Bitmap transport

skia/ext/bitmap_platform_device_mac.cc

 // Copyright (c) 2006-2008 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 "skia/ext/bitmap_platform_device_mac.h"
 
 #include <time.h>
 
 #include "SkMatrix.h"
 #include "SkRegion.h"
@@ skipping 150 matching lines @@
   bitmap.setIsOpaque(is_opaque);
 
   if (is_opaque) {
 #ifndef NDEBUG
     // To aid in finding bugs, we set the background color to something
     // obviously wrong so it will be noticable when it is not cleared
     bitmap.eraseARGB(255, 0, 255, 128);  // bright bluish green
 #endif
   }
 
-  CGColorSpaceRef color_space =
-    CGColorSpaceCreateWithName(kCGColorSpaceGenericRGB);
-  // allocate a bitmap context with 4 components per pixel (BGRA). Apple
-  // recommends these flags for improved CG performance.
-  CGContextRef bitmap_context =
-    CGBitmapContextCreate(data, width, height, 8, width*4,
-                          color_space,
-                          kCGImageAlphaPremultipliedFirst |
-                              kCGBitmapByteOrder32Host);
+  if (!context) {
+    CGColorSpaceRef color_space =
+      CGColorSpaceCreateWithName(kCGColorSpaceGenericRGB);
+    // allocate a bitmap context with 4 components per pixel (BGRA). Apple
+    // recommends these flags for improved CG performance.
+    context =
+      CGBitmapContextCreate(data, width, height, 8, width*4,
+                            color_space,
+                            kCGImageAlphaPremultipliedFirst |
+                                kCGBitmapByteOrder32Host);
 
-  // Change the coordinate system to match WebCore's
-  CGContextTranslateCTM(bitmap_context, 0, height);
-  CGContextScaleCTM(bitmap_context, 1.0, -1.0);
-  CGColorSpaceRelease(color_space);
+    // Change the coordinate system to match WebCore's
+    CGContextTranslateCTM(context, 0, height);
+    CGContextScaleCTM(context, 1.0, -1.0);
+    CGColorSpaceRelease(color_space);
+  }
 
   // The device object will take ownership of the graphics context.
   return new BitmapPlatformDeviceMac(
-      new BitmapPlatformDeviceMacData(bitmap_context), bitmap);
+      new BitmapPlatformDeviceMacData(context), bitmap);
 }
 
 // The device will own the bitmap, which corresponds to also owning the pixel
 // data. Therefore, we do not transfer ownership to the SkDevice's bitmap.
 BitmapPlatformDeviceMac::BitmapPlatformDeviceMac(
     BitmapPlatformDeviceMacData* data, const SkBitmap& bitmap)
     : PlatformDeviceMac(bitmap),
       data_(data) {
 }
 
@@ skipping 89 matching lines @@
       size_t offset = (i + bitmap_start_y) * row_words + bitmap_start_x;
       for (int j = 0; j < width; j++) {
         adjustor(data + offset + j);
       }
     }
   }
 }
 
 }  // namespace skia