}
else if (mode & ANIM_PINGPONG) /* oscillate (border frames once) */
{
+#if 1
+ int max_anim_frames = (num_frames > 1 ? 2 * num_frames - 2 : 1);
+#else
int max_anim_frames = 2 * num_frames - 2;
+#endif
frame = (sync_frame % (delay * max_anim_frames)) / delay;
frame = (frame < num_frames ? frame : max_anim_frames - frame);