ash/desktop_background/wallpaper_resizer.h

   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_