X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/2e992e06a71d90f1df597441af36f69ef390089a..7e721c7a4bb6b253d64ae580e73853ed76d0ad03:/include/wx/dcbuffer.h

diff --git a/include/wx/dcbuffer.h b/include/wx/dcbuffer.h
index 216f4f970b..203f7cd1a3 100644
--- a/include/wx/dcbuffer.h
+++ b/include/wx/dcbuffer.h
@@ -16,29 +16,15 @@
 #include "wx/dcclient.h"
 #include "wx/window.h"
 
-
-// I think this patch should be test on wxMac with
-// wxTEST_PAINTDCDELEGATION as 1, and then with
-// with wxTEST_MEMORYDCDELEGATION as 1.
-#define wxTEST_PAINTDCDELEGATION        0
-#define wxTEST_MEMORYDCDELEGATION       0
-
-
 // Split platforms into two groups - those which have well-working
 // double-buffering by default, and those which do not.
-#if defined(__WXMAC__) || defined(__WXGTK20__)
+#if defined(__WXMAC__) || defined(__WXGTK20__) || defined(__WXDFB__)
     #define wxALWAYS_NATIVE_DOUBLE_BUFFER       1
 #else
     #define wxALWAYS_NATIVE_DOUBLE_BUFFER       0
 #endif
 
 
-#if wxTEST_PAINTDCDELEGATION || wxTEST_MEMORYDCDELEGATION
-    #undef wxALWAYS_NATIVE_DOUBLE_BUFFER
-    #define wxALWAYS_NATIVE_DOUBLE_BUFFER 0
-#endif
-
-
 // ----------------------------------------------------------------------------
 // Double buffering helper.
 // ----------------------------------------------------------------------------
@@ -51,107 +37,63 @@
 // does not prepare the window DC
 #define wxBUFFER_CLIENT_AREA        0x02
 
-class WXDLLEXPORT wxBufferedDC : public wxDC
+// Set when not using specific buffer bitmap. Note that this
+// is private style and not returned by GetStyle.
+#define wxBUFFER_USES_SHARED_BUFFER 0x04
+
+class WXDLLIMPEXP_CORE wxBufferedDC : public wxMemoryDC
 {
 public:
     // Default ctor, must subsequently call Init for two stage construction.
-    wxBufferedDC() : wxDC(), m_targetDc(NULL), m_mainDc(NULL),
-                     m_buffer(NULL), m_style(0)
+    wxBufferedDC()
+        : m_dc(NULL),
+          m_buffer(NULL),
+          m_style(0)
     {
     }
 
     // Construct a wxBufferedDC using a user supplied buffer.
     wxBufferedDC(wxDC *dc,
-                 const wxBitmap &buffer = wxNullBitmap,
+                 wxBitmap& buffer = wxNullBitmap,
                  int style = wxBUFFER_CLIENT_AREA)
-        : wxDC(),
-          m_targetDc(NULL),
-          m_mainDc(NULL)
+        : m_dc(NULL), m_buffer(NULL)
     {
-        // All other members except dcs are initialized in Init
         Init(dc, buffer, style);
     }
 
     // Construct a wxBufferedDC with an internal buffer of 'area'
     // (where area is usually something like the size of the window
     // being buffered)
-    wxBufferedDC(wxDC *dc, const wxSize &area, int style = wxBUFFER_CLIENT_AREA)
-        : wxDC(),
-          m_targetDc(NULL),
-          m_mainDc(NULL)
+    wxBufferedDC(wxDC *dc, const wxSize& area, int style = wxBUFFER_CLIENT_AREA)
+        : m_dc(NULL), m_buffer(NULL)
     {
-        // All other members except dcs are initialized in Init
-        Init(NULL, dc, area, style);
+        Init(dc, area, style);
     }
 
-    // Same, but also receives window to detect whether it is
-    // natively double-buffered.
-    wxBufferedDC(wxWindow* win,
-                 wxDC *dc,
-                 const wxSize &area,
-                 int style = wxBUFFER_CLIENT_AREA)
-        : wxDC(),
-          m_targetDc(NULL),
-          m_mainDc(NULL)
-    {
-        // All other members except dcs are initialized in Init
-        Init(win, dc, area, style);
-    }
-
-    // default copy ctor ok.
-
     // The usually desired  action in the dtor is to blit the buffer.
     virtual ~wxBufferedDC()
     {
-        UnMask();
+        if ( m_dc )
+            UnMask();
     }
 
+    // These reimplement the actions of the ctors for two stage creation
     void Init(wxDC *dc,
-              const wxBitmap &buffer,
+              wxBitmap& buffer = wxNullBitmap,
               int style = wxBUFFER_CLIENT_AREA)
     {
-        wxASSERT_MSG( m_mainDc == NULL,
-                      wxT("wxBufferedDC already initialised") );
-        wxASSERT_MSG( buffer.Ok(),
-                      wxT("invalid bitmap") );
-        m_mainDc = dc;
+        InitCommon(dc, style);
+
         m_buffer = &buffer;
-        m_style = style;
+
         UseBuffer();
     }
 
