我正在寻找一个算法之间的HSL颜色转换为RGB。
在我看来，HSL不是很广泛地使用，所以我没有太多的运气寻找一个转换器。
当前回答
来自Mohsen回答的c#代码。
下面是Mohsen用c#编写的答案代码，如果有人想要的话。注意:Color是自定义类，Vector4来自OpenTK。两者都很容易被你选择的其他东西取代。
Hsl到Rgba
/// <summary>
/// Converts an HSL color value to RGB.
/// Input: Vector4 ( X: [0.0, 1.0], Y: [0.0, 1.0], Z: [0.0, 1.0], W: [0.0, 1.0] )
/// Output: Color ( R: [0, 255], G: [0, 255], B: [0, 255], A: [0, 255] )
/// </summary>
/// <param name="hsl">Vector4 defining X = h, Y = s, Z = l, W = a. Ranges [0, 1.0]</param>
/// <returns>RGBA Color. Ranges [0, 255]</returns>
public static Color HslToRgba(Vector4 hsl)
{
float r, g, b;
if (hsl.Y == 0.0f)
r = g = b = hsl.Z;
else
{
var q = hsl.Z < 0.5f ? hsl.Z * (1.0f + hsl.Y) : hsl.Z + hsl.Y - hsl.Z * hsl.Y;
var p = 2.0f * hsl.Z - q;
r = HueToRgb(p, q, hsl.X + 1.0f / 3.0f);
g = HueToRgb(p, q, hsl.X);
b = HueToRgb(p, q, hsl.X - 1.0f / 3.0f);
}
return new Color((int)(r * 255), (int)(g * 255), (int)(b * 255), (int)(hsl.W * 255));
}
// Helper for HslToRgba
private static float HueToRgb(float p, float q, float t)
{
if (t < 0.0f) t += 1.0f;
if (t > 1.0f) t -= 1.0f;
if (t < 1.0f / 6.0f) return p + (q - p) * 6.0f * t;
if (t < 1.0f / 2.0f) return q;
if (t < 2.0f / 3.0f) return p + (q - p) * (2.0f / 3.0f - t) * 6.0f;
return p;
}
Rgba到Hsl
/// <summary>
/// Converts an RGB color value to HSL.
/// Input: Color ( R: [0, 255], G: [0, 255], B: [0, 255], A: [0, 255] )
/// Output: Vector4 ( X: [0.0, 1.0], Y: [0.0, 1.0], Z: [0.0, 1.0], W: [0.0, 1.0] )
/// </summary>
/// <param name="rgba"></param>
/// <returns></returns>
public static Vector4 RgbaToHsl(Color rgba)
{
float r = rgba.R / 255.0f;
float g = rgba.G / 255.0f;
float b = rgba.B / 255.0f;
float max = (r > g && r > b) ? r : (g > b) ? g : b;
float min = (r < g && r < b) ? r : (g < b) ? g : b;
float h, s, l;
h = s = l = (max + min) / 2.0f;
if (max == min)
h = s = 0.0f;
else
{
float d = max - min;
s = (l > 0.5f) ? d / (2.0f - max - min) : d / (max + min);
if (r > g && r > b)
h = (g - b) / d + (g < b ? 6.0f : 0.0f);
else if (g > b)
h = (b - r) / d + 2.0f;
else
h = (r - g) / d + 4.0f;
h /= 6.0f;
}
return new Vector4(h, s, l, rgba.A / 255.0f);
}
其他回答
我从Brandon Mathis的HSL Picker源代码中得到了这个。
它最初是用CoffeeScript编写的。我使用在线转换器将其转换为JavaScript，并拿出验证用户输入是否为有效RGB值的机制。这个答案适用于我的用例，因为我发现这篇文章上投票最多的答案不能产生有效的HSL值。
注意，它返回一个hsla值，表示不透明/透明。0是完全透明的，1是完全不透明的。
function rgbToHsl(rgb) {
var a, add, b, diff, g, h, hue, l, lum, max, min, r, s, sat;
r = parseFloat(rgb[0]) / 255;
g = parseFloat(rgb[1]) / 255;
b = parseFloat(rgb[2]) / 255;
max = Math.max(r, g, b);
