标签：部分 script ret demo context images move html ddc
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<canvas id="mycanvas"></canvas>
</body>
<script>
var c = document.getElementById("mycanvas");
var ctx = c.getContext("2d");
c.width = window.innerWidth;
c.height = window.innerHeight;
var points = [];
//console.log(ctx.width,ctx.height);
function bgc() {
var bg = ctx.createLinearGradient(0,0,window.innerWidth,window.innerHeight);
bg.addColorStop(0,"#000");
bg.addColorStop(1,"#fff");
ctx.fillStyle = bg;
ctx.fillRect(0,0,window.innerWidth,window.innerHeight);
//ctx.fill();
}
/*创造点点*/
var point = [];
for(var i=0;i<500;i++){
point.push({
x: Math.random()*window.innerWidth,
y: Math.random()*window.innerHeight,
vx: Math.random()-0.5,
vy: Math.random()+0.5,
size: 3+Math.random()
})
}
//console.log(point);
/*开始画点*/
function rads(x) {
return Math.PI*2/360*x;
}
function drawPoint(c) {
c.clearRect(0,0,window.innerWidth,window.innerHeight);
bgc();
var temp;
for(var i=0;i<500;i++){
temp = point[i];
temp.x += point[i].vx;
temp.y += point[i].vy;
temp.size = 2+Math.random();
if(temp.x<0) temp.x = window.innerWidth;
if(temp.x>window.innerWidth) temp.x = 0;
if(temp.y>window.innerHeight) temp.y = 0;
c.beginPath();
//c.fillStyle = "yellow";
c.arc(temp.x,temp.y,temp.size,0,rads(360));
points.push({indexX:temp.x,indexY:temp.y});
c.strokeStyle = "white";
c.stroke();
R = Math.floor(Math.random()*255);
G = Math.floor(Math.random()*255);
B = Math.floor(Math.random()*255);
c.fillStyle = "rgb("+R+","+G+","+B+")";
c.fill();
}
}
// console.log(points);
//这是一个demo,试着看一个点周围是不是能够互相连接,注释掉的部分是一个demo
/*for(var i=0;i<500;i++){
for(var j=0;j<500;j++){
var dis = Math.sqrt(Math.pow(points[i].indexX-points[j].indexX,2)+Math.pow(points[i].indexY-points[j].indexY,2));
if(dis<50){
ctx.beginPath();
ctx.moveTo(points[i].indexX,points[i].indexY);
ctx.lineTo(points[j].indexX,points[j].indexY);
ctx.stroke();
}
}
}*/
drawPoint(ctx);
document.onmousemove = function (event) {
e= event || window.event;
//console.log(e.pageX,e.pageY);
drawPoint(ctx);
for(var i=0;i<500;i++){
var diss = Math.sqrt(Math.pow(e.pageX-points[i].indexX,2)+Math.pow(e.pageY-points[i].indexY,2));
if(diss<100) {
for (var j = 0; j < 500; j++) {
var dis = Math.sqrt(Math.pow(points[i].indexX - points[j].indexX, 2) + Math.pow(points[i].indexY - points[j].indexY, 2));
if (dis < 80) {
ctx.beginPath();
ctx.moveTo(points[i].indexX, points[i].indexY);
ctx.lineTo(points[j].indexX, points[j].indexY);
ctx.stroke();
}
}
}
}
}
</script>
</html>
效果如下:
标签：部分 script ret demo context images move html ddc
原文地址：http://www.cnblogs.com/huqinqin/p/7522144.html