-    void Init(wxWindow* win,
-              wxDC *dc,
-              const wxSize &area = wxDefaultSize,
-              int style = wxBUFFER_CLIENT_AREA)
+    void Init(wxDC *dc, const wxSize &area, int style = wxBUFFER_CLIENT_AREA)
     {
-        wxASSERT_MSG( m_mainDc == NULL,
-                      wxT("wxBufferedDC already initialised") );
+        InitCommon(dc, style);
 
-        m_mainDc = dc;
-        m_style = style;
-
-#if wxTEST_MEMORYDCDELEGATION
-        if ( 0 )
-#elif wxTEST_PAINTDCDELEGATION
-        if ( 1 )
-#else
-        if ( win && win->IsDoubleBuffered() )
-#endif
-        {
-            AttachDC(dc);
-            m_buffer = NULL;
-        }
-        else
-        {
-            PrepareBuffer(win, area);
-            UseBuffer();
-        }
-    }
-
-    void Init(wxDC *dc, const wxSize &area = wxDefaultSize, int style = wxBUFFER_CLIENT_AREA)
-    {
-        Init(NULL, dc, area, style);
+        UseBuffer(area.x, area.y);
     }
 
     // Blits the buffer to the dc, and detaches the dc from the buffer (so it
@@ -164,435 +106,40 @@ public:
 
     // Set and get the style
     void SetStyle(int style) { m_style = style; }
-    int GetStyle() const { return m_style; }
+    int GetStyle() const { return m_style & ~wxBUFFER_USES_SHARED_BUFFER; }
 
 private:
-    // Prepares wxMemoryDC.
-    void UseBuffer();
+    // common part of Init()s
+    void InitCommon(wxDC *dc, int style)
+    {
+        wxASSERT_MSG( !m_dc, _T("wxBufferedDC already initialised") );
 
-    // Allocate m_buffer, if necessary.
-    void PrepareBuffer(wxWindow* win, const wxSize& area);
+        m_dc = dc;
+        m_style = style;
+
+        // inherit the same layout direction as the original DC
+        if (dc && dc->IsOk())
+            SetLayoutDirection(dc->GetLayoutDirection());
+    }
 
-    // DC to which calls are delegated.
-    wxDC*           m_targetDc;
+    // check that the bitmap is valid and use it
+    void UseBuffer(wxCoord w = -1, wxCoord h = -1);
 
-    // This the underlying DC to which we copy everything drawn on
-    // this one in UnMask().
+    // the underlying DC to which we copy everything drawn on this one in
+    // UnMask()
     //
     // NB: Without the existence of a wxNullDC, this must be a pointer, else it
     //     could probably be a reference.
-    wxDC*           m_mainDc;
+    wxDC *m_dc;
 
-    // the buffer (selected in this DC)
-    const wxBitmap* m_buffer;
+    // the buffer (selected in this DC), initially invalid
+    wxBitmap *m_buffer;
 
     // the buffering style
-    int             m_style;
+    int m_style;
 
