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      1 // Copyright (c) 2013 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 ASH_DESKTOP_BACKGROUND_DESKTOP_WALLPAPER_RESIZER_H_
      6 #define ASH_DESKTOP_BACKGROUND_DESKTOP_WALLPAPER_RESIZER_H_
      7 
      8 #include "ash/ash_export.h"
      9 #include "ash/desktop_background/desktop_background_controller.h"
     10 #include "base/memory/weak_ptr.h"
     11 #include "base/observer_list.h"
     12 #include "skia/ext/image_operations.h"
     13 #include "third_party/skia/include/core/SkBitmap.h"
     14 #include "ui/gfx/image/image_skia.h"
     15 #include "ui/gfx/size.h"
     16 
     17 namespace ash {
     18 
     19 class WallpaperResizerObserver;
     20 
     21 // Stores the current wallpaper data and resize it to |target_size| if needed.
     22 class ASH_EXPORT WallpaperResizer {
     23  public:
     24   // Returns a unique identifier corresponding to |image|, suitable for
     25   // comparison against the value returned by original_image_id(). If the image
     26   // is modified, its ID will change.
     27   static uint32_t GetImageId(const gfx::ImageSkia& image);
     28 
     29   WallpaperResizer(int image_resource_id,
     30                    const gfx::Size& target_size,
     31                    WallpaperLayout layout);
     32 
     33   WallpaperResizer(const gfx::ImageSkia& image,
     34                    const gfx::Size& target_size,
     35                    WallpaperLayout layout);
     36 
     37   ~WallpaperResizer();
     38 
     39   const gfx::ImageSkia& image() const { return image_; }
     40   uint32_t original_image_id() const { return original_image_id_; }
     41   WallpaperLayout layout() const { return layout_; }
     42 
     43   // Called on the UI thread to run Resize() on the worker pool and post an
     44   // OnResizeFinished() task back to the UI thread on completion.
     45   void StartResize();
     46 
     47   // Add/Remove observers.
     48   void AddObserver(WallpaperResizerObserver* observer);
     49   void RemoveObserver(WallpaperResizerObserver* observer);
     50 
     51  private:
     52   // Copies |resized_bitmap| to |image_| and notifies observers after Resize()
     53   // has finished running.
     54   void OnResizeFinished(SkBitmap* resized_bitmap);
     55 
     56   ObserverList<WallpaperResizerObserver> observers_;
     57 
     58   // Image that should currently be used for wallpaper. It initially
     59   // contains the original image and is updated to contain the resized
     60   // image by OnResizeFinished().
     61   gfx::ImageSkia image_;
     62 
     63   // Unique identifier corresponding to the original (i.e. pre-resize) |image_|.
     64   uint32_t original_image_id_;
     65 
     66   gfx::Size target_size_;
     67 
     68   WallpaperLayout layout_;
     69 
     70   base::WeakPtrFactory<WallpaperResizer> weak_ptr_factory_;
     71 
     72   DISALLOW_COPY_AND_ASSIGN(WallpaperResizer);
     73 };
     74 
     75 }  // namespace ash
     76 
     77 
     78 #endif  // ASH_DESKTOP_BACKGROUND_DESKTOP_WALLPAPER_RESIZER_H_
     79