diff --git a/src/osx/core/bitmap.cpp b/src/osx/core/bitmap.cpp
index 0f8824d81a..e1a93c67cc 100644
--- a/src/osx/core/bitmap.cpp
+++ b/src/osx/core/bitmap.cpp
@@ -76,7 +76,7 @@ public:
     bool HasAlpha() const;
     WXImage GetImage() const;
 
-    void SetScaleFactor(double scale) { m_scaleFactor = scale; }
+    void SetScaleFactor(double scale);
     double GetScaleFactor() const { return m_scaleFactor; }
 
     const void *GetRawAccess() const;
@@ -369,6 +369,18 @@ WXImage wxBitmapRefData::GetImage() const
     return m_nsImage;
 }
 
+void wxBitmapRefData::SetScaleFactor( double scale )
+{
+    wxCHECK_RET( IsOk() , wxT("invalid bitmap") ) ;
+
+    if ( m_scaleFactor == scale )
+        return ;
+
+    CGContextScaleCTM( m_hBitmap, 1 / GetScaleFactor(), -1 / GetScaleFactor() );
+    m_scaleFactor = scale;
+    CGContextScaleCTM( m_hBitmap, GetScaleFactor(), -GetScaleFactor() );
+}
+
 void wxBitmapRefData::UseAlpha( bool use )
 {
     wxCHECK_RET( IsOk() , wxT("invalid bitmap") ) ;
diff --git a/src/stc/PlatWX.cpp b/src/stc/PlatWX.cpp
index 182f28e842..61d3551bdf 100644
--- a/src/stc/PlatWX.cpp
+++ b/src/stc/PlatWX.cpp
@@ -293,13 +293,12 @@ void SurfaceImpl::InitPixMap(int width, int height, Surface *surface, WindowID w
     wxMemoryDC* mdc = surface
         ? new wxMemoryDC(static_cast<SurfaceImpl*>(surface)->hdc)
         : new wxMemoryDC();
-    mdc->GetImpl()->SetWindow(GETWIN(winid));
     hdc = mdc;
     hdcOwned = true;
     if (width < 1) width = 1;
     if (height < 1) height = 1;
-    bitmap = new wxBitmap();
-    bitmap->CreateWithDIPSize(width, height,(GETWIN(winid))->GetDPIScaleFactor());
+    bitmap = new wxBitmap(GETWIN(winid)->ToPhys(wxSize(width, height)));
+    bitmap->SetScaleFactor(GETWIN(winid)->GetDPIScaleFactor());
     mdc->SelectObject(*bitmap);
 }