Make imageSkia:::extractSubset multi-image aware.

ui/gfx/image/image_skia.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gfx/image/image_skia.h"
 
 #include <limits>
 #include <cmath>
 
 #include "base/logging.h"
 #include "ui/gfx/size.h"
+#include "ui/gfx/skia_util.h"
 
 namespace gfx {
 
 namespace internal {
 
 // A helper class such that ImageSkia can be cheaply copied. ImageSkia holds a
 // refptr instance of ImageSkiaStorage, which in turn holds all of ImageSkia's
 // information.
 class ImageSkiaStorage : public base::RefCounted<ImageSkiaStorage> {
  public:
@@ skipping 130 matching lines @@
   return isNull() ? 0 : storage_->size().width();
 }
 
 int ImageSkia::height() const {
   return isNull() ? 0 : storage_->size().height();
 }
 
 bool ImageSkia::extractSubset(ImageSkia* dst, const SkIRect& subset) const {
   if (isNull())
     return false;
-  SkBitmap dst_bitmap;
-  bool return_value  = storage_->bitmaps()[0].extractSubset(&dst_bitmap,
-                                                            subset);
-  *dst = ImageSkia(dst_bitmap);
+  bool return_value = true;
+  gfx::ImageSkia image;
+  int dip_width = width();
+  std::vector<SkBitmap> bitmaps = storage_->bitmaps();
+  for (std::vector<SkBitmap> ::const_iterator it = bitmaps.begin();
+      it != bitmaps.end(); ++it) {

[Robert Sesek, 2012/06/05 17:52:09]

nit: align under s

[kevers, 2012/06/05 20:29:34]

Done.

+    SkBitmap bitmap = *it;
+    int px_width = it->width();
+    float dip_scale = (float) px_width / (float) dip_width;

[Robert Sesek, 2012/06/05 17:52:09]

C-style casts aren't allowed by the style guide.

[kevers, 2012/06/05 20:29:34]

Changed to static_cast.

+    int x = (int) (subset.left() * dip_scale + 0.5);
+    int y = (int) (subset.top() * dip_scale + 0.5);
+    int w = (int) (subset.width() * dip_scale + 0.5);
+    int h = (int) (subset.height() * dip_scale + 0.5);
+    SkBitmap dst_bitmap;
+    SkIRect scaled_subset = SkIRect::MakeXYWH(x, y, w, h);
+    return_value &= bitmap.extractSubset(&dst_bitmap, scaled_subset);
+    image.AddBitmapForScale(dst_bitmap, dip_scale);
+  }
+  *dst = image;

[Robert Sesek, 2012/06/05 17:52:09]

Should you overwrite dst ven if return_value==false?

[kevers, 2012/06/05 20:29:34]

Changed to store only successfully extracted subsets and to skip updating dst if
the resulting image is empty.  

   return return_value;
 }
 
 const std::vector<SkBitmap> ImageSkia::bitmaps() const {
   return storage_->bitmaps();
 }
 
 const SkBitmap* ImageSkia::bitmap() const {
   if (isNull()) {
     // Callers expect an SkBitmap even if it is |isNull()|.
@@ skipping 47 matching lines @@
 
   if (closest_index >= 0) {
     *bitmap_scale_factor = static_cast<float>(bitmaps[closest_index].width()) /
         width();
   }
 
   return closest_index;
 }
 
 }  // namespace gfx