static void gdImageVLine(gdImagePtr im, int x, int y1, int y2, int col)
{
	if (im->thick > 1) {
		int thickhalf = im->thick >> 1;
		gdImageFilledRectangle(im, x - thickhalf, y1, x + im->thick - thickhalf - 1, y2, col);
	} else {
		if (y2 < y1) {
			int t = y1;
			y1 = y2;
			y2 = t;
		}

		for (; y1 <= y2; y1++) {
			gdImageSetPixel(im, x, y1, col);
		}
	}
	return;
}
Unknown