction);
             }
         } else if (shape == KisScreentoneShapeType_EllipseDotsLegacy) {
             if (interpolation == KisScreentoneInterpolationType_Linear) {
                 KisScreentoneScreentoneFunctions::DotsEllipseLinear_Legacy screentoneFunction;
                 makeTemplate(config, screentoneFunction);
             } else if (interpolation == KisScreentoneInterpolationType_Sinusoidal) {
                 KisScreentoneScreentoneFunctions::DotsEllipseSinusoidal_Legacy screentoneFunction;
                 makeTemplate(config, screentoneFunction);
             }
         } else if (shape == KisScreentoneShapeType_EllipseDots) {
             if (interpolation == KisScreentoneInterpolationType_Linear) {
                 KisScreentoneScreentoneFunctions::DotsEllipseLinear screentoneFunction;
                 makeTemplate(config, screentoneFunction);
             } else if (interpolation == KisScreentoneInterpolationType_Sinusoidal) {
                 KisScreentoneScreentoneFunctions::DotsEllipseSinusoidal screentoneFunction;
                 makeTemplate(config, screentoneFunction);
             }
         } else if (shape == KisScreentoneShapeType_DiamondDots) {
             KisScreentoneScreentoneFunctions::DotsDiamond screentoneFunction;
             makeTemplate(config, screentoneFunction);
         } else if (shape == KisScreentoneShapeType_SquareDots) {
             KisScreentoneScreentoneFunctions::DotsSquare screentoneFunction;
             makeTemplate(config, screentoneFunction);
         }
     } else if (pattern == KisScreentonePatternType_Lines) {
         if (shape == KisScreentoneShapeType_StraightLines) {
             if (interpolation == KisScreentoneInterpolationType_Linear) {
                 KisScreentoneScreentoneFunctions::LinesStraightLinear screentoneFunction;
                 makeTemplate(config, screentoneFunction);
             } else if (interpolation == KisScreentoneInterpolationType_Sinusoidal) {
                 KisScreentoneScreentoneFunctions::LinesStraightSinusoidal screentoneFunction;
                 makeTemplate(config, screentoneFunction);
             }
         } else if (shape == KisScreentoneShapeType_SineWaveLines) {
             if (interpolation == KisScreentoneInterpolationType_Linear) {
                 KisScreentoneScreentoneFunctions::LinesSineWaveLinear screentoneFunction;
                 makeTemplate(config, screentoneFunction);
             } else if (interpolation == KisScreentoneInterpolationType_Sinusoidal) {
                 KisScreentoneScreentoneFunctions::LinesSineWaveSinusoidal screentoneFunction;
                 makeTemplate(config, screentoneFunction);
             }
         } else if (shape == KisScreentoneShapeType_TriangularWaveLines) {
             if (interpolation == KisScreentoneInterpolationType_Linear) {
                 KisScreentoneScreentoneFunctions::LinesTriangularWaveLinear screentoneFunction;
                 makeTemplate(config, screentoneFunction);
             } else if (interpolation == KisScreentoneInterpolationType_Sinusoidal) {
                 KisScreentoneScreentoneFunctions::LinesTriangularWaveSinusoidal screentoneFunction;
                 makeTemplate(config, screentoneFunction);
             }
         } else if (shape == KisScreentoneShapeType_SawtoothWaveLines) {
             if (interpolation == KisScreentoneInterpolationType_Linear) {
                 KisScreentoneScreentoneFunctions::LinesSawToothWaveLinear screentoneFunction;
                 makeTemplate(config, screentoneFunction);
             } else if (interpolation == KisScreentoneInterpolationType_Sinusoidal) {
                 KisScreentoneScreentoneFunctions::LinesSawToothWaveSinusoidal screentoneFunction;
                 makeTemplate(config, screentoneFunction);
             }
         } else if (shape == KisScreentoneShapeType_CurtainsLines) {
             if (interpolation == KisScreentoneInterpolationType_Linear) {
                 KisScreentoneScreentoneFunctions::LinesCurtainsLinear screentoneFunction;
                 makeTemplate(config, screentoneFunction);
             } else if (interpolation == KisScreentoneInterpolationType_Sinusoidal) {
                 KisScreentoneScreentoneFunctions::LinesCurtainsSinusoidal screentoneFunction;
                 makeTemplate(config, screentoneFunction);
             }
         }
     }
 }
 
