ui/gfx/image/image.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.h"

#include <algorithm>
#include <set>

#include "base/logging.h"
#include "base/memory/scoped_ptr.h"
#include "base/stl_util.h"
#include "third_party/skia/include/core/SkBitmap.h"
#include "ui/gfx/image/image_png_rep.h"
#include "ui/gfx/image/image_skia.h"
#include "ui/gfx/image/image_skia_source.h"
#include "ui/gfx/size.h"

#if !defined(OS_IOS)
#include "ui/gfx/codec/png_codec.h"
#endif

#if defined(OS_IOS)
#include "base/mac/foundation_util.h"
#include "ui/gfx/image/image_skia_util_ios.h"
#elif defined(OS_MACOSX)
#include "base/mac/mac_util.h"
#include "ui/gfx/image/image_skia_util_mac.h"
#endif

namespace gfx {

namespace internal {

#if defined(OS_IOS)
scoped_refptr<base::RefCountedMemory> Get1xPNGBytesFromUIImage(
    UIImage* uiimage);
// Caller takes ownership of the returned UIImage.
UIImage* CreateUIImageFromPNG(
    const std::vector<ImagePNGRep>& image_png_reps);
gfx::Size UIImageSize(UIImage* image);
#elif defined(OS_MACOSX)
scoped_refptr<base::RefCountedMemory> Get1xPNGBytesFromNSImage(
    NSImage* nsimage);
// Caller takes ownership of the returned NSImage.
NSImage* NSImageFromPNG(const std::vector<ImagePNGRep>& image_png_reps,
                        CGColorSpaceRef color_space);
gfx::Size NSImageSize(NSImage* image);
#endif // defined(OS_MACOSX)

#if defined(OS_IOS)
ImageSkia* ImageSkiaFromPNG(
    const std::vector<ImagePNGRep>& image_png_reps);
scoped_refptr<base::RefCountedMemory> Get1xPNGBytesFromImageSkia(
    const ImageSkia* skia);
#else
// Returns a 16x16 red image to visually show error in decoding PNG.
// Caller takes ownership of returned ImageSkia.
ImageSkia* GetErrorImageSkia() {
  SkBitmap bitmap;
  bitmap.allocN32Pixels(16, 16);
  bitmap.eraseARGB(0xff, 0xff, 0, 0);
  return new ImageSkia(ImageSkiaRep(bitmap, 1.0f));
}

class PNGImageSource : public ImageSkiaSource {
 public:
  PNGImageSource() {}
  virtual ~PNGImageSource() {}

  virtual ImageSkiaRep GetImageForScale(float scale) OVERRIDE {
    if (image_skia_reps_.empty())
      return ImageSkiaRep();

    const ImageSkiaRep* rep = NULL;
    // gfx::ImageSkia passes one of the resource scale factors. The source
    // should return:
    // 1) The ImageSkiaRep with the highest scale if all available
    // scales are smaller than |scale|.
    // 2) The ImageSkiaRep with the smallest one that is larger than |scale|.
    for (ImageSkiaRepSet::const_iterator iter = image_skia_reps_.begin();
         iter != image_skia_reps_.end(); ++iter) {
      if ((*iter).scale() == scale)
        return (*iter);
      if (!rep || rep->scale() < (*iter).scale())
        rep = &(*iter);
      if (rep->scale() >= scale)
        break;
    }
    return rep ? *rep : ImageSkiaRep();
  }

  const gfx::Size size() const {
    return size_;
  }

  bool AddPNGData(const ImagePNGRep& png_rep) {
    const gfx::ImageSkiaRep rep = ToImageSkiaRep(png_rep);
    if (rep.is_null())
      return false;
    if (size_.IsEmpty())
      size_ = gfx::Size(rep.GetWidth(), rep.GetHeight());
    image_skia_reps_.insert(rep);
    return true;
  }

  static ImageSkiaRep ToImageSkiaRep(const ImagePNGRep& png_rep) {
    scoped_refptr<base::RefCountedMemory> raw_data = png_rep.raw_data;
    CHECK(raw_data.get());
    SkBitmap bitmap;
    if (!PNGCodec::Decode(raw_data->front(), raw_data->size(),
                               &bitmap)) {
      LOG(ERROR) << "Unable to decode PNG for " << png_rep.scale << ".";
      return ImageSkiaRep();
    }
    return ImageSkiaRep(bitmap, png_rep.scale);
  }

 private:
  struct Compare {
    bool operator()(const ImageSkiaRep& rep1, const ImageSkiaRep& rep2) {
      return rep1.scale() < rep2.scale();
    }
  };

  typedef std::set<ImageSkiaRep, Compare> ImageSkiaRepSet;
  ImageSkiaRepSet image_skia_reps_;
  gfx::Size size_;

