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Faster image processing

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This commit is contained in:
Luis Ángel San Martín 2024-08-31 17:11:28 +02:00
parent b12e1212b5
commit 68bf76a8b2
1 changed files with 7 additions and 14 deletions
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21
image_processing/resize_image.cpp
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@ -352,7 +352,6 @@ QVector<QRgb> processRow(int y, int targetWidth, int targetHeight, const QImage
#endif #endif
// Main function to scale the image
QImage scaleImageLanczos(const QImage &sourceImage, int targetWidth, int targetHeight, int a = 3) QImage scaleImageLanczos(const QImage &sourceImage, int targetWidth, int targetHeight, int a = 3)
{ {
QImage targetImage(targetWidth, targetHeight, QImage::Format_ARGB32); QImage targetImage(targetWidth, targetHeight, QImage::Format_ARGB32);
@ -362,24 +361,18 @@ QImage scaleImageLanczos(const QImage &sourceImage, int targetWidth, int targetH
rows[i] = i; rows[i] = i;
} }
// Use a QVector to store the results of the processed rows uchar *imgBits = targetImage.bits();
QVector<QVector<QRgb>> results(targetHeight); int bytesPerLine = targetImage.bytesPerLine();
// Launch concurrent tasks using QtConcurrent::map, which modifies the container in place QtConcurrent::blockingMap(rows, [targetWidth, targetHeight, &sourceImage, a, imgBits, bytesPerLine](int y) {
QtConcurrent::blockingMap(rows, [&results, targetWidth, targetHeight, &sourceImage, a](int y) { QVector<QRgb> rowPixels = processRow(y, targetWidth, targetHeight, sourceImage, a);
results[y] = processRow(y, targetWidth, targetHeight, sourceImage, a); uchar *rowPtr = imgBits + y * bytesPerLine;
std::memcpy(rowPtr, rowPixels.constData(), targetWidth * sizeof(QRgb));
}); });
// Set the pixels in the target image
for (int y = 0; y < targetHeight; ++y) {
const QVector<QRgb> &row = results[y];
for (int x = 0; x < targetWidth; ++x) {
targetImage.setPixel(x, y, row[x]);
}
}
return targetImage; return targetImage;
} }
QPixmap scalePixmapLanczosQt(const QPixmap &pixmap, int targetWidth, int targetHeight, int a) QPixmap scalePixmapLanczosQt(const QPixmap &pixmap, int targetWidth, int targetHeight, int a)
{ {
QImage sourceImage = pixmap.toImage(); QImage sourceImage = pixmap.toImage();