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// 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/compiler_specific.h"
#include "base/macros.h"
#include "skia/ext/platform_device.h"
namespace skia {
class ScopedPlatformPaint;
// A device is basically a wrapper around SkBitmap that provides a surface for
// SkCanvas to draw into. Our device provides a surface Windows can also write
// to. BitmapPlatformDevice creates a bitmap using CreateDIBSection() in a
// format that Skia supports and can then use this to draw ClearType into, etc.
// This pixel data is provided to the bitmap that the device contains so that it
// can be shared.
class SK_API BitmapPlatformDevice : public SkBitmapDevice,
public PlatformDevice {
// Factory function. is_opaque should be set if the caller knows the bitmap
// will be completely opaque and allows some optimizations.
// The |shared_section| parameter is optional (pass NULL for default
// behavior). If |shared_section| is non-null, then it must be a handle to a
// file-mapping object returned by CreateFileMapping. See CreateDIBSection
// for details. If |shared_section| is null, the bitmap backing store is not
// initialized.
static BitmapPlatformDevice* Create(int width, int height,
bool is_opaque, HANDLE shared_section,
bool do_clear = false);
// Create a BitmapPlatformDevice with no shared section. The bitmap is not
// initialized to 0.
static BitmapPlatformDevice* Create(int width, int height, bool is_opaque);
~BitmapPlatformDevice() override;
// Flushes the Windows device context so that the pixel data can be accessed
// directly by Skia. Overridden from SkBaseDevice, this is called when Skia
// starts accessing pixel data.
const SkBitmap& onAccessBitmap() override;
SkBaseDevice* onCreateDevice(const CreateInfo&, const SkPaint*) override;
// PlatformDevice override
// Retrieves the bitmap DC, which is the memory DC for our bitmap data. The
// bitmap DC may be lazily created.
PlatformSurface BeginPlatformPaint(const SkMatrix& transform,
const SkIRect& clip_bounds) override;
// Private constructor.
BitmapPlatformDevice(HBITMAP hbitmap, const SkBitmap& bitmap);
// Bitmap into which the drawing will be done. This bitmap not owned by this
// class, but by the BitmapPlatformPixelRef inside the device's SkBitmap.
// It's only stored here in order to lazy-create the DC (below).
HBITMAP hbitmap_;
// Previous bitmap held by the DC. This will be selected back before the
// DC is destroyed.
HBITMAP old_hbitmap_;
// Lazily-created DC used to draw into the bitmap; see GetBitmapDC().
HDC hdc_;
// Create/destroy hdc_, which is the memory DC for our bitmap data.
HDC GetBitmapDC(const SkMatrix& transform, const SkIRect& clip_bounds);
void ReleaseBitmapDC();
bool IsBitmapDCCreated() const;
// Loads the current transform and clip into the context. Can be called even
// when |hbitmap_| is NULL (will be a NOP).
void LoadConfig(const SkMatrix& transform, const SkIRect& clip_bounds);
friend class ScopedPlatformPaint;
} // namespace skia