blob: 665356f7a34cdb709a4e31f2ec4e924f7b9cb73c [file] [log] [blame]
// 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 "base/basictypes.h"
#include "base/compiler_specific.h"
#include "skia/ext/platform_device.h"
#include "skia/ext/refptr.h"
namespace skia {
// A device is basically a wrapper around SkBitmap that provides a surface for
// SkCanvas to draw into. Our device provides a surface CoreGraphics can also
// write to. BitmapPlatformDevice creates a bitmap using
// CGCreateBitmapContext() in a format that Skia supports and can then use this
// to draw text into, etc. This pixel data is provided to the bitmap that the
// device contains so that it can be shared.
// The device owns the pixel data, when the device goes away, the pixel data
// also becomes invalid. THIS IS DIFFERENT THAN NORMAL SKIA which uses
// reference counting for the pixel data. In normal Skia, you could assign
// another bitmap to this device's bitmap and everything will work properly.
// For us, that other bitmap will become invalid as soon as the device becomes
// invalid, which may lead to subtle bugs. Therefore, DO NOT ASSIGN THE
// DEVICE'S PIXEL DATA TO ANOTHER BITMAP, make sure you copy instead.
class SK_API BitmapPlatformDevice : public SkBitmapDevice, public PlatformDevice {
// Creates a BitmapPlatformDevice instance. |is_opaque| should be set if the
// caller knows the bitmap will be completely opaque and allows some
// optimizations.
// |context| may be NULL. If |context| is NULL, then the bitmap backing store
// is not initialized.
static BitmapPlatformDevice* Create(CGContextRef context,
int width, int height,
bool is_opaque);
// Creates a BitmapPlatformDevice instance. If |is_opaque| is false,
// then the bitmap is initialzed to 0.
static BitmapPlatformDevice* CreateAndClear(int width, int height,
bool is_opaque);
// Creates a context for |data| and calls Create.
// If |data| is NULL, then the bitmap backing store is not initialized.
static BitmapPlatformDevice* CreateWithData(uint8_t* data,
int width, int height,
bool is_opaque);
virtual ~BitmapPlatformDevice();
// PlatformDevice overrides
virtual CGContextRef GetBitmapContext() OVERRIDE;
virtual void DrawToNativeContext(CGContextRef context, int x, int y,
const CGRect* src_rect) OVERRIDE;
// SkBaseDevice overrides
virtual void setMatrixClip(const SkMatrix& transform, const SkRegion& region,
const SkClipStack&) OVERRIDE;
BitmapPlatformDevice(CGContextRef context,
const SkBitmap& bitmap);
virtual SkBaseDevice* onCreateDevice(const SkImageInfo& info,
Usage usage) OVERRIDE;
void ReleaseBitmapContext();
// Sets the transform and clip operations. This will not update the CGContext,
// but will mark the config as dirty. The next call of LoadConfig will
// pick up these changes.
void SetMatrixClip(const SkMatrix& transform, const SkRegion& region);
// Loads the current transform and clip into the context. Can be called even
// when |bitmap_context_| is NULL (will be a NOP).
void LoadConfig();
// Lazily-created graphics context used to draw into the bitmap.
CGContextRef bitmap_context_;
// True when there is a transform or clip that has not been set to the
// context. The context is retrieved for every text operation, and the
// transform and clip do not change as much. We can save time by not loading
// the clip and transform for every one.
bool config_dirty_;
// Translation assigned to the context: we need to keep track of this
// separately so it can be updated even if the context isn't created yet.
SkMatrix transform_;
// The current clipping
SkRegion clip_region_;
} // namespace skia