Added HSL colour conversion

colours.c

@@ -21,7 +21,7 @@ struct ColourRGB HSVtoRGB(struct ColourHSV hsv)
 	double m;
 
 	c = hsv.s * hsv.v;
-	x = c * (1 - fabs(fmod(hsv.h / 60.0, 2) - 1));
+	x = c * (1.0 - fabs(fmod(hsv.h / 60.0, 2) - 1.0));
 	m = hsv.v - c;
 
 	int angle = hsv.h / 60;
@@ -79,16 +79,76 @@ struct ColourRGB HSVtoRGB(struct ColourHSV hsv)
 	return result;
 }
 
-// struct ColourRGB HSLtoRGB(struct ColourHSL hsl)
+struct ColourRGB HSLtoRGB(struct ColourHSL hsl)
-// {
+{
+	struct ColourRGB result;
+	double c;
+	double x;
+	double m;
 
-// }
+	c = hsl.s * (1.0 - fabs(2 * hsl.l - 1));
+	x = c * (1.0 - fabs(fmod(hsl.h / 60.0, 2) - 1.0));
+	m = hsl.l - c/2;
+
+	int angle = hsl.h / 60;
+	switch (angle)
+	{
+	// 0 - 60
+	case 6:
+	case 0:
+		result.r = c;
+		result.g = x;
+		result.b = 0;
+		break;
+	// 60 - 120
+	case 1:
+		result.r = x;
+		result.g = c;
+		result.b = 0;
+		break;
+	// 120 - 180
+	case 2:
+		result.r = 0;
+		result.g = c;
+		result.b = x;
+		break;
+	// 180 - 240
+	case 3:
+		result.r = 0;
+		result.g = x;
+		result.b = c;
+		break;
+	// 240 - 300
+	case 4:
+		result.r = x;
+		result.g = 0;
+		result.b = c;
+		break;
+	// 300 - 360
+	case 5:
+		result.r = c;
+		result.g = 0;
+		result.b = x;
+		break;
+	// Should never happen
+	default:
+		result.r = 0;
+		result.g = 0;
+		result.b = 0;
+		break;
+	}
+
+	result.r += m;
+	result.g += m;
+	result.b += m;
+
+	return result;
+}
 
 struct ColourCMYK RGBtoCMYK(struct ColourRGB rgb)
 {
 	struct ColourCMYK result;
 
-
 	// max(r,g,b)
 	result.k = rgb.r > rgb.g ? rgb.r : rgb.g;
 	result.k = rgb.b > result.k ? rgb.b : result.k;
@@ -119,6 +179,15 @@ struct ColourCMYK HSVtoCMYK(struct ColourHSV hsv)
 	return result;
 }
 
+struct ColourCMYK HSLtoCMYK(struct ColourHSL hsl)
+{
+	struct ColourCMYK result;
+
+	result = RGBtoCMYK(HSLtoRGB(hsl));
+
+	return result;
+}
+
 struct ColourHSV RGBtoHSV(struct ColourRGB rgb)
 {
 	struct ColourHSV result;
@@ -152,16 +221,8 @@ struct ColourHSV RGBtoHSV(struct ColourRGB rgb)
 			result.h = 60 * ((rgb.r - rgb.g) / delta + 4);
 		}
 
-		if(c_max > 0)
-		{
-			result.s = delta / c_max;
-		}
-		else
-		{
-			result.s = 0;
-		}
-
 		result.v = c_max;
+		result.s = delta / result.v;
 	}
 	else
 	{
@@ -186,3 +247,81 @@ struct ColourHSV CMYKtoHSV(struct ColourCMYK cmyk)
 
 	return result;
 }
+
+struct ColourHSV HSLtoHSV(struct ColourHSL hsl)
+{
+	struct ColourHSV result;
+
+	result = RGBtoHSV(HSLtoRGB(hsl));
+
+	return result;
+}
+
+struct ColourHSL RGBtoHSL(struct ColourRGB rgb)
+{
+	struct ColourHSL result;
+
+	double c_max;
+	double c_min;
+	double delta;
+
+	// max(r,g,b)
+	c_max = rgb.r > rgb.g ? rgb.r : rgb.g;
+	c_max = rgb.b > c_max ? rgb.b : c_max;
+
+	// min(r,g,b)
+	c_min = rgb.r < rgb.g ? rgb.r : rgb.g;
+	c_min = rgb.b < c_min ? rgb.b : c_min;
+
+	delta = c_max - c_min;
+
+	if (delta > 0)
+	{
+		if (c_max == rgb.r)
+		{
+			result.h = 60 * fmod((rgb.g - rgb.b) / delta, 6);
+		}
+		else if (c_max == rgb.g)
+		{
+			result.h = 60 * ((rgb.b - rgb.r) / delta + 2);
+		}
+		else
+		{
+			result.h = 60 * ((rgb.r - rgb.g) / delta + 4);
+		}
+
+		result.l = (c_max + c_min) / 2;
+		result.s = delta / (1.0 - fabs(2 * result.l - 1.0));
+	}
+	else
+	{
+		result.h = 0;
+		result.s = 0;
+		result.l = (c_max + c_min) / 2;
+	}
+
+	if (result.h < 0)
+	{
+		result.h += 360;
+	}
+
+	return result;
+}
+
+struct ColourHSL CMYKtoHSL(struct ColourCMYK cmyk)
+{
+	struct ColourHSL result;
+
+	result = RGBtoHSL(CMYKtoRGB(cmyk));
+
+	return result;
+}
+
+struct ColourHSL HSVtoHSL(struct ColourHSV hsv)
+{
+	struct ColourHSL result;
+
+	result = RGBtoHSL(HSVtoRGB(hsv));
+
+	return result;
+}

colours.h

@@ -32,18 +32,18 @@ struct ColourHSL
 
 struct ColourRGB CMYKtoRGB(struct ColourCMYK cmyk);
 struct ColourRGB HSVtoRGB(struct ColourHSV hsv);
-// struct ColourRGB HSLtoRGB(struct ColourHSL hsl);
+struct ColourRGB HSLtoRGB(struct ColourHSL hsl);
 
 struct ColourCMYK RGBtoCMYK(struct ColourRGB rgb);
 struct ColourCMYK HSVtoCMYK(struct ColourHSV hsv);
-// struct ColourCMYK HSLtoCMYK(struct ColourHSL hsl);
+struct ColourCMYK HSLtoCMYK(struct ColourHSL hsl);
 
 struct ColourHSV RGBtoHSV(struct ColourRGB rgb);
 struct ColourHSV CMYKtoHSV(struct ColourCMYK cmyk);
-// struct ColourHSV HSLtoHSV(struct ColourHSL hsl);
+struct ColourHSV HSLtoHSV(struct ColourHSL hsl);
 
 struct ColourHSL RGBtoHSL(struct ColourRGB rgb);
 struct ColourHSL CMYKtoHSL(struct ColourCMYK cmyk);
-// struct ColourHSL HSVtoHSL(struct ColourHSV hsv);
+struct ColourHSL HSVtoHSL(struct ColourHSV hsv);
 
 #endif // COLOURS_H_