Added arrow key navigation to Overview Mode

ash/wm/overview/window_grid.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 "ash/wm/overview/window_grid.h"
+
+#include "ash/screen_util.h"
+#include "ash/shell.h"
+#include "ash/shell_window_ids.h"
+#include "ash/wm/overview/window_selector.h"
+#include "ash/wm/overview/window_selector_item.h"
+#include "base/memory/scoped_vector.h"
+#include "third_party/skia/include/core/SkColor.h"
+#include "ui/aura/window.h"
+#include "ui/compositor/layer_animation_observer.h"
+#include "ui/compositor/scoped_layer_animation_settings.h"
+#include "ui/gfx/vector2d.h"
+#include "ui/views/background.h"
+#include "ui/views/view.h"
+#include "ui/views/widget/widget.h"
+
+namespace ash {
+namespace {
+
+// An observer which holds onto the passed widget until the animation is
+// complete.
+class CleanupWidgetAfterAnimationObserver : public ui::LayerAnimationObserver {
+ public:
+  explicit CleanupWidgetAfterAnimationObserver(
+      scoped_ptr<views::Widget> widget);
+
+  // ui::LayerAnimationObserver:
+  virtual void OnLayerAnimationEnded(
+      ui::LayerAnimationSequence* sequence) OVERRIDE;
+  virtual void OnLayerAnimationAborted(
+      ui::LayerAnimationSequence* sequence) OVERRIDE;
+  virtual void OnLayerAnimationScheduled(
+      ui::LayerAnimationSequence* sequence) OVERRIDE;
+
+ private:
+  virtual ~CleanupWidgetAfterAnimationObserver();
+
+  scoped_ptr<views::Widget> widget_;
+
+  DISALLOW_COPY_AND_ASSIGN(CleanupWidgetAfterAnimationObserver);
+};
+
+CleanupWidgetAfterAnimationObserver::CleanupWidgetAfterAnimationObserver(
+    scoped_ptr<views::Widget> widget)
+    : widget_(widget.Pass()) {
+  widget_->GetNativeWindow()->layer()->GetAnimator()->AddObserver(this);
+}
+
+CleanupWidgetAfterAnimationObserver::~CleanupWidgetAfterAnimationObserver() {
+  widget_->GetNativeWindow()->layer()->GetAnimator()->RemoveObserver(this);
+}
+
+void CleanupWidgetAfterAnimationObserver::OnLayerAnimationEnded(
+    ui::LayerAnimationSequence* sequence) {
+  delete this;
+}
+
+void CleanupWidgetAfterAnimationObserver::OnLayerAnimationAborted(
+    ui::LayerAnimationSequence* sequence) {
+  delete this;
+}
+
+void CleanupWidgetAfterAnimationObserver::OnLayerAnimationScheduled(
+    ui::LayerAnimationSequence* sequence) {
+}
+
+// A comparator for locating a given target window.
+struct WindowSelectorItemComparator
+    : public std::unary_function<WindowSelectorItem*, bool> {
+  explicit WindowSelectorItemComparator(const aura::Window* target_window)
+      : target(target_window) {
+  }
+
+  bool operator()(WindowSelectorItem* window) const {
+    return window->HasSelectableWindow(target);
+  }
+
+  const aura::Window* target;
+};
+
+// Conceptually the window overview is a table or grid of cells having this
+// fixed aspect ratio. The number of columns is determined by maximizing the
+// area of them based on the number of window_list.
+const float kCardAspectRatio = 4.0f / 3.0f;
+
+// The minimum number of cards along the major axis (i.e. horizontally on a
+// landscape orientation).
+const int kMinCardsMajor = 3;
+
+// In the conceptual overview table, the window margin is the space reserved
+// around the window within the cell. This margin does not overlap so the
+// closest distance between adjacent window_list will be twice this amount.
+const int kWindowMargin = 30;
+
+const int kOverviewSelectorTransitionMilliseconds = 500;
+
+// The color and opacity of the overview selector.
+const SkColor kWindowOverviewSelectionColor = SK_ColorBLACK;
+const unsigned char kWindowOverviewSelectorOpacity = 128;
+
+// Initializes the selection widget.
+views::Widget* CreateSelectionWidget(aura::Window* root_window) {
+  views::Widget* selection_widget_ = new views::Widget;
+  views::Widget::InitParams params;
+  params.type = views::Widget::InitParams::TYPE_POPUP;
+  params.keep_on_top = false;
+  params.ownership = views::Widget::InitParams::WIDGET_OWNS_NATIVE_WIDGET;
+  params.opacity = views::Widget::InitParams::TRANSLUCENT_WINDOW;
+  params.parent = Shell::GetContainer(root_window,
+                                      kShellWindowId_DefaultContainer);
+  params.accept_events = false;
+  selection_widget_->set_focus_on_creation(false);
+  selection_widget_->Init(params);
+  views::View* content_view = new views::View;
+  content_view->set_background(
+      views::Background::CreateSolidBackground(kWindowOverviewSelectionColor));
+  selection_widget_->SetContentsView(content_view);
+  selection_widget_->GetNativeWindow()->parent()->StackChildAtBottom(
+      selection_widget_->GetNativeWindow());
+
+  return selection_widget_;
+}
+
+// Returns the vector for the fade in animation.