 // The following utility classes are used to get the preferred order in which
 // the pixels of a cell should be "turn on" based on the distance to the center
 // of the shape (center of the dot, center of the line, etc.). For simplicity
 // they just use the screentone function "as is" except for the round/ellipse
 // dot sinusoidal, which use the linear counterpart (to get an ordering that
 // seems to grow radially)
 template <typename ScreentoneFunction>
 struct LightUpOrderingFunction : public ScreentoneFunction
 {};
 template <>
 struct LightUpOrderingFunction<KisScreentoneScreentoneFunctions::DotsRoundSinusoidal>
     : public KisScreentoneScreentoneFunctions::DotsRoundLinear
 {};
 template <>
 struct LightUpOrderingFunction<KisScreentoneScreentoneFunctions::DotsEllipseSinusoidal>
     : public KisScreentoneScreentoneFunctions::DotsEllipseLinear
 {};
 
 template <typename ScreentoneFunction>
 void KisScreentoneGeneratorTemplate::makeTemplate(const KisScreentoneGeneratorConfigurationSP config,
                                                   ScreentoneFunction screentoneFunction)
 {
     // NOTE: In the following, the word "screen" is used to mean the dot screen
     // of the screentone (the grid of dots/cells)
 
     // Get transformation parameters
     qreal sizeX, sizeY;
     const int alignX = config->alignToPixelGrid() ? config->alignToPixelGridX() : 1;
     const int alignY = config->alignToPixelGrid() ? config->alignToPixelGridY() : 1;
     if (config->sizeMode() == KisScreentoneSizeMode_PixelBased) {
         const bool constrainSize = config->constrainSize();
         sizeX = config->sizeX();
         // Ensure that the size y component is equal to the x component
         // if keepSizeSquare is true
         sizeY = constrainSize ? sizeX : config->sizeY();
     } else {
         const qreal resolution = config->resolution();
         const bool constrainFrequency = config->constrainFrequency();
         const qreal frequencyX = config->frequencyX();
         // Ensure that the frequency y component is equal to the x component
         // if constrainFrequency is true
         const qreal frequencyY = constrainFrequency ? frequencyX : config->frequencyY();
         sizeX = qMax(1.0, resolution / frequencyX);
         sizeY = qMax(1.0, resolution / frequencyY);
     }
     const qreal positionX = config->alignToPixelGrid() ? qRound(config->positionX()) : config->positionX();
     const qreal positionY = config->alignToPixelGrid() ? qRound(config->positionY()) : config->positionY();
     m_screenPosition = QPointF(positionX, positionY);
     const qreal shearX = config->shearX();
     const qreal shearY = config->shearY();
     const qreal rotation = config->rotation();
     // Construct image<->screen transforms
     m_imageToScreenTransform.shear(shearX, shearY);
     m_imageToScreenTransform.scale(qFuzzyIsNull(sizeX) ? 0.0 : 1.0 / sizeX, qFuzzyIsNull(sizeY) ? 0.0 : 1.0 / sizeY);
     m_imageToScreenTransform.rotate(rotation);
     m_imageToScreenTransform.translate(positionX, positionY);
     QTransform screenToImage;
     screenToImage.rotate(-rotation);
     screenToImage.scale(sizeX, sizeY);
     screenToImage.shear(-shearX, -shearY);
     // u1 is the unaligned vector that goes from the origin to the top-right
     // corner of the macrocell. v1 is the aligned version
     // u2 is the unaligned vector that goes from the origin to the bottom-left
     // corner of the macrocell. v2 is the aligned version.
     // At this point we assume the macrocell will have a minimum size given by
     // the alignment
     const QPointF u1 = screenToImage.map(QPointF(static_cast<qreal>(alignX), 0.0));
     const QPointF u2 = screenToImage.map(QPointF(0.0, static_cast<qreal>(alignY)));
