custom widgets: enable anti-aliasing when drawing widgets

Change-Id: I050d8534cacdee63109158dbc150d9d13b43fe5e

vcl/headless/CustomWidgetDraw.cxx

@@ -62,7 +62,10 @@ bool CustomWidgetDraw::drawNativeControl(ControlType eType, ControlPart ePart,
     if (s_pWidgetImplementation == nullptr)
         return false;
 
-    cairo_t* pCairoContext = m_rGraphics.getCairoContext(true);
+    bool bOldAA = m_rGraphics.getAntiAliasB2DDraw();
+    m_rGraphics.setAntiAliasB2DDraw(true);
+
+    cairo_t* pCairoContext = m_rGraphics.getCairoContext(false);
     m_rGraphics.clipRegion(pCairoContext);
 
     cairo_translate(pCairoContext, rControlRegion.Left(), rControlRegion.Top());
@@ -272,6 +275,8 @@ bool CustomWidgetDraw::drawNativeControl(ControlType eType, ControlPart ePart,
 
     m_rGraphics.releaseCairoContext(pCairoContext, true, aExtents);
 
+    m_rGraphics.setAntiAliasB2DDraw(bOldAA);
+
     return bOK;
 }