[开源]Qt图片调整之对比度调节

QImage AdjustContrast(QImage Img, int iContrastValue)
{
    int pixels = Img.width() * Img.height();
    unsigned int *data = (unsigned int *)Img.bits();

    int red, green, blue, nRed, nGreen, nBlue;

    if (iContrastValue > 0 && iContrastValue < 100)
    {
        float param = 1 / (1 - iContrastValue / 100.0) - 1;

        for (int i = 0; i < pixels; ++i)
        {
            nRed = qRed(data[i]);
            nGreen = qGreen(data[i]);
            nBlue = qBlue(data[i]);

            red = nRed + (nRed - 127) * param;
            red = (red < 0x00) ? 0x00 : (red > 0xff) ? 0xff : red;
            green = nGreen + (nGreen - 127) * param;
            green = (gre