bento: Add animation of zero state

Bug: 1158583
Change-Id: I9c444c57c86d368477827f48f75cf9fd3197d117
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2623714
Commit-Queue: Min Chen <minch@chromium.org>
Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#843656}

ash/wm/desks/desk_mini_view_animations.cc

@@ -11,12 +11,14 @@
 #include "ash/wm/desks/desk_mini_view.h"
 #include "ash/wm/desks/desks_bar_view.h"
 #include "ash/wm/desks/expanded_state_new_desk_button.h"
+#include "ash/wm/desks/zero_state_button.h"
 #include "ash/wm/overview/overview_controller.h"
 #include "ash/wm/overview/overview_session.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/layer_animation_observer.h"
 #include "ui/compositor/layer_animator.h"
 #include "ui/compositor/scoped_layer_animation_settings.h"
+#include "ui/gfx/transform_util.h"
 
 namespace ash {
 
@@ -33,6 +35,12 @@ constexpr base::TimeDelta kExistingMiniViewsAnimationDuration =
 constexpr base::TimeDelta kRemovedMiniViewsFadeOutDuration =
     base::TimeDelta::FromMilliseconds(200);
 
+constexpr base::TimeDelta kZeroStateAnimationDuration =
+    base::TimeDelta::FromMilliseconds(200);
+
+// Scale for entering/exiting zero state.
+constexpr float kEnterOrExitZeroStateScale = 0.6f;
+
 // |settings| will be initialized with a fast-out-slow-in animation with the
 // given |duration|.
 void InitScopedAnimationSettings(ui::ScopedLayerAnimationSettings* settings,
@@ -61,26 +69,87 @@ void AnimateMiniViews(std::vector<DeskMiniView*> mini_views,
     AnimateView(mini_view, begin_transform);
 }
 
+// Scales down the given |view| to |kEnterOrExitZeroStateScale| and fading out
+// it at the same time. Scale down animation will be around the |start| point.
+void ScaleDownAndFadeOutView(views::View* view, const gfx::Point& start) {
+  ui::Layer* layer = view->layer();
+  ui::ScopedLayerAnimationSettings settings{layer->GetAnimator()};
+  InitScopedAnimationSettings(&settings, kZeroStateAnimationDuration);
+
+  const gfx::Point end = view->bounds().CenterPoint();
+  layer->SetTransform(gfx::GetScaleTransform(
+      gfx::Point(start.x() - end.x(), start.y() - end.y()),
+      kEnterOrExitZeroStateScale));
+  layer->SetOpacity(0.f);
+}
+
+// Scales up the given |view| from |kEnterOrExitZeroStateScale| to identity and
+// fading in it at the same time. Scale up animation will be around the |start|
+// point.
+void ScaleUpAndFadeInView(views::View* view, const gfx::Point& start) {
+  DCHECK(view);
+  const gfx::Point end = view->bounds().CenterPoint();
+  ui::Layer* layer = view->layer();
+  layer->SetTransform(gfx::GetScaleTransform(
+      gfx::Point(start.x() - end.x(), start.y() - end.y()),
+      kEnterOrExitZeroStateScale));
+
+  ui::ScopedLayerAnimationSettings settings{layer->GetAnimator()};
+  InitScopedAnimationSettings(&settings, kZeroStateAnimationDuration);
+  layer->SetTransform(kEndTransform);
+  layer->SetOpacity(1.f);
+}
+
+void PositionWindowsInOverview() {
+  auto* controller = Shell::Get()->overview_controller();
+  DCHECK(controller->InOverviewSession());
+  controller->overview_session()->PositionWindows(true);
+}
+
 // A self-deleting object that performs a fade out animation on
-// |removed_mini_view|'s layer by changing its opacity from 1 to 0,
-// and deleting |removed_mini_view| and itself when the animation is complete.
+// |removed_mini_view|'s layer by changing its opacity from 1 to 0 and scales
+// down it around the center of |bar_view| while switching back to zero state in
+// Bento. |removed_mini_view_| and the object itserlf will be deleted when the
+// animation is complete.
 // TODO(afakhry): Consider generalizing HidingWindowAnimationObserverBase to be
 // reusable for the mini_view removal animation.
-class RemovedMiniViewFadeOutAnimation : public ui::ImplicitAnimationObserver {
+class RemovedMiniViewAnimation : public ui::ImplicitAnimationObserver {
  public:
-  RemovedMiniViewFadeOutAnimation(DeskMiniView* removed_mini_view)
-      : removed_mini_view_(removed_mini_view) {
+  RemovedMiniViewAnimation(DeskMiniView* removed_mini_view,
+                           DesksBarView* bar_view,
+                           const bool to_zero_state)
+      : removed_mini_view_(removed_mini_view),
+        bar_view_(bar_view),
+        to_zero_state_(to_zero_state) {
     ui::Layer* layer = removed_mini_view_->layer();
     ui::ScopedLayerAnimationSettings settings{layer->GetAnimator()};
     InitScopedAnimationSettings(&settings, kRemovedMiniViewsFadeOutDuration);
     settings.AddObserver(this);
+
+    if (to_zero_state_) {
+      DCHECK(bar_view_);
+      const gfx::Point start = bar_view->bounds().CenterPoint();
+      const gfx::Point end = removed_mini_view->bounds().CenterPoint();
+      layer->SetTransform(gfx::GetScaleTransform(
+          gfx::Point(start.x() - end.x(), start.y() - end.y()),
+          kEnterOrExitZeroStateScale));
+    } else {
       layer->SetTransform(kEndTransform);
+    }
     layer->SetOpacity(0);
   }
 