+    DECLARE_DYNAMIC_CLASS(wxBufferedDC)
     DECLARE_NO_COPY_CLASS(wxBufferedDC)
-public:
-    //
-    // BEGIN DC-DELEGATION IMPLEMENTATION
-    //
-
-    wxDC& GetAttachedDC()
-    {
-        return *m_targetDc;
-    }
-
-    // Use this to set the DC which receives delegated calls.
-    void AttachDC(wxDC* dc)
-    {
-        m_targetDc = dc;
-    #ifdef __WXMSW__
-        SetHDC( dc ? dc->GetHDC() : NULL );
-    #endif
-    }
-
-    // Sets DC to NULL
-    wxDC* DetachDC()
-    {
-        wxDC* retDc = m_targetDc;
-        AttachDC(NULL);
-        return retDc;
-    }
-
-#ifdef __WXGTK__
-    virtual GdkWindow* GetGDKWindow() const
-    {
-        return m_targetDc->GetGDKWindow();
-    }
-#endif
-
-    bool Blit(wxCoord xdest, wxCoord ydest, wxCoord width, wxCoord height,
-              wxDC *source, wxCoord xsrc, wxCoord ysrc,
-              int rop = wxCOPY, bool useMask = false, wxCoord xsrcMask = wxDefaultCoord, wxCoord ysrcMask = wxDefaultCoord)
-        { return m_targetDc->Blit(xdest, ydest, width, height,
-                                  source, xsrc, ysrc, rop,
-                                  useMask, xsrcMask, ysrcMask); }
-    bool Blit(const wxPoint& destPt, const wxSize& sz,
-              wxDC *source, const wxPoint& srcPt,
-              int rop = wxCOPY, bool useMask = false, const wxPoint& srcPtMask = wxDefaultPosition)
-        { return m_targetDc->Blit(destPt, sz, source, srcPt,
-                                  rop, useMask, srcPtMask); }
-    virtual void CalcBoundingBox(wxCoord x, wxCoord y) { m_targetDc->CalcBoundingBox(x, y); }
-#if defined(__WXWINCE__)
-    void CalculateEllipticPoints( wxList* points,
-                                  wxCoord xStart, wxCoord yStart,
-                                  wxCoord w, wxCoord h,
-                                  double sa, double ea )
-        { m_targetDc->CalculateEllipticPoints(points, xStart, yStart, w,
-                                              h, sa, ea); }
-#endif // defined(__WXWINCE__)
-    virtual bool CanDrawBitmap() const { return m_targetDc->CanDrawBitmap(); }
-    virtual bool CanGetTextExtent() const { return m_targetDc->CanGetTextExtent(); }
-    virtual void Clear() { m_targetDc->Clear(); }
-    virtual void ComputeScaleAndOrigin() { m_targetDc->ComputeScaleAndOrigin(); }
-    void CrossHair(wxCoord x, wxCoord y) { m_targetDc->CrossHair(x, y); }
-    void CrossHair(const wxPoint& pt) { m_targetDc->CrossHair(pt); }
-    virtual void DestroyClippingRegion() { m_targetDc->DestroyClippingRegion(); }
-    wxCoord DeviceToLogicalX(wxCoord x) const { return m_targetDc->DeviceToLogicalX(x); }
-    wxCoord DeviceToLogicalXRel(wxCoord x) const { return m_targetDc->DeviceToLogicalXRel(x); }
-    wxCoord DeviceToLogicalY(wxCoord y) const { return m_targetDc->DeviceToLogicalY(y); }
-    wxCoord DeviceToLogicalYRel(wxCoord y) const { return m_targetDc->DeviceToLogicalYRel(y); }
-#if defined(__WXWINCE__)
-    virtual void DoDrawEllipticArcRot( wxCoord x, wxCoord y,
-                                       wxCoord w, wxCoord h,
-                                       double sa = 0, double ea = 0, double angle = 0 )
-        { m_targetDc->DoDrawEllipticArcRot(x, y, w, h,
-                                           sa, ea, angle); }
-#endif // defined(__WXWINCE__)
-    void DrawArc(wxCoord x1, wxCoord y1, wxCoord x2, wxCoord y2,
-                 wxCoord xc, wxCoord yc)
-        { m_targetDc->DrawArc(x1, y1, x2, y2,
-                              xc, yc); }
-    void DrawArc(const wxPoint& pt1, const wxPoint& pt2, const wxPoint& centre)
-        { m_targetDc->DrawArc(pt1, pt2, centre); }
-    void DrawBitmap(const wxBitmap &bmp, wxCoord x, wxCoord y,
-                    bool useMask = false)
-        { m_targetDc->DrawBitmap(bmp, x, y, useMask); }
-    void DrawBitmap(const wxBitmap &bmp, const wxPoint& pt,
-                    bool useMask = false)
-        { m_targetDc->DrawBitmap(bmp, pt, useMask); }
-    void DrawCheckMark(wxCoord x, wxCoord y,
-                       wxCoord width, wxCoord height)
-        { m_targetDc->DrawCheckMark(x, y, width, height); }
-    void DrawCheckMark(const wxRect& rect) { m_targetDc->DrawCheckMark(rect); }
-    void DrawCircle(wxCoord x, wxCoord y, wxCoord radius) { m_targetDc->DrawCircle(x, y, radius); }
-    void DrawCircle(const wxPoint& pt, wxCoord radius) { m_targetDc->DrawCircle(pt, radius); }
-    void DrawEllipse(wxCoord x, wxCoord y, wxCoord width, wxCoord height)
-        { m_targetDc->DrawEllipse(x, y, width, height); }
-    void DrawEllipse(const wxPoint& pt, const wxSize& sz) { m_targetDc->DrawEllipse(pt, sz); }
-    void DrawEllipse(const wxRect& rect) { m_targetDc->DrawEllipse(rect); }
-    void DrawEllipticArc(wxCoord x, wxCoord y, wxCoord w, wxCoord h,
-                         double sa, double ea)
-        { m_targetDc->DrawEllipticArc(x, y, w, h,
-                                      sa, ea); }
-    void DrawEllipticArc(const wxPoint& pt, const wxSize& sz,
-                         double sa, double ea)
-        { m_targetDc->DrawEllipticArc(pt, sz, sa, ea); }
-#if defined(__WXWINCE__)
-    void DrawEllipticArcRot( wxCoord x, wxCoord y,
-                             wxCoord width, wxCoord height,
-                             double sa = 0, double ea = 0, double angle = 0 )
-        { m_targetDc->DrawEllipticArcRot(x, y, width, height,
-                                         sa, ea, angle); }
-    void DrawEllipticArcRot( const wxPoint& pt,
-                             const wxSize& sz,
-                             double sa = 0, double ea = 0, double angle = 0 )
-        { m_targetDc->DrawEllipticArcRot(pt, sz, sa, ea,
-                                         angle); }
-    void DrawEllipticArcRot( const wxRect& rect,
-                             double sa = 0, double ea = 0, double angle = 0 )
-        { m_targetDc->DrawEllipticArcRot(rect, sa, ea, angle); }
-#endif // defined(__WXWINCE__)
-    void DrawIcon(const wxIcon& icon, wxCoord x, wxCoord y) { m_targetDc->DrawIcon(icon, x, y); }
-    void DrawIcon(const wxIcon& icon, const wxPoint& pt) { m_targetDc->DrawIcon(icon, pt); }
-    virtual void DrawLabel(const wxString& text,
