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/scoped_transform_overview_window.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"
+#include "ui/wm/core/window_animations.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;
+
+const int kOverviewSelectorTransitionMilliseconds = 100;
+
+// The color and opacity of the overview selector.
+const SkColor kWindowOverviewSelectionColor = SK_ColorBLACK;
+const unsigned char kWindowOverviewSelectorOpacity = 128;
+
+// Returns the vector for the fade in animation.
+gfx::Vector2d GetSlideVectorForFadeIn(WindowSelector::Direction direction,
+                           const gfx::Rect& bounds) {

[flackr, 2014/06/03 17:12:07]

nit: align.

[Nina, 2014/06/04 20:21:13]

Done.

+  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,
+                       const std::vector<WindowSelectorItem*>& windows)
+                           : root_window_(root_window) {

[flackr, 2014/06/03 17:12:07]

Sorry, I mean this should have only 4 spaces in front of it.

[Nina, 2014/06/04 20:21:13]

Done.

+  for (std::vector<WindowSelectorItem*>::const_iterator iter = windows.begin();
+       iter != windows.end(); ++iter) {
+    if ((*iter)->GetRootWindow() == root_window)
+      window_list_.push_back(*iter);
+  }
+  DCHECK(!window_list_.empty());
+  PositionWindows(true);
+}
+
+WindowGrid::~WindowGrid() {
+}
+
+void 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;
+
+  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;
+
+  // 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()) {

[flackr, 2014/06/03 17:12:07]

How about early return here:
if (empty())
  return;

[Nina, 2014/06/04 20:21:13]

Done.

+    PositionWindows(true);
+
+    // If existing, reposition the selection widget.
+    if (selection_widget_) {
+      if (selected_index_ >= removed_index && selected_index_ != 0)
+        selected_index_--;
+      ui::ScopedLayerAnimationSettings animation_settings(
+            selection_widget_->GetNativeWindow()->layer()->GetAnimator());
+      animation_settings.SetTransitionDuration(
+          base::TimeDelta::FromMilliseconds(
+              ScopedTransformOverviewWindow::kTransitionMilliseconds));
+      animation_settings.SetPreemptionStrategy(
+          ui::LayerAnimator::IMMEDIATELY_ANIMATE_TO_NEW_TARGET);
+      selection_widget_->SetBounds(SelectedWindow()->target_bounds());
+    }
+  }
+}
+
+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.
+  num_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())))));
+  int num_rows = ((window_list_.size() + num_columns_ - 1) / num_columns_);
+  window_size.set_width(std::min(
+      static_cast<int>(total_bounds.width() / num_columns_),
+      static_cast<int>(total_bounds.height() * kCardAspectRatio / num_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() >= num_columns_ ? 0 :
+      (num_columns_ - window_list_.size()) * window_size.width()) +
+      (total_bounds.width() - num_columns_ * window_size.width())) / 2;
+  int y_offset = total_bounds.y() + (total_bounds.height() -
+      num_rows * window_size.height()) / 2;
+  for (size_t i = 0; i < window_list_.size(); ++i) {
+    gfx::Transform transform;
+    int column = i % num_columns_;
+    int row = i / num_columns_;
+    gfx::Rect target_bounds(window_size.width() * column + x_offset,
+                            window_size.height() * row + y_offset,
+                            window_size.width(),
+                            window_size.height());
+    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 (num_columns_ > window_list_.size())
+    num_columns_ = window_list_.size();
+}
+
+bool WindowGrid::Move(WindowSelector::Direction direction) {
+  bool out_of_bounds = MoveSelectedIndex(direction);
+  // If the selection widget is already active, fade it out in the selection
+  // direction.
+  if (selection_widget_) {
+    views::Widget* old_selection = selection_widget_.get();
+    gfx::Vector2d fade_out_direction =
+        GetSlideVectorForFadeIn(
+            direction, selection_widget_->GetNativeWindow()->bounds());
+
+    // 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 newly selected window is in this grid, animate a new selection
+    // widget.
+    InitSelectionWidget(direction);
+  }
+
+  return out_of_bounds;
+}
+
+WindowSelectorItem* WindowGrid::SelectedWindow() const {
+  CHECK(selected_index_ < window_list_.size());
+  return window_list_[selected_index_];
+}
+
+void WindowGrid::InitSelectionWidget(WindowSelector::Direction direction) {
+  selection_widget_.reset(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);
+  // Disable the "bounce in" animation when showing the window.
+  wm::SetWindowVisibilityAnimationTransition(
+      selection_widget_->GetNativeWindow(), wm::ANIMATE_NONE);
+  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());
+
+  const gfx::Rect target_bounds = SelectedWindow()->target_bounds();
+  gfx::Vector2d fade_out_direction =
+          GetSlideVectorForFadeIn(direction, target_bounds);
+  gfx::Display dst_display = gfx::Screen::GetScreenFor(root_window_)->
+      GetDisplayMatching(target_bounds);
+
+  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);
+
+  // Send an a11y alert so that if ChromeVox is enabled, the item label is read.
+  SelectedWindow()->SendFocusAlert();
+}
+
+bool WindowGrid::MoveSelectedIndex(WindowSelector::Direction direction) {
+  if (selection_widget_) {
+    switch (direction) {
+      case WindowSelector::RIGHT:
+        if (selected_index_ >= window_list_.size() - 1)
+          return true;
+        else

