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
17namespace ash {
18
19class WallpaperResizerObserver;
20
21// Stores the current wallpaper data and resize it to |target_size| if needed.
22class 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