HaikuControlLook: De-convolute edge color computation.

Previously it used "contrast" and "brightness" values that were
computed in strange ways. Now it behaves more like the other
color computation functions and deals with the "flags" directly.

Comparing many controls, colors on button frames in all states appear
to be the same (or nearly the same, within 1-2 RGB values) before
and after this change.


Change-Id: Ia6d696c29fc76c73c88cc97af97ea45e1ff089ff
Reviewed-on: https://review.haiku-os.org/c/haiku/+/9321
Reviewed-by: waddlesplash <[email protected]>

headers/private/interface/HaikuControlLook.h

@@ -347,14 +347,11 @@ protected:
 									float rightBottomRadius,
 									const rgb_color& base,
 									const rgb_color& background,
-									float contrast, float brightness = 1.0,
 									uint32 flags = 0,
 									uint32 borders = B_ALL_BORDERS);
 
 			void				_DrawOuterResessedFrame(BView* view,
 									BRect& rect, const rgb_color& base,
-									float contrast = 1.0f,
-									float brightness = 1.0f,
 									uint32 flags = 0,
 									uint32 borders = B_ALL_BORDERS);
 
@@ -529,13 +526,8 @@ protected:
 									orientation orientation);
 
 	// Border color methods
-			rgb_color			_EdgeLightColor(const rgb_color& base,
-									float contrast, float brightness,
-									uint32 flags);
-
-			rgb_color			_EdgeShadowColor(const rgb_color& base,
-									float contrast, float brightness,
-									uint32 flags);
+			rgb_color			_EdgeColor(const rgb_color& base,
+									bool shadow, uint32 flags);
 
 			rgb_color			_FrameLightColor(const rgb_color& base,
 									uint32 flags);