     QPointF v1(qRound(u1.x()), qRound(u1.y()));
     QPointF v2(qRound(u2.x()), qRound(u2.y()));
     // If the following condition is met, that means that the screen is
     // transformed in such a way that the cell corners are colinear so we move
     // v1 or v2 to a neighbor position and give the cell some area
     if (qFuzzyCompare(v1.y() * v2.x(), v2.y() * v1.x()) &&
         !qFuzzyIsNull(v1.x() * v2.x() + v1.y() * v2.y())) {
         // Choose point to move based on distance from non aligned point to
         // aligned point
         const qreal dist1 = kisSquareDistance(u1, v1);
         const qreal dist2 = kisSquareDistance(u2, v2);
         const QPointF *p_u = dist1 > dist2 ? &u1 : &u2;
         QPointF *p_v = dist1 > dist2 ? &v1 : &v2;
         // Then we get the closest pixel aligned point to the current, colinear,
         // point
         QPair<int, qreal> dists[4]{
             {1, kisSquareDistance(*p_u, *p_v + QPointF(0.0, -1.0))},
             {2, kisSquareDistance(*p_u, *p_v + QPointF(1.0, 0.0))},
             {3, kisSquareDistance(*p_u, *p_v + QPointF(0.0, 1.0))},
             {4, kisSquareDistance(*p_u, *p_v + QPointF(-1.0, 0.0))}
         };
         std::sort(
             std::begin(dists), std::end(dists),
             [](const QPair<int, qreal> &a, const QPair<int, qreal> &b)
             {
                 return a.second < b.second;
             }
         );
         // Move the point
         if (dists[0].first == 1) {
             p_v->setY(p_v->y() - 1.0);
         } else if (dists[0].first == 2) {
             p_v->setX(p_v->x() + 1.0);
         } else if (dists[0].first == 3) {
             p_v->setY(p_v->y() + 1.0);
         } else {
             p_v->setX(p_v->x() - 1.0);
         }
     }
     qreal v1Length = std::sqrt(v1.x() * v1.x() + v1.y() * v1.y());
     qreal v2Length = std::sqrt(v2.x() * v2.x() + v2.y() * v2.y());
     // The macrocell will have a minimum size derived from the alignment but if
     // its size doesn't contain enough pixels to cover all the range of
     // intensities we expand it.
     QSize macrocellTiles(1, 1);
     while (macrocellTiles.width() * v1Length * macrocellTiles.height() * v2Length < 256) {
         if (macrocellTiles.width() * v1Length > macrocellTiles.height() * v2Length) {
             macrocellTiles.setHeight(macrocellTiles.height() + 1);
         } else {
             macrocellTiles.setWidth(macrocellTiles.width() + 1);
         }
     }
     // Get size in cells of the macrocell
     m_macrocellSize = QSize(alignX * macrocellTiles.width(), alignY * macrocellTiles.height());
     const QSizeF macrocellSizeF = m_macrocellSize;
     // Scale the top and left vectors and lengths to the final macrocell size
     v1 *= macrocellTiles.width();
     v2 *= macrocellTiles.height();
     v1Length *= macrocellTiles.width();
     v2Length *= macrocellTiles.height();
     // Compute other useful quantities
     const QPointF v3 = v1 + v2;
     const QPointF l1 = v1;
     const QPointF l2 = v2;
     const QPointF l3 = -v1;
     const QPointF l4 = -v2;
     const qreal v1MicrocellLength = v1Length / macrocellSizeF.width();
     const qreal v2MicrocellLength = v2Length / macrocellSizeF.height();
     m_v1 = v1;
     m_v2 = v2;
     // Construct template<->screen transforms
     const QPolygonF quad(
         {
             QPointF(0.0, 0.0),
             v1 / macrocellSizeF.width(),
             v1 / macrocellSizeF.width() + v2 / macrocellSizeF.height(),
             v2 / macrocellSizeF.height()
         }
     );
     QTransform::quadToSquare(quad, m_templateToScreenTransform);
     m_screenToTemplateTransform = m_templateToScreenTransform.inverted();
 