  DISALLOW_COPY_AND_ASSIGN(PNGImageSource);
};

ImageSkia* ImageSkiaFromPNG(
    const std::vector<ImagePNGRep>& image_png_reps) {
  if (image_png_reps.empty())
    return GetErrorImageSkia();
  scoped_ptr<PNGImageSource> image_source(new PNGImageSource);

  for (size_t i = 0; i < image_png_reps.size(); ++i) {
    if (!image_source->AddPNGData(image_png_reps[i]))
      return GetErrorImageSkia();
  }
  const gfx::Size& size = image_source->size();
  DCHECK(!size.IsEmpty());
  if (size.IsEmpty())
    return GetErrorImageSkia();
  return new ImageSkia(image_source.release(), size);
}

scoped_refptr<base::RefCountedMemory> Get1xPNGBytesFromImageSkia(
    const ImageSkia* image_skia) {
  ImageSkiaRep image_skia_rep = image_skia->GetRepresentation(1.0f);

  scoped_refptr<base::RefCountedBytes> png_bytes(new base::RefCountedBytes());
  if (image_skia_rep.scale() != 1.0f ||
      !PNGCodec::EncodeBGRASkBitmap(image_skia_rep.sk_bitmap(), false,
          &png_bytes->data())) {
    return NULL;
  }
  return png_bytes;
}
#endif

class ImageRepPNG;
class ImageRepSkia;
class ImageRepCocoa;
class ImageRepCocoaTouch;

// An ImageRep is the object that holds the backing memory for an Image. Each
// RepresentationType has an ImageRep subclass that is responsible for freeing
// the memory that the ImageRep holds. When an ImageRep is created, it expects
// to take ownership of the image, without having to retain it or increase its
// reference count.
class ImageRep {
 public:
  explicit ImageRep(Image::RepresentationType rep) : type_(rep) {}

  // Deletes the associated pixels of an ImageRep.
  virtual ~ImageRep() {}

  // Cast helpers ("fake RTTI").
  ImageRepPNG* AsImageRepPNG() {
    CHECK_EQ(type_, Image::kImageRepPNG);
    return reinterpret_cast<ImageRepPNG*>(this);
  }

  ImageRepSkia* AsImageRepSkia() {
    CHECK_EQ(type_, Image::kImageRepSkia);
    return reinterpret_cast<ImageRepSkia*>(this);
  }

#if defined(OS_IOS)
  ImageRepCocoaTouch* AsImageRepCocoaTouch() {
    CHECK_EQ(type_, Image::kImageRepCocoaTouch);
    return reinterpret_cast<ImageRepCocoaTouch*>(this);
  }
#elif defined(OS_MACOSX)
  ImageRepCocoa* AsImageRepCocoa() {
    CHECK_EQ(type_, Image::kImageRepCocoa);
    return reinterpret_cast<ImageRepCocoa*>(this);
  }
#endif

  Image::RepresentationType type() const { return type_; }

  virtual int Width() const = 0;
  virtual int Height() const = 0;
  virtual gfx::Size Size() const = 0;

 private:
  Image::RepresentationType type_;
};

class ImageRepPNG : public ImageRep {
 public:
  ImageRepPNG() : ImageRep(Image::kImageRepPNG) {
  }

  ImageRepPNG(const std::vector<ImagePNGRep>& image_png_reps)
      : ImageRep(Image::kImageRepPNG),
        image_png_reps_(image_png_reps) {
  }

  virtual ~ImageRepPNG() {
  }

  virtual int Width() const OVERRIDE {
    return Size().width();
  }

  virtual int Height() const OVERRIDE {
    return Size().height();
  }

  virtual gfx::Size Size() const OVERRIDE {
    // Read the PNG data to get the image size, caching it.
    if (!size_cache_) {
      for (std::vector<ImagePNGRep>::const_iterator it = image_reps().begin();
           it != image_reps().end(); ++it) {
        if (it->scale == 1.0f) {
          size_cache_.reset(new gfx::Size(it->Size()));
          return *size_cache_;
        }
      }
      size_cache_.reset(new gfx::Size);
    }

    return *size_cache_;
  }

  const std::vector<ImagePNGRep>& image_reps() const { return image_png_reps_; }

 private:
  std::vector<ImagePNGRep> image_png_reps_;

