support gradients and stroke+fill

core/fxge/win32/win32_int.h

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #ifndef CORE_FXGE_WIN32_WIN32_INT_H_
 #define CORE_FXGE_WIN32_WIN32_INT_H_
 
 #include "core/fxge/win32/dwrite_int.h"
@@ skipping 127 matching lines @@
                    int blend_type) override;
   FX_BOOL DrawCosmeticLine(FX_FLOAT x1,
                            FX_FLOAT y1,
                            FX_FLOAT x2,
                            FX_FLOAT y2,
                            FX_DWORD color,
                            int alpha_flag,
                            void* pIccTransform,
                            int blend_type) override;
   FX_BOOL GetClipBox(FX_RECT* pRect) override;
-  void* GetPlatformSurface() override { return (void*)m_hDC; }
+  void* GetPlatformSurface() const override { return (void*)m_hDC; }
 
   virtual void* GetClipRgn();
   virtual FX_BOOL SetClipRgn(void* pRgn);
   virtual FX_BOOL DeleteDeviceRgn(void* pRgn);
   virtual void DrawLine(FX_FLOAT x1, FX_FLOAT y1, FX_FLOAT x2, FX_FLOAT y2);
 
   FX_BOOL GDI_SetDIBits(const CFX_DIBitmap* pBitmap,
                         const FX_RECT* pSrcRect,
                         int left,
                         int top,
@@ skipping 186 matching lines @@
                       int blend_type) override;
   FX_BOOL DrawDeviceText(int nChars,
                          const FXTEXT_CHARPOS* pCharPos,
                          CFX_Font* pFont,
                          CFX_FontCache* pCache,
                          const CFX_Matrix* pObject2Device,
                          FX_FLOAT font_size,
                          FX_DWORD color,
                          int alpha_flag,
                          void* pIccTransform) override;
-  void* GetPlatformSurface() override { return (void*)m_hDC; }
+  void* GetPlatformSurface() const override { return (void*)m_hDC; }
 
   HDC m_hDC;
   FX_BOOL m_bCmykOutput;
   int m_Width, m_Height, m_nBitsPerPixel;
   int m_HorzSize, m_VertSize;
   CPSOutput* m_pPSOutput;
   CFX_PSRenderer m_PSRenderer;
 };
 void _Color2Argb(FX_ARGB& argb,
                  FX_DWORD color,
                  int alpha_flag,
                  void* pIccTransform);
 
 #endif  // CORE_FXGE_WIN32_WIN32_INT_H_