src/ash/desktop_background/wallpaper_resizer.cc

   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 #include "ash/desktop_background/wallpaper_resizer.h"
   6
   7 #include "ash/desktop_background/wallpaper_resizer_observer.h"
   8 #include "base/bind.h"
   9 #include "base/logging.h"
  10 #include "base/threading/sequenced_worker_pool.h"
  11 #include "base/threading/worker_pool.h"
  12 #include "content/public/browser/browser_thread.h"
  13 #include "ui/base/resource/resource_bundle.h"
  14 #include "ui/gfx/skia_util.h"
  15
  16 using content::BrowserThread;
  17
  18 namespace ash {
  19 namespace {
  20
  21 // For our scaling ratios we need to round positive numbers.
  22 int RoundPositive(double x) {
  23   return static_cast<int>(floor(x + 0.5));
  24 }
  25
  26 // Resizes |orig_bitmap| to |target_size| using |layout| and stores the
  27 // resulting bitmap at |resized_bitmap_out|.
  28 void Resize(SkBitmap orig_bitmap,
  29             const gfx::Size& target_size,
  30             WallpaperLayout layout,
  31             SkBitmap* resized_bitmap_out) {
  32   DCHECK(BrowserThread::GetBlockingPool()->RunsTasksOnCurrentThread());
  33   SkBitmap new_bitmap = orig_bitmap;
  34
  35   const int orig_width = orig_bitmap.width();
  36   const int orig_height = orig_bitmap.height();
  37   const int new_width = target_size.width();
  38   const int new_height = target_size.height();
  39
  40   if (orig_width > new_width || orig_height > new_height) {
  41     gfx::Rect wallpaper_rect(0, 0, orig_width, orig_height);
  42     gfx::Size cropped_size = gfx::Size(std::min(new_width, orig_width),
  43                                        std::min(new_height, orig_height));
  44     switch (layout) {
  45       case WALLPAPER_LAYOUT_CENTER:
  46         wallpaper_rect.ClampToCenteredSize(cropped_size);
  47         orig_bitmap.extractSubset(&new_bitmap,
  48                                   gfx::RectToSkIRect(wallpaper_rect));
  49         break;
  50       case WALLPAPER_LAYOUT_TILE:
  51         wallpaper_rect.set_size(cropped_size);
  52         orig_bitmap.extractSubset(&new_bitmap,
  53                                   gfx::RectToSkIRect(wallpaper_rect));
  54         break;
  55       case WALLPAPER_LAYOUT_STRETCH:
  56         new_bitmap = skia::ImageOperations::Resize(
  57             orig_bitmap, skia::ImageOperations::RESIZE_LANCZOS3,
  58             new_width, new_height);
  59         break;
  60       case WALLPAPER_LAYOUT_CENTER_CROPPED:
  61         if (orig_width > new_width && orig_height > new_height) {
  62           // The dimension with the smallest ratio must be cropped, the other
  63           // one is preserved. Both are set in gfx::Size cropped_size.
  64           double horizontal_ratio = static_cast<double>(new_width) /
  65               static_cast<double>(orig_width);
  66           double vertical_ratio = static_cast<double>(new_height) /
  67               static_cast<double>(orig_height);
  68
  69           if (vertical_ratio > horizontal_ratio) {
  70             cropped_size = gfx::Size(
  71                 RoundPositive(static_cast<double>(new_width) / vertical_ratio),
  72                 orig_height);
  73           } else {
  74             cropped_size = gfx::Size(orig_width, RoundPositive(
  75                 static_cast<double>(new_height) / horizontal_ratio));
  76           }
  77           wallpaper_rect.ClampToCenteredSize(cropped_size);
  78           SkBitmap sub_image;
  79           orig_bitmap.extractSubset(&sub_image,
  80                                     gfx::RectToSkIRect(wallpaper_rect));
  81           new_bitmap = skia::ImageOperations::Resize(
  82               sub_image, skia::ImageOperations::RESIZE_LANCZOS3,
  83               new_width, new_height);
  84         }
  85     }
  86   }
  87
  88   *resized_bitmap_out = new_bitmap;
  89   resized_bitmap_out->setImmutable();
  90 }
  91
  92 }  // namespace
  93
  94 WallpaperResizer::WallpaperResizer(int image_resource_id,
  95                                    const gfx::Size& target_size,
  96                                    WallpaperLayout layout)
  97     : wallpaper_image_(*(ui::ResourceBundle::GetSharedInstance().
  98           GetImageNamed(image_resource_id).ToImageSkia())),
  99       target_size_(target_size),
 100       layout_(layout),
 101       weak_ptr_factory_(this) {
 102 }
 103
 104 WallpaperResizer::WallpaperResizer(const gfx::ImageSkia& image,
 105                                    const gfx::Size& target_size,
 106                                    WallpaperLayout layout)
 107     : wallpaper_image_(image),
 108       target_size_(target_size),
 109       layout_(layout),
 110       weak_ptr_factory_(this) {
 111 }
 112
 113 WallpaperResizer::~WallpaperResizer() {
 114 }
 115
 116 void WallpaperResizer::StartResize() {
 117   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 118   SkBitmap* resized_bitmap = new SkBitmap;
 119   if (!content::BrowserThread::PostBlockingPoolTaskAndReply(
 120           FROM_HERE,
 121           base::Bind(&Resize, *wallpaper_image_.bitmap(), target_size_,
 122                      layout_, resized_bitmap),
 123           base::Bind(&WallpaperResizer::OnResizeFinished,
 124                      weak_ptr_factory_.GetWeakPtr(),
 125                      base::Owned(resized_bitmap)))) {
 126     LOG(WARNING) << "PostSequencedWorkerTask failed. "
 127                  << "Wallpaper may not be resized.";
 128   }
 129 }
 130
 131 void WallpaperResizer::AddObserver(WallpaperResizerObserver* observer) {
 132   observers_.AddObserver(observer);
 133 }
 134
 135 void WallpaperResizer::RemoveObserver(WallpaperResizerObserver* observer) {
 136   observers_.RemoveObserver(observer);
 137 }
 138
 139 void WallpaperResizer::OnResizeFinished(SkBitmap* resized_bitmap) {
 140   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 141   wallpaper_image_ = gfx::ImageSkia::CreateFrom1xBitmap(*resized_bitmap);
 142   FOR_EACH_OBSERVER(WallpaperResizerObserver, observers_,
 143                     OnWallpaperResized());
 144 }
 145
 146 } // namespace ash