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      1 // Copyright 2014 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 MOJO_SERVICES_PUBLIC_CPP_VIEW_MANAGER_VIEW_OBSERVER_H_
      6 #define MOJO_SERVICES_PUBLIC_CPP_VIEW_MANAGER_VIEW_OBSERVER_H_
      7 
      8 #include <vector>
      9 
     10 #include "base/basictypes.h"
     11 
     12 #include "mojo/services/public/cpp/view_manager/view.h"
     13 #include "mojo/services/public/interfaces/input_events/input_events.mojom.h"
     14 
     15 namespace gfx {
     16 class Rect;
     17 }
     18 
     19 namespace mojo {
     20 
     21 class View;
     22 
     23 // A note on -ing and -ed suffixes:
     24 //
     25 // -ing methods are called before changes are applied to the local view model.
     26 // -ed methods are called after changes are applied to the local view model.
     27 //
     28 // If the change originated from another connection to the view manager, it's
     29 // possible that the change has already been applied to the service-side model
     30 // prior to being called, so for example in the case of OnViewDestroying(), it's
     31 // possible the view has already been destroyed on the service side.
     32 
     33 class ViewObserver {
     34  public:
     35   struct TreeChangeParams {
     36     TreeChangeParams();
     37     View* target;
     38     View* old_parent;
     39     View* new_parent;
     40     View* receiver;
     41   };
     42 
     43   virtual void OnTreeChanging(const TreeChangeParams& params) {}
     44   virtual void OnTreeChanged(const TreeChangeParams& params) {}
     45 
     46   virtual void OnViewReordering(View* view,
     47                                 View* relative_view,
     48                                 OrderDirection direction) {}
     49   virtual void OnViewReordered(View* view,
     50                                View* relative_view,
     51                                OrderDirection direction) {}
     52 
     53   virtual void OnViewDestroying(View* view) {}
     54   virtual void OnViewDestroyed(View* view) {}
     55 
     56   virtual void OnViewBoundsChanging(View* view,
     57                                     const gfx::Rect& old_bounds,
     58                                     const gfx::Rect& new_bounds) {}
     59   virtual void OnViewBoundsChanged(View* view,
     60                                    const gfx::Rect& old_bounds,
     61                                    const gfx::Rect& new_bounds) {}
     62 
     63   virtual void OnViewFocusChanged(View* gained_focus, View* lost_focus) {}
     64 
     65   virtual void OnViewInputEvent(View* view, const EventPtr& event) {}
     66 
     67  protected:
     68   virtual ~ViewObserver() {}
     69 };
     70 
     71 }  // namespace mojo
     72 
     73 #endif  // MOJO_SERVICES_PUBLIC_CPP_VIEW_MANAGER_VIEW_OBSERVER_H_
     74