通过近似选择颜色区域

Question

有谁知道图像处理器（如 Photoshop 或 Gimp）用来选择具有相似颜色的区域的方法名称？另外，任何人都可以指出一些链接来解释这个方法（如果可能的话，用 C++ 代码）？

Answer 1

如果您有兴趣，这可能是一个检查颜色是否与另一种颜色相似的示例。 它还像 gimp 和 paint.net 的魔杖一样使用容差。

但是，此示例比较的是价值差异，而不是颜色或亮度的差异。

/*\ function to check if the color at this position is similar to the one you chose
|*  Parameters:
|*    int color       - the value of the color of choice
|*    int x           - position x of the pixel
|*    int y           - position y of the pixel
|*    float tolerance - how much this pixels color can differ to still be considered similar
\*/

bool isSimilar(int color, int x, int y, float tolerance)
{
    // calculate difference between your color and the max value color can have
    int diffMaxColor = 0xFFFFFF - color;
    // set the minimum difference between your color and the minimum value of color
    int diffMinColor = color;
    // pseudo function to get color ( could return 'colorMap[y * width + x];')
    int chkColor = getColor(x, y); 
    // now checking whether or not the color of the pixel is in the range between max and min with tolerance
    if(chkColor > (color + (diffMaxColor * tolerance)) || chkColor < ((1 - tolerance) * diffMinColor))
    {
        // the color is outside our tolerated range
        return false;
    }
    // the color is inside our tolerated range
    return true;
}