  // Cached to avoid having to parse the raw data multiple times.
  mutable scoped_ptr<gfx::Size> size_cache_;

  DISALLOW_COPY_AND_ASSIGN(ImageRepPNG);
};

class ImageRepSkia : public ImageRep {
 public:
  // Takes ownership of |image|.
  explicit ImageRepSkia(ImageSkia* image)
      : ImageRep(Image::kImageRepSkia),
        image_(image) {
  }

  virtual ~ImageRepSkia() {
  }

  virtual int Width() const OVERRIDE {
    return image_->width();
  }

  virtual int Height() const OVERRIDE {
    return image_->height();
  }

  virtual gfx::Size Size() const OVERRIDE {
    return image_->size();
  }

  ImageSkia* image() { return image_.get(); }

 private:
  scoped_ptr<ImageSkia> image_;

  DISALLOW_COPY_AND_ASSIGN(ImageRepSkia);
};

#if defined(OS_IOS)
class ImageRepCocoaTouch : public ImageRep {
 public:
  explicit ImageRepCocoaTouch(UIImage* image)
      : ImageRep(Image::kImageRepCocoaTouch),
        image_(image) {
    CHECK(image);
  }

  virtual ~ImageRepCocoaTouch() {
    base::mac::NSObjectRelease(image_);
    image_ = nil;
  }

  virtual int Width() const OVERRIDE {
    return Size().width();
  }

  virtual int Height() const OVERRIDE {
    return Size().height();
  }

  virtual gfx::Size Size() const OVERRIDE {
    return internal::UIImageSize(image_);
  }

  UIImage* image() const { return image_; }

 private:
  UIImage* image_;

  DISALLOW_COPY_AND_ASSIGN(ImageRepCocoaTouch);
};
#elif defined(OS_MACOSX)
class ImageRepCocoa : public ImageRep {
 public:
  explicit ImageRepCocoa(NSImage* image)
      : ImageRep(Image::kImageRepCocoa),
        image_(image) {
    CHECK(image);
  }

  virtual ~ImageRepCocoa() {
    base::mac::NSObjectRelease(image_);
    image_ = nil;
  }

  virtual int Width() const OVERRIDE {
    return Size().width();
  }

  virtual int Height() const OVERRIDE {
    return Size().height();
  }

  virtual gfx::Size Size() const OVERRIDE {
    return internal::NSImageSize(image_);
  }

  NSImage* image() const { return image_; }

 private:
  NSImage* image_;

  DISALLOW_COPY_AND_ASSIGN(ImageRepCocoa);
};
#endif  // defined(OS_MACOSX)

// The Storage class acts similarly to the pixels in a SkBitmap: the Image
// class holds a refptr instance of Storage, which in turn holds all the
// ImageReps. This way, the Image can be cheaply copied.
class ImageStorage : public base::RefCounted<ImageStorage> {
 public:
  ImageStorage(Image::RepresentationType default_type)
      : default_representation_type_(default_type),
#if defined(OS_MACOSX) && !defined(OS_IOS)
        default_representation_color_space_(
            base::mac::GetGenericRGBColorSpace()),
#endif  // defined(OS_MACOSX) && !defined(OS_IOS)
        representations_deleter_(&representations_) {
  }

  Image::RepresentationType default_representation_type() {
    return default_representation_type_;
  }
  Image::RepresentationMap& representations() { return representations_; }

#if defined(OS_MACOSX) && !defined(OS_IOS)
  void set_default_representation_color_space(CGColorSpaceRef color_space) {
    default_representation_color_space_ = color_space;
  }
  CGColorSpaceRef default_representation_color_space() {
    return default_representation_color_space_;
  }
#endif  // defined(OS_MACOSX) && !defined(OS_IOS)

 private:
  friend class base::RefCounted<ImageStorage>;

  ~ImageStorage() {}

  // The type of image that was passed to the constructor. This key will always
  // exist in the |representations_| map.
  Image::RepresentationType default_representation_type_;