-                           const wxBitmap& image,
-                           const wxRect& rect,
-                           int alignment = wxALIGN_LEFT | wxALIGN_TOP,
-                           int indexAccel = -1,
-                           wxRect *rectBounding = NULL)
-        { m_targetDc->DrawLabel(text, image, rect, alignment,
-                                indexAccel, rectBounding); }
-    void DrawLabel(const wxString& text, const wxRect& rect,
-                   int alignment = wxALIGN_LEFT | wxALIGN_TOP,
-                   int indexAccel = -1)
-        { m_targetDc->DrawLabel(text, rect, alignment, indexAccel); }
-    void DrawLine(wxCoord x1, wxCoord y1, wxCoord x2, wxCoord y2)
-        { m_targetDc->DrawLine(x1, y1, x2, y2); }
-    void DrawLine(const wxPoint& pt1, const wxPoint& pt2) { m_targetDc->DrawLine(pt1, pt2); }
-    void DrawLines(int n, wxPoint points[],
-                   wxCoord xoffset = 0, wxCoord yoffset = 0)
-        { m_targetDc->DrawLines(n, points, xoffset, yoffset); }
-    void DrawLines(const wxList *list,
-                   wxCoord xoffset = 0, wxCoord yoffset = 0)
-        { m_targetDc->DrawLines(list, xoffset, yoffset); }
-    virtual void DrawObject(wxDrawObject* drawobject) { m_targetDc->DrawObject(drawobject); }
-    void DrawPoint(wxCoord x, wxCoord y) { m_targetDc->DrawPoint(x, y); }
-    void DrawPoint(const wxPoint& pt) { m_targetDc->DrawPoint(pt); }
-    void DrawPolyPolygon(int n, int count[], wxPoint points[],
-                         wxCoord xoffset = 0, wxCoord yoffset = 0,
-                         int fillStyle = wxODDEVEN_RULE)
-        { m_targetDc->DrawPolyPolygon(n, count, points, xoffset,
-                                      yoffset, fillStyle); }
-    void DrawPolygon(int n, wxPoint points[],
-                     wxCoord xoffset = 0, wxCoord yoffset = 0,
-                     int fillStyle = wxODDEVEN_RULE)
-        { m_targetDc->DrawPolygon(n, points, xoffset, yoffset,
-                                  fillStyle); }
-    void DrawPolygon(const wxList *list,
-                     wxCoord xoffset = 0, wxCoord yoffset = 0,
-                     int fillStyle = wxODDEVEN_RULE)
-        { m_targetDc->DrawPolygon(list, xoffset, yoffset, fillStyle); }
-    void DrawRectangle(wxCoord x, wxCoord y, wxCoord width, wxCoord height)
-        { m_targetDc->DrawRectangle(x, y, width, height); }
-    void DrawRectangle(const wxPoint& pt, const wxSize& sz) { m_targetDc->DrawRectangle(pt, sz); }
-    void DrawRectangle(const wxRect& rect) { m_targetDc->DrawRectangle(rect); }
-    void DrawRotatedText(const wxString& text, wxCoord x, wxCoord y, double angle)
-        { m_targetDc->DrawRotatedText(text, x, y, angle); }
-    void DrawRotatedText(const wxString& text, const wxPoint& pt, double angle)
-        { m_targetDc->DrawRotatedText(text, pt, angle); }
-    void DrawRoundedRectangle(wxCoord x, wxCoord y, wxCoord width, wxCoord height,
-                              double radius)
-        { m_targetDc->DrawRoundedRectangle(x, y, width, height,
-                                           radius); }
-    void DrawRoundedRectangle(const wxPoint& pt, const wxSize& sz,
-                             double radius)
-        { m_targetDc->DrawRoundedRectangle(pt, sz, radius); }
-    void DrawRoundedRectangle(const wxRect& r, double radius)
-        { m_targetDc->DrawRoundedRectangle(r, radius); }
-#if wxUSE_SPLINES
-    void DrawSpline(wxCoord x1, wxCoord y1,
-                    wxCoord x2, wxCoord y2,
-                    wxCoord x3, wxCoord y3)
-        { m_targetDc->DrawSpline(x1, y1, x2, y2,
-                                 x3, y3); }
-    void DrawSpline(int n, wxPoint points[]) { m_targetDc->DrawSpline(n, points); }
-    void DrawSpline(wxList *points) { m_targetDc->DrawSpline(points); }
-#endif // wxUSE_SPLINES
-    void DrawText(const wxString& text, wxCoord x, wxCoord y)
-        { m_targetDc->DrawText(text, x, y); }
-    void DrawText(const wxString& text, const wxPoint& pt) { m_targetDc->DrawText(text, pt); }
-    virtual void EndDoc() { m_targetDc->EndDoc(); }
-    virtual void EndPage() { m_targetDc->EndPage(); }
-    bool FloodFill(wxCoord x, wxCoord y, const wxColour& col,
-                   int style = wxFLOOD_SURFACE)
-        { return m_targetDc->FloodFill(x, y, col, style); }
-    bool FloodFill(const wxPoint& pt, const wxColour& col,
-                   int style = wxFLOOD_SURFACE)
-        { return m_targetDc->FloodFill(pt, col, style); }
-    virtual const wxBrush&  GetBackground() const { return m_targetDc->GetBackground(); }
-    virtual int GetBackgroundMode() const { return m_targetDc->GetBackgroundMode(); }
-    virtual const wxBrush&  GetBrush() const { return m_targetDc->GetBrush(); }
-    virtual wxCoord GetCharHeight() const { return m_targetDc->GetCharHeight(); }
-    virtual wxCoord GetCharWidth() const { return m_targetDc->GetCharWidth(); }
-    void GetClippingBox(wxCoord *x, wxCoord *y, wxCoord *w, wxCoord *h) const
-        { m_targetDc->GetClippingBox(x, y, w, h); }
-    void GetClippingBox(wxRect& rect) const { m_targetDc->GetClippingBox(rect); }
-    void GetClippingBox(long *x, long *y, long *w, long *h) const
-        { m_targetDc->GetClippingBox(x, y, w, h); }
-    virtual int GetDepth() const { return m_targetDc->GetDepth(); }
-    void GetDeviceOrigin(wxCoord *x, wxCoord *y) const { m_targetDc->GetDeviceOrigin(x, y); }
-    wxPoint GetDeviceOrigin() const { return m_targetDc->GetDeviceOrigin(); }
-    void GetDeviceOrigin(long *x, long *y) const { m_targetDc->GetDeviceOrigin(x, y); }
-    virtual const wxFont&   GetFont() const { return m_targetDc->GetFont(); }
-    virtual int GetLogicalFunction() const { return m_targetDc->GetLogicalFunction(); }
-    void GetLogicalOrigin(wxCoord *x, wxCoord *y) const { m_targetDc->GetLogicalOrigin(x, y); }
-    wxPoint GetLogicalOrigin() const { return m_targetDc->GetLogicalOrigin(); }
-    void GetLogicalOrigin(long *x, long *y) const { m_targetDc->GetLogicalOrigin(x, y); }
-    virtual void GetLogicalScale(double *x, double *y) { m_targetDc->GetLogicalScale(x, y); }
-    virtual int GetMapMode() const { return m_targetDc->GetMapMode(); }
