feat: added support for hsl colors (#924)

include/dpp/utility.h

@@ -420,6 +420,26 @@ namespace dpp {
 		 */
 		uint32_t DPP_EXPORT cmyk(int c, int m, int y, int k);
 
+		/**
+		 * @brief Convert doubles to HSL for sending in embeds
+		 *
+		 * @param h hue value, between 0 and 1 inclusive
+		 * @param s saturation value in percentage, between 0 and 1 inclusive
+		 * @param l lightness value in percentage, between 0 and 1 inclusive
+		 * @return uint32_t returned integer colour value
+		 */
+		uint32_t DPP_EXPORT hsl(double h, double s, double l);
+
+		/**
+		 * @brief Convert ints to HSL for sending in embeds
+		 *
+		 * @param h hue value, between 0 and 360 inclusive
+		 * @param s saturation value in percentage, between 0 and 100 inclusive
+		 * @param l lightness value in percentage, between 0 and 100 inclusive
+		 * @return uint32_t returned integer colour value
+		 */
+		uint32_t DPP_EXPORT hsl(int h, int s, int l);
+
 		/**
 		 * @brief Output hex values of a section of memory for debugging
 		 * 

src/dpp/utility.cpp

@@ -299,7 +299,45 @@ namespace dpp {
 		uint32_t cmyk(int c, int m, int y, int k) {
 			return cmyk(c / 255.0, m / 255.0, y / 255.0, k / 255.0);
 		}
+
+		uint32_t hsl(int h, int s, int l) {
+			double hue = static_cast<double>(h) / 360.0;
+			double saturation = static_cast<double>(s) / 100.0;
+			double lightness = static_cast<double>(l) / 100.0;
+			return hsl(hue, saturation, lightness);
+		}
 
+		uint32_t hsl(double h, double s, double l) {
+			const auto hue_to_rgb = [](double p, double q, double t){
+				if (t < 0) {
+					t += 1;
+				} else if (t > 1) {
+					t -= 1;
+				} 
+				if (t < 1.0 / 6.0) {
+					return p + (q - p) * 6.0 * t;
+				} else if (t < 0.5) {
+					return q;
+				} else if (t < 2.0 / 3.0) {
+					return p + (q - p) * (2.0 / 3.0 - t) * 6.0;
+				}
+				return p;
+			};
+
+			double r, g, b;
+
+			if (s == 0) {
+				r = g = b = l; // Gray scale
+			} else {
+				double q = l < 0.5 ? l * (1 + s) : l + s - l * s;
+				double p = 2 * l - q;
+				r = hue_to_rgb(p, q, h + 1.0 / 3.0);
+				g = hue_to_rgb(p, q, h);
+				b = hue_to_rgb(p, q, h - 1.0 / 3.0);
+			}
+			return rgb(r, g, b);
+		}
+
 		void exec(const std::string& cmd, std::vector<std::string> parameters, cmd_result_t callback) {
 			auto t = std::thread([cmd, parameters, callback]() {
 				utility::set_thread_name("async_exec");