#if defined(OS_MACOSX) && !defined(OS_IOS)
  // The default representation's colorspace. This is used for converting to
  // NSImage. This field exists to compensate for PNGCodec not writing or
  // reading colorspace ancillary chunks. (sRGB, iCCP).
  // Not owned.
  CGColorSpaceRef default_representation_color_space_;
#endif  // defined(OS_MACOSX) && !defined(OS_IOS)

  // All the representations of an Image. Size will always be at least one, with
  // more for any converted representations.
  Image::RepresentationMap representations_;

  STLValueDeleter<Image::RepresentationMap> representations_deleter_;

  DISALLOW_COPY_AND_ASSIGN(ImageStorage);
};

}  // namespace internal

Image::Image() {
  // |storage_| is NULL for empty Images.
}

Image::Image(const std::vector<ImagePNGRep>& image_reps) {
  // Do not store obviously invalid ImagePNGReps.
  std::vector<ImagePNGRep> filtered;
  for (size_t i = 0; i < image_reps.size(); ++i) {
    if (image_reps[i].raw_data.get() && image_reps[i].raw_data->size())
      filtered.push_back(image_reps[i]);
  }

  if (filtered.empty())
    return;

  storage_ = new internal::ImageStorage(Image::kImageRepPNG);
  internal::ImageRepPNG* rep = new internal::ImageRepPNG(filtered);
  AddRepresentation(rep);
}

Image::Image(const ImageSkia& image) {
  if (!image.isNull()) {
    storage_ = new internal::ImageStorage(Image::kImageRepSkia);
    internal::ImageRepSkia* rep = new internal::ImageRepSkia(
        new ImageSkia(image));
    AddRepresentation(rep);
  }
}

#if defined(OS_IOS)
Image::Image(UIImage* image)
    : storage_(new internal::ImageStorage(Image::kImageRepCocoaTouch)) {
  if (image) {
    internal::ImageRepCocoaTouch* rep = new internal::ImageRepCocoaTouch(image);
    AddRepresentation(rep);
  }
}
#elif defined(OS_MACOSX)
Image::Image(NSImage* image) {
  if (image) {
    storage_ = new internal::ImageStorage(Image::kImageRepCocoa);
    internal::ImageRepCocoa* rep = new internal::ImageRepCocoa(image);
    AddRepresentation(rep);
  }
}
#endif

Image::Image(const Image& other) : storage_(other.storage_) {
}

Image& Image::operator=(const Image& other) {
  storage_ = other.storage_;
  return *this;
}

Image::~Image() {
}

// static
Image Image::CreateFrom1xBitmap(const SkBitmap& bitmap) {
  return Image(ImageSkia::CreateFrom1xBitmap(bitmap));
}

// static
Image Image::CreateFrom1xPNGBytes(const unsigned char* input,
                                  size_t input_size) {
  if (input_size == 0u)
    return Image();

  scoped_refptr<base::RefCountedBytes> raw_data(new base::RefCountedBytes());
  raw_data->data().assign(input, input + input_size);

  return CreateFrom1xPNGBytes(raw_data);
}

Image Image::CreateFrom1xPNGBytes(
    const scoped_refptr<base::RefCountedMemory>& input) {
  if (!input.get() || input->size() == 0u)
    return Image();

  std::vector<ImagePNGRep> image_reps;
  image_reps.push_back(ImagePNGRep(input, 1.0f));
  return Image(image_reps);
}

const SkBitmap* Image::ToSkBitmap() const {
  // Possibly create and cache an intermediate ImageRepSkia.
  return ToImageSkia()->bitmap();
}

const ImageSkia* Image::ToImageSkia() const {
  internal::ImageRep* rep = GetRepresentation(kImageRepSkia, false);
  if (!rep) {
    switch (DefaultRepresentationType()) {
      case kImageRepPNG: {
        internal::ImageRepPNG* png_rep =
            GetRepresentation(kImageRepPNG, true)->AsImageRepPNG();
        rep = new internal::ImageRepSkia(
            internal::ImageSkiaFromPNG(png_rep->image_reps()));
        break;
      }
#if defined(OS_IOS)
      case kImageRepCocoaTouch: {
        internal::ImageRepCocoaTouch* native_rep =
            GetRepresentation(kImageRepCocoaTouch, true)
                ->AsImageRepCocoaTouch();
        rep = new internal::ImageRepSkia(new ImageSkia(
            ImageSkiaFromUIImage(native_rep->image())));
        break;
      }
#elif defined(OS_MACOSX)
      case kImageRepCocoa: {
        internal::ImageRepCocoa* native_rep =
            GetRepresentation(kImageRepCocoa, true)->AsImageRepCocoa();
        rep = new internal::ImageRepSkia(new ImageSkia(
            ImageSkiaFromNSImage(native_rep->image())));
        break;
      }
#endif
      default:
        NOTREACHED();
    }
    CHECK(rep);
    AddRepresentation(rep);
  }
  return rep->AsImageRepSkia()->image();
}