-    virtual void GetMultiLineTextExtent(const wxString& text,
-                                        wxCoord *width,
-                                        wxCoord *height,
-                                        wxCoord *heightLine = NULL,
-                                        wxFont *font = NULL)
-        { m_targetDc->GetMultiLineTextExtent(text, width, height, heightLine,
-                                             font); }
-#if WXWIN_COMPATIBILITY_2_4
-    virtual bool GetOptimization() { return m_targetDc->GetOptimization(); }
-#endif // WXWIN_COMPATIBILITY_2_4
-    virtual wxSize GetPPI() const { return m_targetDc->GetPPI(); }
-    bool GetPartialTextExtents(const wxString& text, wxArrayInt& widths) const
-        { return m_targetDc->GetPartialTextExtents(text, widths); }
-    virtual const wxPen&    GetPen() const { return m_targetDc->GetPen(); }
-    bool GetPixel(wxCoord x, wxCoord y, wxColour *col) const
-        { return m_targetDc->GetPixel(x, y, col); }
-    bool GetPixel(const wxPoint& pt, wxColour *col) const { return m_targetDc->GetPixel(pt, col); }
-    void GetSize(int *width, int *height) const { m_targetDc->GetSize(width, height); }
-    wxSize GetSize() const { return m_targetDc->GetSize(); }
-    void GetSizeMM(int* width, int* height) const { m_targetDc->GetSizeMM(width, height); }
-    wxSize GetSizeMM() const { return m_targetDc->GetSizeMM(); }
-    virtual const wxColour& GetTextBackground() const { return m_targetDc->GetTextBackground(); }
-    void GetTextExtent(const wxString& string,
-                       wxCoord *x, wxCoord *y,
-                       wxCoord *descent = NULL,
-                       wxCoord *externalLeading = NULL,
-                       wxFont *theFont = NULL) const
-        { m_targetDc->GetTextExtent(string, x, y, descent,
-                                    externalLeading, theFont); }
-    void GetTextExtent(const wxString& string,
-                       long *x, long *y,
-                       long *descent = NULL,
-                       long *externalLeading = NULL,
-                       wxFont *theFont = NULL) const
-        { m_targetDc->GetTextExtent(string, x, y, descent,
-                                    externalLeading, theFont); }
-    virtual const wxColour& GetTextForeground() const { return m_targetDc->GetTextForeground(); }
-    virtual void GetUserScale(double *x, double *y) const { m_targetDc->GetUserScale(x, y); }
-    void GradientFillConcentric(const wxRect& rect,
-                                const wxColour& initialColour,
-                                const wxColour& destColour)
-        { m_targetDc->GradientFillConcentric(rect, initialColour, destColour); }
-    void GradientFillConcentric(const wxRect& rect,
-                                const wxColour& initialColour,
-                                const wxColour& destColour,
-                                const wxPoint& circleCenter)
-        { m_targetDc->GradientFillConcentric(rect, initialColour, destColour, circleCenter); }
-    void GradientFillLinear(const wxRect& rect,
-                            const wxColour& initialColour,
-                            const wxColour& destColour,
-                            wxDirection nDirection = wxEAST)
-        { m_targetDc->GradientFillLinear(rect, initialColour, destColour, nDirection); }
-    wxCoord LogicalToDeviceX(wxCoord x) const { return m_targetDc->LogicalToDeviceX(x); }
-    wxCoord LogicalToDeviceXRel(wxCoord x) const { return m_targetDc->LogicalToDeviceXRel(x); }
-    wxCoord LogicalToDeviceY(wxCoord y) const { return m_targetDc->LogicalToDeviceY(y); }
-    wxCoord LogicalToDeviceYRel(wxCoord y) const { return m_targetDc->LogicalToDeviceYRel(y); }
-    wxCoord MaxX() const { return m_targetDc->MaxX(); }
-    wxCoord MaxY() const { return m_targetDc->MaxY(); }
-    wxCoord MinX() const { return m_targetDc->MinX(); }
-    wxCoord MinY() const { return m_targetDc->MinY(); }
-    virtual bool Ok() const { return m_targetDc->Ok(); }
-    void ResetBoundingBox()
-        { m_targetDc->ResetBoundingBox(); }
-#if defined(__WXWINCE__)
-    void Rotate( wxList* points, double angle, wxPoint center = wxPoint(0,0) )
-        { m_targetDc->Rotate(points, angle, center, 0)); }
-#endif // defined(__WXWINCE__)
-    virtual void SetAxisOrientation(bool xLeftRight, bool yBottomUp)
-        { m_targetDc->SetAxisOrientation(xLeftRight, yBottomUp); }
-    virtual void SetBackground(const wxBrush& brush) { m_targetDc->SetBackground(brush); }
-    virtual void SetBackgroundMode(int mode) { m_targetDc->SetBackgroundMode(mode); }
-    virtual void SetBrush(const wxBrush& brush) { m_targetDc->SetBrush(brush); }
-    void SetClippingRegion(wxCoord x, wxCoord y, wxCoord width, wxCoord height)
-        { m_targetDc->SetClippingRegion(x, y, width, height); }
-    void SetClippingRegion(const wxPoint& pt, const wxSize& sz)
-        { m_targetDc->SetClippingRegion(pt, sz); }
-    void SetClippingRegion(const wxRect& rect) { m_targetDc->SetClippingRegion(rect); }
-    void SetClippingRegion(const wxRegion& region) { m_targetDc->SetClippingRegion(region); }
-    virtual void SetDeviceOrigin(wxCoord x, wxCoord y) { m_targetDc->SetDeviceOrigin(x, y); }
-    virtual void SetFont(const wxFont& font) { m_targetDc->SetFont(font); }
-    virtual void SetLogicalFunction(int function) { m_targetDc->SetLogicalFunction(function); }
-    virtual void SetLogicalOrigin(wxCoord x, wxCoord y) { m_targetDc->SetLogicalOrigin(x, y); }
-    virtual void SetLogicalScale(double x, double y) { m_targetDc->SetLogicalScale(x, y); }
-    virtual void SetMapMode(int mode) { m_targetDc->SetMapMode(mode); }
-#if WXWIN_COMPATIBILITY_2_4
-    virtual void SetOptimization(bool opt) { m_targetDc->SetOptimization(opt); }
-#endif // WXWIN_COMPATIBILITY_2_4
-#if wxUSE_PALETTE
-    virtual void SetPalette(const wxPalette& palette) { m_targetDc->SetPalette(palette); }
-#endif // wxUSE_PALETTE
-    virtual void SetPen(const wxPen& pen) { m_targetDc->SetPen(pen); }
-    virtual void SetTextBackground(const wxColour& colour) { m_targetDc->SetTextBackground(colour); }
