athena: Allow getting into split-view mode from overview-mode.

athena/wm/window_overview_mode.cc

Index: athena/wm/window_overview_mode.cc
diff --git a/athena/wm/window_overview_mode.cc b/athena/wm/window_overview_mode.cc
index 4cb5d2c87fe1b11f164bb1fc3b9e527bcb3f3569..9d369d0ef646d755fb69b9a379bff427dfc9a2d9 100644
--- a/athena/wm/window_overview_mode.cc
+++ b/athena/wm/window_overview_mode.cc
@@ -9,6 +9,7 @@
 #include <vector>
 
 #include "athena/common/closure_animation_observer.h"
+#include "athena/wm/overview_toolbar.h"
 #include "athena/wm/public/window_list_provider.h"
 #include "base/bind.h"
 #include "base/macros.h"
@@ -300,6 +301,7 @@ class WindowOverviewModeImpl : public WindowOverviewMode,
   void DragWindow(const ui::GestureEvent& event) {
     CHECK(dragged_window_);
     CHECK_EQ(ui::ET_GESTURE_SCROLL_UPDATE, event.type());
+    CHECK(overview_toolbar_);
     gfx::Vector2dF dragged_distance =
         dragged_start_location_ - event.location();
     WindowOverviewState* dragged_state =
@@ -309,11 +311,50 @@ class WindowOverviewModeImpl : public WindowOverviewMode,
     transform.Translate(-dragged_distance.x(), 0);
     dragged_window_->SetTransform(transform);
 
+    // Update the toolbar.
+    const int kMinDistanceForActionButtons = 20;
+    if (fabs(dragged_distance.x()) > kMinDistanceForActionButtons)
+      overview_toolbar_->ShowActionButtons();
+    else
+      overview_toolbar_->HideActionButtons();
+
+    // See if the touch-point is above one of the action-buttons.
+    OverviewToolbar::ActionType new_action =
+        overview_toolbar_->GetHighlightAction(event);
+
+    // If the touch-point is not above any of the action buttons, then highlight
+    // the close-button by default, if the user has dragged enough to close the
+    // window.
+    if (new_action == OverviewToolbar::ACTION_TYPE_NONE) {
+      if (fabs(dragged_distance.x()) > kMinDistanceForDismissal)
+        new_action = OverviewToolbar::ACTION_TYPE_CLOSE;
+      else
+        new_action = OverviewToolbar::ACTION_TYPE_NONE;
+    }
+    OverviewToolbar::ActionType previous_action =
+        overview_toolbar_->current_action();
+    overview_toolbar_->SetHighlightAction(new_action);
+
+    // If the user has selected to get into split-view mode, then show the
+    // window with full opacity. Otherwise, fade it out as it closes. Animate
+    // the opacity if transitioning to/from the split-view button.
+    bool animate_opacity =
+        (new_action != previous_action) &&
+        ((new_action == OverviewToolbar::ACTION_TYPE_SPLIT) ||
+         (previous_action == OverviewToolbar::ACTION_TYPE_SPLIT));
     float ratio = std::min(
         1.f, std::abs(dragged_distance.x()) / kMinDistanceForDismissal);
     float opacity =
-        gfx::Tween::FloatValueBetween(ratio, kMaxOpacity, kMinOpacity);
-    dragged_window_->layer()->SetOpacity(opacity);
+        (new_action == OverviewToolbar::ACTION_TYPE_SPLIT)
+            ? 1
+            : gfx::Tween::FloatValueBetween(ratio, kMaxOpacity, kMinOpacity);
+    if (animate_opacity) {
+      ui::ScopedLayerAnimationSettings settings(
+          dragged_window_->layer()->GetAnimator());
+      dragged_window_->layer()->SetOpacity(opacity);
+    } else {
+      dragged_window_->layer()->SetOpacity(opacity);
+    }
   }
 
   bool ShouldCloseDragWindow(const ui::GestureEvent& event) const {
@@ -392,6 +433,19 @@ class WindowOverviewModeImpl : public WindowOverviewMode,
     dragged_window_ = NULL;
   }
 
+  void EndDragWindow(const ui::GestureEvent& gesture) {
+    CHECK(dragged_window_);
+    CHECK(overview_toolbar_);
+    OverviewToolbar::ActionType action = overview_toolbar_->current_action();
+    overview_toolbar_.reset();
+    if (action == OverviewToolbar::ACTION_TYPE_SPLIT)
+      delegate_->OnSplitViewMode(NULL, dragged_window_);

[mfomitchev, 2014/08/13 15:12:31]

Why not pass the left window here as well? The bottom window in the stack should
be the left window, and it seems it would be cleaner if the overview mode
ensured that rather than relying on SplitViewController.

[sadrul, 2014/08/13 16:20:12]

The purpose here is to tell the delegate that the user has explicitly selected
the window on the right. The delegate (which is responsible for actually going
into the split-view mode) is responsible for deciding whether to keep the
foremost window on the left, or whether to switch to a different window on the
left (e.g. if the selected window on the right belongs to a multi-window app,
perhaps the left window would switch to a window that belongs to the same app).
That's a detail the overview-mode itself does not need to worry about.

[mfomitchev, 2014/08/13 17:42:52]

Acknowledged.

+    else if (ShouldCloseDragWindow(gesture))
+      CloseDragWindow(gesture);
+    else
+      RestoreDragWindow();
+  }
+
   // ui::EventHandler:
   virtual void OnMouseEvent(ui::MouseEvent* mouse) OVERRIDE {
     if (mouse->type() == ui::ET_MOUSE_PRESSED) {
@@ -422,6 +476,8 @@ class WindowOverviewModeImpl : public WindowOverviewMode,
           std::abs(gesture->details().scroll_y_hint()) * 2) {
         dragged_start_location_ = gesture->location();
         dragged_window_ = SelectWindowAt(gesture);
+        if (dragged_window_)
+          overview_toolbar_.reset(new OverviewToolbar(container_));
       }
     } else if (gesture->type() == ui::ET_GESTURE_SCROLL_UPDATE) {
       if (dragged_window_)
@@ -430,19 +486,12 @@ class WindowOverviewModeImpl : public WindowOverviewMode,
         DoScroll(gesture->details().scroll_y());
       gesture->SetHandled();
     } else if (gesture->type() == ui::ET_GESTURE_SCROLL_END) {
-      if (dragged_window_) {
-        if (ShouldCloseDragWindow(*gesture))
-          CloseDragWindow(*gesture);
-        else
-          RestoreDragWindow();
-      }
+      if (dragged_window_)
+        EndDragWindow(*gesture);
       gesture->SetHandled();
     } else if (gesture->type() == ui::ET_SCROLL_FLING_START) {
       if (dragged_window_) {
-        if (ShouldCloseDragWindow(*gesture))
-          CloseDragWindow(*gesture);
-        else
-          RestoreDragWindow();
+        EndDragWindow(*gesture);
       } else {
         CreateFlingerFor(*gesture);
         AddAnimationObserver();
@@ -487,6 +536,7 @@ class WindowOverviewModeImpl : public WindowOverviewMode,
 
   aura::Window* dragged_window_;
   gfx::Point dragged_start_location_;
+  scoped_ptr<OverviewToolbar> overview_toolbar_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowOverviewModeImpl);
 };