RGB、HSV色彩模式转换函数及模拟windows调色板
RGB、HSV色彩模式转换函数及模拟windows调色板
function HextoRGB(hex) {
hex = hex.toUpperCase();
if(hex.charAt(0) == "#") hex = hex.substring(1,hex.length);
var rgb = new Array(3);
rgb.r = hex.substring(0,2);
rgb.g = hex.substring(2,4);
rgb.b = hex.substring(4,6);
rgb.r = parseInt(rgb.r,16);
rgb.g = parseInt(rgb.g,16);
rgb.b = parseInt(rgb.b,16);
if(isNaN(rgb.r)) rgb.r = 0;
if(isNaN(rgb.g)) rgb.g = 0;
if(isNaN(rgb.b)) rgb.b = 0;
return rgb;
}
function RGBtoHex(R, G, B) {
var n = Math.round(B);
n += Math.round(G) << 8;
n += Math.round(R) << 16;
return DectoHex(n);
}
// turns decimal integer (e.g., bgColor) into hexadecimal string
function DectoHex(num) {
var i = 0; var j = 20;
var str = "#";
while(j >= 0) {
i = (num >> j)%16;
if(i >= 10) {
if(i == 10) str += "A";
else if(i == 11) str += "B";
else if(i == 12) str += "C";
else if(i == 13) str += "D";
else if(i == 14) str += "E";
else str += "F";
} else
str += i;
j -= 4;
}
return str;
}
function MIN() {
var min = 255;
for(var i = 0; i < arguments.length; i++)
if(arguments[i] < min)
min = arguments[i];
return min;
}
function MAX() {
var max = 0;
for(var i = 0; i < arguments.length; i++)
if(arguments[i] > max)
max = arguments[i];
return max;
}
function RGBtoCMYK(r,g,b) { // doesn't distort! not really usable...
r /= 255;
g /= 255;
b /= 255;
var cmyk = new Array(4);
cmyk.c = Math.pow(1-r,.45);
cmyk.m = Math.pow(1-g,.45);
cmyk.y = Math.pow(1-b,.45);
cmyk.k = MIN(cmyk.c,cmyk.y,cmyk.m);
cmyk.c -= cmyk.k;
cmyk.m -= cmyk.k;
cmyk.y -= cmyk.k;
return cmyk;
}
function RGBtoHSV(r,g,b) {
r /= 255;
g /= 255;
b /= 255;
var min, max, delta;
var hsv = new Array(3);
min = MIN(r,g,b);
max = MAX(r,g,b);
hsv.v = max;
delta = max - min;
if (max != 0) hsv.s = delta/max;
else {
hsv.s = .005;
hsv.h = 0;
return hsv;
}
if(delta == 0) {
hsv.s = .005;
hsv.h = 0;
return hsv;
}
if (r == max) hsv.h = (g-b)/delta;
else if(g == max) hsv.h = 2+(b-r)/delta;
else hsv.h = 4+(r-g)/delta;
hsv.h *= 60;
if(hsv.h<0) hsv.h += 360;
if(hsv.h>=360) hsv.h -= 360;
return hsv;
}
function HSVtoRGB(h,s,v) {
var rgb = new Array(3);
var i;
var f, p, q, t;
if(s == 0) {
rgb.r = rgb.g = rgb.b = v*255;
return rgb;
}
h /= 60;
i = Math.floor(h);
f = h-i;
p = v*(1-s);
q = v*(1-s*f);
t = v*(1-s*(1-f));
switch(i) {
case 0:
rgb.r = v;
rgb.g = t;
rgb.b = p;
break;
case 1:
rgb.r = q;
rgb.g = v;
rgb.b = p;
break;
case 2:
rgb.r = p;
rgb.g = v;
rgb.b = t;
break;
case 3:
rgb.r = p;
rgb.g = q;
rgb.b = v;
break;
case 4:
rgb.r = t;
rgb.g = p;
rgb.b = v;
break;
default:
rgb.r = v;
rgb.g = p;
rgb.b = q;
break;
}
rgb.r *= 255;
rgb.g *= 255;
rgb.b *= 255;
return rgb;
}
function RGBtoHLS(R,G,B) {
R /= 255;
G /= 255;
B /= 255;
var max, min,diff,r_dist,g_dist,b_dist;
var hls = new Array(3);
max = MAX(R,G,B);
min = MIN(R,G,B);
diff = max-min;
hls.l = (max+min)/2;
if (diff==0) {
hls.h = 0;
hls.s = 0;
} else {
if (hls.l<0.5) hls.s = diff/(max+min);
else hls.s = diff/(2-max-min);
r_dist = (max-R)/diff;
g_dist = (max-G)/diff;
b_dist = (max-B)/diff;
if (R == max) { hls.h = b_dist-g_dist; }
else if (G == max) { hls.h = 2+r_dist-b_dist; }
else if (B == max) { hls.h = 4+g_dist-r_dist; }
hls.h *= 60;
if (hls.h<0) hls.h += 360;
if (hls.h>=360) hls.h -= 360;
}
return hls;
}
function RGB(q1,q2,hue) {
if (hue>360) hue=hue-360;
if (hue<0) hue=hue+360;
if (hue<60) return (q1+(q2-q1)*hue/60);
else if (hue<180) return(q2);
else if (hue<240) return(q1+(q2-q1)*(240-hue)/60);
else return(q1);
}
function HLStoRGB(H,L,S) {
var p1,p2;
var rgb = new Array(3);
if (L<=0.5) p2=L*(1+S);
else p2=L+S-(L*S);
p1=2*L-p2;
if (S==0) {
rgb.r=L;
rgb.g=L;
rgb.b=L;
} else {
rgb.r=RGB(p1,p2,H+120);
rgb.g=RGB(p1,p2,H);
rgb.b=RGB(p1,p2,H-120);
}
rgb.r *= 255;
rgb.g *= 255;
rgb.b *= 255;
return rgb;
}
RGB 0~255
H 0~359
S、L、V 0~100
要注意的是 HLS和HSV模式转RGB的函数，输入的 L\S或者S\V值要预先除以100
找了很久才找到的，总会有用到的时候吧（我现在就正好要用到）
另外提供WEB216安全色的算法（这个其实很简单-_-bbb 附赠品 :p）
输入的值是字符串 #3E6A95 这样的
function snaptoSafe(c) {
var safe=new Array;
safe[0]=parseInt(c.substr(1,2),16);
safe[1]=parseInt(c.substr(3,2),16);
safe[2]=parseInt(c.substr(5,2),16);
var i;
for(i=0;i<safe.length;i++) {
safe[i]=Math.round(safe[i]/51)*51;
safe[i]=safe[i].toString(16);
if(safe[i].length<2) safe[i]='0'+safe[i];
}
var thecolor='#'+safe[0]+safe[1]+safe[2];
return thecolor;
}
返回离该色彩最近的安全色
附件代码：
本文转自：色彩模式转换函数(附实例-模拟windows调色板)
参考推荐：
米扑博客颜色表 （强烈推荐）
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