Qt图片调整之饱和度调节

来源：互联网发布：硬笔书法网络课程编辑：程序博客网时间：2024/06/05 10:12
原理较简单不作详述
QImage AdjustSaturation(QImage Img, int iSaturateValue){    int red, green, blue, nRed, nGreen, nBlue;    int pixels = Img.width() * Img.height();    unsigned int *data = (unsigned int *)Img.bits();    float Increment = iSaturateValue/100.0;    float delta = 0;    float minVal, maxVal;    float L, S;    float alpha;    for (int i = 0; i < pixels; ++i)    {        nRed = qRed(data[i]);        nGreen = qGreen(data[i]);        nBlue = qBlue(data[i]);        minVal = std::min(std::min(nRed, nGreen), nBlue);        maxVal = std::max(std::max(nRed, nGreen), nBlue);        delta = (maxVal - minVal) / 255.0;        L = 0.5*(maxVal + minVal) / 255.0;        S = std::max(0.5*delta / L, 0.5*delta / (1 - L));        if (Increment > 0)        {            alpha = std::max(S, 1 - Increment);            alpha = 1.0 / alpha - 1;            red = nRed + (nRed - L*255.0)*alpha;            red = (red < 0x00) ? 0x00 : (red > 0xff) ? 0xff : red;            green = nGreen + (nGreen - L*255.0)*alpha;            green = (green < 0x00) ? 0x00 : (green > 0xff) ? 0xff : green;            blue = nBlue + (nBlue - L*255.0)*alpha;            blue = (blue < 0x00) ? 0x00 : (blue > 0xff) ? 0xff : blue;        }        else        {            alpha = Increment;            red = L*255.0 + (nRed - L * 255.0)*(1+alpha);            red = (red < 0x00) ? 0x00 : (red > 0xff) ? 0xff : red;            green = L*255.0 + (nGreen - L * 255.0)*(1+alpha);            green = (green < 0x00) ? 0x00 : (green > 0xff) ? 0xff : green;            blue = L*255.0 + (nBlue - L * 255.0)*(1+alpha);            blue = (blue < 0x00) ? 0x00 : (blue > 0xff) ? 0xff : blue;        }        data[i] = qRgba(red, green, blue, qAlpha(data[i]));    }    return Img;}
0 0