     // Construct the template
 
     // Compute template dimensions
     const QPoint topLeft(
         static_cast<int>(qMin(0.0, qMin(v1.x(), qMin(v2.x(), v1.x() + v2.x())))),
         static_cast<int>(qMin(0.0, qMin(v1.y(), qMin(v2.y(), v1.y() + v2.y()))))
     );
     const QPoint bottomRight(
         static_cast<int>(qMax(0.0, qMax(v1.x(), qMax(v2.x(), v1.x() + v2.x())))),
         static_cast<int>(qMax(0.0, qMax(v1.y(), qMax(v2.y(), v1.y() + v2.y()))))
     );
     // Add an 1 pixel border around the template, useful for bilinear interpolation
     m_templateSize = QSize(bottomRight.x() - topLeft.x() + 2, bottomRight.y() - topLeft.y() + 2);
     m_originOffset = -topLeft + QPoint(1, 1);
 
     m_templateData = QVector<qreal>(m_templateSize.width() * m_templateSize.height(), -1.0);
 
     // Convenience struct to store some info for a single pixel during the
     // construction of the template
     struct AuxiliaryPoint
     {
         // Pixel index with respect to the template image
         int templatePixelIndex;
         // An pseudo index that orders the pixel with respect to a cell from
         // top-left to bottom right
         qreal microcellPixelIndex;
         // Spot function value at the top-left corner of the pixel
         qreal valueAtCorner;
         // Spot function value at the center of the pixel
         qreal valueAtCenter;
         // Distance from the "center" of the shape to the top-left corner of the
         // pixel
         qreal distanceToCorner;
         // Distance from the "center" of the shape to the center of the pixel
         qreal distanceToCenter;
     };
     // Convenience struct to store some info for a single microcell during the
     // construction of the template
     struct AuxiliaryMicrocell
     {
         // The order in which this cell should light up pixels with respect to
         // the other cells
         int index;
         // List of points in this cell
         QVector<AuxiliaryPoint> auxiliaryPoints;
     };
 
     QVector<AuxiliaryMicrocell> auxiliaryMicrocells(m_macrocellSize.width() * m_macrocellSize.height());
 
     // Set the ordered index for each auxiliary microcell
     // Use makeCellOrderList to shuffle the microcell activation order so that
     // they follow bayer matrix like patters. This allows to grow the
     // microcells in a way that they don't visually cluster
     QVector<int> microcellIndices = makeCellOrderList(m_macrocellSize.width(), m_macrocellSize.height());
     for (int i = 0; i < auxiliaryMicrocells.size(); ++i) {
         auxiliaryMicrocells[i].index = microcellIndices[i];
     }
 
     // "Rasterize" the macrocell: get all the points of the template that lie
     // inside the macrocell and store them as auxiliary points that contain
     // some info useful for sorting later.
     // The template will have a representation of the complete transformed
     // macrocell, but also some other areas outside (parts of adjacent
     // macrocells) if, for example, the screen is rotated. To get later a value
     // from the template we only use the pixels inside the macrocell, but the
     // pixels outside are useful to perform bilinear interpolation
 
     // Get the horizontal and vertical points at cell corners
     QVector<QPointF> horizontalCellPositions;
     for (int i = -1; i <= m_macrocellSize.width() + 1; ++i) {
         horizontalCellPositions.append(v1 / static_cast<qreal>(m_macrocellSize.width()) * static_cast<qreal>(i));
     }
     QVector<QPointF> verticalCellPositions;
     for (int i = -1; i <= m_macrocellSize.height() + 1; ++i) {
         verticalCellPositions.append(v2 / static_cast<qreal>(m_macrocellSize.height()) * static_cast<qreal>(i));
     }
 
     int totalNumberOfAuxiliaryPoints = 0;
 
     // Convenience function that tells if a pixel should belong to the left or
     // to the right side of an edge. Used only when the point lies exactly in
     // the edge
     auto pointBelongsToLeftSideOfEdge = [](const QPointF &point, const QPointF &edgeStart, const QPointF &edgeDirection) -> bool
     {
         const qreal r = (point.x() - edgeStart.x()) * edgeDirection.y() - (point.y() - edgeStart.y()) * edgeDirection.x();
         return (r == 0.0) && ((edgeDirection.y() == 0.0 && edgeDirection.x() > 0.0) || (edgeDirection.y() > 0.0));
     };
 
     // This is used to get an estimate of how far a given point is from the
     // "center" of the shape (center of dot, center of line, etc.)
     LightUpOrderingFunction<ScreentoneFunction> lightUpOrderingFunction;
 
