Animate frame color change

ARC++ app may update the color programatically, which
can result in noticable flashing.

This will make the color change transition smooth by
animating the color from currently used color".

TBR=wutao@chromium.org
BUG=b/88534690
TEST=manual. also covered by unit test

Change-Id: Ia15976cb1ec425ddb4e23ec6a253667fa6f774d9
Reviewed-on: https://chromium-review.googlesource.com/1101504
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568474}

ash/frame/default_frame_header.cc

@@ -27,8 +27,10 @@ using views::Widget;
 namespace {
 
 // Color for the window title text.
-const SkColor kTitleTextColor = SkColorSetRGB(40, 40, 40);
-const SkColor kLightTitleTextColor = SK_ColorWHITE;
+constexpr SkColor kTitleTextColor = SkColorSetRGB(40, 40, 40);
+constexpr SkColor kLightTitleTextColor = SK_ColorWHITE;
+// This is 2x of the slide ainmation duration.
+constexpr int kColorUpdateDurationMs = 240;
 
 // Tiles an image into an area, rounding the top corners.
 void TileRoundRect(gfx::Canvas* canvas,
@@ -54,6 +56,35 @@ void TileRoundRect(gfx::Canvas* canvas,
 
 namespace ash {
 
+DefaultFrameHeader::ColorAnimator::ColorAnimator(
+    gfx::AnimationDelegate* delegate)
+    : animation_(delegate) {
+  animation_.SetSlideDuration(kColorUpdateDurationMs);
+  animation_.SetTweenType(gfx::Tween::EASE_IN);
+  animation_.Reset(1);
+}
+
+DefaultFrameHeader::ColorAnimator::ColorAnimator::~ColorAnimator() = default;
+
+void DefaultFrameHeader::ColorAnimator::SetTargetColor(SkColor target) {
+  target_color_ = target;
+  start_color_ = current_color_;
+  if (current_color_ == kDefaultFrameColor) {
+    // Changing from default should be set immediately.
+    current_color_ = target_color_;
+    animation_.Reset(1);
+  } else {
+    animation_.Reset(0);
+  }
+  animation_.Show();
+}
+
+SkColor DefaultFrameHeader::ColorAnimator::GetCurrentColor() {
+  current_color_ = color_utils::AlphaBlend(
+      target_color_, start_color_, animation_.CurrentValueBetween(0, 255));
+  return current_color_;
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 // DefaultFrameHeader, public:
 
@@ -62,8 +93,8 @@ DefaultFrameHeader::DefaultFrameHeader(
     views::View* header_view,
     FrameCaptionButtonContainerView* caption_button_container)
     : FrameHeader(target_widget, header_view),
-      active_frame_color_(kDefaultFrameColor),
-      inactive_frame_color_(kDefaultFrameColor) {
+      active_frame_color_(this),
+      inactive_frame_color_(this) {
   DCHECK(caption_button_container);
   SetCaptionButtonContainer(caption_button_container);
 }
@@ -93,8 +124,9 @@ void DefaultFrameHeader::DoPaintHeader(gfx::Canvas* canvas) {
 
   cc::PaintFlags flags;
   int active_alpha = activation_animation().CurrentValueBetween(0, 255);
-  flags.setColor(color_utils::AlphaBlend(active_frame_color_,
-                                         inactive_frame_color_, active_alpha));
+  flags.setColor(color_utils::AlphaBlend(
+      active_frame_color_.GetCurrentColor(),
+      inactive_frame_color_.GetCurrentColor(), active_alpha));
   flags.setAntiAlias(true);
   if (width_in_pixels_ > 0) {
     canvas->Save();
@@ -131,12 +163,12 @@ SkColor DefaultFrameHeader::GetTitleColor() const {
 void DefaultFrameHeader::SetFrameColorsImpl(SkColor active_frame_color,
                                             SkColor inactive_frame_color) {
   bool updated = false;
-  if (active_frame_color_ != active_frame_color) {
-    active_frame_color_ = active_frame_color;
+  if (active_frame_color_.target_color() != active_frame_color) {
+    active_frame_color_.SetTargetColor(active_frame_color);
     updated = true;
   }
-  if (inactive_frame_color_ != inactive_frame_color) {
-    inactive_frame_color_ = inactive_frame_color;
+  if (inactive_frame_color_.target_color() != inactive_frame_color) {
+    inactive_frame_color_.SetTargetColor(inactive_frame_color);
     updated = true;
   }
 
@@ -147,7 +179,17 @@ void DefaultFrameHeader::SetFrameColorsImpl(SkColor active_frame_color,
 }
 
 SkColor DefaultFrameHeader::GetCurrentFrameColor() const {
-  return mode() == MODE_ACTIVE ? active_frame_color_ : inactive_frame_color_;
+  return mode() == MODE_ACTIVE ? active_frame_color_.target_color()
+                               : inactive_frame_color_.target_color();
+}
+
+gfx::SlideAnimation*
+DefaultFrameHeader::GetAnimationForActiveFrameColorForTest() {
+  return active_frame_color_.animation();
+}
+
+SkColor DefaultFrameHeader::GetActiveFrameColorForPaintForTest() {
+  return active_frame_color_.GetCurrentColor();
 }
 
 }  // namespace ash

ash/frame/default_frame_header.h

@@ -9,6 +9,7 @@
 
 #include "ash/ash_export.h"
 #include "ash/frame/frame_header.h"
+#include "ash/public/cpp/ash_constants.h"
 #include "base/compiler_specific.h"  // override
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
@@ -27,8 +28,12 @@ class ASH_EXPORT DefaultFrameHeader : public FrameHeader {
 
   void SetThemeColor(SkColor theme_color);
 
