ofz#947 line dashing is very problematic memory and size wise

Change-Id: I29ed7cd774d3ede077edfe2893c7a9e72b83abad
Reviewed-on: https://gerrit.libreoffice.org/35748Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

drawinglayer/source/primitive2d/polygonprimitive2d.cxx

@@ -345,10 +345,16 @@ namespace drawinglayer
                     bUseDecomposition = true;
                 }
 
-                if(bUseDecomposition)
+                if (bUseDecomposition)
                 {
                     // get correct range by using the decomposition fallback, reasons see above cases
+
+                    // ofz#947 to optimize calculating the range, turn any slow dashes into a solid line
+                    // when just calculating bounds
+                    attribute::StrokeAttribute aOrigStrokeAttribute = maStrokeAttribute;
+                    const_cast<PolygonStrokePrimitive2D*>(this)->maStrokeAttribute = attribute::StrokeAttribute();
                     aRetval = BufferedDecompositionPrimitive2D::getB2DRange(rViewInformation);
+                    const_cast<PolygonStrokePrimitive2D*>(this)->maStrokeAttribute = aOrigStrokeAttribute;
                 }
                 else
                 {