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#ifndef BASE_GFX_PLATFORM_DEVICE_H__
#define BASE_GFX_PLATFORM_DEVICE_H__

#include <vector>

#include "SkDevice.h"

class SkMatrix;
class SkPath;
class SkRegion;

namespace gfx {

// 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. It also provides functionality to play well with GDI drawing functions.
// This class is abstract and must be subclassed. It provides the basic
// interface to implement it either with or without a bitmap backend.
class PlatformDevice : public SkDevice {
 public:
  // The DC that corresponds to the bitmap, used for GDI operations drawing
  // into the bitmap. This is possibly heavyweight, so it should be existant
  // only during one pass of rendering.
  virtual HDC getBitmapDC() = 0;

  // Draws to the given screen DC, if the bitmap DC doesn't exist, this will
  // temporarily create it. However, if you have created the bitmap DC, it will
  // be more efficient if you don't free it until after this call so it doesn't
  // have to be created twice.  If src_rect is null, then the entirety of the
  // source device will be copied.
  virtual void drawToHDC(HDC dc, int x, int y, const RECT* src_rect) = 0;

  // Invoke before using GDI functions. See description in platform_device.cc
  // for specifics.
  // NOTE: x,y,width and height are relative to the current transform.
  virtual void prepareForGDI(int x, int y, int width, int height) { }

  // Invoke after using GDI functions. See description in platform_device.cc
  // for specifics.
  // NOTE: x,y,width and height are relative to the current transform.
  virtual void postProcessGDI(int x, int y, int width, int height) { }

  // Sets the opacity of each pixel in the specified region to be opaque.
  virtual void makeOpaque(int x, int y, int width, int height) { }

  // Call this function to fix the alpha channels before compositing this layer
  // onto another. Internally, the device uses a special alpha method to work
  // around problems with Windows. This call will put the values into what
  // Skia expects, so it can be composited onto other layers.
  //
  // After this call, no more drawing can be done because the
  // alpha channels will be "correct", which, if this function is called again
  // will make them wrong. See the implementation for more discussion.
  virtual void fixupAlphaBeforeCompositing() { }

  // Returns if the preferred rendering engine is vectorial or bitmap based.
  virtual bool IsVectorial() = 0;

  // Initializes the default settings and colors in a device context.
  static void InitializeDC(HDC context);

  // Loads a SkPath into the GDI context. The path can there after be used for
  // clipping or as a stroke.
  static void LoadPathToDC(HDC context, const SkPath& path);

  // Loads a SkRegion into the GDI context.
  static void LoadClippingRegionToDC(HDC context, const SkRegion& region,
                                     const SkMatrix& transformation);

 protected:
  // Arrays must be inside structures.
  struct CubicPoints {
    SkPoint p[4];
  };
  typedef std::vector<CubicPoints> CubicPath;
  typedef std::vector<CubicPath> CubicPaths;

  // Forwards |bitmap| to SkDevice's constructor.
  PlatformDevice(const SkBitmap& bitmap);

  // Loads the specified Skia transform into the device context, excluding
  // perspective (which GDI doesn't support).
  static void LoadTransformToDC(HDC dc, const SkMatrix& matrix);

  // Transforms SkPath's paths into a series of cubic path.
  static bool SkPathToCubicPaths(CubicPaths* paths, const SkPath& skpath);
};

}  // namespace gfx

#endif  // BASE_GFX_PLATFORM_DEVICE_H__