AS3 求两条直线的交点

//粘贴到帧上运行即可

var p1Start:Point = new Point(0,0);

var p1End:Point = new Point(50,50);

var p2Start:Point = new Point(50,50);

var p2End:Point = new Point(100,100);

var p:Point = new Point();

trace(checkPoint())

function checkPoint()

{

	if (p1Start.x == p1End.x)

	{

		if (p2Start.x == p2End.x)

		{

			trace("平行线");

			p = null;

		}

		else

		{

			p.x = p1Start.x;

			p.y = p2Start.y+(p1Start.x-p2Start.x)/(p2End.x-p2Start.x)*(p2End.y-p2Start.y);

		}

	}

	else if (p2Start.x == p2End.x)

	{

		p.x = p2Start.x;

		p.y = p1Start.y+(p2Start.x-p1Start.x)/(p1End.x-p1Start.x)*(p1End.y-p1Start.y);

	}

	else

	{

		var K1:Number = (p1Start.y-p1End.y)/(p1Start.x-p1End.x);

		var K2:Number = (p2Start.y-p2End.y)/(p2Start.x-p2End.x);

		if (K1 == K2)

		{

			trace("平行线");

			p = null;

		}

		else

		{

			var B1:Number = (p1Start.x*p1End.y-p1Start.y*p1End.x)/(p1Start.x-p1End.x);

			var B2:Number = (p2Start.x*p2End.y-p2Start.y*p2End.x)/(p2Start.x-p2End.x);

			p.x = (B2 - B1) / (K1 - K2);

			p.y = K1 * p.x + B1;

		}

	}

	return p;

}