RGB to HSB color conversion

[pixelwit]

I've managed to cobble this code together form various sources which converts from RGB to HSB:

function rgb2Hex (r,g,b){
    return(r<<16 | g<<8 | b);
}
function hsb2rgb(h, s, v) {
    var r, g, b;
    if (h == 360) {h = 0;}
    else if (h>360 or h<0) {return 0;}
    s /= 100;
    v /= 100;
    h /= 60;
    var i = Math.floor(h);
    var f = h-i;
    var p = v*(1-s);
    var q = v*(1-(s*f));
    var t = v*(1-(s*(1-f)));
    if (i==0) {r=v; g=t; b=p;}
    else if (i==1) {r=q; g=v; b=p;}
    else if (i==2) {r=p; g=v; b=t;}
    else if (i==3) {r=p; g=q; b=v;}
    else if (i==4) {r=t; g=p; b=v;}
    else if (i==5) {r=v; g=p; b=q;}
    r = Math.floor(r*255);
    g = Math.floor(g*255);
    b = Math.floor(b*255);
    return (rgb2Hex(r, g, b));
}

Now I'd like to be able to go the other way and convert from RGB to HSB. Can anyone lend a hand?

Thanks for your time,

-PiXELWiT
http://www.pixelwit.com

[pixelwit]

I did some searching on the Net and found this handy link: http://www.efg2.com/Lab/Library/Color/Science.htm

So after doing a little more cobbling and tweaking I finally have everything the way I like it. Here it is if you're interested:

function hsv2rgb(hue, sat, val) {
    var red, grn, blu, i, f, p, q, t;
    hue%=360;
    if(val==0) {return({r:0, g:0, v:0});}
    sat/=100;
    val/=100;
    hue/=60;
    i = Math.floor(hue);
    f = hue-i;
    p = val*(1-sat);
    q = val*(1-(sat*f));
    t = val*(1-(sat*(1-f)));
    if (i==0) {red=val; grn=t; blu=p;}
    else if (i==1) {red=q; grn=val; blu=p;}
    else if (i==2) {red=p; grn=val; blu=t;}
    else if (i==3) {red=p; grn=q; blu=val;}
    else if (i==4) {red=t; grn=p; blu=val;}
    else if (i==5) {red=val; grn=p; blu=q;}
    red = Math.floor(red*255);
    grn = Math.floor(grn*255);
    blu = Math.floor(blu*255);
    return ({r:red, g:grn, b:blu});
}
//
function rgb2hsv(red, grn, blu) {
    var x, val, f, i, hue, sat, val;
    red/=255;
    grn/=255;
    blu/=255;
    x = Math.min(Math.min(red, grn), blu);
    val = Math.max(Math.max(red, grn), blu);
    if (x==val){
        return({h:undefined, s:0, v:val*100});
    }
    f = (red == x) ? grn-blu : ((grn == x) ? blu-red : red-grn);
    i = (red == x) ? 3 : ((grn == x) ? 5 : 1);
    hue = Math.floor((i-f/(val-x))*60)%360;
    sat = Math.floor(((val-x)/val)*100);
    val = Math.floor(val*100);
    return({h:hue, s:sat, v:val});
}
//
// Usage
h = 360;
s = 50;
v = 25;
trace("H"+h+" S"+s+" V"+v);
trace ("Converts to");
col = hsv2rgb(h, s, v);
r = col.r;
g = col.g;
b = col.b;
trace("R"+r+" G"+g+" B"+b);
trace("");
trace("R"+r+" G"+g+" B"+b);
trace ("Converts to");
col = rgb2hsv(r, g, b);
h = col.h;
s = col.s;
v = col.v;
trace ("H"+h+" S"+s+" V"+v);

Hope it helps,

-PiXELWiT
http://www.pixelwit.com