Merge pull request 'Libraries/Graphics2D: Added RGB to HSV and HSV to RGB conversion' (#9) from GasInfinity/erythros:master into master

Reviewed-on: https://git.checksum.fail/alec/erythros/pulls/9

1 files changed, 81 insertions, 0 deletions

diff --git a/Boot/Libraries/Graphics2D.HC b/Boot/Libraries/Graphics2D.HC
index 000332a..446ff26 100644
--- a/Boot/Libraries/Graphics2D.HC
+++ b/Boot/Libraries/Graphics2D.HC
@@ -21,6 +21,87 @@ U32 Color(I64 r, I64 g, I64 b, I64 a = 255) {
   return c;
 }
 
+U32 ColorHSVToRGB(I64 hue, I64 saturation, I64 value) {
+  if(!(0 <= hue < 360))
+    hue = 0;
+  if(!(0 <= saturation <= 100))
+    saturation = 100;
+  if(!(0 <= value <= 100))
+    value = 100;
+
+  F64 s = saturation / 100.0;
+  F64 v = value / 100.0;
+
+  F64 c = v * s;
+  F64 x = c * (1 - Abs(((hue / 60.0) % 2) - 1));
+  F64 m = v - c;
+
+  F64 r, g, b;
+  switch(hue) {
+    case 0...59:
+      r = c;
+      g = x;
+      b = 0;
+      break;
+    case 60...119:
+      r = x;
+      g = c;
+      b = 0;
+      break;
+    case 120...179:
+      r = 0;
+      g = c;
+      b = x;
+      break;
+    case 180...239:
+      r = 0;
+      g = x;
+      b = c;
+      break;
+    case 240...299:
+      r = x;
+      g = 0;
+      b = c;
+      break;
+    case 300...359:
+      r = c;
+      g = 0;
+      b = x;
+      break;
+  }
+
+  return Color(ToI64((r + m) * 255), ToI64((g + m) * 255), ToI64((b + m) * 255));
+}
+
+U0 ColorRGBToHSV(U32 color, I64 *hue, I64 *saturation, I64 *value) {
+  if(!hue || !saturation || !value)
+    return;
+  
+  F64 r = color.u8[2] / 255.0;
+  F64 g = color.u8[1] / 255.0;
+  F64 b = color.u8[0] / 255.0;
+
+  F64 cMax = Max(r, Max(g, b));
+  F64 cMin = Min(r, Min(g, b));
+
+  F64 delta = cMax - cMin;
+
+  if(delta == 0)
+    *hue = 0;
+  else if(cMax == r)
+    *hue = 60 * (((g - b) / delta) % 6);
+  else if(cMax == g)
+    *hue = 60 * (((b - r) / delta) + 2);
+  else
+    *hue = 60 * (((r - g) / delta) + 4);
+
+  if(cMax != 0)
+    *saturation = (delta / cMax) * 100;
+  else
+    *saturation = 0;
+  *value = cMax * 100;
+}
+
 /*
  * ISO Latin-1 Font
  *