X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/a96827606ef54312168c7f48aea419d36c4b2f43..eea4d01c65f9b29baa1193db762b4c6b8144af24:/src/common/dcbufcmn.cpp

diff --git a/src/common/dcbufcmn.cpp b/src/common/dcbufcmn.cpp
index 58d40b5f9b..2a8314d43e 100644
--- a/src/common/dcbufcmn.cpp
+++ b/src/common/dcbufcmn.cpp
@@ -105,6 +105,8 @@ IMPLEMENT_DYNAMIC_CLASS(wxSharedDCBufferManager, wxModule)
 
 void wxBufferedDC::UseBuffer(wxCoord w, wxCoord h)
 {
+    wxCHECK_RET( w >= -1 && h >= -1, "Invalid buffer size" );
+
     if ( !m_buffer || !m_buffer->IsOk() )
     {
         if ( w == -1 || h == -1 )
@@ -118,18 +120,21 @@ void wxBufferedDC::UseBuffer(wxCoord w, wxCoord h)
 
     // now that the DC is valid we can inherit the attributes (fonts, colours,
     // layout direction, ...) from the original DC
-    if ( m_dc->IsOk() )
+    if ( m_dc && m_dc->IsOk() )
         CopyAttributes(*m_dc);
 }
 
 void wxBufferedDC::UnMask()
 {
-    wxCHECK_RET( m_dc, _T("no underlying wxDC?") );
-    wxASSERT_MSG( m_buffer && m_buffer->IsOk(), _T("invalid backing store") );
+    wxCHECK_RET( m_dc, wxT("no underlying wxDC?") );
+    wxASSERT_MSG( m_buffer && m_buffer->IsOk(), wxT("invalid backing store") );
 
     wxCoord x = 0,
             y = 0;
 
+    // Ensure the scale matches the device
+    SetUserScale(1.0, 1.0);
+
     if ( m_style & wxBUFFER_CLIENT_AREA )
         GetDeviceOrigin(&x, &y);