_cairo_gstate_unset_font (gstate);
_cairo_gstate_concat_matrix (cairo_gstate_t *gstate,		      cairo_matrix_t *matrix){    cairo_matrix_t tmp;    cairo_matrix_copy (&tmp, matrix);    cairo_matrix_multiply (&gstate->ctm, &tmp, &gstate->ctm);    cairo_matrix_invert (&tmp);    cairo_matrix_multiply (&gstate->ctm_inverse, &gstate->ctm_inverse, &tmp);    return CAIRO_STATUS_SUCCESS;}