ofz#3754 Divide-by-zero

Change-Id: I2e8504dd67d2a7ad1e83a95d7be5a1d1086de5d5
Reviewed-on: https://gerrit.libreoffice.org/43758Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

filter/source/graphicfilter/idxf/dxf2mtf.cxx

@@ -761,7 +761,7 @@ DXF2GDIMetaFile::~DXF2GDIMetaFile()
 
 bool DXF2GDIMetaFile::Convert(const DXFRepresentation & rDXF, GDIMetaFile & rMTF, sal_uInt16 nminpercent, sal_uInt16 nmaxpercent)
 {
-    double fWidth,fHeight,fScale;
+    double fWidth,fHeight,fScale(0.0);
     DXFTransform aTransform;
     Size aPrefSize;
     const DXFLayer * pLayer;
@@ -824,7 +824,6 @@ bool DXF2GDIMetaFile::Convert(const DXFRepresentation & rDXF, GDIMetaFile & rMTF
             fHeight=pDXF->aBoundingBox.fMaxY-pDXF->aBoundingBox.fMinY;
             if (fWidth<=0 || fHeight<=0) {
                 bStatus=false;
-                fScale = 0;  // -Wall added this...
             }
             else {
                 if (fWidth>fHeight)
@@ -843,6 +842,9 @@ bool DXF2GDIMetaFile::Convert(const DXFRepresentation & rDXF, GDIMetaFile & rMTF
     else {
         fHeight=pVPort->fHeight;
         fWidth=fHeight*pVPort->fAspectRatio;
+        if (fWidth<=0 || fHeight<=0) {
+            bStatus=false;
+        } else {
             if (fWidth>fHeight)
                 fScale=10000.0/fWidth;
             else
@@ -854,6 +856,7 @@ bool DXF2GDIMetaFile::Convert(const DXFRepresentation & rDXF, GDIMetaFile & rMTF
                     DXFTransform(fScale,fScale,fScale,DXFVector(0,0,0))
                 )
             );
+        }
         aPrefSize.Width() =(long)(fWidth*fScale+1.5);
         aPrefSize.Height()=(long)(fHeight*fScale+1.5);
     }