确定 HSL 变化以将一种颜色转换为另一种颜色

I use LESS，我想利用各种综合颜色函数 http://lesscss.org/functions/#color-operations允许仅设置几种基本颜色，然后派生其他变化色相、饱和度、亮度、旋转、 ecc.

假设我的着色器中有以下 2 种颜色（本例中为浅绿色和深绿色）：

@primary-color:    rgb(0,100,60);
@secondary-color:  rgb(185,215,50); 

我只想明确设置@primary-color进而obtain @secondary-color经过适当的 HSL 转换后。 （例如darken(hsl(90, 80%, 50%), 20%) )

有什么办法可以确定我必须应用什么 hsl 设置@primary-color为了获得@secondary-color?

换句话说：

给定 2 个 RGB 颜色定义，有什么方法可以确定两者之间的差异Hue, 饱和 and 亮度，存在于它们之间，表示@secondary-color作为一个变体@primary-color?

P.S.：如有必要，也许还可以借助 Photoshop 等外部工具。

这是计算两种颜色的色相、饱和度和亮度值之间的差异，然后用它根据第一种颜色计算第二种颜色的方法。

各个步骤如下：

• 色差计算：使用以下公式计算两种给定颜色之间的色相、饱和度和亮度差异hue(), saturation() and lightness()功能。这个函数可以单独使用，只是单独输出差异。
• Arriving at the secondary color based on primary: This is a three step process and they are as follows:
  • 使用 调整原色的色调spin()通过传递两种颜色之间的色调差异来实现功能
  • 通过使用调整色调调整颜色（来自上一步）的饱和度saturate() or desaturate()功能取决于差异。
  • 使用 调整饱和度调整颜色的亮度（来自上一步）darken() or lighten()功能取决于差异。

这个答案是对此的较少改编SASS文章 http://thesassway.com/advanced/how-to-programtically-go-from-one-color-to-another-in-sass关于如何从一种颜色计算另一种颜色。

@primary: rgb(0,100,60); /* primary color */
@secondary: rgb(185,215,50); /* secondary color */

/* mixin to calculate the difference between two given colors */
.color-diff(@color1; @color2){ 
    @hueDiff: hue(@color2) - hue(@color1);
    @saturationDiff: saturation(@color1) - saturation(@color2);
    @lightnessDiff: lightness(@color1)- lightness(@color2);

    color1: @color1; color2:@color2; /* just for testing, can be removed */
}

/* Step 1: mixin to adjust the hue difference between the colors */
.adjust-hue(@color; @diff){ 
    @hueAdjusted: spin(@color, @hueDiff);
}

/* Step 2: mixin to adjust the saturation difference */
.adjust-saturation(@color; @diff) when (@diff > 0){
    @satAdjusted: desaturate(@color, abs(@diff)); /* desaturate if diff is greater than 0 */
}
.adjust-saturation(@color; @diff) when not (@diff > 0){
    @satAdjusted: saturate(@color, abs(@diff)); /* saturate if diff is not greater than 0 */
}

/* Step 3: mixin to adjust the lightness diff between the colors */
.adjust-lightness(@color; @diff) when (@diff > 0){
    @lightnessAdjusted: darken(@color, abs(@diff)); /* darken if diff is greater than 0 */
}
.adjust-lightness(@color; @diff) when not (@diff > 0){
    @lightnessAdjusted: lighten(@color, abs(@diff)); /* else lighten */
}

div{
    .color-diff(@primary; @secondary);
    .adjust-hue(@primary; @hueDiff);
    .adjust-saturation(@hueAdjusted; @saturationDiff);
    .adjust-lightness(@satAdjusted; @lightnessDiff);
    color: @lightnessAdjusted; /* final output value */
}

编译后的CSS：

div {
    color1: #00643c;
    color2: #b9d732;
    color: #b9d732;
}

如果您只想获得两种颜色之间的差异，那么您可以使用如下所示的循环来输出色调、饱和度和亮度值的差异。

@color-list-1: rgb(0,100,60), #B0BCA7, #ABCDEF; /* list of primary colors */
@color-list-2: rgb(185,215,50), #BADA55, #FEDCBA; /* list of secondary colors */

#output{
    .loop-colors(@index) when (@index > 0){
        @primary: extract(@color-list-1, @index);
        @secondary: extract(@color-list-2, @index);
        .color-diff(@primary; @secondary);

        /* output the values of the comparison */
        color-comparison-@{index}+: ~"Hue Difference: @{hueDiff}";
        color-comparison-@{index}+: ~"Saturation Difference: @{saturationDiff}";        
        color-comparison-@{index}+: ~"Lightness Difference: @{lightnessDiff}";
        .loop-colors(@index - 1);
    }
    .loop-colors(length(@color-list-1));
}

上面的代码将比较两个列表中的相应值并输出它们的差异，如下所示：

#output {
  color-comparison-3: Hue Difference: -180, Saturation Difference: -29.142857142857153%, Lightness Difference: -5.882352941176478%;
  color-comparison-2: Hue Difference: -19.849624060150404, Saturation Difference: -50.70282063269439%, Lightness Difference: 10.196078431372548%;
  color-comparison-1: Hue Difference: -85.09090909090908, Saturation Difference: 32.65306122448979%, Lightness Difference: -32.352941176470594%;
}