CrOS Shelf: Calculate color for shelf notification badges

The color for the shelf notification badges is calculated by getting a
light vibrant color from the shelf app icon image. If no color can be
calculated then white is used as the default notification color.

Bug: 1080827
Change-Id: I2b858b7c15f1a54191afe063716c64a9fa58b925
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2241291
Commit-Queue: Matthew Mourgos <mmourgos@chromium.org>
Reviewed-by: Toni Baržić <tbarzic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#796037}

ash/BUILD.gn

@@ -1910,6 +1910,7 @@ test("ash_unittests") {
     "shelf/login_shelf_gesture_controller_unittest.cc",
     "shelf/login_shelf_view_unittest.cc",
     "shelf/scrollable_shelf_view_unittest.cc",
+    "shelf/shelf_app_button_unittest.cc",
     "shelf/shelf_application_menu_model_unittest.cc",
     "shelf/shelf_background_animator_unittest.cc",
     "shelf/shelf_button_pressed_metric_tracker_unittest.cc",

ash/shelf/shelf_app_button.cc

@@ -28,6 +28,7 @@
 #include "ui/gfx/animation/animation_delegate.h"
 #include "ui/gfx/animation/throb_animation.h"
 #include "ui/gfx/canvas.h"
+#include "ui/gfx/color_analysis.h"
 #include "ui/gfx/geometry/vector2d.h"
 #include "ui/gfx/image/image_skia_operations.h"
 #include "ui/gfx/scoped_canvas.h"
@@ -48,10 +49,10 @@ constexpr int kStatusIndicatorActiveSize = 8;
 constexpr int kStatusIndicatorRunningSize = 4;
 constexpr int kStatusIndicatorThickness = 2;
 constexpr int kNotificationIndicatorRadiusDip = 7;
-constexpr SkColor kIndicatorColor = SK_ColorWHITE;
+constexpr SkColor kDefaultIndicatorColor = SK_ColorWHITE;
 
 // Slightly different colors and alpha in the new UI.
-constexpr SkColor kIndicatorColorActive = kIndicatorColor;
+constexpr SkColor kIndicatorColorActive = kDefaultIndicatorColor;
 constexpr SkColor kIndicatorColorRunning = SkColorSetA(SK_ColorWHITE, 0x7F);
 
 // The time threshold before an item can be dragged.
@@ -66,6 +67,30 @@ constexpr float kAppIconScale = 1.2f;
 // The drag and drop app icon scaling up or down animation transition duration.
 constexpr int kDragDropAppIconScaleTransitionMs = 200;
 
+// Uses the icon image to calculate the light vibrant color to be used for
+// the notification indicator.
+base::Optional<SkColor> CalculateNotificationColor(gfx::ImageSkia image) {
+  const SkBitmap* source = image.bitmap();
+  if (!source || source->empty() || source->isNull())
+    return base::nullopt;
+
+  std::vector<color_utils::ColorProfile> color_profiles;
+  color_profiles.push_back(color_utils::ColorProfile(
+      color_utils::LumaRange::LIGHT, color_utils::SaturationRange::VIBRANT));
+
+  std::vector<color_utils::Swatch> best_swatches =
+      color_utils::CalculateProminentColorsOfBitmap(
+          *source, color_profiles, nullptr /* bitmap region */,
+          color_utils::ColorSwatchFilter());
+
+  // If the best swatch color is transparent, then
+  // CalculateProminentColorsOfBitmap() failed to find a suitable color.
+  if (best_swatches.empty() || best_swatches[0].color == SK_ColorTRANSPARENT)
+    return base::nullopt;
+
+  return best_swatches[0].color;
+}
+
 // Simple AnimationDelegate that owns a single ThrobAnimation instance to
 // keep all Draw Attention animations in sync.
 class ShelfAppButtonAnimation : public gfx::AnimationDelegate {
@@ -177,8 +202,15 @@ class ShelfAppButton::AppNotificationIndicatorView : public views::View {
         flags);
   }
 
+  void SetColor(SkColor new_color) {
+    indicator_color_ = new_color;
+    SchedulePaint();
+  }
+
+  SkColor GetColorForTest() { return indicator_color_; }
+
  private:
-  const SkColor indicator_color_;
+  SkColor indicator_color_;
 
   DISALLOW_COPY_AND_ASSIGN(AppNotificationIndicatorView);
 };
@@ -343,7 +375,8 @@ ShelfAppButton::ShelfAppButton(ShelfView* shelf_view,
   AddChildView(indicator_);
   AddChildView(icon_view_);
   if (is_notification_indicator_enabled_) {
-    notification_indicator_ = new AppNotificationIndicatorView(kIndicatorColor);
+    notification_indicator_ =
+        new AppNotificationIndicatorView(kDefaultIndicatorColor);
     notification_indicator_->SetPaintToLayer();
     notification_indicator_->layer()->SetFillsBoundsOpaquely(false);
     notification_indicator_->SetVisible(false);
@@ -383,6 +416,13 @@ void ShelfAppButton::SetImage(const gfx::ImageSkia& image) {
   }
   icon_image_ = image;
 
