Html5 Canvas绘制点与点相交线动态背景代码

function Intersect2lines(l1, l2) {
  var p1 = l1.a,
    p2 = l1.b,
    p3 = l2.a,
    p4 = l2.b;
  var denominator = (p4.y - p3.y) * (p2.x - p1.x) - (p4.x - p3.x) * (p2.y - p1.y);
  var ua = ((p4.x - p3.x) * (p1.y - p3.y) - (p4.y - p3.y) * (p1.x - p3.x)) / denominator;
  var ub = ((p2.x - p1.x) * (p1.y - p3.y) - (p2.y - p1.y) * (p1.x - p3.x)) / denominator;
  var x = p1.x + ua * (p2.x - p1.x);
  var y = p1.y + ua * (p2.y - p1.y);
  if (ua > 0 && ub > 0) {
    markPoint({
      x: x,
      y: y
    })
  }
}

这是一款基于Html5 Canvas制作的点与点相交线网页动态背景特效。