the color module has a base type and some hsl functions so far. it's used by newer png, image algorithms, simpledisplay, and soon, html.d

color.d

@@ -0,0 +1,133 @@
+module arsd.color;
+
+// NOTE: this is obsolete. use color.d instead.
+
+import std.stdio;
+import std.math;
+import std.conv;
+import std.algorithm;
+
+struct Color {
+	ubyte r;
+	ubyte g;
+	ubyte b;
+	ubyte a;
+
+	this(int red, int green, int blue, int alpha = 255) {
+		this.r = cast(ubyte) red;
+		this.g = cast(ubyte) green;
+		this.b = cast(ubyte) blue;
+		this.a = cast(ubyte) alpha;
+	}
+
+	static Color transparent() {
+		return Color(0, 0, 0, 0);
+	}
+
+	static Color white() {
+		return Color(255, 255, 255);
+	}
+
+	static Color black() {
+		return Color(0, 0, 0);
+	}
+}
+
+
+Color fromHsl(real[3] hsl) {
+	return fromHsl(hsl[0], hsl[1], hsl[2]);
+}
+
+Color fromHsl(real h, real s, real l) {
+	h = h % 360;
+
+	real C = (1 - abs(2 * l - 1)) * s;
+
+	real hPrime = h / 60;
+
+	real X = C * (1 - abs(hPrime % 2 - 1));
+
+	real r, g, b;
+
+	if(h is real.nan)
+		r = g = b = 0;
+	else if (hPrime >= 0 && hPrime < 1) {
+		r = C;
+		g = X;
+		b = 0;
+	} else if (hPrime >= 1 && hPrime < 2) {
+		r = X;
+		g = C;
+		b = 0;
+	} else if (hPrime >= 2 && hPrime < 3) {
+		r = 0;
+		g = C;
+		b = X;
+	} else if (hPrime >= 3 && hPrime < 4) {
+		r = 0;
+		g = X;
+		b = C;
+	} else if (hPrime >= 4 && hPrime < 5) {
+		r = X;
+		g = 0;
+		b = C;
+	} else if (hPrime >= 5 && hPrime < 6) {
+		r = C;
+		g = 0;
+		b = X;
+	}
+
+	real m = l - C / 2;
+
+	r += m;
+	g += m;
+	b += m;
+
+	return Color(
+		cast(ubyte)(r * 255),
+		cast(ubyte)(g * 255),
+		cast(ubyte)(b * 255),
+		255);
+}
+
+real[3] toHsl(Color c) {
+	real r1 = cast(real) c.r / 255;
+	real g1 = cast(real) c.g / 255;
+	real b1 = cast(real) c.b / 255;
+
+	real maxColor = max(r1, g1, b1);
+	real minColor = min(r1, g1, b1);
+
+	real L = (maxColor + minColor) / 2 ;
+	real S = 0;
+	real H = 0;
+	if(maxColor != minColor) {
+		if(L < 0.5) {
+			S = (maxColor - minColor) / (maxColor + minColor);
+		} else {
+			S = (maxColor - minColor) / (2.0 - maxColor - minColor);
+		}
+		if(r1 == maxColor) {
+			H = (g1-b1) / (maxColor - minColor);
+		} else if(g1 == maxColor) {
+			H = 2.0 + (b1 - r1) / (maxColor - minColor);
+		} else {
+			H = 4.0 + (r1 - g1) / (maxColor - minColor);
+		}
+	}
+
+	H = H * 60;
+	if(H < 0){
+		H += 360;
+	}
+
+	return [H, S, L]; 
+}
+/*
+void main(string[] args) {
+	auto color1 = toHsl(Color(255, 0, 0));
+	auto color = fromHsl(color1[0] + 60, color1[1], color1[2]);
+
+	writefln("#%02x%02x%02x", color.r, color.g, color.b);
+}
+*/