QImage Rotation and Translation & Invert Specific Colors

[karankumar1609]

reference from THIS

#include <QtGui>
 
    int main(int argc, char** argv)
    {
        QApplication app(argc, argv);
        QPixmap pixmap("logo.png");
        QImage image = pixmap.toImage();
        QRgb col;
        int gray;
        int width = pixmap.width();
        int height = pixmap.height();
        for (int i = 0; i < width; ++i)
        {
            for (int j = 0; j < height; ++j)
            {
                col = image.pixel(i, j);
                gray = qGray(col);
                image.setPixel(i, j, qRgb(gray, gray, gray));
            }
        }
        pixmap = pixmap.fromImage(image);
        QLabel label;
        label.setPixmap(pixmap);
        label.show();
        return app.exec();
    }

#include <QtGui>
     
    int main(int argc, char** argv)
    {
        QApplication app(argc, argv);
        QPixmap pixmap("logo.png");
        QImage image = pixmap.toImage();
        QRgb col;
        int gray;
        int width = pixmap.width();
        int height = pixmap.height();
        for (int i = 0; i < width; ++i)
        {
            for (int j = 0; j < height; ++j)
            {
                col = image.pixel(i, j);
                gray = qGray(col);
                image.setPixel(i, j, qRgb(gray, gray, gray));
            }
        }
        pixmap = pixmap.fromImage(image);
        QLabel label;
        label.setPixmap(pixmap);
        label.show();
        return app.exec();
    }

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following example convert the image into an gray scale image.
HERE:

gray = qGray(col);

convert the QRgb color set into a gray color.
You can use QRed, QBlue etc. according to your need.