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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_DEVICE_WIN_H_
#define SKIA_EXT_PLATFORM_DEVICE_WIN_H_
#include <windows.h>
#include <vector>
#include "SkDevice.h"
class SkMatrix;
class SkPath;
class SkRegion;
namespace skia {
// 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 PlatformDeviceWin : 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.
PlatformDeviceWin(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 skia
#endif // SKIA_EXT_PLATFORM_DEVICE_WIN_H_