     // Visit all the pixels on the template and add an auxiliary point for each
     // one that falls inside the macrocell
     for (int i = 0; i < m_templateData.size(); ++i) {
         // Transform the pixel position from template to screen coordinates.
         // We transform both the point at the pixel corner (used for sampling
         // the screentone function) and the point at pixel center (used to
         // compute to which cell the pixel belongs)
         const int templateY = i / m_templateSize.width();
         const int templateX = i - m_templateSize.width() * templateY;
         const QPointF pixelCornerPoint(
             static_cast<qreal>(templateX - m_originOffset.x()),
             static_cast<qreal>(templateY - m_originOffset.y())
         );
         const QPointF pixelCenterPoint(pixelCornerPoint + QPointF(0.5, 0.5));
         const QPointF pixelCenterScreenPoint = m_templateToScreenTransform.map(pixelCenterPoint);
         const QPointF macrocellPos(pixelCenterScreenPoint.x() * v1MicrocellLength, pixelCenterScreenPoint.y() * v2MicrocellLength);
         // Initial estimate for the microcell position
         int microcellX = static_cast<int>(std::floor(macrocellPos.x() * static_cast<qreal>(m_macrocellSize.width()) / v1Length));
         int microcellY = static_cast<int>(std::floor(macrocellPos.y() * static_cast<qreal>(m_macrocellSize.height()) / v2Length));
         // Discard this pixel if it is clearly outside the macrocell
         if (microcellX < -1 || microcellX > m_macrocellSize.width() ||
             microcellY < -1 || microcellY > m_macrocellSize.height()) {
             continue;
         }
         // If the pixel center lies exactly in a border between cells we must
         // decide if it should belong to a neighbor cell. This is an usual
         // problem in rasterization. Here we treat the pixel as if it belonged
         const QPointF topLeftCorner(horizontalCellPositions[microcellX + 1] + verticalCellPositions[microcellY + 1]);
         const QPointF topRightCorner(horizontalCellPositions[microcellX + 1 + 1] + verticalCellPositions[microcellY + 1]);
         const QPointF bottomRightCorner(horizontalCellPositions[microcellX + 1 + 1] + verticalCellPositions[microcellY + 1 + 1]);
         const QPointF bottomLeftCorner(horizontalCellPositions[microcellX + 1] + verticalCellPositions[microcellY + 1 + 1]);
         if (pointBelongsToLeftSideOfEdge(pixelCenterPoint, topLeftCorner, l1)) {
             --microcellY;
         }
         if (pointBelongsToLeftSideOfEdge(pixelCenterPoint, topRightCorner, l2)) {
             ++microcellX;
         }
         if (pointBelongsToLeftSideOfEdge(pixelCenterPoint, bottomRightCorner, l3)) {
             ++microcellY;
         }
         if (pointBelongsToLeftSideOfEdge(pixelCenterPoint, bottomLeftCorner, l4)) {
             --microcellX;
         }
         // Discard the pixel since the modified microcell position is for a cell
         // that belongs to another macrocell
         if (microcellX < 0 || microcellX >= m_macrocellSize.width() ||
             microcellY < 0 || microcellY >= m_macrocellSize.height()) {
             continue;
         }
         // Add the pixel to the auxiliary points collection
         const int microcellIndex = microcellY * m_macrocellSize.width() + microcellX;
         const qreal microcellPixelIndexX = macrocellPos.x() - static_cast<qreal>(microcellX) * v1MicrocellLength;
         const qreal microcellPixelIndexY = macrocellPos.y() - static_cast<qreal>(microcellY) * v2MicrocellLength;
         const qreal microcellPixelIndex = microcellPixelIndexY * v1MicrocellLength + microcellPixelIndexX;
         const QPointF pixelCornerScreenPoint = m_templateToScreenTransform.map(pixelCornerPoint);
         auxiliaryMicrocells[microcellIndex].auxiliaryPoints.push_back(
             {
                 i,
                 microcellPixelIndex,
                 screentoneFunction(pixelCornerScreenPoint.x(), pixelCornerScreenPoint.y()),
                 screentoneFunction(pixelCenterScreenPoint.x(), pixelCenterScreenPoint.y()),
                 lightUpOrderingFunction(pixelCornerScreenPoint.x(), pixelCornerScreenPoint.y()),
                 lightUpOrderingFunction(pixelCenterScreenPoint.x(), pixelCenterScreenPoint.y()),
             }
         );
         ++totalNumberOfAuxiliaryPoints;
     }
 
