Extracting more than one wallpaper prominent color

components/wallpaper/wallpaper_color_calculator.cc

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/wallpaper/wallpaper_color_calculator.h"
 
 #include <string>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/task_runner.h"
 #include "base/task_runner_util.h"
 #include "components/wallpaper/wallpaper_color_calculator_observer.h"
 
 namespace wallpaper {
 
 namespace {
 
 // The largest image size, in pixels, to synchronously calculate the prominent
 // color. This is a simple heuristic optimization because extraction on images
 // smaller than this should run very quickly, and offloading the task to another
 // thread would actually take longer.
 const int kMaxPixelsForSynchronousCalculation = 100;
 
-// Wrapper for color_utils::CalculateProminentColorOfBitmap() that records
+// Wrapper for color_utils::CalculateProminentColorsOfBitmap() that records
 // wallpaper specific metrics.
 //
 // NOTE: |image| is intentionally a copy to ensure it exists for the duration of
 // the calculation.
-SkColor CalculateWallpaperColor(const gfx::ImageSkia image,
-                                color_utils::LumaRange luma,
-                                color_utils::SaturationRange saturation) {
+std::vector<SkColor> CalculateWallpaperColor(
+    const gfx::ImageSkia image,
+    const color_utils::ColorProfiles& color_profiles) {
   base::TimeTicks start_time = base::TimeTicks::Now();
-  const SkColor prominent_color = color_utils::CalculateProminentColorOfBitmap(
-      *image.bitmap(), luma, saturation);
+  const std::vector<SkColor> prominent_colors =
+      color_utils::CalculateProminentColorsOfBitmap(*image.bitmap(),
+                                                    color_profiles);
 
-  UMA_HISTOGRAM_TIMES("Ash.Wallpaper.ColorExtraction.Durations",
-                      base::TimeTicks::Now() - start_time);
-  UMA_HISTOGRAM_BOOLEAN("Ash.Wallpaper.ColorExtractionResult",
-                        prominent_color != SK_ColorTRANSPARENT);
+  // TODO(warx): reconsider these UMAs for multiple colors calculation.

[Qiang(Joe) Xu, 2017/06/19 22:51:30]

This is a workaround to please the wallpaper_color_calculator_unittest

+  if (1u == color_profiles.size()) {
+    UMA_HISTOGRAM_TIMES("Ash.Wallpaper.ColorExtraction.Durations",
+                        base::TimeTicks::Now() - start_time);
+    UMA_HISTOGRAM_BOOLEAN("Ash.Wallpaper.ColorExtractionResult",
+                          prominent_colors[0] != SK_ColorTRANSPARENT);
+  }
 
-  return prominent_color;
+  return prominent_colors;
 }
 
 bool ShouldCalculateSync(const gfx::ImageSkia& image) {
   return image.width() * image.height() <= kMaxPixelsForSynchronousCalculation;
 }
 
 }  // namespace
 
 WallpaperColorCalculator::WallpaperColorCalculator(
     const gfx::ImageSkia& image,
-    color_utils::LumaRange luma,
-    color_utils::SaturationRange saturation,
+    const color_utils::ColorProfiles& color_profiles,
     scoped_refptr<base::TaskRunner> task_runner)
     : image_(image),
-      luma_(luma),
-      saturation_(saturation),
+      color_profiles_(color_profiles),
       task_runner_(std::move(task_runner)),
-      weak_ptr_factory_(this) {}
+      weak_ptr_factory_(this) {
+  prominent_colors_ =
+      std::vector<SkColor>(color_profiles_.size(), SK_ColorTRANSPARENT);
+}
 
-WallpaperColorCalculator::~WallpaperColorCalculator() {}
+WallpaperColorCalculator::~WallpaperColorCalculator() = default;
 
 void WallpaperColorCalculator::AddObserver(
     WallpaperColorCalculatorObserver* observer) {
   observers_.AddObserver(observer);
 }
 
 void WallpaperColorCalculator::RemoveObserver(
     WallpaperColorCalculatorObserver* observer) {
   observers_.RemoveObserver(observer);
 }
 
 bool WallpaperColorCalculator::StartCalculation() {
   if (ShouldCalculateSync(image_)) {
-    const SkColor prominent_color =
-        CalculateWallpaperColor(image_, luma_, saturation_);
-    NotifyCalculationComplete(prominent_color);
+    const std::vector<SkColor> prominent_colors =
+        CalculateWallpaperColor(image_, color_profiles_);
+    NotifyCalculationComplete(prominent_colors);
     return true;
   }
 
   image_.MakeThreadSafe();
   if (base::PostTaskAndReplyWithResult(
           task_runner_.get(), FROM_HERE,
-          base::Bind(&CalculateWallpaperColor, image_, luma_, saturation_),
+          base::Bind(&CalculateWallpaperColor, image_, color_profiles_),
           base::Bind(&WallpaperColorCalculator::OnAsyncCalculationComplete,
                      weak_ptr_factory_.GetWeakPtr(), base::TimeTicks::Now()))) {
     return true;
   }
 
   LOG(WARNING) << "PostSequencedWorkerTask failed. "
-               << "Wallpaper promiment color may not be calculated.";
+               << "Wallpaper prominent colors may not be calculated.";
 
-  prominent_color_ = SK_ColorTRANSPARENT;
+  prominent_colors_ =
+      std::vector<SkColor>(color_profiles_.size(), SK_ColorTRANSPARENT);
   return false;
 }
 
 void WallpaperColorCalculator::SetTaskRunnerForTest(
     scoped_refptr<base::TaskRunner> task_runner) {
   task_runner_ = task_runner;
 }
 
 void WallpaperColorCalculator::OnAsyncCalculationComplete(
     base::TimeTicks async_start_time,
-    SkColor prominent_color) {
+    const std::vector<SkColor>& prominent_colors) {
   UMA_HISTOGRAM_TIMES("Ash.Wallpaper.ColorExtraction.UserDelay",
                       base::TimeTicks::Now() - async_start_time);
-  NotifyCalculationComplete(prominent_color);
+  NotifyCalculationComplete(prominent_colors);
 }
 
 void WallpaperColorCalculator::NotifyCalculationComplete(
-    SkColor prominent_color) {
-  prominent_color_ = prominent_color;
+    const std::vector<SkColor>& prominent_colors) {
+  prominent_colors_ = prominent_colors;
   for (auto& observer : observers_)
     observer.OnColorCalculationComplete();
 
   // This could be deleted!
 }
 
 }  // namespace wallpaper