+gfx::Vector2d GetVectorFor(WindowSelector::Direction direction,
+                           gfx::Rect bounds) {
+  gfx::Vector2d vector;
+  switch (direction) {
+    case WindowSelector::DOWN:
+      vector.set_y(bounds.width());
+      break;
+    case WindowSelector::RIGHT:
+      vector.set_x(bounds.height());
+      break;
+    case WindowSelector::UP:
+      vector.set_y(-bounds.width());
+      break;
+    case WindowSelector::LEFT:
+      vector.set_x(-bounds.height());
+      break;
+  }
+  return vector;
+}
+
+}  // namespace
+
+WindowGrid::WindowGrid(aura::Window* root_window,
+                       std::vector<WindowSelectorItem*> window_list)
+                         : root_window_(root_window),
+                           window_list_(window_list),
+                           selected_index_(0) {
+  PositionWindows(true);
+}
+
+WindowGrid::~WindowGrid() {
+}
+
+WindowSelectorItem* WindowGrid::RemoveWindow(aura::Window* window) {
+  ScopedVector<WindowSelectorItem>::iterator iter =
+      std::find_if(window_list_.begin(), window_list_.end(),
+                   WindowSelectorItemComparator(window));
+  if (iter == window_list_.end())
+    return NULL;
+
+  WindowSelectorItem* removed_item = *iter;
+
+  removed_item->RemoveWindow(window);
+
+  // If there are still windows in this selector entry then the overview is
+  // still active and the active selection remains the same.
+  if (!removed_item->empty())
+    return NULL;
+
+  // We need to get this value before we erase the window to prevent unspecified
+  // behavior.
+  size_t removed_index = iter - window_list_.begin();
+
+  window_list_.erase(iter);
+
+  if (!empty()) {
+    PositionWindows(true);
+
+    // If existing, reposition the selection widget.
+    if (selection_widget_) {
+      if (selected_index_ >= removed_index) {
+        if (selected_index_ != 0) {
+          selected_index_--;
+        }
+      }
+      selection_widget_->SetBounds(GetSelectionBounds());
+    }
+  }
+
+  return removed_item;
+}
+
+void WindowGrid::PositionWindows(bool animate) {
+  CHECK(!window_list_.empty());
+
+  gfx::Size window_size;
+  gfx::Rect total_bounds = ScreenUtil::ConvertRectToScreen(
+      root_window_,
+      ScreenUtil::GetDisplayWorkAreaBoundsInParent(
+          Shell::GetContainer(root_window_, kShellWindowId_DefaultContainer)));
+
+  // Find the minimum number of window_list per row that will fit all of the
+  // window_list on screen.
+  columns_ = std::max(
+      total_bounds.width() > total_bounds.height() ? kMinCardsMajor : 1,
+      static_cast<int>(ceil(sqrt(total_bounds.width() * window_list_.size() /
+                                 (kCardAspectRatio * total_bounds.height())))));
+  rows_ = ((window_list_.size() + columns_ - 1) / columns_);
+  window_size.set_width(std::min(
+      static_cast<int>(total_bounds.width() / columns_),
+      static_cast<int>(total_bounds.height() * kCardAspectRatio / rows_)));
+  window_size.set_height(window_size.width() / kCardAspectRatio);
+
+  // Calculate the X and Y offsets necessary to center the grid.
+  int x_offset = total_bounds.x() + ((window_list_.size() >= columns_ ? 0 :
+      (columns_ - window_list_.size()) * window_size.width()) +
+      (total_bounds.width() - columns_ * window_size.width())) / 2;
+  int y_offset = total_bounds.y() + (total_bounds.height() -
+      rows_ * window_size.height()) / 2;
+  for (size_t i = 0; i < window_list_.size(); ++i) {
+    gfx::Transform transform;
+    int column = i % columns_;
+    int row = i / columns_;
+    gfx::Rect target_bounds(window_size.width() * column + x_offset,
+                            window_size.height() * row + y_offset,
+                            window_size.width(),
+                            window_size.height());
+    target_bounds.Inset(kWindowMargin, kWindowMargin);
+    window_list_[i]->SetBounds(root_window_, target_bounds, animate);
+  }
+
+  // If we have less than |kMinCardsMajor| windows, adjust the column_ value to
+  // reflect how many "real" columns we have.
+  if (columns_ > window_list_.size())
+    columns_ = window_list_.size();
+}
+
+bool WindowGrid::Move(WindowSelector::Direction direction) {
+  bool out_of_bounds = MoveSelectedIndex(direction);
+
+  if (selection_widget_) {
+    gfx::Vector2d fade_out_direction =
+        GetVectorFor(direction, selection_widget_->GetNativeWindow()->bounds());
+    // If the selection widget is already active, fade it out in the selection
+    // direction.
