--- utils/ImageOutputDev.old    2017-07-31 19:35:23.000000000 +0200
+++ utils/ImageOutputDev.cc     2018-03-20 05:04:46.000000000 +0200
@@ -232,10 +232,10 @@
   }

   double *mat = state->getCTM();
-  double width2 = mat[0] + mat[2];
-  double height2 = mat[1] + mat[3];
-  double xppi = fabs(width*72.0/width2) + 0.5;
-  double yppi = fabs(height*72.0/height2) + 0.5;
+  double width2 = sqrt(mat[0]*mat[0] + mat[1]*mat[1]);
+  double height2 = sqrt(mat[2]*mat[2] + mat[3]*mat[3]);
+  double xppi = fabs(width*72.0/width2);
+  double yppi = fabs(height*72.0/height2);
   if (xppi < 1.0)
     printf("%5.3f ", xppi);
   else