dojo.provide("dojo.gfx.color.hsv");
dojo.require("dojo.lang.array");
dojo.require("dojo.math");
dojo.lang.extend(dojo.gfx.color.Color, {
toHsv: function() {
return dojo.gfx.color.rgb2hsv(this.toRgb());
}
});
// Default input range for RBG values is 0-255
dojo.gfx.color.rgb2hsv = function(/* int || Array */r, /* int */g, /* int */b, /* Object? */options){
// summary
// converts an RGB value set to HSV, ranges depending on optional options object.
// patch for options by Matthew Eernisse
if (dojo.lang.isArray(r)) {
if(g) {
options = g;
}
b = r[2] || 0;
g = r[1] || 0;
r = r[0] || 0;
}
var opt = {
inputRange: (options && options.inputRange) ? options.inputRange : 255,
outputRange: (options && options.outputRange) ? options.outputRange : [255, 255, 255]
};
// r,g,b, each 0 to 255, to HSV.
// h = 0.0 to 360.0 (corresponding to 0..360.0 degrees around hexcone)
// s = 0.0 (shade of gray) to 1.0 (pure color)
// v = 0.0 (black) to 1.0 {white)
//
// Based on C Code in "Computer Graphics -- Principles and Practice,"
// Foley et al, 1996, p. 592.
//
// our calculatuions are based on 'regular' values (0-360, 0-1, 0-1)
// but we return bytes values (0-255, 0-255, 0-255)
var h = null;
var s = null;
var v = null;
switch(opt.inputRange) {
// 0.0-1.0
case 1:
r = (r * 255);
g = (g * 255);
b = (b * 255);
break;
// 0-100
case 100:
r = (r / 100) * 255;
g = (g / 100) * 255;
b = (b / 100) * 255;
break;
// 0-255
default:
// Do nothing
break;
}
var min = Math.min(r, g, b);
v = Math.max(r, g, b);
var delta = v - min;
// calculate saturation (0 if r, g and b are all 0)
s = (v == 0) ? 0 : delta/v;
if (s == 0){
// achromatic: when saturation is, hue is undefined
h = 0;
}else{
// chromatic
if (r == v){
// between yellow and magenta
h = 60 * (g - b) / delta;
}else{
if (g == v){
// between cyan and yellow
h = 120 + 60 * (b - r) / delta;
}else{
if (b == v){
// between magenta and cyan
h = 240 + 60 * (r - g) / delta;
}
}
}
if (h <= 0){
h += 360;
}
}
// Hue
switch (opt.outputRange[0]) {
case 360:
// Do nothing
break;
case 100:
h = (h / 360) * 100;
break;
case 1:
h = (h / 360);
break;
default: // 255
h = (h / 360) * 255;
break;
}
// Saturation
switch (opt.outputRange[1]) {
case 100:
s = s * 100;
case 1:
// Do nothing
break;
default: // 255
s = s * 255;
break;
}
// Value
switch (opt.outputRange[2]) {
case 100:
v = (v / 255) * 100;
break;
case 1:
v = (v / 255);
break;
default: // 255
// Do nothing
break;
}
h = dojo.math.round(h);
s = dojo.math.round(s);
v = dojo.math.round(v);
return [h, s, v];
}
// Based on C Code in "Computer Graphics -- Principles and Practice,"
// Foley et al, 1996, p. 593.
//
// H = 0 to 255 (corresponding to 0..360 degrees around hexcone) 0 for S = 0
// S = 0 (shade of gray) to 255 (pure color)
// V = 0 (black) to 255 (white)
dojo.gfx.color.hsv2rgb = function(/* int || Array */h, /* int */s, /* int */v, /* Object? */options){
// summary
// converts an HSV value set to RGB, ranges depending on optional options object.
// patch for options by Matthew Eernisse
if (dojo.lang.isArray(h)) {
if(s){
options = s;
}
v = h[2] || 0;
s = h[1] || 0;
h = h[0] || 0;
}
var opt = {
inputRange: (options && options.inputRange) ? options.inputRange : [255, 255, 255],
outputRange: (options && options.outputRange) ? options.outputRange : 255
};
switch(opt.inputRange[0]) {
// 0.0-1.0
case 1: h = h * 360; break;
// 0-100
case 100: h = (h / 100) * 360; break;
// 0-360
case 360: h = h; break;
// 0-255
default: h = (h / 255) * 360;
}
if (h == 360){ h = 0;}
// no need to alter if inputRange[1] = 1
switch(opt.inputRange[1]){
case 100: s /= 100; break;
case 255: s /= 255;
}
// no need to alter if inputRange[1] = 1
switch(opt.inputRange[2]){
case 100: v /= 100; break;
case 255: v /= 255;
}
var r = null;
var g = null;
var b = null;
if (s == 0){
// color is on black-and-white center line
// achromatic: shades of gray
r = v;
g = v;
b = v;
}else{
// chromatic color
var hTemp = h / 60; // h is now IN [0,6]
var i = Math.floor(hTemp); // largest integer <= h
var f = hTemp - i; // fractional part of h
var p = v * (1 - s);
var q = v * (1 - (s * f));
var t = v * (1 - (s * (1 - f)));
switch(i){
case 0: r = v; g = t; b = p; break;
case 1: r = q; g = v; b = p; break;
case 2: r = p; g = v; b = t; break;
case 3: r = p; g = q; b = v; break;
case 4: r = t; g = p; b = v; break;
case 5: r = v; g = p; b = q; break;
}
}
switch(opt.outputRange){
case 1:
r = dojo.math.round(r, 2);
g = dojo.math.round(g, 2);
b = dojo.math.round(b, 2);
break;
case 100:
r = Math.round(r * 100);
g = Math.round(g * 100);
b = Math.round(b * 100);
break;
default:
r = Math.round(r * 255);
g = Math.round(g * 255);
b = Math.round(b * 255);
}
return [r, g, b];
}