+    views::Widget* old_selection = selection_widget_.get();
+
+    // CleanupWidgetAfterAnimationObserver will delete itself (and the
+    // widget) when the animation is complete.
+    {
+      new CleanupWidgetAfterAnimationObserver(selection_widget_.Pass());
+      ui::ScopedLayerAnimationSettings animation_settings(
+          old_selection->GetNativeWindow()->layer()->GetAnimator());
+      animation_settings.SetTransitionDuration(
+          base::TimeDelta::FromMilliseconds(
+              kOverviewSelectorTransitionMilliseconds));
+      animation_settings.SetPreemptionStrategy(
+          ui::LayerAnimator::IMMEDIATELY_ANIMATE_TO_NEW_TARGET);
+      old_selection->SetOpacity(0);
+      old_selection->GetNativeWindow()->SetBounds(
+          old_selection->GetNativeWindow()->bounds() + fade_out_direction);
+      old_selection->Hide();
+    }
+  }
+  if (!out_of_bounds) {
+    // The selected window is in this grid, animate a new selection widget.
+    const gfx::Rect target_bounds = GetSelectionBounds();
+    gfx::Vector2d fade_out_direction =
+            GetVectorFor(direction, target_bounds);
+    gfx::Display dst_display = gfx::Screen::GetScreenFor(
+        root_window_)->GetDisplayMatching(target_bounds);
+
+    selection_widget_.reset(CreateSelectionWidget(root_window_));
+    selection_widget_->Show();
+    // New selection widget starts with 0 opacity and fades in.
+    selection_widget_->GetNativeWindow()->layer()->SetOpacity(0);
+    selection_widget_->GetNativeWindow()->SetBoundsInScreen(
+        target_bounds - fade_out_direction, dst_display);
+    ui::ScopedLayerAnimationSettings animation_settings(
+        selection_widget_->GetNativeWindow()->layer()->GetAnimator());
+    animation_settings.SetTransitionDuration(base::TimeDelta::FromMilliseconds(
+        kOverviewSelectorTransitionMilliseconds));
+    animation_settings.SetPreemptionStrategy(
+        ui::LayerAnimator::IMMEDIATELY_ANIMATE_TO_NEW_TARGET);
+    selection_widget_->SetBounds(target_bounds);
+    selection_widget_->SetOpacity(kWindowOverviewSelectorOpacity);
+    SelectedWindow()->window_label()->GetContentsView()->
+        NotifyAccessibilityEvent(ui::AX_EVENT_FOCUS, true);
+  } else {
+    selection_widget_.reset();
+    selected_index_ = 0;
+  }
+  return out_of_bounds;
+}
+
+WindowSelectorItem* WindowGrid::SelectedWindow() const {
+  CHECK(selected_index_ < window_list_.size());
+  return window_list_[selected_index_];
+}
+
+bool WindowGrid::MoveSelectedIndex(WindowSelector::Direction direction) {
+  bool out_of_bounds = false;
+  // If the selection widget is active, update the index.
+  if (selection_widget_) {
+    switch (direction) {
+      case WindowSelector::RIGHT:
+        if (selected_index_ >= window_list_.size() - 1)
+          out_of_bounds = true;
+        else
+          selected_index_++;
+        break;
+      case WindowSelector::LEFT:
+        if (selected_index_ == 0)
+          out_of_bounds = true;
+        else
+          selected_index_--;
+        break;
+      case WindowSelector::DOWN:
+        if (selected_index_ + columns_ >= window_list_.size())
+          selected_index_ = (selected_index_ + 1) % columns_;
+        else
+          selected_index_ += columns_;
+        if (selected_index_ == 0 || selected_index_ >= window_list_.size())
+          out_of_bounds = true;
+        break;
+      case WindowSelector::UP:
+        if (selected_index_ == 0) {
+          out_of_bounds = true;
+        } else {
+          if (selected_index_ < columns_) {
+            selected_index_--;
+            if (!(selected_index_ + columns_ >= window_list_.size())) {
+              selected_index_ += columns_  * (rows_ - 1);
+              if (selected_index_ >= window_list_.size())
+                selected_index_ -= columns_;
+            }
+          } else {
+            selected_index_ -= columns_;
+          }
+        }
+        break;
+    }
+  } else {
+    // If the selection widget is not active, position the index in the "first"
+    // window relative to the chosen direction.
+    if (direction == WindowSelector::LEFT)
+      selected_index_ = window_list_.size() - 1;
+    if (direction == WindowSelector::UP) {
+      selected_index_ = rows_ * columns_ - 1;
+      if (selected_index_ >= window_list_.size())
+        selected_index_ -= columns_;
+    }
+  }
+  return out_of_bounds;
+}
+
+const gfx::Rect WindowGrid::GetSelectionBounds() const {
+  gfx::Rect bounds = SelectedWindow()->target_bounds();
+  bounds.Inset(-kWindowMargin, -kWindowMargin);
+  return bounds;
+}
+
+}  // namespace ash