components/wallpaper/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 "components/wallpaper/wallpaper_resizer.h"
   6
   7 #include "base/bind.h"
   8 #include "base/location.h"
   9 #include "base/logging.h"
  10 #include "base/threading/sequenced_worker_pool.h"
  11 #include "base/threading/worker_pool.h"
  12 #include "components/wallpaper/wallpaper_resizer_observer.h"
  13 #include "third_party/skia/include/core/SkImage.h"
  14 #include "ui/gfx/image/image_skia_rep.h"
  15 #include "ui/gfx/skia_util.h"
  16
  17 using base::SequencedWorkerPool;
  18
  19 namespace wallpaper {
  20 namespace {
  21
  22 // For our scaling ratios we need to round positive numbers.
  23 int RoundPositive(double x) {
  24   return static_cast<int>(floor(x + 0.5));
  25 }
  26
  27 // Resizes |orig_bitmap| to |target_size| using |layout| and stores the
  28 // resulting bitmap at |resized_bitmap_out|.
  29 void Resize(SkBitmap orig_bitmap,
  30             const gfx::Size& target_size,
  31             WallpaperLayout layout,
  32             SkBitmap* resized_bitmap_out,
  33             SequencedWorkerPool* worker_pool) {
  34   DCHECK(worker_pool->RunsTasksOnCurrentThread());
  35   SkBitmap new_bitmap = orig_bitmap;
  36
  37   const int orig_width = orig_bitmap.width();
  38   const int orig_height = orig_bitmap.height();
  39   const int new_width = target_size.width();
  40   const int new_height = target_size.height();
  41
  42   if (orig_width > new_width || orig_height > new_height) {
  43     gfx::Rect wallpaper_rect(0, 0, orig_width, orig_height);
  44     gfx::Size cropped_size = gfx::Size(std::min(new_width, orig_width),
  45                                        std::min(new_height, orig_height));
  46     switch (layout) {
  47       case WALLPAPER_LAYOUT_CENTER:
  48         wallpaper_rect.ClampToCenteredSize(cropped_size);
  49         orig_bitmap.extractSubset(&new_bitmap,
  50                                   gfx::RectToSkIRect(wallpaper_rect));
  51         break;
  52       case WALLPAPER_LAYOUT_TILE:
  53         wallpaper_rect.set_size(cropped_size);
  54         orig_bitmap.extractSubset(&new_bitmap,
  55                                   gfx::RectToSkIRect(wallpaper_rect));
  56         break;
  57       case WALLPAPER_LAYOUT_STRETCH:
  58         new_bitmap = skia::ImageOperations::Resize(
  59             orig_bitmap, skia::ImageOperations::RESIZE_LANCZOS3, new_width,
  60             new_height);
  61         break;
  62       case WALLPAPER_LAYOUT_CENTER_CROPPED:
  63         if (orig_width > new_width && orig_height > new_height) {
  64           // The dimension with the smallest ratio must be cropped, the other
  65           // one is preserved. Both are set in gfx::Size cropped_size.
  66           double horizontal_ratio =
  67               static_cast<double>(new_width) / static_cast<double>(orig_width);
  68           double vertical_ratio = static_cast<double>(new_height) /
  69                                   static_cast<double>(orig_height);
  70
  71           if (vertical_ratio > horizontal_ratio) {
  72             cropped_size = gfx::Size(
  73                 RoundPositive(static_cast<double>(new_width) / vertical_ratio),
  74                 orig_height);
  75           } else {
  76             cropped_size = gfx::Size(
  77                 orig_width, RoundPositive(static_cast<double>(new_height) /
  78                                           horizontal_ratio));
  79           }
  80           wallpaper_rect.ClampToCenteredSize(cropped_size);
  81           SkBitmap sub_image;
  82           orig_bitmap.extractSubset(&sub_image,
  83                                     gfx::RectToSkIRect(wallpaper_rect));
  84           new_bitmap = skia::ImageOperations::Resize(
  85               sub_image, skia::ImageOperations::RESIZE_LANCZOS3, new_width,
  86               new_height);
  87         }
  88     }
  89   }
  90
  91   *resized_bitmap_out = new_bitmap;
  92   resized_bitmap_out->setImmutable();
  93 }
  94
  95 }  // namespace
  96
  97 // static
  98 uint32_t WallpaperResizer::GetImageId(const gfx::ImageSkia& image) {
  99   const gfx::ImageSkiaRep& image_rep = image.GetRepresentation(1.0f);
 100   return image_rep.is_null() ? 0 : image_rep.sk_bitmap().getGenerationID();
 101 }
 102
 103 WallpaperResizer::WallpaperResizer(const gfx::ImageSkia& image,
 104                                    const gfx::Size& target_size,
 105                                    WallpaperLayout layout,
 106                                    base::SequencedWorkerPool* worker_pool_ptr)
 107     : image_(image),
 108       original_image_id_(GetImageId(image_)),
 109       target_size_(target_size),
 110       layout_(layout),
 111       worker_pool_(worker_pool_ptr),
 112       weak_ptr_factory_(this) {
 113   image_.MakeThreadSafe();
 114 }
 115
 116 WallpaperResizer::~WallpaperResizer() {
 117 }
 118
 119 void WallpaperResizer::StartResize() {
 120   SkBitmap* resized_bitmap = new SkBitmap;
 121   scoped_refptr<SequencedWorkerPool> worker_pool_refptr(worker_pool_);
 122   if (!worker_pool_->PostTaskAndReply(
 123           FROM_HERE, base::Bind(&Resize, *image_.bitmap(), target_size_,
 124                                 layout_, resized_bitmap, worker_pool_refptr),
 125           base::Bind(&WallpaperResizer::OnResizeFinished,
 126                      weak_ptr_factory_.GetWeakPtr(),
 127                      base::Owned(resized_bitmap)))) {
 128     LOG(WARNING) << "PostSequencedWorkerTask failed. "
 129                  << "Wallpaper may not be resized.";
 130   }
 131 }
 132
 133 void WallpaperResizer::AddObserver(WallpaperResizerObserver* observer) {
 134   observers_.AddObserver(observer);
 135 }
 136
 137 void WallpaperResizer::RemoveObserver(WallpaperResizerObserver* observer) {
 138   observers_.RemoveObserver(observer);
 139 }
 140
 141 void WallpaperResizer::OnResizeFinished(SkBitmap* resized_bitmap) {
 142   image_ = gfx::ImageSkia::CreateFrom1xBitmap(*resized_bitmap);
 143   FOR_EACH_OBSERVER(WallpaperResizerObserver, observers_, OnWallpaperResized());
 144 }
 145
 146 }  // namespace wallpaper