M20 Ash: Animate window header transition from active to inactive

ash/wm/frame_painter.cc

 // Copyright (c) 2012 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/wm/frame_painter.h"
 
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
 #include "ash/wm/window_util.h"
 #include "base/logging.h"  // DCHECK
 #include "grit/ui_resources.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "third_party/skia/include/core/SkPaint.h"
 #include "third_party/skia/include/core/SkPath.h"
 #include "third_party/skia/include/core/SkShader.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/window.h"
+#include "ui/base/animation/slide_animation.h"
 #include "ui/base/hit_test.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/base/theme_provider.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/font.h"
 #include "ui/gfx/image/image.h"
 #include "ui/views/controls/button/image_button.h"
 #include "ui/views/widget/widget.h"
 #include "ui/views/widget/widget_delegate.h"
 
@@ skipping 34 matching lines @@
 const int kCloseButtonOffsetX = 0;
 // Space between close button and top edge of window.
 const int kCloseButtonOffsetY = 0;
 // In the pre-Ash era the web content area had a frame along the left edge, so
 // user-generated theme images for the new tab page assume they are shifted
 // right relative to the header.  Now that we have removed the left edge frame
 // we need to copy the theme image for the window header from a few pixels
 // inset to preserve alignment with the NTP image, or else we'll break a bunch
 // of existing themes.  We do something similar on OS X for the same reason.
 const int kThemeFrameBitmapOffsetX = 5;
+// Duration of crossfade animation for activating and deactivating frame.
+const int kActivationCrossfadeDurationMs = 200;
 
 // Tiles an image into an area, rounding the top corners.  Samples the |bitmap|
 // starting |bitmap_offset_x| pixels from the left of the image.
 void TileRoundRect(gfx::Canvas* canvas,
                    int x, int y, int w, int h,
                    SkPaint* paint,
                    const SkBitmap& bitmap,
                    int corner_radius,
                    int bitmap_offset_x) {
   // To get the shader to sample the image |inset_y| pixels in but tile across
@@ skipping 48 matching lines @@
     : frame_(NULL),
       window_icon_(NULL),
       maximize_button_(NULL),
       close_button_(NULL),
       window_(NULL),
       button_separator_(NULL),
       top_left_corner_(NULL),
       top_edge_(NULL),
       top_right_corner_(NULL),
       header_left_edge_(NULL),
-      header_right_edge_(NULL) {
+      header_right_edge_(NULL),
+      previous_theme_frame_(NULL),
+      previous_opacity_(0),
+      crossfade_theme_frame_(NULL),
+      crossfade_opacity_(0),
+      crossfade_animation_(NULL) {
   if (!instances_)
     instances_ = new std::set<FramePainter*>();
   instances_->insert(this);
 }
 
 FramePainter::~FramePainter() {
   // Sometimes we are destroyed before the window closes, so ensure we clean up.
   if (window_)
     window_->RemoveObserver(this);
   instances_->erase(this);
@@ skipping 124 matching lines @@
 
 void FramePainter::PaintHeader(views::NonClientFrameView* view,
                                gfx::Canvas* canvas,
                                HeaderMode header_mode,
                                const SkBitmap* theme_frame,
                                const SkBitmap* theme_frame_overlay) {
   int opacity = UseSoloWindowHeader(NULL) ?
       kSoloWindowOpacity :
       (header_mode == ACTIVE ? kActiveWindowOpacity : kInactiveWindowOpacity);
 
+  if (previous_theme_frame_ && previous_theme_frame_ != theme_frame) {
+    crossfade_animation_.reset(new ui::SlideAnimation(this));
+    crossfade_theme_frame_ = previous_theme_frame_;
+    crossfade_opacity_ = previous_opacity_;
+    crossfade_animation_->SetSlideDuration(kActivationCrossfadeDurationMs);
+    crossfade_animation_->Show();
+  }
+
+  header_frame_bounds_ = gfx::Rect(0, 0, view->width(), theme_frame->height());
+
+  const int kCornerRadius = 2;
   SkPaint paint;
-  paint.setAlpha(opacity);
+
+  if (crossfade_animation_.get() && crossfade_animation_->is_animating()) {
+    double current_value = crossfade_animation_->GetCurrentValue();
+    int old_alpha = (1 - current_value) * crossfade_opacity_;
+    int new_alpha = current_value * opacity;
+
+    // Draw the old header background, clipping the corners to be rounded.
+    paint.setAlpha(old_alpha);
+    paint.setXfermodeMode(SkXfermode::kPlus_Mode);
+    TileRoundRect(canvas,
+                  0, 0, view->width(), theme_frame->height(),
+                  &paint,
+                  *crossfade_theme_frame_,
+                  kCornerRadius,
+                  kThemeFrameBitmapOffsetX);
+
+    paint.setAlpha(new_alpha);
+  } else {
+    paint.setAlpha(opacity);
+  }
+
   // Draw the header background, clipping the corners to be rounded.
-  const int kCornerRadius = 2;
   TileRoundRect(canvas,
                 0, 0, view->width(), theme_frame->height(),
                 &paint,
                 *theme_frame,
                 kCornerRadius,
                 kThemeFrameBitmapOffsetX);
 
+  previous_theme_frame_ = theme_frame;
+  previous_opacity_ = opacity;
+
   // Draw the theme frame overlay, if available.
   if (theme_frame_overlay)
     canvas->DrawBitmapInt(*theme_frame_overlay, 0, 0);
 
   // Separator between the maximize and close buttons.
   canvas->DrawBitmapInt(*button_separator_,
                         close_button_->x() - button_separator_->width(),
                         close_button_->y());
 
   // We don't need the extra lightness in the edges when we're maximized.
@@ skipping 157 matching lines @@
          it != instances_->end();
          ++it) {
       FramePainter* painter = *it;
       if (IsVisibleNormalWindow(painter->window_) && painter->frame_)
         painter->frame_->non_client_view()->SchedulePaint();
     }
   }
 }
 
 ///////////////////////////////////////////////////////////////////////////////
+// ui::AnimationDelegate overrides:
+
+void FramePainter::AnimationProgressed(const ui::Animation* animation) {
+  frame_->SchedulePaintInRect(gfx::Rect(header_frame_bounds_));
+}
+
+///////////////////////////////////////////////////////////////////////////////
 // FramePainter, private:
 
 void FramePainter::SetButtonImages(views::ImageButton* button,
                                    int normal_bitmap_id,
                                    int hot_bitmap_id,
                                    int pushed_bitmap_id) {
   ui::ThemeProvider* theme_provider = frame_->GetThemeProvider();
   button->SetImage(views::CustomButton::BS_NORMAL,
                    theme_provider->GetBitmapNamed(normal_bitmap_id));
   button->SetImage(views::CustomButton::BS_HOT,
@@ skipping 22 matching lines @@
     if (*it != ignore && IsVisibleNormalWindow(*it)) {
       normal_window_count++;
       if (normal_window_count > 1)
         return false;
     }
   }
   return normal_window_count == 1;
 }
 
 }  // namespace ash