Touch gestures for System Tray/ IME/ Stylus/ Notifications

ash/system/tray/system_tray.cc

 // Copyright (c) 2012 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/system/tray/system_tray.h"
 
 #include <algorithm>
 #include <map>
 #include <vector>
 
@@ skipping 182 matching lines @@
  private:
   SystemTray* tray_;
 
   DISALLOW_COPY_AND_ASSIGN(ActivationObserver);
 };
 
 // SystemTray
 
 SystemTray::SystemTray(Shelf* shelf)
     : TrayBackgroundView(shelf), shelf_(shelf) {
+  target_view_ = this;
+
   SetInkDropMode(InkDropMode::ON);
 
   // Since user avatar is on the right hand side of System tray of a
   // horizontal shelf and that is sufficient to indicate separation, no
   // separator is required.
   set_separator_visibility(false);
 }
 
 SystemTray::~SystemTray() {
   // Destroy any child views that might have back pointers before ~View().
@@ skipping 405 matching lines @@
   TrayBubbleView* bubble_view = GetSystemBubble()->bubble_view();
   // If system tray bubble is in the process of closing, do not try to activate
   // bubble.
   if (bubble_view->GetWidget()->IsClosed())
     return;
   bubble_view->set_can_activate(true);
   bubble_view->GetWidget()->Activate();
 }
 
 void SystemTray::OnGestureEvent(ui::GestureEvent* event) {
-  if (Shell::Get()
-          ->maximize_mode_controller()
-          ->IsMaximizeModeWindowManagerEnabled() &&
-      shelf_->IsHorizontalAlignment() && ProcessGestureEvent(*event)) {
+  target_view_ = this;

[xdai1, 2017/06/30 17:46:54]

What if you press and drag on a bubble view and then use another finger to press
or drag on the system tray? Does it cause problem?

[minch1, 2017/06/30 19:08:04]

Add |is_on_bubble_| instead, please check.

+  if (ProcessGestureEvent(*event))
     event->SetHandled();
-  } else {
+  else
     TrayBackgroundView::OnGestureEvent(event);
-  }
 }
 
 gfx::Rect SystemTray::GetWorkAreaBoundsInScreen() const {
   return shelf_->GetUserWorkAreaBounds();
 }
 
 bool SystemTray::PerformAction(const ui::Event& event) {
   // If we're already showing a full system tray menu, either default or
   // detailed menu, hide it; otherwise, show it (and hide any popup that's
   // currently shown).
   if (HasSystemBubble() && full_system_tray_menu_) {
     system_bubble_->bubble()->Close();
   } else {
     ShowDefaultView(BUBBLE_CREATE_NEW);
     if (event.IsKeyEvent() || (event.flags() & ui::EF_TOUCH_ACCESSIBILITY))
       ActivateBubble();
   }
   return true;
 }
 
 bool SystemTray::ProcessGestureEvent(const ui::GestureEvent& event) {
+  if (!Shell::Get()
+           ->maximize_mode_controller()
+           ->IsMaximizeModeWindowManagerEnabled() ||
+      !shelf_->IsHorizontalAlignment()) {
+    return false;
+  }
+
   if (event.type() == ui::ET_GESTURE_SCROLL_BEGIN)
     return StartGestureDrag(event);
 
   if (!HasSystemBubble() || !is_in_drag_)
     return false;
 
   if (event.type() == ui::ET_GESTURE_SCROLL_UPDATE) {
     UpdateGestureDrag(event);
     return true;
   }
 
   if (event.type() == ui::ET_GESTURE_SCROLL_END ||
       event.type() == ui::ET_SCROLL_FLING_START) {
     CompleteGestureDrag(event);
     return true;
   }
 
   // Unexpected event. Reset the drag state and close the bubble.
   is_in_drag_ = false;
   CloseSystemBubble();
   return false;
 }
 
 bool SystemTray::StartGestureDrag(const ui::GestureEvent& gesture) {
-  // Close the system bubble if there is already a full one opened. And return
-  // false to let shelf handle the event.
-  if (HasSystemBubble() && full_system_tray_menu_) {
-    system_bubble_->bubble()->Close();
-    return false;
+  if (target_view_ == this) {
+    // Dragging happens on the system tray. Close the system bubble if there is
+    // already a full one opened. And return false to let shelf handle the
+    // event.
+    if (HasSystemBubble() && full_system_tray_menu_) {
+      system_bubble_->bubble()->Close();
+      return false;
+    }
+
+    // If the scroll sequence begins to scroll downward, return false so that
+    // the event will instead by handled by the shelf.
+    if (gesture.details().scroll_y_hint() > 0)
+      return false;
+
+    ShowDefaultView(BUBBLE_CREATE_NEW);
   }
 
