Comment 29 for bug 1538361

Sorry, I'm on Windows, those instructions are like Greek to me, and they do not appear to be relevant.

however, here is an alternative approach. Instead of using the function sprintf, use the function g_sprintf.

So, for example, replace the call:
  sprintf(obuf,"transform=\"matrix(%lf,%lf,%lf,%lf,%lf,%lf)\"\n",cos(esc),-sin(esc),sin(esc),cos(esc),1.25*x,1.25*y);
with the call:
g_sprintf(obuf,"transform=\"matrix(%lf,%lf,%lf,%lf,%lf,%lf)\"\n",cos(esc),-sin(esc),sin(esc),cos(esc),1.25*x,1.25*y);

this has the advantage of keeping the format %lf. It appears to yield exactly the same benefits as the suggestion in comment 24 above, namely a correct transform matrix. In order to use this, you need to declare the header

#include <glib/gprintf.h>