X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/c0e69d720d8b15f788fe0998806f18c46f7d5d8b..66f75561893ea7b4bf429d1882d9cc0407ba932d:/src/common/dcgraph.cpp?ds=sidebyside

diff --git a/src/common/dcgraph.cpp b/src/common/dcgraph.cpp
index ee399d4907..9206732e71 100644
--- a/src/common/dcgraph.cpp
+++ b/src/common/dcgraph.cpp
@@ -57,8 +57,10 @@ static bool TranslateRasterOp(wxRasterOperationMode function, wxCompositionMode
 {
     switch ( function )
     {
-        case wxCOPY:       // (default) src
-            *op = wxCOMPOSITION_SOURCE; //
+        case wxCOPY: // src
+            // since we are supporting alpha, _OVER is closer to the intention than _SOURCE
+            // since the latter would overwrite even when alpha is is not set to opaque
+            *op = wxCOMPOSITION_OVER; 
             break;
         case wxOR:         // src OR dst
             *op = wxCOMPOSITION_ADD;
@@ -203,7 +205,7 @@ void wxGCDCImpl::Init()
     m_font = *wxNORMAL_FONT;
     m_brush = *wxWHITE_BRUSH;
 
-    m_graphicContext = NULL;
+    m_graphicContext = wxGraphicsContext::Create();
     m_logicalFunctionSupported = true;
 }
 
@@ -505,7 +507,7 @@ void wxGCDCImpl::SetLogicalFunction( wxRasterOperationMode function )
     if (m_logicalFunctionSupported)
         m_logicalFunctionSupported = m_graphicContext->SetCompositionMode(mode);
 
-    if (mode == wxCOMPOSITION_XOR)
+    if ( function == wxXOR )
         m_graphicContext->SetAntialiasMode(wxANTIALIAS_NONE);
     else
         m_graphicContext->SetAntialiasMode(wxANTIALIAS_DEFAULT);
@@ -981,7 +983,7 @@ void wxGCDCImpl::DoGetTextExtent( const wxString &str, wxCoord *width, wxCoord *
                               wxCoord *descent, wxCoord *externalLeading ,
                               const wxFont *theFont ) const
 {
-    wxCHECK_RET( IsOk(), wxT("wxGCDC(cg)::DoGetTextExtent - invalid DC") );
+    wxCHECK_RET( m_graphicContext, wxT("wxGCDC(cg)::DoGetTextExtent - invalid DC") );
 
     if ( theFont )
     {
@@ -1009,7 +1011,7 @@ void wxGCDCImpl::DoGetTextExtent( const wxString &str, wxCoord *width, wxCoord *
 
 bool wxGCDCImpl::DoGetPartialTextExtents(const wxString& text, wxArrayInt& widths) const
 {
-    wxCHECK_MSG( IsOk(), false, wxT("wxGCDC(cg)::DoGetPartialTextExtents - invalid DC") );
+    wxCHECK_MSG( m_graphicContext, false, wxT("wxGCDC(cg)::DoGetPartialTextExtents - invalid DC") );
     widths.Clear();
     widths.Add(0,text.Length());
     if ( text.IsEmpty() )
@@ -1047,7 +1049,10 @@ void wxGCDCImpl::Clear(void)
     m_graphicContext->SetBrush( m_backgroundBrush );
     wxPen p = *wxTRANSPARENT_PEN;
     m_graphicContext->SetPen( p );
+    wxCompositionMode formerMode = m_graphicContext->GetCompositionMode();
+    m_graphicContext->SetCompositionMode(wxCOMPOSITION_SOURCE);
     DoDrawRectangle( 0, 0, 32000 , 32000 );
+    m_graphicContext->SetCompositionMode(formerMode);
     m_graphicContext->SetPen( m_pen );
     m_graphicContext->SetBrush( m_brush );
 }