-  // If the scroll sequence begins to scroll downward, return false so that the
-  // event will instead by handled by the shelf.
-  if (gesture.details().scroll_y_hint() > 0)
-    return false;
-
   is_in_drag_ = true;
   gesture_drag_amount_ = 0.f;
-  ShowDefaultView(BUBBLE_CREATE_NEW);
   system_tray_bubble_bounds_ =
       system_bubble_->bubble_view()->GetWidget()->GetWindowBoundsInScreen();
   SetBubbleBounds(gesture.location());
   return true;
 }
 
 void SystemTray::UpdateGestureDrag(const ui::GestureEvent& gesture) {
   SetBubbleBounds(gesture.location());
   gesture_drag_amount_ += gesture.details().scroll_y();
 }
 
 void SystemTray::CompleteGestureDrag(const ui::GestureEvent& gesture) {
   const bool hide_bubble = !ShouldShowSystemBubbleAfterScrollSequence(gesture);
   gfx::Rect target_bounds = system_tray_bubble_bounds_;
 
   if (hide_bubble)
     target_bounds.set_y(shelf_->GetIdealBounds().y());
 
   system_bubble_->bubble()->AnimateToTargetBounds(target_bounds, hide_bubble);
   is_in_drag_ = false;
 }
 
 void SystemTray::SetBubbleBounds(const gfx::Point& location) {

[xdai1, 2017/06/30 17:46:54]

From the function's name, it may be better to make it accept a (const gfx::Rect&
bounds_in_screen) parameter? and move the screen coordinates conversion logic to
the upper function? If so, is this possible that we eliminate the necessarily of
maintaining |target_view_| and only make it a parameter of
SystemTray::ProcessGestureEvent()?

[minch1, 2017/06/30 19:08:04]

Sorry, I found after change the rule for SetBubbleBounds actually we don't need
to argument |location|. But we still need to know which view the dragging is
triggered on. Add a flag |is_on_bubble_| and always set it in
ProcessGestureEvent. Please check. Thanks.

   gfx::Point location_in_screen_coordinates(location);
-  View::ConvertPointToScreen(this, &location_in_screen_coordinates);
-
-  // System tray bubble should not be dragged higher than its original height.
-  if (location_in_screen_coordinates.y() < system_tray_bubble_bounds_.y())
-    location_in_screen_coordinates.set_y(system_tray_bubble_bounds_.y());
+  View::ConvertPointToScreen(target_view_, &location_in_screen_coordinates);
 
   gfx::Rect bounds_on_location = system_tray_bubble_bounds_;
-  bounds_on_location.set_y(location_in_screen_coordinates.y());
+  // System tray bubble should not be dragged higher than its original height.
+  int bounds_y = (target_view_ == this ? shelf_->GetIdealBounds().y()
+                                       : system_tray_bubble_bounds_.y()) +
+                 gesture_drag_amount_;
+  bounds_on_location.set_y(std::max(bounds_y, system_tray_bubble_bounds_.y()));
   system_bubble_->bubble_view()->GetWidget()->SetBounds(bounds_on_location);
 }
 
 bool SystemTray::ShouldShowSystemBubbleAfterScrollSequence(
     const ui::GestureEvent& sequence_end) {
   // If the scroll sequence terminates with a fling, show the system menu if the
   // fling was fast enough and in the correct direction.
   if (sequence_end.type() == ui::ET_SCROLL_FLING_START &&
       fabs(sequence_end.details().velocity_y()) > kFlingVelocity) {
     return sequence_end.details().velocity_y() < 0;
   }
 
   DCHECK(sequence_end.type() == ui::ET_GESTURE_SCROLL_END ||
          sequence_end.type() == ui::ET_SCROLL_FLING_START);
-  // Show the system menu if it is already at least one-third visible.
-  return -gesture_drag_amount_ >= system_tray_bubble_bounds_.height() / 3.0;
+
+  // Keep the bubble's original state if the |gesture_drag_amount_| doesn't
+  // exceed one-third of the bubble's height.
+  if (target_view_ == this)
+    return -gesture_drag_amount_ >= system_tray_bubble_bounds_.height() / 3.0;
+  return gesture_drag_amount_ < system_tray_bubble_bounds_.height() / 3.0;
 }
 
 void SystemTray::CloseSystemBubbleAndDeactivateSystemTray() {
   activation_observer_.reset();
   system_bubble_.reset();
   // When closing a system bubble with the alternate shelf layout, we need to
   // turn off the active tinting of the shelf.
   if (full_system_tray_menu_) {
     SetIsActive(false);
     full_system_tray_menu_ = false;
@@ skipping 21 matching lines @@
           .work_area()
           .height();
   if (work_area_height > 0) {
     UMA_HISTOGRAM_CUSTOM_COUNTS(
         "Ash.SystemMenu.PercentageOfWorkAreaHeightCoveredByMenu",
         100 * bubble_view->height() / work_area_height, 1, 300, 100);
   }
 }
 
 }  // namespace ash