     // Sort the auxiliary points of each auxiliary microcell with respect to
     // different criteria
     for (int i = 0; i < auxiliaryMicrocells.size(); ++i) {
         std::sort(auxiliaryMicrocells[i].auxiliaryPoints.begin(), auxiliaryMicrocells[i].auxiliaryPoints.end(),
             [](const AuxiliaryPoint &a, const AuxiliaryPoint &b) {
                 if (qFuzzyCompare(a.valueAtCorner, b.valueAtCorner)) {
                     if (qFuzzyCompare(a.valueAtCenter, b.valueAtCenter)) {
                         if (qFuzzyCompare(a.distanceToCenter, b.distanceToCenter)) {
                             if (qFuzzyCompare(a.distanceToCorner, b.distanceToCorner)) {
                                 return a.microcellPixelIndex < b.microcellPixelIndex;
                             }
                             return a.distanceToCorner < b.distanceToCorner;
                         }
                         return a.distanceToCenter < b.distanceToCenter;
                     }
                     return a.valueAtCenter < b.valueAtCenter;
                 }
                 return a.valueAtCorner < b.valueAtCorner;
             }
         );
     }
 
     // Sort the auxiliary microcells themselves
     std::sort(auxiliaryMicrocells.begin(), auxiliaryMicrocells.end(),
         [](const AuxiliaryMicrocell &a, const AuxiliaryMicrocell &b) {
             return a.index < b.index;
         }
     );
 
     // Fill the template pixels inside the macrocell with the sorted auxiliary
     // points
     {
         int macrocellPixelIndex = 0;
         QVector<int> microcellPixelIndices(auxiliaryMicrocells.size());
         while (macrocellPixelIndex < totalNumberOfAuxiliaryPoints) {
             for (int i = 0; i < auxiliaryMicrocells.size(); ++i) {
                 if (microcellPixelIndices[i] == auxiliaryMicrocells[i].auxiliaryPoints.size()) {
                     continue;
                 }
                 m_templateData[auxiliaryMicrocells[i].auxiliaryPoints[microcellPixelIndices[i]].templatePixelIndex] =
                     totalNumberOfAuxiliaryPoints - 1 == 0 ? 0 // to avoid UB from division by zero
                                                           : static_cast<qreal>(macrocellPixelIndex) / static_cast<qreal>(totalNumberOfAuxiliaryPoints - 1);
                 ++microcellPixelIndices[i];
                 ++macrocellPixelIndex;
             }
         }
     }
 
     // Fill the rest of the template pixels by copying the values from the
     // already set ones
     for (int i = 0; i < m_templateData.size(); ++i) {
         if (m_templateData[i] < 0.0) {
             int templateY = i / m_templateSize.width();
             int templateX = i - m_templateSize.width() * templateY;
             QPointF pixelCenterPoint(
                 static_cast<qreal>(templateX - m_originOffset.x()) + 0.5,
                 static_cast<qreal>(templateY - m_originOffset.y()) + 0.5
             );
             const QPointF pixelCenterScreenPoint = m_templateToScreenTransform.map(pixelCenterPoint);
             const qreal a = -std::floor(pixelCenterScreenPoint.x() / macrocellSizeF.width());
             const qreal b = -std::floor(pixelCenterScreenPoint.y() / macrocellSizeF.height());
             pixelCenterPoint += QPointF(a * v1.x() + b * v2.x(), a * v1.y() + b * v2.y());
 
             int x = static_cast<int>(std::floor(pixelCenterPoint.x())) + m_originOffset.x();
             int y = static_cast<int>(std::floor(pixelCenterPoint.y())) + m_originOffset.y();
             int macrocellPointIndex = y * m_templateSize.width() + x;
 