#if defined(OS_IOS)
UIImage* Image::ToUIImage() const {
  internal::ImageRep* rep = GetRepresentation(kImageRepCocoaTouch, false);
  if (!rep) {
    switch (DefaultRepresentationType()) {
      case kImageRepPNG: {
        internal::ImageRepPNG* png_rep =
            GetRepresentation(kImageRepPNG, true)->AsImageRepPNG();
        rep = new internal::ImageRepCocoaTouch(internal::CreateUIImageFromPNG(
            png_rep->image_reps()));
        break;
      }
      case kImageRepSkia: {
        internal::ImageRepSkia* skia_rep =
            GetRepresentation(kImageRepSkia, true)->AsImageRepSkia();
        UIImage* image = UIImageFromImageSkia(*skia_rep->image());
        base::mac::NSObjectRetain(image);
        rep = new internal::ImageRepCocoaTouch(image);
        break;
      }
      default:
        NOTREACHED();
    }
    CHECK(rep);
    AddRepresentation(rep);
  }
  return rep->AsImageRepCocoaTouch()->image();
}
#elif defined(OS_MACOSX)
NSImage* Image::ToNSImage() const {
  internal::ImageRep* rep = GetRepresentation(kImageRepCocoa, false);
  if (!rep) {
    CGColorSpaceRef default_representation_color_space =
        storage_->default_representation_color_space();

    switch (DefaultRepresentationType()) {
      case kImageRepPNG: {
        internal::ImageRepPNG* png_rep =
            GetRepresentation(kImageRepPNG, true)->AsImageRepPNG();
        rep = new internal::ImageRepCocoa(internal::NSImageFromPNG(
            png_rep->image_reps(), default_representation_color_space));
        break;
      }
      case kImageRepSkia: {
        internal::ImageRepSkia* skia_rep =
            GetRepresentation(kImageRepSkia, true)->AsImageRepSkia();
        NSImage* image = NSImageFromImageSkiaWithColorSpace(*skia_rep->image(),
            default_representation_color_space);
        base::mac::NSObjectRetain(image);
        rep = new internal::ImageRepCocoa(image);
        break;
      }
      default:
        NOTREACHED();
    }
    CHECK(rep);
    AddRepresentation(rep);
  }
  return rep->AsImageRepCocoa()->image();
}
#endif

scoped_refptr<base::RefCountedMemory> Image::As1xPNGBytes() const {
  if (IsEmpty())
    return new base::RefCountedBytes();

  internal::ImageRep* rep = GetRepresentation(kImageRepPNG, false);

  if (rep) {
    const std::vector<ImagePNGRep>& image_png_reps =
        rep->AsImageRepPNG()->image_reps();
    for (size_t i = 0; i < image_png_reps.size(); ++i) {
      if (image_png_reps[i].scale == 1.0f)
        return image_png_reps[i].raw_data;
    }
    return new base::RefCountedBytes();
  }

  scoped_refptr<base::RefCountedMemory> png_bytes(NULL);
  switch (DefaultRepresentationType()) {
#if defined(OS_IOS)
    case kImageRepCocoaTouch: {
      internal::ImageRepCocoaTouch* cocoa_touch_rep =
          GetRepresentation(kImageRepCocoaTouch, true)
              ->AsImageRepCocoaTouch();
      png_bytes = internal::Get1xPNGBytesFromUIImage(
          cocoa_touch_rep->image());
      break;
    }
#elif defined(OS_MACOSX)
    case kImageRepCocoa: {
      internal::ImageRepCocoa* cocoa_rep =
          GetRepresentation(kImageRepCocoa, true)->AsImageRepCocoa();
      png_bytes = internal::Get1xPNGBytesFromNSImage(cocoa_rep->image());
      break;
    }
#endif
    case kImageRepSkia: {
      internal::ImageRepSkia* skia_rep =
          GetRepresentation(kImageRepSkia, true)->AsImageRepSkia();
      png_bytes = internal::Get1xPNGBytesFromImageSkia(skia_rep->image());
      break;
    }
    default:
      NOTREACHED();
  }
  if (!png_bytes.get() || !png_bytes->size()) {
    // Add an ImageRepPNG with no data such that the conversion is not
    // attempted each time we want the PNG bytes.
    AddRepresentation(new internal::ImageRepPNG());
    return new base::RefCountedBytes();
  }

