colorspace.js

struts hibernet spring

	if (H > 360){ H -= 360; }

	return [L, C, H];
}

dojo.gfx.Colorspace.prototype.LCHab_to_Lab = function(){
	var src = this.munge('LCH', arguments);

	var H_rad = src.H * (Math.PI / 180);
	var L = src.L;
	var a = src.C / Math.pow(Math.pow(Math.tan(H_rad), 2) + 1, 0.5);
	if ((90 < src.H) && (src.H < 270)){ a= -a; }

	var b = Math.pow(Math.pow(src.C, 2) - Math.pow(a, 2), 0.5);
	if (src.H > 180){ b = -b; }

	return [L, a, b];
}

//////////////////////////////////////////////////////////////////////////////////////////////////////
//
// this function converts an XYZ color array (col) from one whitepoint (src_w) to another (dst_w)
//

dojo.gfx.Colorspace.prototype.chromaticAdaptation = function(col, src_w, dst_w){
	col = this.munge('XYZ', [col]);
	var old_wp = this.whitePoint;

	this.whitePoint = src_w;
	var wp_src = this.getWhitePoint();

	this.whitePoint = dst_w;
	var wp_dst = this.getWhitePoint();

	this.whitePoint = old_wp;

	switch(this.chromaticAdaptationAlg){
		case 'xyz_scaling':
			var ma = [[1,0,0],[0,1,0],[0,0,1]];
			var mai = [[1,0,0],[0,1,0],[0,0,1]];
			break;
		case 'bradford':
			var ma = [[0.8951, -0.7502, 0.0389],[0.2664, 1.7135, -0.0685],[-0.1614, 0.0367, 1.0296]];
			var mai = [[0.986993, 0.432305, -0.008529],[-0.147054, 0.518360, 0.040043],[0.159963, 0.049291, 0.968487]];
			break;
		case 'von_kries':
			var ma = [[0.40024, -0.22630, 0.00000],[0.70760, 1.16532, 0.00000],[-0.08081, 0.04570, 0.91822]]
			var mai = [[1.859936, 0.361191, 0.000000],[-1.129382, 0.638812, 0.000000],[0.219897, -0.000006, 1.089064]]
			break;
		default:
			dojo.debug("The "+this.chromaticAdaptationAlg+" chromatic adaptation algorithm matricies are not defined");
	}

	var domain_src = dojo.math.matrix.multiply( [[wp_src.x, wp_src.y, wp_src.z]], ma);
	var domain_dst = dojo.math.matrix.multiply( [[wp_dst.x, wp_dst.y, wp_dst.z]], ma);

	var centre = [
		[domain_dst[0][0]/domain_src[0][0], 0, 0],
		[0, domain_dst[0][1]/domain_src[0][1], 0],
		[0, 0, domain_dst[0][2]/domain_src[0][2]]
	];

	var m = dojo.math.matrix.multiply( dojo.math.matrix.multiply( ma, centre ), mai );
	var dst = dojo.math.matrix.multiply( [[ col.X, col.Y, col.Z ]], m );
	return dst[0];
}

//////////////////////////////////////////////////////////////////////////////////////////////////////
dojo.gfx.Colorspace.prototype.getRGB_XYZ_Matrix = function(){
	var wp = this.getWhitePoint();
	var pr = this.getPrimaries();

	var Xr = pr.xr / pr.yr;
	var Yr = 1;
	var Zr = (1 - pr.xr - pr.yr) / pr.yr;

	var Xg = pr.xg / pr.yg;
	var Yg = 1;
	var Zg = (1 - pr.xg - pr.yg) / pr.yg;

	var Xb = pr.xb / pr.yb;
	var Yb = 1;
	var Zb = (1 - pr.xb - pr.yb) / pr.yb;

	var m1 = [[Xr, Yr, Zr],[Xg, Yg, Zg],[Xb, Yb, Zb]];
	var m2 = [[wp.X, wp.Y, wp.Z]];
	var sm = dojo.math.matrix.multiply(m2, dojo.math.matrix.inverse(m1));

	var Sr = sm[0][0];
	var Sg = sm[0][1];
	var Sb = sm[0][2];

	var m4 = [[Sr*Xr, Sr*Yr, Sr*Zr],
		  [Sg*Xg, Sg*Yg, Sg*Zg],
		  [Sb*Xb, Sb*Yb, Sb*Zb]];

	return m4;
}

dojo.gfx.Colorspace.prototype.getXYZ_RGB_Matrix = function(){
	var m = this.getRGB_XYZ_Matrix();
	return dojo.math.matrix.inverse(m);
}

dojo.gfx.Colorspace.prototype.XYZ_to_Luv = function(){
	var src = this.munge('XYZ', arguments);

	var wp = this.getWhitePoint();
	var ud = (4 * src.X) / (src.X + 15 * src.Y + 3 * src.Z);
	var vd = (9 * src.Y) / (src.X + 15 * src.Y + 3 * src.Z);

