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   bitmap.setConfig(SkBitmap::kARGB_8888_Config,
  22                    size.width,
  23                    size.height,
  24                    0,
  25                    is_opaque ? kOpaque_SkAlphaType : kPremul_SkAlphaType);
  26
  27   if (!bitmap.allocPixels())
  28     return bitmap;
  29
  30   void* data = bitmap.getPixels();
  31
  32   // Allocate a bitmap context with 4 components per pixel (BGRA). Apple
  33   // recommends these flags for improved CG performance.
  34 #define HAS_ARGB_SHIFTS(a, r, g, b) \
  35             (SK_A32_SHIFT == (a) && SK_R32_SHIFT == (r) \
  36              && SK_G32_SHIFT == (g) && SK_B32_SHIFT == (b))
  37 #if defined(SK_CPU_LENDIAN) && HAS_ARGB_SHIFTS(24, 16, 8, 0)
  38   base::ScopedCFTypeRef<CGColorSpaceRef> color_space(
  39       CGColorSpaceCreateDeviceRGB());
  40   base::ScopedCFTypeRef<CGContextRef> context(CGBitmapContextCreate(
  41       data,
  42       size.width,
  43       size.height,
  44       8,
  45       size.width * 4,
  46       color_space,
  47       kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Host));
  48 #else
  49 #error We require that Skia's and CoreGraphics's recommended \
  50        image memory layout match.
  51 #endif
  52 #undef HAS_ARGB_SHIFTS
  53
  54   DCHECK(context);
  55   if (!context)
  56     return bitmap;
  57
  58   CGRect imageRect = CGRectMake(0.0, 0.0, size.width, size.height);
  59   CGContextSetBlendMode(context, kCGBlendModeCopy);
  60   CGContextDrawImage(context, imageRect, image);
  61
  62   return bitmap;
  63 }
  64
  65 UIImage* SkBitmapToUIImageWithColorSpace(const SkBitmap& skia_bitmap,
  66                                          CGFloat scale,
  67                                          CGColorSpaceRef color_space) {
  68   if (skia_bitmap.isNull())
  69     return nil;
  70
  71   // First convert SkBitmap to CGImageRef.
  72   base::ScopedCFTypeRef<CGImageRef> cg_image(
  73       SkCreateCGImageRefWithColorspace(skia_bitmap, color_space));
  74
  75   // Now convert to UIImage.
  76   return [UIImage imageWithCGImage:cg_image.get()
  77                              scale:scale
  78                        orientation:UIImageOrientationUp];
  79 }
  80
  81 std::vector<SkBitmap> ImageDataToSkBitmaps(NSData* image_data) {
  82   DCHECK(image_data);
  83   base::ScopedCFTypeRef<CFDictionaryRef> empty_dictionary(
  84       CFDictionaryCreate(NULL, NULL, NULL, 0, NULL, NULL));
  85   std::vector<SkBitmap> frames;
  86
  87   base::ScopedCFTypeRef<CGImageSourceRef> source(
  88       CGImageSourceCreateWithData((CFDataRef)image_data, empty_dictionary));
  89
  90   size_t count = CGImageSourceGetCount(source);
  91   for (size_t index = 0; index < count; ++index) {
  92     base::ScopedCFTypeRef<CGImageRef> cg_image(
  93         CGImageSourceCreateImageAtIndex(source, index, empty_dictionary));
  94
  95     CGSize size = CGSizeMake(CGImageGetWidth(cg_image),
  96                              CGImageGetHeight(cg_image));
  97     const SkBitmap bitmap = CGImageToSkBitmap(cg_image, size, false);
  98     if (!bitmap.empty())
  99       frames.push_back(bitmap);
 100   }
 101
 102   DLOG_IF(WARNING, frames.size() != count) << "Only decoded " << frames.size()
 103       << " frames for " << count << " expected.";
 104   return frames;
 105 }
 106
 107 }  // namespace gfx