Extracting more than one wallpaper prominent color

ui/gfx/color_analysis.cc

Index: ui/gfx/color_analysis.cc
diff --git a/ui/gfx/color_analysis.cc b/ui/gfx/color_analysis.cc
index 6a2e87850f69ddbdfc9b2656616dcf5409b0310a..568adbaf3e5bfe3c005e108020e88c6eb7e90c3c 100644
--- a/ui/gfx/color_analysis.cc
+++ b/ui/gfx/color_analysis.cc
@@ -455,6 +455,57 @@ SkColor CalculateProminentColor(const SkBitmap& bitmap,
   return best_color;
 }
 
+SkColor CalculateProminentColorOfBitmap(const SkBitmap& bitmap,
+                                        LumaRange luma,
+                                        SaturationRange saturation) {
+  if (bitmap.empty() || bitmap.isNull())
+    return SK_ColorTRANSPARENT;
+
+  // The hue is not relevant to our bounds or goal colors.
+  HSL lower_bound = {
+      -1,
+  };
+  HSL upper_bound = {
+      -1,
+  };
+  HSL goal = {
+      -1,
+  };
+
+  switch (luma) {
+    case LumaRange::LIGHT:
+      lower_bound.l = 0.55f;
+      upper_bound.l = 1;
+      goal.l = 0.74f;
+      break;
+    case LumaRange::NORMAL:
+      lower_bound.l = 0.3f;
+      upper_bound.l = 0.7f;
+      goal.l = 0.5f;
+      break;
+    case LumaRange::DARK:
+      lower_bound.l = 0;
+      upper_bound.l = 0.45f;
+      goal.l = 0.26f;
+      break;
+  }
+
+  switch (saturation) {
+    case SaturationRange::VIBRANT:
+      lower_bound.s = 0.35f;
+      upper_bound.s = 1;
+      goal.s = 1;
+      break;
+    case SaturationRange::MUTED:
+      lower_bound.s = 0;
+      upper_bound.s = 0.4f;
+      goal.s = 0.3f;
+      break;
+  }
+
+  return CalculateProminentColor(bitmap, lower_bound, upper_bound, goal);

[bruthig, 2017/06/20 15:32:14]

estade@ will be able to better advise but IIUC CalculateProminentColor() is the
expensive part of the algorithm and it would be much much cheaper to only
process the image once and pull out the colors for the color profiles.  Where-as
this appears to be processing the image once per color profile which will be
unacceptably slow.

[Evan Stade, 2017/06/20 17:11:08]

yes, as explained in the email, we only want to repeat the last loop in
CalculateProminentColor (the one over box_colors). The rest of that function is
expensive and need not be repeated.

[Qiang(Joe) Xu, 2017/06/20 22:48:55]

done, thanks for explaining!

+}
+
 } // namespace
 
 KMeanImageSampler::KMeanImageSampler() {
@@ -723,55 +774,15 @@ SkColor CalculateKMeanColorOfBitmap(const SkBitmap& bitmap) {
       bitmap, kDefaultLowerHSLBound, kDefaultUpperHSLBound, &sampler);
 }
 
-SkColor CalculateProminentColorOfBitmap(const SkBitmap& bitmap,
-                                        LumaRange luma,
-                                        SaturationRange saturation) {
-  if (bitmap.empty() || bitmap.isNull())
-    return SK_ColorTRANSPARENT;
-
-  // The hue is not relevant to our bounds or goal colors.
-  HSL lower_bound = {
-      -1,
-  };
-  HSL upper_bound = {
-      -1,
-  };
-  HSL goal = {
-      -1,
-  };
-
-  switch (luma) {
-    case LumaRange::LIGHT:
-      lower_bound.l = 0.55f;
-      upper_bound.l = 1;
-      goal.l = 0.74f;
-      break;
-    case LumaRange::NORMAL:
-      lower_bound.l = 0.3f;
-      upper_bound.l = 0.7f;
-      goal.l = 0.5f;
-      break;
-    case LumaRange::DARK:
-      lower_bound.l = 0;
-      upper_bound.l = 0.45f;
-      goal.l = 0.26f;
-      break;
-  }
-
-  switch (saturation) {
-    case SaturationRange::VIBRANT:
-      lower_bound.s = 0.35f;
-      upper_bound.s = 1;
-      goal.s = 1;
-      break;
-    case SaturationRange::MUTED:
-      lower_bound.s = 0;
-      upper_bound.s = 0.4f;
-      goal.s = 0.3f;
-      break;
+std::vector<SkColor> CalculateProminentColorsOfBitmap(
+    const SkBitmap& bitmap,
+    const ColorProfiles& color_profiles) {
+  std::vector<SkColor> colors;
+  for (auto profile : color_profiles) {
+    colors.push_back(CalculateProminentColorOfBitmap(bitmap, profile.luma,
+                                                     profile.saturation));
   }
-
-  return CalculateProminentColor(bitmap, lower_bound, upper_bound, goal);
+  return colors;
 }
 
 gfx::Matrix3F ComputeColorCovariance(const SkBitmap& bitmap) {