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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef UI_VIEWS_COREWM_COMPOUND_EVENT_FILTER_H_
      6 #define UI_VIEWS_COREWM_COMPOUND_EVENT_FILTER_H_
      7 
      8 #include "base/compiler_specific.h"
      9 #include "base/observer_list.h"
     10 #include "ui/base/events/event.h"
     11 #include "ui/base/events/event_handler.h"
     12 #include "ui/gfx/native_widget_types.h"
     13 #include "ui/views/views_export.h"
     14 
     15 namespace aura {
     16 class CursorManager;
     17 class RootWindow;
     18 }
     19 
     20 namespace ui {
     21 class GestureEvent;
     22 class KeyEvent;
     23 class LocatedEvent;
     24 class MouseEvent;
     25 class TouchEvent;
     26 }
     27 
     28 namespace views {
     29 namespace corewm {
     30 
     31 // CompoundEventFilter gets all events first and can provide actions to those
     32 // events. It implements global features such as click to activate a window and
     33 // cursor change when moving mouse.
     34 // Additional event filters can be added to CompoundEventFilter. Events will
     35 // pass through those additional filters in their addition order and could be
     36 // consumed by any of those filters. If an event is consumed by a filter, the
     37 // rest of the filter(s) and CompoundEventFilter will not see the consumed
     38 // event.
     39 class VIEWS_EXPORT CompoundEventFilter : public ui::EventHandler {
     40  public:
     41   CompoundEventFilter();
     42   virtual ~CompoundEventFilter();
     43 
     44   // Returns the cursor for the specified component.
     45   static gfx::NativeCursor CursorForWindowComponent(int window_component);
     46 
     47   // Used to allow a mouse event to show the cursor even when
     48   // the cursor is hidden by |CursorClient::ShowCursor(false)|.
     49   void set_cursor_hidden_by_filter(bool cursor_hidden_by_filter) {
     50     cursor_hidden_by_filter_ = cursor_hidden_by_filter;
     51   }
     52 
     53   // Adds/removes additional event filters. This does not take ownership of
     54   // the EventHandler.
     55   // NOTE: These handlers are deprecated. Use env::AddPreTargetEventHandler etc.
     56   // instead.
     57   void AddHandler(ui::EventHandler* filter);
     58   void RemoveHandler(ui::EventHandler* filter);
     59 
     60  private:
     61   // Updates the cursor if the target provides a custom one, and provides
     62   // default resize cursors for window edges.
     63   void UpdateCursor(aura::Window* target, ui::MouseEvent* event);
     64 
     65   // Dispatches event to additional filters.
     66   void FilterKeyEvent(ui::KeyEvent* event);
     67   void FilterMouseEvent(ui::MouseEvent* event);
     68   void FilterTouchEvent(ui::TouchEvent* event);
     69 
     70   // Sets the visibility of the cursor if the event is not synthesized and
     71   // 1) it's hiding (show=false) when the cursor is currently shown, or
     72   // 2) it's showing (show=true) if the cursor is previously hidden
     73   //    by this event filter (see |cursor_hidden_by_filter_|),
     74   // so that it doesn't change the cursor visibility if the cursor was
     75   // intentionally hidden by other components.
     76   void SetCursorVisibilityOnEvent(aura::Window* target,
     77                                   ui::Event* event,
     78                                   bool show);
     79 
     80   // Enables or disables mouse events if the event is not synthesized.
     81   void SetMouseEventsEnableStateOnEvent(aura::Window* target,
     82                                         ui::Event* event,
     83                                         bool enable);
     84 
     85   // Overridden from ui::EventHandler:
     86   virtual void OnKeyEvent(ui::KeyEvent* event) OVERRIDE;
     87   virtual void OnMouseEvent(ui::MouseEvent* event) OVERRIDE;
     88   virtual void OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
     89   virtual void OnTouchEvent(ui::TouchEvent* event) OVERRIDE;
     90   virtual void OnGestureEvent(ui::GestureEvent* event) OVERRIDE;
     91 
     92   // Additional pre-target event handlers.
     93   ObserverList<ui::EventHandler, true> handlers_;
     94 
     95   // True if the cursur was hidden by the filter.
     96   bool cursor_hidden_by_filter_;
     97 
     98   DISALLOW_COPY_AND_ASSIGN(CompoundEventFilter);
     99 };
    100 
    101 }  // namespace corewm
    102 }  // namespace views
    103 
    104 #endif  // UI_VIEWS_COREWM_COMPOUND_EVENT_FILTER_H_
    105