             // if for some reason the target reference pixel is not set, we try
             // find another one just by wrapping around the macrocell
             if (m_templateData[macrocellPointIndex] < 0.0) {
                 if (pointBelongsToLeftSideOfEdge(pixelCenterPoint, QPointF(0.0, 0.0), l1)) {
                     pixelCenterPoint += v2;
                 }
                 if (pointBelongsToLeftSideOfEdge(pixelCenterPoint, v1, l2)) {
                     pixelCenterPoint -= v1;
                 }
                 if (pointBelongsToLeftSideOfEdge(pixelCenterPoint, v3, l3)) {
                     pixelCenterPoint -= v2;
                 }
                 if (pointBelongsToLeftSideOfEdge(pixelCenterPoint, v2, l4)) {
                     pixelCenterPoint += v1;
                 }
                 templateX = static_cast<int>(std::floor(pixelCenterPoint.x())) + m_originOffset.x();
                 templateY = static_cast<int>(std::floor(pixelCenterPoint.y())) + m_originOffset.y();
                 macrocellPointIndex = templateY * m_templateSize.width() + templateX;
             }
 
             m_templateData[i] = m_templateData[macrocellPointIndex];
         }
     }
 }
 
 QVector<int> KisScreentoneGeneratorTemplate::makeCellOrderList(int macrocellColumns, int macrocellRows) const
 {
     if (macrocellColumns == 1 && macrocellRows == 1) {
         return {0};
     }
 
     struct Candidate
     {
         int availableCellIndex;
         int index;
         int distanceSquared;
         int averageDistance;
     };
 
     const int numberOfCells = macrocellColumns * macrocellRows;
     QVector<int> processedCells;
     QVector<int> availableCells;
 
     // Insert the cell with index 0 in the first position
     processedCells.push_back(0);
     for (int i = 1; i < numberOfCells; ++i) {
         availableCells.push_back(i);
     }
 
     while (availableCells.size() > 0) {
         QVector<Candidate> candidates;
         for (int i = 0; i < availableCells.size(); ++i) {
             const int availableCellY = availableCells[i] / macrocellColumns;
             const int availableCellX = availableCells[i] - availableCellY * macrocellColumns;
             int averageDistanceToProcessedCells = 0;
             int minimumDistanceToProcessedCells = std::numeric_limits<int>::max();
             for (int j = 0; j < processedCells.size(); ++j) {
                 const int processedCellY = processedCells[j] / macrocellColumns;
                 const int processedCellX = processedCells[j] - processedCellY * macrocellColumns;
 
                 int distanceToCurrentProcessedCell = std::numeric_limits<int>::max();
                 for (int y = -1; y < 2; ++y) {
                     for (int x = -1; x < 2; ++x) {
                         const int xx = processedCellX + macrocellColumns * x;
                         const int yy = processedCellY + macrocellRows * y;
                         const int deltaX = availableCellX - xx;
                         const int deltaY = availableCellY - yy;
                         const int distanceSquared = deltaX * deltaX + deltaY * deltaY;
                         if (distanceSquared < distanceToCurrentProcessedCell) {
                             distanceToCurrentProcessedCell = distanceSquared;
                         }
                     }
                 }
                 if (distanceToCurrentProcessedCell < minimumDistanceToProcessedCells) {
                     minimumDistanceToProcessedCells = distanceToCurrentProcessedCell;
                 }
                 averageDistanceToProcessedCells += distanceToCurrentProcessedCell;
             }
             candidates.push_back({i, availableCells[i], minimumDistanceToProcessedCells, averageDistanceToProcessedCells});
         }
 
         // Find the best candidate
         int bestCandidateIndex = 0;
         for (int i = 0; i < candidates.size(); ++i) {
             if (candidates[i].distanceSquared > candidates[bestCandidateIndex].distanceSquared ||
                 (candidates[i].distanceSquared == candidates[bestCandidateIndex].distanceSquared &&
                 candidates[i].averageDistance > candidates[bestCandidateIndex].averageDistance)) {
                 bestCandidateIndex = i;
             }
         }
         
         processedCells.push_back(candidates[bestCandidateIndex].index);
         availableCells.remove(candidates[bestCandidateIndex].availableCellIndex);
     }
 
     QVector<int> cellOrderList(numberOfCells);
     for (int i = 1; i < numberOfCells; ++i) {
         cellOrderList[processedCells[i]] = i;
     }
 
     return cellOrderList;
 }