-  SkColor active_frame_color_for_testing() { return active_frame_color_; }
-  SkColor inactive_frame_color_for_testing() { return inactive_frame_color_; }
+  SkColor active_frame_color_for_testing() {
+    return active_frame_color_.target_color();
+  }
+  SkColor inactive_frame_color_for_testing() {
+    return inactive_frame_color_.target_color();
+  }
 
  protected:
   // FrameHeader:
@@ -47,8 +52,34 @@ class ASH_EXPORT DefaultFrameHeader : public FrameHeader {
   void SetFrameColorsImpl(SkColor active_frame_color,
                           SkColor inactive_frame_color);
 
-  SkColor active_frame_color_;
-  SkColor inactive_frame_color_;
+  gfx::SlideAnimation* GetAnimationForActiveFrameColorForTest();
+  SkColor GetActiveFrameColorForPaintForTest();
+
+  // A utility class to animate color value.
+  class ColorAnimator {
+   public:
+    explicit ColorAnimator(gfx::AnimationDelegate* delegate);
+    ~ColorAnimator();
+
+    void SetTargetColor(SkColor target);
+    SkColor target_color() const { return target_color_; };
+    SkColor GetCurrentColor();
+    float get_value() const { return animation_.GetCurrentValue(); }
+
+    gfx::SlideAnimation* animation() { return &animation_; }
+
+   private:
+    gfx::SlideAnimation animation_;
+    SkColor start_color_ = kDefaultFrameColor;
+    SkColor target_color_ = kDefaultFrameColor;
+    ;
+    SkColor current_color_ = kDefaultFrameColor;
+
+    DISALLOW_COPY_AND_ASSIGN(ColorAnimator);
+  };
+
+  ColorAnimator active_frame_color_;
+  ColorAnimator inactive_frame_color_;
 
   int width_in_pixels_ = -1;
 

ash/frame/default_frame_header_unittest.cc

@@ -10,6 +10,8 @@
 #include "ash/frame/caption_buttons/frame_caption_button_container_view.h"
 #include "ash/public/cpp/shell_window_ids.h"
 #include "ash/test/ash_test_base.h"
+#include "ui/gfx/animation/animation_test_api.h"
+#include "ui/gfx/color_utils.h"
 #include "ui/views/test/test_views.h"
 #include "ui/views/widget/widget.h"
 #include "ui/views/window/non_client_view.h"
@@ -69,7 +71,6 @@ TEST_F(DefaultFrameHeaderTest, FrameColors) {
 
   DefaultFrameHeader frame_header(w.get(), w->non_client_view()->frame_view(),
                                   &container);
-
   // Check frame color is sensitive to mode.
   SkColor active = SkColorSetRGB(70, 70, 70);
   SkColor inactive = SkColorSetRGB(200, 200, 200);
@@ -78,6 +79,48 @@ TEST_F(DefaultFrameHeaderTest, FrameColors) {
   EXPECT_EQ(active, frame_header.GetCurrentFrameColor());
   frame_header.mode_ = FrameHeader::MODE_INACTIVE;
   EXPECT_EQ(inactive, frame_header.GetCurrentFrameColor());
+  EXPECT_EQ(active, frame_header.GetActiveFrameColorForPaintForTest());
+
+  // Update to the new value which has no blue, which should animate.
+  frame_header.mode_ = FrameHeader::MODE_ACTIVE;
+  SkColor new_active = SkColorSetRGB(70, 70, 0);
+  frame_header.SetFrameColors(new_active, SK_ColorBLACK);
+
+  gfx::SlideAnimation* animation =
+      frame_header.GetAnimationForActiveFrameColorForTest();
+  gfx::AnimationTestApi test_api(animation);
+
+  // animate half way through.
+  base::TimeTicks now = base::TimeTicks::Now();
+  test_api.SetStartTime(now);
+  test_api.Step(now + base::TimeDelta::FromMilliseconds(120));
+
+  // GetCurrentFrameColor should return the target color.
+  EXPECT_EQ(new_active, frame_header.GetCurrentFrameColor());
+
+  // The color used for paint should be somewhere between 0 and 70.
+  SkColor new_active_for_paint =
+      frame_header.GetActiveFrameColorForPaintForTest();
+  EXPECT_NE(new_active, new_active_for_paint);
+  EXPECT_EQ(53u, SkColorGetB(new_active_for_paint));
+
+  // Now update to the new value which is full blue.
+  SkColor new_new_active = SkColorSetRGB(70, 70, 255);
+  frame_header.SetFrameColors(new_new_active, SK_ColorBLACK);
+
+  now = base::TimeTicks::Now();
+  test_api.SetStartTime(now);
+  test_api.Step(now + base::TimeDelta::FromMilliseconds(20));
+
+  // Again, GetCurrentFrameColor should return the target color.
+  EXPECT_EQ(new_new_active, frame_header.GetCurrentFrameColor());
+
+  // The start value should be the previous paint color, so it should be
+  // near 53.
+  SkColor new_new_active_for_paint =
+      frame_header.GetActiveFrameColorForPaintForTest();
+  EXPECT_NE(new_active_for_paint, new_new_active_for_paint);
+  EXPECT_EQ(54u, SkColorGetB(new_new_active_for_paint));
 }
 
 }  // namespace ash