+  if (is_notification_indicator_enabled_) {
+    base::Optional<SkColor> notification_color =
+        CalculateNotificationColor(icon_image_);
+    notification_indicator_->SetColor(
+        notification_color.value_or(kDefaultIndicatorColor));
+  }
+
   const int icon_size = shelf_view_->GetButtonIconSize() * icon_scale_;
 
   // Resize the image maintaining our aspect ratio.
@@ -918,4 +958,8 @@ void ShelfAppButton::SetInkDropAnimationStarted(bool started) {
   }
 }
 
+SkColor ShelfAppButton::GetNotificationIndicatorColorForTest() {
+  return notification_indicator_->GetColorForTest();
+}
+
 }  // namespace ash

ash/shelf/shelf_app_button.h

@@ -118,6 +118,9 @@ class ASH_EXPORT ShelfAppButton : public ShelfButton,
   // Return the bounds in the local coordinates enclosing the small ripple area.
   gfx::Rect CalculateSmallRippleArea() const;
 
+  // Gets the color of the |notification_indicator_| for test usage.
+  SkColor GetNotificationIndicatorColorForTest();
+
  protected:
   // ui::EventHandler:
   void OnGestureEvent(ui::GestureEvent* event) override;

ash/shelf/shelf_app_button_unittest.cc

+// Copyright 2020 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 "ash/shelf/shelf_app_button.h"
+
+#include "ash/shelf/shelf_test_util.h"
+#include "ash/shelf/shelf_view.h"
+#include "ash/shelf/shelf_view_test_api.h"
+#include "ash/test/ash_test_base.h"
+#include "base/test/scoped_feature_list.h"
+#include "ui/base/ui_base_features.h"
+#include "ui/gfx/color_palette.h"
+
+namespace ash {
+
+class ShelfAppButtonTest : public AshTestBase {
+ public:
+  ShelfAppButtonTest() {
+    scoped_feature_list_.InitWithFeatures({features::kNotificationIndicator},
+                                          {});
+  }
+  ~ShelfAppButtonTest() override = default;
+
+  // AshTestBase:
+  void SetUp() override {
+    AshTestBase::SetUp();
+
+    test_api_.reset(
+        new ShelfViewTestAPI(GetPrimaryShelf()->GetShelfViewForTesting()));
+  }
+
+  void TearDown() override {
+    test_api_.reset();
+    AshTestBase::TearDown();
+  }
+
+  ShelfViewTestAPI* test_api() { return test_api_.get(); }
+
+  void SetImageForButton(int button_num, gfx::ImageSkia image) {
+    test_api()->GetButton(button_num)->SetImage(image);
+  }
+
+  SkColor GetNotificationColorForButton(int button_num) {
+    return test_api()
+        ->GetButton(button_num)
+        ->GetNotificationIndicatorColorForTest();
+  }
+
+ private:
+  std::unique_ptr<ShelfViewTestAPI> test_api_;
+
+  base::test::ScopedFeatureList scoped_feature_list_;
+};
+
+// Test that the notification indicator has a color which is calculated
+// correctly when an image is set for the ShelfAppButton.
+TEST_F(ShelfAppButtonTest, NotificatonBadgeColor) {
+  ShelfTestUtil::AddAppShortcut("app_id", TYPE_PINNED_APP);
+
+  const int width = 64;
+  const int height = 64;
+
+  SkBitmap all_black_icon;
+  all_black_icon.allocN32Pixels(width, height);
+  all_black_icon.eraseColor(SK_ColorBLACK);
+
+  SetImageForButton(0, gfx::ImageSkia::CreateFrom1xBitmap(all_black_icon));
+
+  // For an all black icon, a white notification badge is expected, since there
+  // is no other light vibrant color to get from the icon.
+  EXPECT_EQ(SK_ColorWHITE, GetNotificationColorForButton(0));
+
+  // Create an icon that is half kGoogleRed300 and half kGoogleRed600.
+  SkBitmap red_icon;
+  red_icon.allocN32Pixels(width, height);
+  red_icon.eraseColor(gfx::kGoogleRed300);
+  red_icon.erase(gfx::kGoogleRed600, {0, 0, width, height / 2});
+
+  SetImageForButton(0, gfx::ImageSkia::CreateFrom1xBitmap(red_icon));
+
+  // For the red icon, the notification badge should calculate and use the
+  // kGoogleRed300 color as the light vibrant color taken from the icon.
+  EXPECT_EQ(gfx::kGoogleRed300, GetNotificationColorForButton(0));
+}
+
+}  // namespace ash