  // Do not insert representations for scale factors other than 1x even if
  // they are available because:
  // - Only the 1x PNG bytes can be accessed.
  // - ImageRepPNG is not used as an intermediate type in converting to a
  //   final type eg (converting from ImageRepSkia to ImageRepPNG to get an
  //   ImageRepCocoa).
  std::vector<ImagePNGRep> image_png_reps;
  image_png_reps.push_back(ImagePNGRep(png_bytes, 1.0f));
  rep = new internal::ImageRepPNG(image_png_reps);
  AddRepresentation(rep);
  return png_bytes;
}

SkBitmap Image::AsBitmap() const {
  return IsEmpty() ? SkBitmap() : *ToSkBitmap();
}

ImageSkia Image::AsImageSkia() const {
  return IsEmpty() ? ImageSkia() : *ToImageSkia();
}

#if defined(OS_MACOSX) && !defined(OS_IOS)
NSImage* Image::AsNSImage() const {
  return IsEmpty() ? nil : ToNSImage();
}
#endif

scoped_refptr<base::RefCountedMemory> Image::Copy1xPNGBytes() const {
  scoped_refptr<base::RefCountedMemory> original = As1xPNGBytes();
  scoped_refptr<base::RefCountedBytes> copy(new base::RefCountedBytes());
  copy->data().assign(original->front(), original->front() + original->size());
  return copy;
}

ImageSkia* Image::CopyImageSkia() const {
  return new ImageSkia(*ToImageSkia());
}

SkBitmap* Image::CopySkBitmap() const {
  return new SkBitmap(*ToSkBitmap());
}

#if defined(OS_IOS)
UIImage* Image::CopyUIImage() const {
  UIImage* image = ToUIImage();
  base::mac::NSObjectRetain(image);
  return image;
}
#elif defined(OS_MACOSX)
NSImage* Image::CopyNSImage() const {
  NSImage* image = ToNSImage();
  base::mac::NSObjectRetain(image);
  return image;
}
#endif

bool Image::HasRepresentation(RepresentationType type) const {
  return storage_.get() && storage_->representations().count(type) != 0;
}

size_t Image::RepresentationCount() const {
  if (!storage_.get())
    return 0;

  return storage_->representations().size();
}

bool Image::IsEmpty() const {
  return RepresentationCount() == 0;
}

int Image::Width() const {
  if (IsEmpty())
    return 0;
  return GetRepresentation(DefaultRepresentationType(), true)->Width();
}

int Image::Height() const {
  if (IsEmpty())
    return 0;
  return GetRepresentation(DefaultRepresentationType(), true)->Height();
}

gfx::Size Image::Size() const {
  if (IsEmpty())
    return gfx::Size();
  return GetRepresentation(DefaultRepresentationType(), true)->Size();
}

void Image::SwapRepresentations(Image* other) {
  storage_.swap(other->storage_);
}

#if defined(OS_MACOSX)  && !defined(OS_IOS)
void Image::SetSourceColorSpace(CGColorSpaceRef color_space) {
  if (storage_.get())
    storage_->set_default_representation_color_space(color_space);
}
#endif  // defined(OS_MACOSX) && !defined(OS_IOS)

Image::RepresentationType Image::DefaultRepresentationType() const {
  CHECK(storage_.get());
  return storage_->default_representation_type();
}

internal::ImageRep* Image::GetRepresentation(
    RepresentationType rep_type, bool must_exist) const {
  CHECK(storage_.get());
  RepresentationMap::iterator it = storage_->representations().find(rep_type);
  if (it == storage_->representations().end()) {
    CHECK(!must_exist);
    return NULL;
  }
  return it->second;
}

void Image::AddRepresentation(internal::ImageRep* rep) const {
  CHECK(storage_.get());
  storage_->representations().insert(std::make_pair(rep->type(), rep));
}

}  // namespace gfx