text: // 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 SKIA_EXT_BITMAP_PLATFORM_DEVICE_WIN_H_
  #define SKIA_EXT_BITMAP_PLATFORM_DEVICE_WIN_H_
  
  #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 {
   public:
    // 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;
  
   protected:
    SkBaseDevice* onCreateDevice(const CreateInfo&, const SkPaint*) override;
  
   private:
    // PlatformDevice override
    // Retrieves the bitmap DC, which is the memory DC for our bitmap data. The
    // bitmap DC may be lazily created.
    NativeDrawingContext 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);
  
    DISALLOW_COPY_AND_ASSIGN(BitmapPlatformDevice);
    friend class ScopedPlatformPaint;
  };
  
  }  // namespace skia
  
  #endif  // SKIA_EXT_BITMAP_PLATFORM_DEVICE_WIN_H_
  