i121591 Corrected some transparent printing stuff for windows

vcl/source/gdi/outdev6.cxx

@@ -302,8 +302,14 @@ void OutputDevice::DrawTransparent( const PolyPolygon& rPolyPoly,
         const double fTransparency = 0.01 * nTransparencePercent;
         if( mbFillColor )
         {
-            // draw the transparent polygon
-            // NOTE: filled polygons are assumed to be drawn as if they were always closed
+            // #121591#
+            // CAUTION: Only non printing (pixel-renderer) VCL commands from OutputDevices
+            // should be used when printing. Normally this is avoided by the printer being
+            // non-AAed and thus e.g. on WIN GdiPlus calls are not used. It may be necessary
+            // to add (OUTDEV_PRINTER != meOutDevType) to the entering if statement, thus
+            // using the fallbacl some lines below (which is not very good, though). For
+            // now, WinSalGraphics::drawPolyPolygon will detect printer usage and correct
+            // the wrong mapping (see there for details)
             bDrawn = mpGraphics->DrawPolyPolygon( aB2DPolyPolygon, fTransparency, this );
         }
 

vcl/win/source/gdi/salgdi_gdiplus.cxx

@@ -178,6 +178,33 @@ bool WinSalGraphics::drawPolyPolygon( const ::basegfx::B2DPolyPolygon& rPolyPoly
             aGraphics.SetSmoothingMode(Gdiplus::SmoothingModeNone);
         }
 
+        if(mbPrinter)
+        {
+            // #121591#
+            // Normally GdiPlus should not be used for printing at all since printers cannot
+            // print transparent filled polygon geometry and normally this does not happen
+            // since OutputDevice::RemoveTransparenciesFromMetaFile is used as preparation
+            // and no transparent parts should remain for printing. But this can be overriden
+            // by the user and thus happens. This call can only come (currently) from
+            // OutputDevice::DrawTransparent, see comments sthere with the same TaskID.
+            // If it is used, the mapping for the printer is wrong and needs to be corrected. I
+            // checked that there is *no* transformation set (testcode commented out below) and
+            // estimated that a stable factor dependent of the printer's DPI is used. Create
+            // and set a transformation here to correct this
+            const Gdiplus::REAL aDpiX(aGraphics.GetDpiX());
+            const Gdiplus::REAL aDpiY(aGraphics.GetDpiY());
+
+            // test code to check the current transformation at the graphics device
+            //Gdiplus::Matrix matrix;
+            //aGraphics.GetTransform(&matrix);
+            //Gdiplus::REAL elements[6];
+            //matrix.GetElements(elements);
+
+            Gdiplus::Matrix aPrinterTransform;
+            aPrinterTransform.Scale(Gdiplus::REAL(100.0) / aDpiX, Gdiplus::REAL(100.0) / aDpiY);
+            aGraphics.SetTransform(&aPrinterTransform);
+        }
+
         aGraphics.FillPath(&aTestBrush, &aPath);
     }