Refactor the PlatformContext layer to have only one class.

skia/ext/vector_platform_device_win.h

+// Copyright (c) 2009 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_VECTOR_PLATFORM_DEVICE_WIN_H_
+#define SKIA_EXT_VECTOR_PLATFORM_DEVICE_WIN_H_
+
+#include "skia/ext/platform_device.h"
+#include "third_party/skia/include/core/SkMatrix.h"
+#include "third_party/skia/include/core/SkRegion.h"
+
+namespace skia {
+
+// A device is basically a wrapper around SkBitmap that provides a surface for
+// SkCanvas to draw into. This specific device is not not backed by a surface
+// and is thus unreadable. This is because the backend is completely vectorial.
+// This device is a simple wrapper over a Windows device context (HDC) handle.
+class VectorPlatformDevice : public PlatformDevice {
+ public:
+  // Factory function. The DC is kept as the output context.
+  static VectorPlatformDevice* create(HDC dc, int width, int height);
+
+  VectorPlatformDevice(HDC dc, const SkBitmap& bitmap);
+  virtual ~VectorPlatformDevice();
+
+  virtual HDC getBitmapDC() {
+    return hdc_;
+  }
+
+  virtual void drawPaint(const SkDraw& draw, const SkPaint& paint);
+  virtual void drawPoints(const SkDraw& draw, SkCanvas::PointMode mode,
+                          size_t count, const SkPoint[], const SkPaint& paint);
+  virtual void drawRect(const SkDraw& draw, const SkRect& r,
+                        const SkPaint& paint);
+  virtual void drawPath(const SkDraw& draw, const SkPath& path,
+                        const SkPaint& paint);
+  virtual void drawBitmap(const SkDraw& draw, const SkBitmap& bitmap,
+                          const SkMatrix& matrix, const SkPaint& paint);
+  virtual void drawSprite(const SkDraw& draw, const SkBitmap& bitmap,
+                          int x, int y, const SkPaint& paint);
+  virtual void drawText(const SkDraw& draw, const void* text, size_t len,
+                        SkScalar x, SkScalar y, const SkPaint& paint);
+  virtual void drawPosText(const SkDraw& draw, const void* text, size_t len,
+                           const SkScalar pos[], SkScalar constY,
+                           int scalarsPerPos, const SkPaint& paint);
+  virtual void drawTextOnPath(const SkDraw& draw, const void* text, size_t len,
+                              const SkPath& path, const SkMatrix* matrix,
+                              const SkPaint& paint);
+  virtual void drawVertices(const SkDraw& draw, SkCanvas::VertexMode,
+                            int vertexCount,
+                            const SkPoint verts[], const SkPoint texs[],
+                            const SkColor colors[], SkXfermode* xmode,
+                            const uint16_t indices[], int indexCount,
+                            const SkPaint& paint);
+  virtual void drawDevice(const SkDraw& draw, SkDevice*, int x, int y,
+                          const SkPaint&);
+
+
+  virtual void setMatrixClip(const SkMatrix& transform, const SkRegion& region);
+  virtual void drawToHDC(HDC dc, int x, int y, const RECT* src_rect);
+  virtual bool IsVectorial() { return true; }
+
+  void LoadClipRegion();
+
+ private:
+  // Applies the SkPaint's painting properties in the current GDI context, if
+  // possible. If GDI can't support all paint's properties, returns false. It
+  // doesn't execute the "commands" in SkPaint.
+  bool ApplyPaint(const SkPaint& paint);
+
+  // Selects a new object in the device context. It can be a pen, a brush, a
+  // clipping region, a bitmap or a font. Returns the old selected object.
+  HGDIOBJ SelectObject(HGDIOBJ object);
+
+  // Creates a brush according to SkPaint's properties.
+  bool CreateBrush(bool use_brush, const SkPaint& paint);
+
+  // Creates a pen according to SkPaint's properties.
+  bool CreatePen(bool use_pen, const SkPaint& paint);
+
+  // Restores back the previous objects (pen, brush, etc) after a paint command.
+  void Cleanup();
+
+  // Creates a brush according to SkPaint's properties.
+  bool CreateBrush(bool use_brush, COLORREF color);
+
+  // Creates a pen according to SkPaint's properties.
+  bool CreatePen(bool use_pen, COLORREF color, int stroke_width,
+                 float stroke_miter, DWORD pen_style);
+
+  // Draws a bitmap in the the device, using the currently loaded matrix.
+  void InternalDrawBitmap(const SkBitmap& bitmap, int x, int y,
+                          const SkPaint& paint);
+
+  // The Windows Device Context handle. It is the backend used with GDI drawing.
+  // This backend is write-only and vectorial.
+  HDC hdc_;
+
+  // Translation assigned to the DC: we need to keep track of this separately
+  // so it can be updated even if the DC isn't created yet.
+  SkMatrix transform_;
+
+  // The current clipping
+  SkRegion clip_region_;
+
+  // Previously selected brush before the current drawing.
+  HGDIOBJ previous_brush_;
+
+  // Previously selected pen before the current drawing.
+  HGDIOBJ previous_pen_;
+
+  // Copy & assign are not supported.
+  VectorPlatformDevice(const VectorPlatformDevice&);
+  const VectorPlatformDevice& operator=(const VectorPlatformDevice&);
+};
+
+}  // namespace skia
+
+#endif  // SKIA_EXT_VECTOR_PLATFORM_DEVICE_WIN_H_
+