Implement getting/releasing HDC in Cairo wxGraphicsContext (wxMSW)

interface/wx/renderer.h

@@ -306,9 +306,6 @@ public:
     it changes them, so it is safe to assume that the same pen, brush and colours
     that were active before the call to this function are still in effect after it.
 
-    @note Under wxMSW drawing on wxGCDC is possible only if it's associated with
-    GDI+ or Direct2D wxGraphicsContext.
-
     @library{wxcore}
     @category{gdi}
 */

src/common/cairo.cpp

@@ -184,7 +184,9 @@
     m( cairo_get_font_options, \
        (cairo_t* cr, cairo_font_options_t* options), (cr, options) ) \
     m( cairo_user_to_device_distance, \
-       (cairo_t* cr, double *dx, double* dy), (cr, dx, dy) )
+       (cairo_t* cr, double *dx, double* dy), (cr, dx, dy) ) \
+    m( cairo_surface_mark_dirty, \
+       (cairo_surface_t* surface), (surface))
 
 #ifdef __WXMAC__
 #define wxCAIRO_PLATFORM_METHODS(m) \

src/generic/graphicc.cpp

@@ -513,15 +513,8 @@ public:
     virtual void GetPartialTextExtents(const wxString& text, wxArrayDouble& widths) const wxOVERRIDE;
 
 #ifdef __WXMSW__
-    virtual WXHDC GetNativeHDC() wxOVERRIDE
-    {
-        wxFAIL_MSG("Can't get HDC from Cairo context");
-        return NULL;
-    };
-    virtual void ReleaseNativeHDC(WXHDC WXUNUSED(hdc)) wxOVERRIDE
-    {
-        wxFAIL_MSG("Can't release HDC for Cairo context");
-    };
+    virtual WXHDC GetNativeHDC() wxOVERRIDE;
+    virtual void ReleaseNativeHDC(WXHDC WXUNUSED(hdc)) wxOVERRIDE;
 #endif
 
 protected:
@@ -3086,6 +3079,21 @@ void wxCairoContext::EndLayer()
     cairo_paint_with_alpha(m_context, double(opacity));
 }
 
+#ifdef __WXMSW__
+WXHDC wxCairoContext::GetNativeHDC()
+{
+    wxCHECK_MSG(m_mswSurface, NULL, "Can't get HDC from Cairo context");
+    cairo_surface_flush(m_mswSurface);
+    return cairo_win32_surface_get_dc(m_mswSurface);
+};
+
+void wxCairoContext::ReleaseNativeHDC(WXHDC WXUNUSED(hdc))
+{
+    wxCHECK_RET(m_mswSurface, "Can't release HDC for Cairo context");
+    cairo_surface_mark_dirty(m_mswSurface);
+};
+#endif // __WXMSW__
+
 //-----------------------------------------------------------------------------
 // wxCairoRenderer declaration
 //-----------------------------------------------------------------------------