CMKY与RGB的转换

 　　有朋友可能会问，CMYK是浮点数，要保存怎么办？可以乘0xFF(255)。

void RGB2CMYK(int red, int green, int blue,
double& c, double& m, double& y, double& k)
{
    c = (0xFF - red  ) / 255.0;
    m = (0xFF - green) / 255.0;
    y = (0xFF - blue ) / 255.0;
    k = Math.min(c, Math.min(m, y));

    if (k == 1.0)
    {
        c = m = y = 0;
    }
    else
    {
        c = (c - k) / (1 - k);
        m = (m - k) / (1 - k);
        y = (y - k) / (1 - k);
    }
}


void CMYK2RGB(double c, double m, double y, double k, int& r, int& g, int& b)
{
    r = (int)((1.0 - c) * (1.0 - k) * 0xFF);
    g = (int)((1.0 - m) * (1.0 - k) * 0xFF);
    b = (int)((1.0 - y) * (1.0 - k) * 0xFF);
}