min = Math.min(r, g, b);
diff = max - min;
add = max + min;
hue = min === max ? 0 : r === max ? ((60 * (g - b) / diff) + 360) % 360 : g === max ? (60 * (b - r) / diff) + 120 : (60 * (r - g) / diff) + 240;
lum = 0.5 * add;
sat = lum === 0 ? 0 : lum === 1 ? 1 : lum <= 0.5 ? diff / add : diff / (2 - add);
h = Math.round(hue);
s = Math.round(sat * 100);
l = Math.round(lum * 100);
a = parseFloat(rgb[3]) || 1;
return [h, s, l, a];
}
对于所有说Garry Tan解决方案转换不正确从RGB到HSL和回来。这是因为他在代码中遗漏了数字的一部分。 我纠正了他的代码(javascript)。 对不起，俄语的链接，但在英语缺席- HSL-wiki
function toHsl(r, g, b)
{
r /= 255.0;
g /= 255.0;
b /= 255.0;
var max = Math.max(r, g, b);
var min = Math.min(r, g, b);
var h, s, l = (max + min) / 2.0;
if(max == min)
{
h = s = 0;
}
else
{
var d = max - min;
s = (l > 0.5 ? d / (2.0 - max - min) : d / (max + min));
if(max == r && g >= b)
{
h = 1.0472 * (g - b) / d ;
}
else if(max == r && g < b)
{
h = 1.0472 * (g - b) / d + 6.2832;
}
else if(max == g)
{
h = 1.0472 * (b - r) / d + 2.0944;
}
else if(max == b)
{
h = 1.0472 * (r - g) / d + 4.1888;
}
}
return {
str: 'hsl(' + parseInt(h / 6.2832 * 360.0 + 0.5) + ',' + parseInt(s * 100.0 + 0.5) + '%,' + parseInt(l * 100.0 + 0.5) + '%)',
obj: { h: parseInt(h / 6.2832 * 360.0 + 0.5), s: parseInt(s * 100.0 + 0.5), l: parseInt(l * 100.0 + 0.5) }
};
};
来自Mohsen回答的c#代码。
下面是Mohsen用c#编写的答案代码，如果有人想要的话。注意:Color是自定义类，Vector4来自OpenTK。两者都很容易被你选择的其他东西取代。
Hsl到Rgba
/// <summary>
/// Converts an HSL color value to RGB.
/// Input: Vector4 ( X: [0.0, 1.0], Y: [0.0, 1.0], Z: [0.0, 1.0], W: [0.0, 1.0] )
/// Output: Color ( R: [0, 255], G: [0, 255], B: [0, 255], A: [0, 255] )
/// </summary>
/// <param name="hsl">Vector4 defining X = h, Y = s, Z = l, W = a. Ranges [0, 1.0]</param>
/// <returns>RGBA Color. Ranges [0, 255]</returns>
public static Color HslToRgba(Vector4 hsl)
{
float r, g, b;
if (hsl.Y == 0.0f)
r = g = b = hsl.Z;
else
{
var q = hsl.Z < 0.5f ? hsl.Z * (1.0f + hsl.Y) : hsl.Z + hsl.Y - hsl.Z * hsl.Y;
var p = 2.0f * hsl.Z - q;
r = HueToRgb(p, q, hsl.X + 1.0f / 3.0f);
g = HueToRgb(p, q, hsl.X);
b = HueToRgb(p, q, hsl.X - 1.0f / 3.0f);
}
return new Color((int)(r * 255), (int)(g * 255), (int)(b * 255), (int)(hsl.W * 255));
}
// Helper for HslToRgba
private static float HueToRgb(float p, float q, float t)
{
if (t < 0.0f) t += 1.0f;
if (t > 1.0f) t -= 1.0f;
if (t < 1.0f / 6.0f) return p + (q - p) * 6.0f * t;
if (t < 1.0f / 2.0f) return q;
if (t < 2.0f / 3.0f) return p + (q - p) * (2.0f / 3.0f - t) * 6.0f;
return p;
}
Rgba到Hsl
/// <summary>
/// Converts an RGB color value to HSL.