-    virtual void SetTextForeground(const wxColour& colour) { m_targetDc->SetTextForeground(colour); }
-    virtual void SetUserScale(double x, double y) { m_targetDc->SetUserScale(x, y); }
-    virtual bool StartDoc(const wxString& message) { return m_targetDc->StartDoc(message); }
-    virtual void StartPage() { m_targetDc->StartPage(); }
-protected:
-    virtual bool DoBlit(wxCoord xdest, wxCoord ydest,
-                        wxCoord width, wxCoord height,
-                        wxDC *source, wxCoord xsrc, wxCoord ysrc,
-                        int rop = wxCOPY, bool useMask = false, wxCoord xsrcMask = wxDefaultCoord, wxCoord ysrcMask = wxDefaultCoord)
-        { return m_targetDc->Blit(xdest, ydest, width, height,
-                                  source, xsrc, ysrc, rop,
-                                  useMask, xsrcMask, ysrcMask); }
-    virtual void DoCrossHair(wxCoord x, wxCoord y) { m_targetDc->CrossHair(x, y); }
-    virtual void DoDrawArc(wxCoord x1, wxCoord y1,
-                           wxCoord x2, wxCoord y2,
-                           wxCoord xc, wxCoord yc)
-        { m_targetDc->DrawArc(x1, y1, x2, y2,
-                              xc, yc); }
-    virtual void DoDrawBitmap(const wxBitmap &bmp, wxCoord x, wxCoord y,
-                              bool useMask = false)
-        { m_targetDc->DrawBitmap(bmp, x, y, useMask); }
-    virtual void DoDrawCheckMark(wxCoord x, wxCoord y,
-                                 wxCoord width, wxCoord height)
-        { m_targetDc->DrawCheckMark(x, y, width, height); }
-    virtual void DoDrawEllipse(wxCoord x, wxCoord y,
-                               wxCoord width, wxCoord height)
-        { m_targetDc->DrawEllipse(x, y, width, height); }
-    virtual void DoDrawEllipticArc(wxCoord x, wxCoord y, wxCoord w, wxCoord h,
-                                   double sa, double ea)
-        { m_targetDc->DrawEllipticArc(x, y, w, h,
-                                      sa, ea); }
-    virtual void DoDrawIcon(const wxIcon& icon, wxCoord x, wxCoord y)
-        { m_targetDc->DrawIcon(icon, x, y); }
-    virtual void DoDrawLine(wxCoord x1, wxCoord y1, wxCoord x2, wxCoord y2)
-        { m_targetDc->DrawLine(x1, y1, x2, y2); }
-    virtual void DoDrawLines(int n, wxPoint points[],
-                             wxCoord xoffset, wxCoord yoffset)
-        { m_targetDc->DrawLines(n, points, xoffset, yoffset); }
-    virtual void DoDrawPoint(wxCoord x, wxCoord y) { m_targetDc->DrawPoint(x, y); }
-    virtual void DoDrawPolyPolygon(int n, int count[], wxPoint points[],
-                               wxCoord xoffset, wxCoord yoffset,
-                               int fillStyle)
-        { m_targetDc->DrawPolyPolygon(n, count, points, xoffset,
-                                      yoffset, fillStyle); }
-    virtual void DoDrawPolygon(int n, wxPoint points[],
-                               wxCoord xoffset, wxCoord yoffset,
-                               int fillStyle = wxODDEVEN_RULE)
-        { m_targetDc->DrawPolygon(n, points, xoffset, yoffset,
-                                  fillStyle); }
-    virtual void DoDrawRectangle(wxCoord x, wxCoord y, wxCoord width, wxCoord height)
-        { m_targetDc->DrawRectangle(x, y, width, height); }
-    virtual void DoDrawRotatedText(const wxString& text,
-                                   wxCoord x, wxCoord y, double angle)
-        { m_targetDc->DrawRotatedText(text, x, y, angle); }
-    virtual void DoDrawRoundedRectangle(wxCoord x, wxCoord y,
-                                        wxCoord width, wxCoord height,
-                                        double radius)
-        { m_targetDc->DrawRoundedRectangle(x, y, width, height,
-                                           radius); }
-#if wxUSE_SPLINES
-    virtual void DoDrawSpline(wxList *points) { m_targetDc->DrawSpline(points); }
-#endif // wxUSE_SPLINES
-    virtual void DoDrawText(const wxString& text, wxCoord x, wxCoord y)
-        { m_targetDc->DrawText(text, x, y); }
-    virtual bool DoFloodFill(wxCoord x, wxCoord y, const wxColour& col,
-                             int style = wxFLOOD_SURFACE)
-        { return m_targetDc->FloodFill(x, y, col, style); }
-    virtual void DoGetClippingBox(wxCoord *x, wxCoord *y,
-                                  wxCoord *w, wxCoord *h) const
-        { m_targetDc->GetClippingBox(x, y, w, h); }
-    virtual void DoGetDeviceOrigin(wxCoord *x, wxCoord *y) const
-        { m_targetDc->GetDeviceOrigin(x, y); }
-    virtual void DoGetLogicalOrigin(wxCoord *x, wxCoord *y) const
-        { m_targetDc->GetLogicalOrigin(x, y); }
-    virtual bool DoGetPartialTextExtents(const wxString& text, wxArrayInt& widths) const
-        { return m_targetDc->GetPartialTextExtents(text, widths); }
-    virtual bool DoGetPixel(wxCoord x, wxCoord y, wxColour *col) const
-        { return m_targetDc->GetPixel(x, y, col); }
-    virtual void DoGetSize(int *width, int *height) const { m_targetDc->GetSize(width, height); }
-    virtual void DoGetSizeMM(int* width, int* height) const { m_targetDc->GetSizeMM(width, height); }
-    virtual void DoGetTextExtent(const wxString& string,
-                                 wxCoord *x, wxCoord *y,
-                                 wxCoord *descent = NULL,
-                                 wxCoord *externalLeading = NULL,
-                                 wxFont *theFont = NULL) const
-        { m_targetDc->GetTextExtent(string, x, y, descent,
-                                    externalLeading, theFont); }
-    virtual void DoGradientFillLinear(const wxRect& rect,
-                                      const wxColour& initialColour,
-                                      const wxColour& destColour,
-                                      wxDirection nDirection = wxEAST)
-        { m_targetDc->GradientFillLinear(rect, initialColour, destColour, nDirection); }
-    virtual void DoSetClippingRegion(wxCoord x, wxCoord y,
-                                     wxCoord width, wxCoord height)
-        { m_targetDc->SetClippingRegion(x, y, width, height); }
-    virtual void DoSetClippingRegionAsRegion(const wxRegion& region)
-        { m_targetDc->SetClippingRegion(region); }
 };
 
