用MATLAB编写RGB到HSL和HSL到RGB颜色空间的转换程序：rgb2hsl.m和hsl2rgb.m

Posted 2023-05-06

用MATLAB编写RGB到HSL和HSL到RGB颜色空间的转换程序：rgb2hsl.m和hsl2rgb.m

参考技术A function hsl=rgb2hsl(rgb)

%Converts Red-Green-Blue Color value to Hue-Saturation-Luminance Color value
%
%Usage
% HSL = rgb2hsl(RGB)
%
% converts RGB, a M X 3 color matrix with values between 0 and 1
% into HSL, a M X 3 color matrix with values between 0 and 1
%
%See also hsl2rgb, rgb2hsv, hsv2rgb

%Suresh E Joel, April 26,2003

if nargin<1,
error('Too few arguements for rgb2hsl');
return;
elseif nargin>1,
error('Too many arguements for rgb2hsl');
return;
end;

if max(max(rgb))>1 | min(min(rgb))<0,
error('RGB values have to be between 0 and 1');
return;
end;

for i=1:size(rgb,1),
mx=max(rgb(i,:));%max of the 3 colors
mn=min(rgb(i,:));%min of the 3 colors
imx=find(rgb(i,:)==mx);%which color has the max
hsl(i,3)=(mx+mn)/2;%luminance is half of max value + min value
if(mx-mn)==0,%if all three colors have same value,
hsl(i,2)=0;%then s=0 and
hsl(i,1)=0;%h is undefined but for practical reasons 0
return;
end;
if hsl(i,3)<0.5,
hsl(i,2)=(mx-mn)/(mx+mn);
else
hsl(i,2)=(mx-mn)/(2-(mx+mn));
end;
switch(imx(1))%if two colors have same value and be the maximum, use the first color
case 1 %Red is the max color
hsl(i,1)=((rgb(i,2)-rgb(i,3))/(mx-mn))/6;
case 2 %Green is the max color
hsl(i,1)=(2+(rgb(i,3)-rgb(i,1))/(mx-mn))/6;
case 3 %Blue is the max color
hsl(i,1)=(4+(rgb(i,1)-rgb(i,2))/(mx-mn))/6;
end;
if hsl(i,1)<0,hsl(i,1)=hsl(i,1)+1;end;%if hue is negative, add 1 to get it within 0 and 1
end;

hsl=round(hsl*100000)/100000; %Sometimes the result is 1+eps instead of 1 or 0-eps instead of 0 ... so to get rid of this I am rounding to 5 decimal places)本回答被提问者采纳

AS3-HSL到RGB类

This requires the [RGB](http://snipplr.com/view/34818/as3--rgb-class-for-rgb-to-hex/) class I posted as well

/**
 * @author Rivaledsouls
 * @version 1.0
 * Feel free to use this code as you wish as long as you cite
 * me, Rivaledsouls, for use of the code in any projects where 
 * you share the source.
 * (c) 2010
 */
 
package utils.color{
	public class HSL {
		private var luminance:Number;
		private var saturation:Number;
		private var hue:Number;
 
		/**
		 * Contructs an HSL object for containing Hue Saturation and Luminance values, and
		 * converting them to an RGB or Hex color
		 * @param	h Hue (0-360)
		 * @param	s Saturation(0-1)
		 * @param	l Luminance(0-1)
		 */
		public function HSL(h:Number=0, s:Number=1, l:Number=.5) {
			hue = h;
			saturation = s;
			luminance = l;
		}
 
		/*
		 * Getters for each channel
		 */
		public function get Hue():Number {
			return hue;
		}
		public function get Saturation():Number {
			return saturation;
		}
		public function get Luminance():Number {
			return luminance;
		}
		/*
		 *Setters for each channel
		 */
		public function set Hue(Value:Number):void {
			hue = (Value>360)? Value-360 : ((Value<0)?Value+360:Value);
		}
		public function set Saturation(Value:Number):void {
			saturation = (Value>1)? 1 : ((Value<0)?0:Value);
		}
		public function set Luminance(Value:Number):void {
			luminance = (Value>1)? 1 : ((Value<0)?0:Value);
		}
		/**
		 * Converts the HSL object to an RGB object defining the same color
		 * @return RGB object
		 */
		public function toRGB():RGB{
			return getRGB(hue, saturation, luminance);
		}
		/**
		 * Converts the HSL object to a Hex value defining the same color
		 * @return Hex value of HSL color
		 */
		public function toHex():uint {
			return toRGB().Hex;
		}
 
		/**
		 * Static method for directly converting HSL values to Hex
		 * @param	h Hue (0-360)
		 * @param	s Saturation(0-1)
		 * @param	l Luminance(0-1)
		 * @return a Hex value represnting the given HSL values
		 */
		public static function getHex(h:Number, s:Number, l:Number):uint{
			return getRGB(h, s, l).Hex;
		}
		/**
		 * Static method for directly converting HSL values to
		 * an RGB object
		 * @param	h Hue (0-360)
		 * @param	s Saturation(0-1)
		 * @param	l Luminance(0-1)
		 * @return an RGB object represnting the given HSL values
		 */
		public static function getRGB(h:Number, s:Number, l:Number):RGB{
			h = h / 360;
			var r:Number;
			var g:Number;
			var b:Number;
 
			if(l==0)
			{
				r=g=b=0;
			}
			else
			{
				if(s == 0)
				{
					r=g=b=l;
				}
				else
				{
					var t2:Number = (l<=0.5)? l*(1+s):l+s-(l*s);
					var t1:Number = 2*l-t2;
					var t3:Vector.<Number> = new Vector.<Number>();
					t3.push(h+1/3);
					t3.push(h);
					t3.push(h-1/3);
					var clr:Vector.<Number> = new Vector.<Number>();
					clr.push(0);
					clr.push(0);
					clr.push(0);
					for(var i:int=0;i<3;i++)
					{
						if(t3[i]<0)
							t3[i]+=1;
						if(t3[i]>1)
							t3[i]-=1;
 
						if(6*t3[i] < 1)
							clr[i]=t1+(t2-t1)*t3[i]*6;
						else if(2*t3[i]<1)
							clr[i]=t2;
						else if(3*t3[i]<2)
							clr[i]=(t1+(t2-t1)*((2/3)-t3[i])*6);
						else
							clr[i]=t1;
					}
					r=clr[0];
					g=clr[1];
					b=clr[2];
				}
			}
			return new RGB(int(r*255),int(g*255),int(b*255));
		}
	}
 
}