-  ~RemovedMiniViewFadeOutAnimation() override {
+  RemovedMiniViewAnimation(const RemovedMiniViewAnimation&) = delete;
+  RemovedMiniViewAnimation& operator=(const RemovedMiniViewAnimation&) = delete;
+
+  ~RemovedMiniViewAnimation() override {
     DCHECK(removed_mini_view_->parent());
     removed_mini_view_->parent()->RemoveChildViewT(removed_mini_view_);
+    if (to_zero_state_) {
+      DCHECK(bar_view_);
+      bar_view_->zero_state_default_desk_button()->SetVisible(true);
+      bar_view_->zero_state_new_desk_button()->SetVisible(true);
+    }
   }
 
   // ui::ImplicitAnimationObserver:
@@ -88,8 +157,8 @@ class RemovedMiniViewFadeOutAnimation : public ui::ImplicitAnimationObserver {
 
  private:
   DeskMiniView* removed_mini_view_;
-
-  DISALLOW_COPY_AND_ASSIGN(RemovedMiniViewFadeOutAnimation);
+  DesksBarView* bar_view_;
+  const bool to_zero_state_;
 };
 
 }  // namespace
@@ -110,9 +179,7 @@ void PerformNewDeskMiniViewAnimation(
     DCHECK(!layer->GetTargetTransform().IsIdentity());
 
     layer->SetTransform(gfx::Transform());
-    auto* controller = Shell::Get()->overview_controller();
-    DCHECK(controller->InOverviewSession());
-    controller->overview_session()->PositionWindows(true);
+    PositionWindowsInOverview();
   }
 
   gfx::Transform begin_transform;
@@ -160,7 +227,8 @@ void PerformRemoveDeskMiniViewAnimation(
   gfx::Transform mini_views_right_begin_transform;
   mini_views_right_begin_transform.Translate(-shift_x, 0);
 
-  new RemovedMiniViewFadeOutAnimation(removed_mini_view);
+  new RemovedMiniViewAnimation(removed_mini_view, /*bar_view=*/nullptr,
+                               /*to_zero_state=*/false);
 
   AnimateMiniViews(mini_views_left, mini_views_left_begin_transform);
   AnimateMiniViews(mini_views_right, mini_views_right_begin_transform);
@@ -171,4 +239,39 @@ void PerformRemoveDeskMiniViewAnimation(
   }
 }
 
+void PerformZeroStateToExpandedStateMiniViewAnimation(DesksBarView* bar_view) {
+  ui::Layer* layer = bar_view->background_view()->layer();
+  ui::ScopedLayerAnimationSettings settings{layer->GetAnimator()};
+  InitScopedAnimationSettings(&settings, kZeroStateAnimationDuration);
+  layer->SetTransform(kEndTransform);
+
+  const gfx::Point start = bar_view->bounds().CenterPoint();
+  for (auto* mini_view : bar_view->mini_views())
+    ScaleUpAndFadeInView(mini_view, start);
+
+  ScaleUpAndFadeInView(bar_view->expanded_state_new_desk_button(), start);
+  PositionWindowsInOverview();
+}
+
+void PerformExpandedStateToZeroStateMiniViewAnimation(
+    DesksBarView* bar_view,
+    std::vector<DeskMiniView*> removed_mini_views) {
+  for (auto* mini_view : removed_mini_views)
+    new RemovedMiniViewAnimation(mini_view, bar_view, /*to_zero_state=*/true);
+
+  const gfx::Rect bounds = bar_view->bounds();
+  ScaleDownAndFadeOutView(bar_view->expanded_state_new_desk_button(),
+                          bounds.CenterPoint());
+
+  ui::Layer* layer = bar_view->background_view()->layer();
+  ui::ScopedLayerAnimationSettings settings{layer->GetAnimator()};
+  InitScopedAnimationSettings(&settings, kZeroStateAnimationDuration);
+
+  gfx::Transform transform;
+  transform.Translate(0,
+                      -(bounds.height() - DesksBarView::kZeroStateBarHeight));
+  layer->SetTransform(transform);
+  PositionWindowsInOverview();
+}
+
 }  // namespace ash

ash/wm/desks/desk_mini_view_animations.h

@@ -54,6 +54,29 @@ void PerformRemoveDeskMiniViewAnimation(
     ExpandedStateNewDeskButton* expanded_state_new_desk_button,
     int shift_x);
 
