Make imageSkia:::extractSubset multi-image aware.

ui/gfx/image/image_skia.cc

Index: ui/gfx/image/image_skia.cc
diff --git a/ui/gfx/image/image_skia.cc b/ui/gfx/image/image_skia.cc
index df9d99b2a8e79b767825bd43c97a39148e91b91e..ec43a6f0be9bba88726e82ed77d5ef55e9890316 100644
--- a/ui/gfx/image/image_skia.cc
+++ b/ui/gfx/image/image_skia.cc
@@ -9,6 +9,7 @@
 
 #include "base/logging.h"
 #include "ui/gfx/size.h"
+#include "ui/gfx/skia_util.h"
 
 namespace gfx {
 
@@ -159,10 +160,25 @@ int ImageSkia::height() const {
 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;
 }