	var udr = (4 * wp.X) / (wp.X + 15 * wp.Y + 3 * wp.Z);
	var vdr = (9 * wp.Y) / (wp.X + 15 * wp.Y + 3 * wp.Z);
	var yr = src.Y / wp.Y;

	var L = (yr > this.epsilon()) ? 116 * Math.pow(yr, 1/3) - 16 : this.kappa() * yr;
	var u = 13 * L * (ud-udr);
	var v = 13 * L * (vd-vdr);

	return [L, u, v];
}

dojo.gfx.Colorspace.prototype.Luv_to_XYZ = function(){
	var src = this.munge('Luv', arguments);

	var wp = this.getWhitePoint();
	var uz = (4 * wp.X) / (wp.X + 15 * wp.Y + 3 * wp.Z);
	var vz = (9 * wp.Y) / (wp.X + 15 * wp.Y + 3 * wp.Z);
	var Y = (src.L > this.kappa() * this.epsilon()) ? Math.pow((src.L + 16) / 116, 3) : src.L / this.kappa();

	var a = (1 / 3) * (((52 * src.L) / (src.u + 13 * src.L * uz)) - 1);
	var b = -5 * Y;
	var c = - (1 / 3);
	var d = Y * (((39 * src.L) / (src.v + 13 * src.L * vz)) - 5);

	var X = (d - b) / (a - c);
	var Z = X * a + b;

	return [X, Y, Z];
}

dojo.gfx.Colorspace.prototype.Luv_to_LCHuv = function(){
	var src = this.munge('Luv', arguments);

	var L = src.L;
	var C = Math.pow(src.u * src.u + src.v * src.v, 0.5);
	var H = Math.atan2(src.v, src.u) * (180 / Math.PI);

	if (H < 0){ H += 360; }
	if (H > 360){ H -= 360; }

	return [L, C, H];
}

dojo.gfx.Colorspace.prototype.LCHuv_to_Luv = function(){
	var src = this.munge('LCH', arguments);

	var H_rad = src.H * (Math.PI / 180);
	var L = src.L;
	var u = src.C / Math.pow(Math.pow(Math.tan(H_rad), 2) + 1, 0.5);
	var v = Math.pow(src.C * src.C - u * u, 0.5);

	if ((90 < src.H) && (src.H < 270)){ u *= -1; }
	if (src.H > 180){ v *= -1; }

	return [L, u, v];
}

dojo.gfx.Colorspace.colorTemp_to_whitePoint = function(T){
	if (T < 4000){
		dojo.debug("Can't find a white point for temperatures under 4000K");
		return [0,0];
	}

	if (T > 25000){
		dojo.debug("Can't find a white point for temperatures over 25000K");
		return [0,0];
	}

	var T1 = T;
	var T2 = T * T;
	var T3 = T2 * T;

	var ten9 = Math.pow(10, 9);
	var ten6 = Math.pow(10, 6);
	var ten3 = Math.pow(10, 3);

	if (T <= 7000){
		var x = (-4.6070 * ten9 / T3) + (2.9678 * ten6 / T2) + (0.09911 * ten3 / T) + 0.244063;
	}else{
		var x = (-2.0064 * ten9 / T3) + (1.9018 * ten6 / T2) + (0.24748 * ten3 / T) + 0.237040;
	}
	var y = -3.000 * x * x + 2.870 * x - 0.275;

	return [x, y];
}

dojo.gfx.Colorspace.prototype.RGB_to_CMY = function(){
	var src = this.munge('RGB', arguments);

	var C = 1 - src.R;
	var M = 1 - src.G;
	var Y = 1 - src.B;

	return [C, M, Y];
}

dojo.gfx.Colorspace.prototype.CMY_to_RGB = function(){
	var src = this.munge('CMY', arguments);

	var R = 1 - src.C;
	var G = 1 - src.M;
	var B = 1 - src.Y;

	return [R, G, B];
}

dojo.gfx.Colorspace.prototype.RGB_to_CMYK = function(){
	var src = this.munge('RGB', arguments);

	var K = Math.min(1-src.R, 1-src.G, 1-src.B);
	var C = (1 - src.R - K) / (1 - K);
	var M = (1 - src.G - K) / (1 - K);
	var Y = (1 - src.B - K) / (1 - K);

	return [C, M, Y, K];
}

dojo.gfx.Colorspace.prototype.CMYK_to_RGB = function(){
	var src = this.munge('CMYK', arguments);

	var R = 1 - Math.min(1, src.C * (1-src.K) + src.K);
	var G = 1 - Math.min(1, src.M * (1-src.K) + src.K);
	var B = 1 - Math.min(1, src.Y * (1-src.K) + src.K);

	return [R, G, B];
}

dojo.gfx.Colorspace.prototype.CMY_to_CMYK = function(){
	var src = this.munge('CMY', arguments);

	var K = Math.min(src.C, src.M, src.Y);
	var C = (src.C - K) / (1 - K);
	var M = (src.M - K) / (1 - K);
	var Y = (src.Y - K) / (1 - K);

	return [C, M, Y, K];
}

dojo.gfx.Colorspace.prototype.CMYK_to_CMY = function(){
	var src = this.munge('CMYK', arguments);

	var C = Math.min(1, src.C * (1-src.K) + src.K);
	var M = Math.min(1, src.M * (1-src.K) + src.K);
	var Y = Math.min(1, src.Y * (1-src.K) + src.K);

	return [C, M, Y];
}

dojo.gfx.Colorspace.prototype.RGB_to_HSV = function(){
	var src = this.munge('RGB', arguments);

