我正在尝试在 iPad 上使用画布对象；用户需要用手指绘制一条自由曲线，当他松开手指时，系统必须关闭曲线并填充它。
实际上我写下了以下代码，但问题是它绘制但它没有关闭手指释放的路径。
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=768px, maximum-scale=1.0" />
<title>sketchpad</title>
<script type="text/javascript" charset="utf-8">
window.addEventListener('load',function(){
// get the canvas element and its context
var canvas = document.getElementById('sketchpad');
var context = canvas.getContext('2d');
var img = new Image();
img.src = 'imp_02.jpg';
context.drawImage(img,0,0,600,600);
var colorPurple = "#cb3594";
context.strokeStyle=colorPurple;
context.lineWidth = 5;
context.fillStyle = "red";
// create a drawer which tracks touch movements
var drawer = {
isDrawing: false,
touchstart: function(coors){
context.beginPath();
context.moveTo(coors.x, coors.y);
this.isDrawing = true;
},
touchmove: function(coors){
if (this.isDrawing) {
context.lineTo(coors.x, coors.y);
context.stroke();
}
},
touchend: function(coors){
if (this.isDrawing) {
context.touchmove(coors);
context.closePath();
this.isDrawing = false;
}
}
};
// create a function to pass touch events and coordinates to drawer
function draw(event){
// get the touch coordinates
var coors = {
x: event.targetTouches[0].pageX,
y: event.targetTouches[0].pageY
};
// pass the coordinates to the appropriate handler
drawer[event.type](coors);
}
// attach the touchstart, touchmove, touchend event listeners.
canvas.addEventListener('touchstart',draw, false);
canvas.addEventListener('touchmove',draw, false);
canvas.addEventListener('touchend',draw, false);
// prevent elastic scrolling
document.body.addEventListener('touchmove',function(event){
event.preventDefault();
},false); // end body.onTouchMove
},false); // end window.onLoad
</script>
<style type="text/css"><!--
body{margin:0;padding:0; font-family:Arial;}
#container{position:relative;}
#sketchpad{ border: 1px solid #000;}
--></style>
</head>
<body>
<div id="container">
<canvas id="sketchpad" width="766" height="944">
Sorry, your browser is not supported.
</canvas>
</div>
</body>
</html>
我不明白我错过了什么。有没有人可以帮助我.....我将不胜感激！