skia/ext/skia_utils_ios.mm

   1 // Copyright 2012 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 "skia/ext/skia_utils_ios.h"
   6
   7 #import <ImageIO/ImageIO.h>
   8 #import <UIKit/UIKit.h>
   9
  10 #include "base/logging.h"
  11 #include "base/mac/scoped_cftyperef.h"
  12 #include "third_party/skia/include/utils/mac/SkCGUtils.h"
  13
  14 namespace gfx {
  15
  16 SkBitmap CGImageToSkBitmap(CGImageRef image, CGSize size, bool is_opaque) {
  17   SkBitmap bitmap;
  18   if (!image)
  19     return bitmap;
  20
  21   if (!bitmap.tryAllocN32Pixels(size.width, size.height, is_opaque))
  22     return bitmap;
  23
  24   void* data = bitmap.getPixels();
  25
  26   // Allocate a bitmap context with 4 components per pixel (BGRA). Apple
  27   // recommends these flags for improved CG performance.
  28 #define HAS_ARGB_SHIFTS(a, r, g, b) \
  29             (SK_A32_SHIFT == (a) && SK_R32_SHIFT == (r) \
  30              && SK_G32_SHIFT == (g) && SK_B32_SHIFT == (b))
  31 #if defined(SK_CPU_LENDIAN) && HAS_ARGB_SHIFTS(24, 16, 8, 0)
  32   base::ScopedCFTypeRef<CGColorSpaceRef> color_space(
  33       CGColorSpaceCreateDeviceRGB());
  34   base::ScopedCFTypeRef<CGContextRef> context(CGBitmapContextCreate(
  35       data,
  36       size.width,
  37       size.height,
  38       8,
  39       size.width * 4,
  40       color_space,
  41       kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Host));
  42 #else
  43 #error We require that Skia's and CoreGraphics's recommended \
  44        image memory layout match.
  45 #endif
  46 #undef HAS_ARGB_SHIFTS
  47
  48   DCHECK(context);
  49   if (!context)
  50     return bitmap;
  51
  52   CGRect imageRect = CGRectMake(0.0, 0.0, size.width, size.height);
  53   CGContextSetBlendMode(context, kCGBlendModeCopy);
  54   CGContextDrawImage(context, imageRect, image);
  55
  56   return bitmap;
  57 }
  58
  59 UIImage* SkBitmapToUIImageWithColorSpace(const SkBitmap& skia_bitmap,
  60                                          CGFloat scale,
  61                                          CGColorSpaceRef color_space) {
  62   if (skia_bitmap.isNull())
  63     return nil;
  64
  65   // First convert SkBitmap to CGImageRef.
  66   base::ScopedCFTypeRef<CGImageRef> cg_image(
  67       SkCreateCGImageRefWithColorspace(skia_bitmap, color_space));
  68
  69   // Now convert to UIImage.
  70   return [UIImage imageWithCGImage:cg_image.get()
  71                              scale:scale
  72                        orientation:UIImageOrientationUp];
  73 }
  74
  75 std::vector<SkBitmap> ImageDataToSkBitmaps(NSData* image_data) {
  76   DCHECK(image_data);
  77   base::ScopedCFTypeRef<CFDictionaryRef> empty_dictionary(
  78       CFDictionaryCreate(NULL, NULL, NULL, 0, NULL, NULL));
  79   std::vector<SkBitmap> frames;
  80
  81   base::ScopedCFTypeRef<CGImageSourceRef> source(
  82       CGImageSourceCreateWithData((CFDataRef)image_data, empty_dictionary));
  83
  84   size_t count = CGImageSourceGetCount(source);
  85   for (size_t index = 0; index < count; ++index) {
  86     base::ScopedCFTypeRef<CGImageRef> cg_image(
  87         CGImageSourceCreateImageAtIndex(source, index, empty_dictionary));
  88
  89     CGSize size = CGSizeMake(CGImageGetWidth(cg_image),
  90                              CGImageGetHeight(cg_image));
  91     const SkBitmap bitmap = CGImageToSkBitmap(cg_image, size, false);
  92     if (!bitmap.empty())
  93       frames.push_back(bitmap);
  94   }
  95
  96   DLOG_IF(WARNING, frames.size() != count) << "Only decoded " << frames.size()
  97       << " frames for " << count << " expected.";
  98   return frames;
  99 }
 100
 101 }  // namespace gfx