fix: Wrong RGB -> HSL convertion (#505)

Tests will follow as part of #690
boostorg · Jun 24, 2022 · 5273678 · 5273678
1 parent 1c6c427
commit 5273678
Showing 1 changed file with 4 additions and 5 deletions.
diff --git a/include/boost/gil/extension/toolbox/color_spaces/hsl.hpp b/include/boost/gil/extension/toolbox/color_spaces/hsl.hpp
@@ -75,6 +75,7 @@ struct default_color_converter_impl< rgb_t, hsl_t >
       {
 
          float32_t diff = max_color - min_color;
+         float32_t sum = max_color + min_color;
 
          // lightness calculation
 
@@ -84,13 +85,11 @@ struct default_color_converter_impl< rgb_t, hsl_t >
 
          if( lightness < 0.5f )
          {
-            saturation = diff
-                       / ( min_color + max_color );
+            saturation = diff / ( sum );
          }
          else
          {
-            saturation = ( max_color - min_color )
-                       / ( 2.f - diff );
+            saturation = diff / ( 2.f - sum );
 
          }
 
@@ -115,7 +114,7 @@ struct default_color_converter_impl< rgb_t, hsl_t >
          {
             // max_color is blue
             hue = 4.f
-                + ( temp_red - temp_blue )
+                + ( temp_red - temp_green )
                 / diff;
          }