screen_write_vline
void screen_write_vline(struct screen_write_ctx *, u_int, int, int,
screen_write_vline(ctx, sy - i, 0, 0, &gc);
screen_write_vline(ctx, sy, 0, 0, &gc);
screen_write_vline(ctx, sy, 0, 0, &gc);
screen_write_vline(ctx, sy, 0, 0, &gc);
screen_write_vline(ctx, sy, 0, 0, &gc);
screen_write_vline(ctx, sy, 0, 0, &gc);
screen_write_vline(ctx, sy, 0, 0, &gc);
screen_write_vline(ctx, sy - i, 0, 0, &gc);