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// Copyright (c) 2006-2008 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 SKIA_EXT_PLATFORM_CANVAS_MAC_H_
#define SKIA_EXT_PLATFORM_CANVAS_MAC_H_
#include "skia/ext/platform_device_mac.h"
#include "third_party/skia/include/core/SkCanvas.h"
namespace skia {
// This class is a specialization of the regular SkCanvas that is designed to
// work with a gfx::PlatformDevice to manage platform-specific drawing. It
// allows using both Skia operations and platform-specific operations.
class PlatformCanvasMac : public SkCanvas {
public:
// Set is_opaque if you are going to erase the bitmap and not use
// tranparency: this will enable some optimizations. The shared_section
// parameter is passed to gfx::PlatformDevice::create. See it for details.
//
// If you use the version with no arguments, you MUST call initialize()
PlatformCanvasMac();
PlatformCanvasMac(int width, int height, bool is_opaque);
PlatformCanvasMac(int width, int height, bool is_opaque,
CGContextRef context);
PlatformCanvasMac(int width, int height, bool is_opaque,
uint8_t* context);
virtual ~PlatformCanvasMac();
// For two-part init, call if you use the no-argument constructor above
bool initialize(int width, int height, bool is_opaque);
bool initialize(int width, int height, bool is_opaque, uint8_t* data);
// These calls should surround calls to platform drawing routines. The CG
// context returned by beginPlatformPaint is the one that can be used to
// draw into.
// Call endPlatformPaint when you are done and want to use Skia operations
// again; this will synchronize the bitmap.
virtual CGContextRef beginPlatformPaint();
virtual void endPlatformPaint();
// Returns the platform device pointer of the topmost rect with a non-empty
// clip. In practice, this is usually either the top layer or nothing, since
// we usually set the clip to new layers when we make them.
//
// If there is no layer that is not all clipped out, this will return a
// dummy device so callers do not have to check. If you are concerned about
// performance, check the clip before doing any painting.
//
// This is different than SkCanvas' getDevice, because that returns the
// bottommost device.
//
// Danger: the resulting device should not be saved. It will be invalidated
// by the next call to save() or restore().
PlatformDeviceMac& getTopPlatformDevice() const;
// Allow callers to see the non-virtual function even though we have an
// override of a virtual one.
using SkCanvas::clipRect;
// Return the stride (length of a line in bytes) for the given width. Because
// we use 32-bits per pixel, this will be roughly 4*width. However, for
// alignment reasons we may wish to increase that.
static size_t StrideForWidth(unsigned width);
protected:
// Creates a device store for use by the canvas. We override this so that
// the device is always our own so we know that we can use GDI operations
// on it. Simply calls into createPlatformDevice().
virtual SkDevice* createDevice(SkBitmap::Config, int width, int height,
bool is_opaque, bool isForLayer);
// Creates a device store for use by the canvas. By default, it creates a
// BitmapPlatformDevice object. Can be overridden to change the object type.
virtual SkDevice* createPlatformDevice(int width, int height, bool is_opaque,
CGContextRef context);
private:
// Unimplemented. This is to try to prevent people from calling this function
// on SkCanvas. SkCanvas' version is not virtual, so we can't prevent this
// 100%, but hopefully this will make people notice and not use the function.
// Calling SkCanvas' version will create a new device which is not compatible
// with us and we will crash if somebody tries to draw into it with
// CoreGraphics.
SkDevice* setBitmapDevice(const SkBitmap& bitmap);
// Disallow copy and assign.
PlatformCanvasMac(const PlatformCanvasMac&);
PlatformCanvasMac& operator=(const PlatformCanvasMac&);
};
} // namespace skia
#endif // SKIA_EXT_PLATFORM_CANVAS_MAC_H_
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