// 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.
#ifndef UI_GFX_IMAGE_IMAGE_SKIA_H_
#define UI_GFX_IMAGE_IMAGE_SKIA_H_
#include <vector>
#include "base/basictypes.h"
#include "base/gtest_prod_util.h"
#include "base/memory/ref_counted.h"
#include "base/memory/scoped_ptr.h"
#include "ui/gfx/gfx_export.h"
#include "ui/gfx/image/image_skia_rep.h"
namespace gfx {
class ImageSkiaSource;
class Size;
namespace internal {
class ImageSkiaStorage;
} // namespace internal
namespace test {
class TestOnThread;
}
// Container for the same image at different densities, similar to NSImage.
// Image height and width are in DIP (Density Indepent Pixel) coordinates.
//
// ImageSkia should be used whenever possible instead of SkBitmap.
// Functions that mutate the image should operate on the gfx::ImageSkiaRep
// returned from ImageSkia::GetRepresentation, not on ImageSkia.
//
// ImageSkia is cheap to copy and intentionally supports copy semantics.
class GFX_EXPORT ImageSkia {
public:
typedef std::vector<ImageSkiaRep> ImageSkiaReps;
// Creates an instance with no bitmaps.
ImageSkia();
// Creates an instance that will use the |source| to get the image
// for scale factors. |size| specifes the size of the image in DIP.
// ImageSkia owns |source|.
ImageSkia(ImageSkiaSource* source, const gfx::Size& size);
// Creates an instance that uses the |source|. The constructor loads the image
// at |scale| and uses its dimensions to calculate the size in DIP. ImageSkia
// owns |source|.
ImageSkia(ImageSkiaSource* source, float scale);
explicit ImageSkia(const gfx::ImageSkiaRep& image_rep);
// Copies a reference to |other|'s storage.
ImageSkia(const ImageSkia& other);
// Copies a reference to |other|'s storage.
ImageSkia& operator=(const ImageSkia& other);
~ImageSkia();
// Changes the value of GetSupportedScales() to |scales|.
static void SetSupportedScales(const std::vector<float>& scales);
// Returns a vector with the scale factors which are supported by this
// platform, in ascending order.
static const std::vector<float>& GetSupportedScales();
// Returns the maximum scale supported by this platform.
static float GetMaxSupportedScale();
// Creates an image from the passed in bitmap.
// DIP width and height are based on scale factor of 1x.
// Adds ref to passed in bitmap.
// WARNING: The resulting image will be pixelated when painted on a high
// density display.
static ImageSkia CreateFrom1xBitmap(const SkBitmap& bitmap);
// Returns a deep copy of this ImageSkia which has its own storage with
// the ImageSkiaRep instances that this ImageSkia currently has.
// This can be safely passed to and manipulated by another thread.
// Note that this does NOT generate ImageSkiaReps from its source.
// If you want to create a deep copy with ImageSkiaReps for supported
// scale factors, you need to explicitly call
// |EnsureRepsForSupportedScales()| first.
scoped_ptr<ImageSkia> DeepCopy() const;
// Returns true if this object is backed by the same ImageSkiaStorage as
// |other|. Will also return true if both images are isNull().
bool BackedBySameObjectAs(const gfx::ImageSkia& other) const;
// Adds |image_rep| to the image reps contained by this object.
void AddRepresentation(const gfx::ImageSkiaRep& image_rep);
// Removes the image rep of |scale| if present.
void RemoveRepresentation(float scale);
// Returns true if the object owns an image rep whose density matches
// |scale| exactly.
bool HasRepresentation(float scale) const;
// Returns the image rep whose density best matches |scale|.
// Returns a null image rep if the object contains no image reps.
const gfx::ImageSkiaRep& GetRepresentation(float scale) const;
// Make the ImageSkia instance read-only. Note that this only prevent
// modification from client code, and the storage may still be
// modified by the source if any (thus, it's not thread safe). This
// detaches the storage from currently accessing thread, so its safe
// to pass it to other thread as long as it is accessed only by that
// thread. If this ImageSkia's storage will be accessed by multiple
// threads, use |MakeThreadSafe()| method.
void SetReadOnly();
// Make the image thread safe by making the storage read only and remove
// its source if any. All ImageSkia that shares the same storage will also
// become thread safe. Note that in order to make it 100% thread safe,
// this must be called before it's been passed to anther thread.
void MakeThreadSafe();
bool IsThreadSafe() const;
// Returns true if this is a null object.
bool isNull() const { return storage_.get() == NULL; }
// Width and height of image in DIP coordinate system.
int width() const;
int height() const;
gfx::Size size() const;
// Returns pointer to 1x bitmap contained by this object. If there is no 1x
// bitmap, the bitmap whose scale factor is closest to 1x is returned.
// This function should only be used in unittests and on platforms which do
// not support scale factors other than 1x.
// TODO(pkotwicz): Return null SkBitmap when the object has no 1x bitmap.
const SkBitmap* bitmap() const { return &GetBitmap(); }
// Returns a vector with the image reps contained in this object.
// There is no guarantee that this will return all images rep for
// supported scale factors.
std::vector<gfx::ImageSkiaRep> image_reps() const;
// When the source is available, generates all ImageReps for
// supported scale factors. This method is defined as const as
// the state change in the storage is agnostic to the caller.
void EnsureRepsForSupportedScales() const;
private:
friend class test::TestOnThread;
FRIEND_TEST_ALL_PREFIXES(ImageSkiaTest, EmptyOnThreadTest);
FRIEND_TEST_ALL_PREFIXES(ImageSkiaTest, StaticOnThreadTest);
FRIEND_TEST_ALL_PREFIXES(ImageSkiaTest, SourceOnThreadTest);
// Initialize ImageSkiaStorage with passed in parameters.
// If the image rep's bitmap is empty, ImageStorage is set to NULL.
void Init(const gfx::ImageSkiaRep& image_rep);
SkBitmap& GetBitmap() const;
// Checks if the current thread can read/modify the ImageSkia.
bool CanRead() const;
bool CanModify() const;
// Detach the storage from the currently assinged thread
// so that other thread can access the storage.
void DetachStorageFromThread();
// A refptr so that ImageRepSkia can be copied cheaply.
scoped_refptr<internal::ImageSkiaStorage> storage_;
};
} // namespace gfx
#endif // UI_GFX_IMAGE_IMAGE_SKIA_H_