你如何获得#xxxxxx 颜色的色调? [英] How do you get the hue of a #xxxxxx colour?

问题描述

如何提取以 #rrggbb 给出的颜色的色调分量?

How do you extract the hue component of a color given as #rrggbb?

推荐答案

如果你搜索有关如何将 RGB 转换为 HSL，您会找到许多算法，包括在 谢尔盖.

If you search for how to convert RGB to HSL, you'll find a number of algorithms, including in the Wikipedia article linked by Sergey.

首先，提取十六进制颜色表示法的 RGB 分量.

First, extract the RGB components of the hex color notation.

var color='#c7d92c'; // A nice shade of green.
var r = parseInt(color.substr(1,2), 16); // Grab the hex representation of red (chars 1-2) and convert to decimal (base 10).
var g = parseInt(color.substr(3,2), 16);
var b = parseInt(color.substr(5,2), 16);

这将为您提供颜色的字节 (0-255) 表示.在本例中为 199、217、44.

That'll get you the byte (0-255) representation of your color. In this case, 199, 217, 44.

然后你可以使用维基百科文章中的公式来计算色调，或者无耻地窃取别人的代码:

You can then use the formulae from the Wikipedia article to calculate hue, or shamelessly steal someone else's code:

function rgbToHsl(r, g, b){
    r /= 255, g /= 255, b /= 255;
    var max = Math.max(r, g, b), min = Math.min(r, g, b);
    var h, s, l = (max + min) / 2;

    if(max == min){
        h = s = 0; // achromatic
    }else{
        var d = max - min;
        s = l > 0.5 ? d / (2 - max - min) : d / (max + min);
        switch(max){
            case r: h = (g - b) / d + (g < b ? 6 : 0); break;
            case g: h = (b - r) / d + 2; break;
            case b: h = (r - g) / d + 4; break;
        }
        h /= 6;
    }

    return [h, s, l];
}

(请参阅源页面以获取文档和hslToRgb()代码>函数.)

(See the source page for documentation and a hslToRgb() function.)

我们现在可以将这两个片段放在一起并获得色调:

We can now put those two snippets together and get the hue:

var hue = rgbToHsl(r, g, b)[0] * 360;

[0] 是抓取色调–该函数返回一个数组 ([h,s,l]).我们乘以 360，因为色调返回为 0 到 1 之间的值；我们想把它转换成度数.

The [0] is to grab the hue – the function returns an array ([h,s,l]). We multiply by 360 since hue is returned as a value between 0 and 1; we want to convert it to degrees.

使用 #c7d92c 的示例颜色，hue 将为 ~66.24.Photoshop 的颜色选择器显示该颜色的色调为 66°.所以看起来我们很好！

With the example color of #c7d92c, hue will be ~66.24. Photoshop's color picker says the hue of that color is 66° so it looks like we're good!

这篇关于你如何获得#xxxxxx 颜色的色调?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！