+// Performs the animation of switching from zero state desks bar to expanded
+// state desks bar. It scales up and fades in the current mini views and the
+// ExpandedStateNewDeskButton. Also animates the bar's background view from the
+// zero state bar's height to the expanded bar's height.
+void PerformZeroStateToExpandedStateMiniViewAnimation(DesksBarView* bar_view);
+
+// Performs the animation of switching from expanded state desks bar to zero
+// state desks bar. This happens when a desk is removed such that a single desk
+// is remaining. It scales down and fades out the |removed_mini_views| and the
+// ExpandedStateNewDeskButton. |removed_mini_views| will be removed from the
+// views hierarchy. But the ExpandedStateNewDeskButton will be kept and set to
+// invisible. It will also animate the bar's background view from the expanded
+// bar's height to zero state bar's height.
+//
+// * Notes:
+// - It assumes the background view, |removed_mini_views| and the
+//   ExpandedStateNewDeskButton are still laid out at their previous positions
+//   before the bar state transition.
+// - Layout will be done once the animation is completed.
+void PerformExpandedStateToZeroStateMiniViewAnimation(
+    DesksBarView* bar_view,
+    std::vector<DeskMiniView*> removed_mini_views);
+
 }  // namespace ash
 
 #endif  // ASH_WM_DESKS_DESK_MINI_VIEW_ANIMATIONS_H_

ash/wm/desks/desks_bar_view.cc

@@ -505,7 +505,6 @@ void DesksBarView::OnDeskRemoved(const Desk* desk) {
   auto partition_iter = mini_views_.erase(iter);
 
   UpdateMinimumWidthToFitContents();
-  overview_grid_->OnDesksChanged();
   const bool is_bento_enabled = features::IsBentoEnabled();
   if (is_bento_enabled)
     expanded_state_new_desk_button_->UpdateButtonState();
@@ -517,12 +516,15 @@ void DesksBarView::OnDeskRemoved(const Desk* desk) {
 
   // Switch to zero state if there is a single desk after removing.
   if (is_bento_enabled && mini_views_.size() == 1) {
-    scroll_view_contents_->RemoveChildView(removed_mini_view);
-    scroll_view_contents_->RemoveChildView(mini_views_[0]);
+    std::vector<DeskMiniView*> removed_mini_views;
+    removed_mini_views.push_back(removed_mini_view);
+    removed_mini_views.push_back(mini_views_[0]);
     mini_views_.clear();
-    SetExpanded(false);
+    // Keep current layout until the animation is completed.
+    PerformExpandedStateToZeroStateMiniViewAnimation(this, removed_mini_views);
     return;
   }
+  overview_grid_->OnDesksChanged();
   PerformRemoveDeskMiniViewAnimation(
       removed_mini_view,
       std::vector<DeskMiniView*>(mini_views_.begin(), partition_iter),
@@ -549,7 +551,10 @@ void DesksBarView::UpdateNewMiniViews(bool initializing_bar_view,
   const auto& desks = DesksController::Get()->desks();
   if (is_bento_enabled) {
     if (IsZeroState() && !expanding_bar_view) {
-      SetExpanded(false);
+      UpdateBentoDeskButtonsVisibility();
+      gfx::Transform transform;
+      transform.Translate(0, -(height() - kZeroStateBarHeight));
+      background_view_->layer()->SetTransform(transform);
       return;
     }
   } else if (desks.size() < 2) {
@@ -602,9 +607,9 @@ void DesksBarView::UpdateNewMiniViews(bool initializing_bar_view,
   UpdateMinimumWidthToFitContents();
   overview_grid_->OnDesksChanged();
 
-  // TODO(mimch): Add the expanding animation.
   if (expanding_bar_view) {
-    SetExpanded(true);
+    UpdateBentoDeskButtonsVisibility();
+    PerformZeroStateToExpandedStateMiniViewAnimation(this);
     return;
   }
 
@@ -663,16 +668,4 @@ void DesksBarView::UpdateBentoDeskButtonsVisibility() {
   expanded_state_new_desk_button_->SetVisible(!is_zero_state);
 }
 
-void DesksBarView::SetExpanded(bool expanded) {
-  DCHECK(features::IsBentoEnabled());
-
-  UpdateBentoDeskButtonsVisibility();
-  gfx::Transform transform;
-  if (!expanded)
-    transform.Translate(0, -(height() - kZeroStateBarHeight));
-
-  background_view_->layer()->SetTransform(transform);
-  overview_grid_->PositionWindows(/*animate=*/true, /*ignored_items=*/{});
-}
-
 }  // namespace ash

ash/wm/desks/desks_bar_view.h

@@ -155,10 +155,6 @@ class ASH_EXPORT DesksBarView : public views::View,
   // Bento is enabled.
   void UpdateBentoDeskButtonsVisibility();
 
-  // Translates the background view and positions windows in overview while
-  // switching between zero state desks bar and expanded desks bar.
-  void SetExpanded(bool expanded);
-
   // A view that shows a dark gary transparent background that can be animated
   // when the very first mini_views are created.
   views::View* background_view_;