Qt5 fix SalGraphics::invert

... and also print the invert mode name into the inverted region
when running "./bin/run vcldemo --show ellipse".

Change-Id: Id461a32756583df1ef778320c29c45c0e7e4fbc8
Reviewed-on: https://gerrit.libreoffice.org/65326
Tested-by: Jenkins
Reviewed-by: Jan-Marek Glogowski <glogow@fbihome.de>

vcl/qt5/Qt5Graphics_GDI.cxx

@@ -485,15 +485,17 @@ void Qt5Graphics::invert(long nX, long nY, long nWidth, long nHeight, SalInvert
     if (SalInvert::N50 & nFlags)
     {
         aPainter.setCompositionMode(QPainter::RasterOp_SourceXorDestination);
-        aPainter.setBrush(Qt::DiagCrossPattern);
-        aPainter.fillRect(nX, nY, nWidth, nHeight, aPainter.brush());
+        QBrush aBrush(Qt::white, Qt::Dense4Pattern);
+        aPainter.fillRect(nX, nY, nWidth, nHeight, aBrush);
     }
     else
     {
         if (SalInvert::TrackFrame & nFlags)
         {
             aPainter.setCompositionMode(QPainter::RasterOp_SourceXorDestination);
-            aPainter.setPen(Qt::DashLine);
+            QPen aPen(Qt::white);
+            aPen.setStyle(Qt::DotLine);
+            aPainter.setPen(aPen);
             aPainter.drawRect(nX, nY, nWidth, nHeight);
         }
         else

vcl/workben/vcldemo.cxx

@@ -766,8 +766,11 @@ public:
             {
                 auto aRegions = partition(rCtx, 2, 2);
                 doInvert(rDev, aRegions[0], InvertFlags::NONE);
+                rDev.DrawText(aRegions[0], "InvertFlags::NONE");
                 doInvert(rDev, aRegions[1], InvertFlags::N50);
+                rDev.DrawText(aRegions[1], "InvertFlags::N50");
                 doInvert(rDev, aRegions[3], InvertFlags::TrackFrame);
+                rDev.DrawText(aRegions[3], "InvertFlags::TrackFrame");
             }
         }
     };