Function grayPixel

source/util/pixelMatch.cpp:67–73

}

double grayPixel(const U8* img, U32 i) {
    double a = double(img[i + 3]) / 255;
    U8 r = blend(img[i + 0], a);
    U8 g = blend(img[i + 1], a);
    U8 b = blend(img[i + 2], a);
    return rgb2y(r, g, b);
}

// check if a pixel is likely a part of anti-aliasing;
// based on "Anti-aliased Pixel and Intensity Slope Detector" paper by V. Vysniauskas, 2009