	// Based on C Code in "Computer Graphics -- Principles and Practice,"
	// Foley et al, 1996, p. 592. 

	var min = Math.min(src.R, src.G, src.B);
	var V = Math.max(src.R, src.G, src.B);

	var delta = V - min;

	var H = null;
	var S = (V == 0) ? 0 : delta / V;

	if (S == 0){
		H = 0;
	}else{
		if (src.R == V){
			H = 60 * (src.G - src.B) / delta;
		}else{
			if (src.G == V){
				H = 120 + 60 * (src.B - src.R) / delta;
			}else{
				if (src.B == V){
					// between magenta and cyan
					H = 240 + 60 * (src.R - src.G) / delta;
				}
			}
		}
		if (H < 0){
			H += 360;
		}
	}

	H = (H == 0) ? 360 : H;

	return [H, S, V];
}

dojo.gfx.Colorspace.prototype.HSV_to_RGB = function(){
	var src = this.munge('HSV', arguments);
	if (src.H == 360){ src.H = 0;}

	// Based on C Code in "Computer Graphics -- Principles and Practice,"
	// Foley et al, 1996, p. 593.
	var r = null;
	var g = null;
	var b = null;

	if (src.S == 0){
		// color is on black-and-white center line
		// achromatic: shades of gray
		var R = src.V;
		var G = src.V;
		var B = src.V;
	}else{
		// chromatic color
		var hTemp = src.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 = src.V * (1 - src.S);
		var q = src.V * (1 - (src.S * f));
		var t = src.V * (1 - (src.S * (1 - f)));

		switch(i){
			case 0: R = src.V; G = t    ; B = p    ; break;
			case 1: R = q    ; G = src.V; B = p    ; break;
			case 2: R = p    ; G = src.V; B = t    ; break;
			case 3: R = p    ; G = q    ; B = src.V; break;
			case 4: R = t    ; G = p    ; B = src.V; break;
			case 5: R = src.V; G = p    ; B = q    ; break;
		}
	}

	return [R, G, B];
}

dojo.gfx.Colorspace.prototype.RGB_to_HSL = function(){
	var src = this.munge('RGB', arguments);

	// based on C code from http://astronomy.swin.edu.au/~pbourke/colour/hsl/
	var min = Math.min(src.R, src.G, src.B);
	var max = Math.max(src.R, src.G, src.B);
	var delta = max - min;

	var H = 0;
	var S = 0;
	var L = (min + max) / 2;

	if ((L > 0) && (L < 1)){
		S = delta / ((L < 0.5) ? (2 * L) : (2 - 2 * L));
	}

	if (delta > 0) {
		if ((max == src.R) && (max != src.G)){
			H += (src.G - src.B) / delta;
		}
		if ((max == src.G) && (max != src.B)){
			H += (2 + (src.B - src.R) / delta);
		}
		if ((max == src.B) && (max != src.R)){
			H += (4 + (src.R - src.G) / delta);
		}
		H *= 60;
	}
	H = (H == 0) ? 360 : H;
	return [H, S, L];
}

dojo.gfx.Colorspace.prototype.HSL_to_RGB = function(){
	var src = this.munge('HSL', arguments);

	// based on C code from http://astronomy.swin.edu.au/~pbourke/colour/hsl/
	while (src.H < 0){ src.H += 360; }
	while (src.H >= 360){ src.H -= 360; }

	var R = 0;
	var G = 0;
	var B = 0;

	if (src.H < 120){
		R = (120 - src.H) / 60;
		G = src.H / 60;
		B = 0;
	}else if (src.H < 240){
		R = 0;
		G = (240 - src.H) / 60;
		B = (src.H - 120) / 60;
	}else{
		R = (src.H - 240) / 60;
		G = 0;
		B = (360 - src.H) / 60;
	}

	R = 2 * src.S * Math.min(R, 1) + (1 - src.S);
	G = 2 * src.S * Math.min(G, 1) + (1 - src.S);
	B = 2 * src.S * Math.min(B, 1) + (1 - src.S);

	if (src.L < 0.5){
		R = src.L * R;
		G = src.L * G;
		B = src.L * B;
	}else{
		R = (1 - src.L) * R + 2 * src.L - 1;
		G = (1 - src.L) * G + 2 * src.L - 1;
		B = (1 - src.L) * B + 2 * src.L - 1;
	}
	return [R, G, B];
}