Implement ui for re-parenting an item from an app list folder to another position or folder in the …

ui/app_list/views/folder_background_view.cc

+// Copyright 2014 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 "ui/app_list/views/folder_background_view.h"
+
+#include "ui/app_list/app_list_constants.h"
+#include "ui/app_list/views/app_list_folder_view.h"
+#include "ui/app_list/views/apps_container_view.h"
+#include "ui/compositor/scoped_layer_animation_settings.h"
+#include "ui/gfx/canvas.h"
+#include "ui/gfx/transform_util.h"
+
+namespace app_list {
+
+namespace {
+
+const float kFolderInkBubbleScale = 1.2f;
+const int kBubbleTransitionDurationMs = 200;
+
+}  // namespace
+
+FolderBackgroundView::FolderBackgroundView()
+    : folder_view_(NULL),
+      show_state_(NO_BUBBLE) {
+  SetPaintToLayer(true);
+  SetFillsBoundsOpaquely(false);
+}
+
+FolderBackgroundView::~FolderBackgroundView() {
+}
+
+void FolderBackgroundView::UpdateFolderContainerBubble(ShowState state) {
+  if (show_state_ == state ||
+      (state == HIDE_BUBBLE && show_state_ == NO_BUBBLE)) {
+    return;
+  }
+
+  show_state_ = state;
+
+  // Set the initial state before the animation starts.
+  const gfx::Rect bounds(layer()->bounds().size());
+  gfx::Transform transform =
+      gfx::GetScaleTransform(bounds.CenterPoint(), kFolderInkBubbleScale);
+  if (show_state_ == SHOW_BUBBLE) {
+    layer()->SetOpacity(0.0f);
+    layer()->SetTransform(transform);
+  } else {
+    layer()->SetOpacity(1.0f);
+    layer()->SetTransform(gfx::Transform());
+  }
+
+  ui::ScopedLayerAnimationSettings settings(layer()->GetAnimator());
+  settings.AddObserver(this);
+  settings.SetTransitionDuration(
+      base::TimeDelta::FromMilliseconds((kBubbleTransitionDurationMs)));
+  if (show_state_ == SHOW_BUBBLE) {
+    layer()->SetOpacity(1.0f);
+    layer()->SetTransform(gfx::Transform());
+  } else {
+    layer()->SetOpacity(0.0f);
+    layer()->SetTransform(transform);
+  }
+
+  SchedulePaint();
+}
+
+int FolderBackgroundView::GetFolderContainerBubbleRadius() const {
+  return GetContentsBounds().height() / 2;
+}
+
+void FolderBackgroundView::OnPaint(gfx::Canvas* canvas) {
+  if (show_state_ == NO_BUBBLE)
+    return;
+
+  // Draw ink bubble that shows the folder boundary.
+  SkPaint paint;
+  paint.setStyle(SkPaint::kFill_Style);
+  paint.setAntiAlias(true);
+  paint.setColor(kFolderBubbleColor);
+  canvas->DrawCircle(GetContentsBounds().CenterPoint(),
+                     GetFolderContainerBubbleRadius(),
+                     paint);
+}
+
+void FolderBackgroundView::OnImplicitAnimationsCompleted() {
+  // Show folder name after the ink bubble disappears.
+  if (show_state_ == HIDE_BUBBLE) {
+    static_cast<AppsContainerView*>(parent())->app_list_folder_view()->
+        UpdateFolderNameVisibility(true);
+  }
+}
+
+}  // namespace app_list