[flackr, 2014/06/03 17:12:07]

No need for else after early return, here and below.

[Nina, 2014/06/04 20:21:13]

Done.

+          selected_index_++;
+        break;
+      case WindowSelector::LEFT:
+        if (selected_index_ == 0)
+          return true;
+        else
+          selected_index_--;
+        break;
+      case WindowSelector::DOWN:
+        if (selected_index_ + num_columns_ >= window_list_.size())
+          selected_index_ = (selected_index_ + 1) % num_columns_;
+        else
+          selected_index_ += num_columns_;

[flackr, 2014/06/03 17:12:07]

how about just always add num_columns, and if >= window_list_.size() (i.e.
overflow) add 1 and % num_columns?

[Nina, 2014/06/04 20:21:13]

Done.

+        if (selected_index_ == 0 || selected_index_ >= window_list_.size())

[flackr, 2014/06/03 17:12:07]

The latter part of this condition isn't possible at this point since it can only
overflow from 325 at which point it's already taken the remainder.

I'd prefer checking for this condition in the condition on 324 which is the only
case where it can happen.

[Nina, 2014/06/04 20:21:13]

Done.

+          return true;
+        break;
+      case WindowSelector::UP:
+        if (selected_index_ == 0) {
+          return true;
+        } else {
+          if (selected_index_ < num_columns_) {
+            selected_index_--;
+            if (!(selected_index_ + num_columns_ >= window_list_.size())) {

[flackr, 2014/06/03 17:12:07]

This looks like it will not work if there's only one row.

[Nina, 2014/06/04 20:21:13]

But it will. If there is only one row, the only thing that happens is
selected_index_-- (supposing selected_index_ != 0) because
selected_index_ + num_columns_ >= window_list_.size()
is true.

[flackr, 2014/06/04 22:25:06]

Ah sorry, I was confused by the decrement being separate. Why is moving left a
special case though? Can't we always do selected_index_ += num_columns_ *
(window_list_.size() / num_columns_) - 1?

[Nina, 2014/06/05 18:04:34]

Oh I didn't realize it would also work that way for one row. Done.

+              selected_index_ +=
+                  num_columns_ * (window_list_.size() / num_columns_);
+              if (selected_index_ >= window_list_.size())
+                selected_index_ -= num_columns_;
+            }
+          } else {
+            selected_index_ -= num_columns_;
+          }
+        }
+        break;
+      }
+    } else {
+     switch (direction) {
+       case WindowSelector::LEFT:
+         selected_index_ = window_list_.size() - 1;
+         break;
+       case WindowSelector::UP:
+         selected_index_ =
+             (window_list_.size() / num_columns_) * num_columns_ - 1;
+         break;
+       case WindowSelector::RIGHT:
+       case WindowSelector::DOWN:
+         selected_index_ = 0;
+         break;
+       }

[flackr, 2014/06/03 17:12:07]

Can you move this to the top of the method and use an early return instead?

[Nina, 2014/06/04 20:21:13]

Done.

+    }
+  return false;
+}
+
+}  // namespace ash