前端刮刮乐特效

前端刮刮乐特效<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta http-equiv="X-UA-Compatib

涤生啊

201人浏览 · 2021-11-18 13:49:17

涤生啊 · 2021-11-18 13:49:17 发布

前端刮刮乐特效

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        img {
            width: 400px;
            height: 300px;
            left: 200px;
            position: absolute;
            z-index: -1;
        }

        canvas {
            margin-left: 200px;
        }
    </style>
</head>

<body>
<img src="http://n.sinaimg.cn/photo/transform/700/w1000h500/20200317/512d-iqyryku6022748.jpg" alt="">

<canvas id="canvas" width="400" height="300"></canvas>
</body>

</html>
<script type="text/javascript">
    var canvas = document.getElementById("canvas");
    var context = canvas.getContext('2d');
    //画蒙布
    context.beginPath();
    context.fillStyle= '#000'
    context.fillRect(0,0,400,300);
    //鼠标按下开刮
    canvas.onmousedown=function(){
        canvas.onmousemove = function(){
            //获取鼠标坐标
            var x = event.clientX;
            var y = event.clientY;
            //destination-out    显示原来的不在后来区域的部分
            context.globalCompositeOperation = "destination-out";
            context.beginPath();
            context.arc(x-200,y,30,0,Math.PI*2);
            context.fill();
        }
    }
    //鼠标抬起不刮开
    canvas.onmouseup=function(){
        canvas.onmousemove = function(){
        }
    }
</script>