if (dvi_document->context)
mdvi_destroy_context (dvi_document->context);
dvi_document->context = mdvi_init_context(dvi_document->params, dvi_document->spec, filename);
if (dvi_document->context)
mdvi_destroy_context (dvi_document->context);
dvi_document->context = mdvi_init_context(dvi_document->params, dvi_document->spec, filename);