 
@@ -602,21 +149,21 @@ protected:
 
 // Creates a double buffered wxPaintDC, optionally allowing the
 // user to specify their own buffer to use.
-class wxBufferedPaintDC : public wxBufferedDC
+class WXDLLIMPEXP_CORE wxBufferedPaintDC : public wxBufferedDC
 {
 public:
     // If no bitmap is supplied by the user, a temporary one will be created.
-    wxBufferedPaintDC(wxWindow *window, const wxBitmap& buffer, int style = wxBUFFER_CLIENT_AREA)
+    wxBufferedPaintDC(wxWindow *window, wxBitmap& buffer, int style = wxBUFFER_CLIENT_AREA)
         : m_paintdc(window)
     {
         // If we're buffering the virtual window, scale the paint DC as well
         if (style & wxBUFFER_VIRTUAL_AREA)
             window->PrepareDC( m_paintdc );
 
-        if( buffer != wxNullBitmap )
+        if( buffer.IsOk() )
             Init(&m_paintdc, buffer, style);
         else
-            Init(window, &m_paintdc, window->GetClientSize(), style);
+            Init(&m_paintdc, GetBufferedSize(window, style), style);
     }
 
     // If no bitmap is supplied by the user, a temporary one will be created.
@@ -627,7 +174,7 @@ public:
         if (style & wxBUFFER_VIRTUAL_AREA)
             window->PrepareDC( m_paintdc );
 