/// Input: Color ( R: [0, 255], G: [0, 255], B: [0, 255], A: [0, 255] )
/// Output: Vector4 ( X: [0.0, 1.0], Y: [0.0, 1.0], Z: [0.0, 1.0], W: [0.0, 1.0] )
/// </summary>
/// <param name="rgba"></param>
/// <returns></returns>
public static Vector4 RgbaToHsl(Color rgba)
{
float r = rgba.R / 255.0f;
float g = rgba.G / 255.0f;
float b = rgba.B / 255.0f;
float max = (r > g && r > b) ? r : (g > b) ? g : b;
float min = (r < g && r < b) ? r : (g < b) ? g : b;
float h, s, l;
h = s = l = (max + min) / 2.0f;
if (max == min)
h = s = 0.0f;
else
{
float d = max - min;
s = (l > 0.5f) ? d / (2.0f - max - min) : d / (max + min);
if (r > g && r > b)
h = (g - b) / d + (g < b ? 6.0f : 0.0f);
else if (g > b)
h = (b - r) / d + 2.0f;
else
h = (r - g) / d + 4.0f;
h /= 6.0f;
}
return new Vector4(h, s, l, rgba.A / 255.0f);
}
这里是修改后的javascript函数，它在0-360度集输出Hue。
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 ; break;
case g: h = 2 + ( (b - r) / d); break;
case b: h = 4 + ( (r - g) / d); break;
}
h*=60;
if (h < 0) h +=360;
}
return([h, s, l]);
}
alert(rgbToHsl(125,115,145));
Mohsen代码的Java实现
注意，所有整数都声明为浮点数(即1f)，必须是浮点数，否则您将选择灰色。
HSL到RGB
/**
* Converts an HSL color value to RGB. Conversion formula
* adapted from http://en.wikipedia.org/wiki/HSL_color_space.
* Assumes h, s, and l are contained in the set [0, 1] and
* returns r, g, and b in the set [0, 255].
*
* @param h The hue
* @param s The saturation
* @param l The lightness
* @return int array, the RGB representation
*/
public static int[] hslToRgb(float h, float s, float l){
float r, g, b;
if (s == 0f) {
r = g = b = l; // achromatic
} else {
float q = l < 0.5f ? l * (1 + s) : l + s - l * s;
float p = 2 * l - q;
r = hueToRgb(p, q, h + 1f/3f);
g = hueToRgb(p, q, h);
b = hueToRgb(p, q, h - 1f/3f);
}
int[] rgb = {to255(r), to255(g), to255(b)};
return rgb;
}
public static int to255(float v) { return (int)Math.min(255,256*v); }
/** Helper method that converts hue to rgb */
public static float hueToRgb(float p, float q, float t) {
if (t < 0f)
t += 1f;
if (t > 1f)
t -= 1f;
if (t < 1f/6f)
return p + (q - p) * 6f * t;
if (t < 1f/2f)
return q;
if (t < 2f/3f)
return p + (q - p) * (2f/3f - t) * 6f;
return p;
}
RGB到HSL
/**
* Converts an RGB color value to HSL. Conversion formula
* adapted from http://en.wikipedia.org/wiki/HSL_color_space.
* Assumes pR, pG, and bpBare contained in the set [0, 255] and
* returns h, s, and l in the set [0, 1].
*
* @param pR The red color value
* @param pG The green color value
* @param pB The blue color value
* @return float array, the HSL representation
*/
public static float[] rgbToHsl(int pR, int pG, int pB) {
float r = pR / 255f;
float g = pG / 255f;
float b = pB / 255f;
float max = (r > g && r > b) ? r : (g > b) ? g : b;
float min = (r < g && r < b) ? r : (g < b) ? g : b;
float h, s, l;
l = (max + min) / 2.0f;
if (max == min) {
h = s = 0.0f;
} else {
float d = max - min;
s = (l > 0.5f) ? d / (2.0f - max - min) : d / (max + min);
if (r > g && r > b)
h = (g - b) / d + (g < b ? 6.0f : 0.0f);
else if (g > b)
h = (b - r) / d + 2.0f;
else
h = (r - g) / d + 4.0f;
h /= 6.0f;
}
float[] hsl = {h, s, l};
return hsl;
}
