static double x2scr_pos_scaled(ASS_Renderer *render_priv, double x)
{
    return x * render_priv->orig_width / render_priv->track->PlayResX +
        render_priv->settings.left_margin;
}
static double x2scr_pos_scaled(ASS_Renderer *render_priv, double x)
{
    return x * render_priv->orig_width / render_priv->track->PlayResX +
        render_priv->settings.left_margin;
}