Index: src/osx/core/dcmemory.cpp
===================================================================
--- src/osx/core/dcmemory.cpp	(revision 3f66f6a5b3583b02c34854556eb83e3a808524ce)
+++ src/osx/core/dcmemory.cpp	(revision f5dccf312d657852ca6c3a9b5a46ccd71667e1c8)
@@ -87,4 +87,6 @@
             CGContextSetStrokeColorSpace( bmCtx, genericColorSpace );
             SetGraphicsContext( wxGraphicsContext::CreateFromNative( bmCtx ) );
+            if (m_graphicContext)
+                m_graphicContext->EnableOffset(true);
         }
         m_ok = (m_graphicContext != NULL) ;
Index: src/common/dcgraph.cpp
===================================================================
--- src/common/dcgraph.cpp	(revision 148971013ee48926dfe153ca39c94be92acde37c)
+++ src/common/dcgraph.cpp	(revision b8abf338c8c83ea7f0dcf29b39dfd2223d16c462)
@@ -877,8 +877,7 @@
     CalcBoundingBox(x + w, y + h);
 
-    if ( m_graphicContext->ShouldOffset() )
-    {
-        // if we are offsetting the entire rectangle is moved 0.5, so the
-        // border line gets off by 1
+    if (m_pen.IsOk() && m_pen.GetStyle() != wxPENSTYLE_TRANSPARENT && m_pen.GetWidth() > 0)
+    {
+        // outline is one pixel larger than what raster-based wxDC implementations draw
         w -= 1;
         h -= 1;
@@ -906,8 +905,7 @@
     CalcBoundingBox(x + w, y + h);
 
-    if ( m_graphicContext->ShouldOffset() )
-    {
-        // if we are offsetting the entire rectangle is moved 0.5, so the
-        // border line gets off by 1
+    if (m_pen.IsOk() && m_pen.GetStyle() != wxPENSTYLE_TRANSPARENT && m_pen.GetWidth() > 0)
+    {
+        // outline is one pixel larger than what raster-based wxDC implementations draw
         w -= 1;
         h -= 1;
@@ -926,11 +924,4 @@
     CalcBoundingBox(x + w, y + h);
 
-    if ( m_graphicContext->ShouldOffset() )
-    {
-        // if we are offsetting the entire rectangle is moved 0.5, so the
-        // border line gets off by 1
-        w -= 1;
-        h -= 1;
-    }
     m_graphicContext->DrawEllipse(x,y,w,h);
 }