Question

是否可以通过php在亮度上对颜色进行排序。

现在我用这个函数计算差值

public function colorDiff($rgb1,$rgb2)
{
        // do the math on each tuple
        // could use bitwise operates more efeceintly but just do strings for now.
        $red1 = hexdec(substr($rgb1,0,2));
        $green1 = hexdec(substr($rgb1,2,2));
        $blue1 = hexdec(substr($rgb1,4,2));

        $red2 = hexdec(substr($rgb2,0,2));
        $green2 = hexdec(substr($rgb2,2,2));
        $blue2 = hexdec(substr($rgb2,4,2));

        return abs($red1 - $red2) + abs($rgreen1 - $green2) + abs($blue2 - $blue2) ;

}

但这不会对亮度的图像进行排序。

Answer 1

您可以使用以下公式获得合适的亮度值（perceived lightness）：

$red * .3 + $green * .59 + $blue * .11

引用链接文章：

对这些重量的解释是由于对于等量的颜色，眼睛对绿色最敏感，然后是红色，然后是蓝色。这意味着，对于等量的绿色和蓝色光，绿色将显得更亮。“

Answer 2

1）你需要数学定义轻盈。所以它应该从颜色到整数来表示亮度

2）如果您认为（例如）它是$ red + $ green + $ blue的总和，您可以使用这种排序

 usort($colors,function ($rgb1,$rgb2){
    $red1 = hexdec(substr($rgb1,0,2));
    $green1 = hexdec(substr($rgb1,2,2));
    $blue1 = hexdec(substr($rgb1,4,2));

    $red2 = hexdec(substr($rgb2,0,2));
    $green2 = hexdec(substr($rgb2,2,2));
    $blue2 = hexdec(substr($rgb2,4,2));

    return ($red1+$green1+$blue1) - ($reg2+$green2+$blue2);
 })

Answer 3

您可以将RGB颜色转换为HSL颜色空间以及L组件上的排序： http://axonflux.com/handy-rgb-to-hsl-and-rgb-to-hsv-color-model-c

Php功能顺序颜色由亮度

3 个答案: