/**
	 * Computes the intersection between two segments. 
	 * @param x1 Starting point of Segment 1
	 * @param y1 Starting point of Segment 1
	 * @param x2 Ending point of Segment 1
	 * @param y2 Ending point of Segment 1
	 * @param x3 Starting point of Segment 2
	 * @param y3 Starting point of Segment 2
	 * @param x4 Ending point of Segment 2
	 * @param y4 Ending point of Segment 2
	 * @return Point where the segments intersect, or null if they don't
	 */
	public Point intersection(
		int x1,int y1,int x2,int y2, 
		int x3, int y3, int x4,int y4
	) {
		int d = (x1-x2)*(y3-y4) - (y1-y2)*(x3-x4);
		if (d == 0) return null;
		
		int xi = ((x3-x4)*(x1*y2-y1*x2)-(x1-x2)*(x3*y4-y3*x4))/d;
		int yi = ((y3-y4)*(x1*y2-y1*x2)-(y1-y2)*(x3*y4-y3*x4))/d;
		
		Point p = new Point(xi,yi);
		if (xi < Math.min(x1,x2) || xi > Math.max(x1,x2)) return null;
		if (xi < Math.min(x3,x4) || xi > Math.max(x3,x4)) return null;
		return p;
	}