Add wxDCImpl::MSWApplyGDIPlusTransform() to formalize wxRendererMSW hack.

Replace the dynamic_cast<> used in wxMSW wxRenderer implementation code with a
virtual function call.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@68180 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/dc.h

@@ -512,6 +512,19 @@ public:
     // this needs to overidden if the axis is inverted
     virtual void SetAxisOrientation(bool xLeftRight, bool yBottomUp);
 
+#ifdef __WXMSW__
+    // Native Windows functions using the underlying HDC don't honour GDI+
+    // transformations which may be applied to it. Using this function we can
+    // transform the coordinates manually before passing them to such functions
+    // (as in e.g. wxRendererMSW code). It doesn't do anything if this is not a
+    // wxGCDC.
+    virtual wxRect MSWApplyGDIPlusTransform(const wxRect& r) const
+    {
+        return r;
+    }
+#endif // __WXMSW__
+
+
     // ---------------------------------------------------------
     // the actual drawing API
 

include/wx/dcgraph.h

@@ -193,6 +193,10 @@ public:
 
     virtual bool DoGetPartialTextExtents(const wxString& text, wxArrayInt& widths) const;
 
+#ifdef __WXMSW__
+    virtual wxRect MSWApplyGDIPlusTransform(const wxRect& r) const;
+#endif // __WXMSW__
+
 protected:
     // scaling variables
     bool m_logicalFunctionSupported;

src/common/dcgraph.cpp

@@ -1156,4 +1156,21 @@ void wxGCDCImpl::DoDrawCheckMark(wxCoord x, wxCoord y,
     wxDCImpl::DoDrawCheckMark(x,y,width,height);
 }
 
+#ifdef __WXMSW__
+wxRect wxGCDCImpl::MSWApplyGDIPlusTransform(const wxRect& r) const
+{
+    wxGraphicsContext* const gc = GetGraphicsContext();
+    wxCHECK_MSG( gc, r, wxT("Invalid wxGCDC") );
+
+    double x = 0,
+           y = 0;
+    gc->GetTransform().TransformPoint(&x, &y);
+
+    wxRect rect(r);
+    rect.Offset(x, y);
+
+    return rect;
+}
+#endif // __WXMSW__
+
 #endif // wxUSE_GRAPHICS_CONTEXT

src/msw/renderer.cpp

@@ -114,28 +114,6 @@
     #define DFCS_HOT 0x1000
 #endif
 
-// When we're using GDI+, the DC might have transforms applied to it,
-// but the renderer APIs don't respect them. So we need to apply
-// the transforms to the rect ourselves.
-inline
-wxRect applyGDIPlusTransformsToRect(wxDC& dc, const wxRect& r)
-{
-    wxRect rect = r;
-#if wxUSE_GRAPHICS_CONTEXT
-    wxGCDC* gcdc = dynamic_cast<wxGCDC*>(&dc);
-    if (gcdc) 
-    {
-        double xtrans = 0;
-        double ytrans = 0;
-        wxGraphicsContext* gc = gcdc->GetGraphicsContext();
-        gc->GetTransform().TransformPoint(&xtrans, &ytrans);
-        rect.x = rect.x + (int)xtrans;
-        rect.y = rect.y + (int)ytrans;
-    }
-#endif
-    return rect;
-}
-
 // ----------------------------------------------------------------------------
 // methods common to wxRendererMSW and wxRendererXP
 // ----------------------------------------------------------------------------
@@ -417,7 +395,9 @@ wxRendererMSW::DrawComboBoxDropButton(wxWindow * WXUNUSED(win),
                                       const wxRect& rect,
                                       int flags)
 {
-    wxRect adjustedRect = applyGDIPlusTransformsToRect(dc, rect);
+    wxCHECK_RET( dc.GetImpl(), wxT("Invalid wxDC") );
+
+    wxRect adjustedRect = dc.GetImpl()->MSWApplyGDIPlusTransform(rect);
     
     RECT r;
     wxCopyRectToRECT(adjustedRect, r);
@@ -439,7 +419,9 @@ wxRendererMSW::DoDrawFrameControl(UINT type,
                                   const wxRect& rect,
                                   int flags)
 {
-    wxRect adjustedRect = applyGDIPlusTransformsToRect(dc, rect);
+    wxCHECK_RET( dc.GetImpl(), wxT("Invalid wxDC") );
+
+    wxRect adjustedRect = dc.GetImpl()->MSWApplyGDIPlusTransform(rect);
 
     RECT r;
     wxCopyRectToRECT(adjustedRect, r);
@@ -642,7 +624,9 @@ wxRendererXP::DrawComboBoxDropButton(wxWindow * win,
         return;
     }
 
-    wxRect adjustedRect = applyGDIPlusTransformsToRect(dc, rect);
+    wxCHECK_RET( dc.GetImpl(), wxT("Invalid wxDC") );
+
+    wxRect adjustedRect = dc.GetImpl()->MSWApplyGDIPlusTransform(rect);
 
     RECT r;
     wxCopyRectToRECT(adjustedRect, r);
@@ -683,7 +667,9 @@ wxRendererXP::DrawHeaderButton(wxWindow *win,
         return m_rendererNative.DrawHeaderButton(win, dc, rect, flags, sortArrow, params);
     }
 
-    wxRect adjustedRect = applyGDIPlusTransformsToRect(dc, rect);
+    wxCHECK_MSG( dc.GetImpl(), -1, wxT("Invalid wxDC") );
+
+    wxRect adjustedRect = dc.GetImpl()->MSWApplyGDIPlusTransform(rect);
 
     RECT r;
     wxCopyRectToRECT(adjustedRect, r);
@@ -727,7 +713,9 @@ wxRendererXP::DrawTreeItemButton(wxWindow *win,
         return;
     }
 
-    wxRect adjustedRect = applyGDIPlusTransformsToRect(dc, rect);
+    wxCHECK_RET( dc.GetImpl(), wxT("Invalid wxDC") );
+
+    wxRect adjustedRect = dc.GetImpl()->MSWApplyGDIPlusTransform(rect);
 
     RECT r;
     wxCopyRectToRECT(adjustedRect, r);
@@ -767,7 +755,9 @@ wxRendererXP::DoDrawButtonLike(HTHEME htheme,
                                const wxRect& rect,
                                int flags)
 {
-    wxRect adjustedRect = applyGDIPlusTransformsToRect(dc, rect);
+    wxCHECK_RET( dc.GetImpl(), wxT("Invalid wxDC") );
+
+    wxRect adjustedRect = dc.GetImpl()->MSWApplyGDIPlusTransform(rect);
 
     RECT r;
     wxCopyRectToRECT(adjustedRect, r);