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Copy pathrotate.html
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61 lines (61 loc) · 2.06 KB
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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>多点旋转</title>
<style>
div{
width:300px;
height: 300px;
background: #ccc;
margin:100px auto;
font:100px/300px "宋体";
color: #fff;
text-align: center;
}
</style>
<script>
window.onload = function(){
function d2a(n){
return n*180/Math.PI;//弧度转成角度
}
var oDiv = document.querySelector("div");
var d = 0;
oDiv.addEventListener("touchstart",function(ev){
var oldD = d;
function getD(ev){//最终求出角度
var x1 = ev.targetTouches[0].pageX;
var y1 = ev.targetTouches[0].pageY;
var x2 = oDiv.offsetLeft + oDiv.offsetWidth/2;
var y2 = oDiv.offsetTop + oDiv.offsetHeight/2;
var x = x1 - x2;
var y = y2 - y1;
//console.log(x,y)
return d2a(Math.atan2(y,x));//Math.atan2(y,x)求出了弧度
}
if(ev.targetTouches.length == 2){
var downD = getD(ev);
}
function fnMove(ev){
if(ev.targetTouches.length == 2){
d = oldD + downD - getD(ev);
//var d = downD - getD(ev);
oDiv.style.webkitTransform = "rotate("+d+"deg)";
}
//一开始默认的角度为0
}
function fnEnd(){
oDiv.removeEventListener("touchmove",fnMove,false);
oDiv.removeEventListener("touchend",fnEnd,false);
}
oDiv.addEventListener("touchmove",fnMove,false);
oDiv.addEventListener("touchend",fnEnd,false);
ev.preventDefault();
},false)
}
</script>
</head>
<body>
<div>1</div>
</body>
</html>