Add ability to constrain dominant color selection to a HSL range.

ui/gfx/color_utils.cc

Index: ui/gfx/color_utils.cc
diff --git a/ui/gfx/color_utils.cc b/ui/gfx/color_utils.cc
index de429495990ae13bcfaaac696953599f87c788ce..25f072f2ef723f5c9e2808c5aa20f32835ba7339 100644
--- a/ui/gfx/color_utils.cc
+++ b/ui/gfx/color_utils.cc
@@ -151,6 +151,22 @@ SkColor HSLToSkColor(const HSL& hsl, SkAlpha alpha) {
       calcHue(temp1, temp2, hue - 1.0 / 3.0));
 }
 
+bool IsWithinHSLRange(const HSL& hsl,
+                      const HSL& lower_bound,
+                      const HSL& upper_bound) {
+  DCHECK(hsl.h >= 0 && hsl.h < 1);

[Matt Giuca, 2014/05/22 05:03:52]

Your comment says this is inclusive, inclusive. What did you end up deciding?

[Matt Giuca, 2014/05/22 05:03:52]

Should also DCHECK the hsl.s and hsl.l, as well as the bounds.

DCHECK(lower_bound.h >= 0 && lower_bound.h <= 1);
DCHECK(upper_bound.h >= lower_bound.h && upper_bound.h <= lower_bound.h + 1);
and so on.

[calamity, 2014/05/22 07:36:36]

The comment says the bounds are inclusive, inclusive. This is an assertion about
the input color. Amended comment and added those checks.

[calamity, 2014/05/22 07:36:36]

Values can be negative to specify ignore.
DCHECKed what I could.

+
+  // If the upper hue is >1, the given hue bounds wrap around at 1.
+  bool matches_hue = upper_bound.h > 1
+                         ? hsl.h >= lower_bound.h || hsl.h <= upper_bound.h - 1
+                         : hsl.h >= lower_bound.h && hsl.h <= upper_bound.h;
+  return (upper_bound.h < 0 || lower_bound.h < 0 || matches_hue) &&
+         (upper_bound.s < 0 || lower_bound.s < 0 ||
+          (hsl.s >= lower_bound.s && hsl.s <= upper_bound.s)) &&
+         (upper_bound.l < 0 || lower_bound.l < 0 ||
+          (hsl.l >= lower_bound.l && hsl.l <= upper_bound.l));
+}
+
 SkColor HSLShift(SkColor color, const HSL& shift) {
   HSL hsl;
   int alpha = SkColorGetA(color);