-        Init(window, &m_paintdc, window->GetClientSize(), style);
+        Init(&m_paintdc, GetBufferedSize(window, style), style);
     }
 
     // default copy ctor ok.
@@ -639,9 +186,19 @@ public:
         UnMask();
     }
 
+protected:
+    // return the size needed by the buffer: this depends on whether we're
+    // buffering just the currently shown part or the total (scrolled) window
+    static wxSize GetBufferedSize(wxWindow *window, int style)
+    {
+        return style & wxBUFFER_VIRTUAL_AREA ? window->GetVirtualSize()
+                                             : window->GetClientSize();
+    }
+
 private:
     wxPaintDC m_paintdc;
 
+    DECLARE_ABSTRACT_CLASS(wxBufferedPaintDC)
     DECLARE_NO_COPY_CLASS(wxBufferedPaintDC)
 };
 
@@ -662,7 +219,7 @@ private:
 
 #ifdef __WXDEBUG__
 
-class wxAutoBufferedPaintDC : public wxAutoBufferedPaintDCBase
+class WXDLLIMPEXP_CORE wxAutoBufferedPaintDC : public wxAutoBufferedPaintDCBase
 {
 public:
 
@@ -680,7 +237,7 @@ private:
     {
         // Help the user to get the double-buffering working properly.
         wxASSERT_MSG( win->GetBackgroundStyle() == wxBG_STYLE_CUSTOM,
-                      wxT("In constructor, you need to call GetBackgroundStyle(wxBG_STYLE_CUSTOM), ")
+                      wxT("In constructor, you need to call SetBackgroundStyle(wxBG_STYLE_CUSTOM), ")
                       wxT("and also, if needed, paint the background manually in the paint event handler."));
     }
 
@@ -695,4 +252,15 @@ typedef wxAutoBufferedPaintDCBase wxAutoBufferedPaintDC;
 #endif
 
 
+// Check if the window is natively double buffered and will return a wxPaintDC
+// if it is, a wxBufferedPaintDC otherwise.  It is the caller's responsibility
+// to delete the wxDC pointer when finished with it.
+inline wxDC* wxAutoBufferedPaintDCFactory(wxWindow* window)
+{
+    if ( window->IsDoubleBuffered() )
+        return new wxPaintDC(window);
+    else
+        return new wxBufferedPaintDC(window);
+}
+
 #endif  // _WX_DCBUFFER_H_