[编辑:以适应OP的附加信息]
此代码使用 2 个三次贝塞尔曲线和 6 个控制手柄来让您选择图像中的眼球。
红色手柄控制眼睛顶部的曲线。蓝色手柄控制眼睛底部的曲线。白色手柄可让您固定在眼角。橙色显示生成的路径(=2 曲线)。
下面是应用程序的图片,这里是它的 Fiddle:http: //jsfiddle.net/m1erickson/98G9F/
这是代码:
<!doctype html>
<html>
<head>
<link rel="stylesheet" type="text/css" media="all" href="css/reset.css" /> <!-- reset css -->
<script src="http://code.jquery.com/jquery-1.9.1.js"></script>
<script src="http://code.jquery.com/ui/1.10.1/jquery-ui.js"></script>
<style>
body { font-family: arial; }
.anchor { background: #fff; position: absolute; display: block; height: 10px; width: 10px; border: 1px solid #333; border-radius:5px;}
.control { background: #fff; position: absolute; display: block; height: 20px; width: 20px; border: 1px solid #333; border-radius:10px;}
.p1, .p2 { background: red; z-index: 50; }
.p3, .p4 { background: blue; }
.pStart { background:white;}
.pEnd {background:white;}
.pStart { left: 54px; top: 166px; }
.pEnd { left: 346px; top: 189px; }
.p1 { left: 150px; top: 39px; }
.p2 { left: 276px; top: 97px; }
.p3 { left: 219px; top: 227px; }
.p4 { left: 147px; top: 224px; }
canvas { border: 1px solid #333;}
#start,#end2{color:green;}
#end1{color:purple;}
#c1,#c3{color:red;}
#c2,#c4{color:blue;}
</style>
</head>
<body>
<a href="#" class="anchor pStart"></a>
<a href="#" class="control p1"></a>
<a href="#" class="control p2"></a>
<a href="#" class="anchor pEnd"></a>
<a href="#" class="control p3"></a>
<a href="#" class="control p4"></a>
<canvas height="400" width="400" id="canvas"></canvas>
<p>context.moveTo(
<span id="start"></span>);
</p>
<p>context.bezierCurveTo(
<span id="c1"></span>,
<span id="c2"></span>,
<span id="end1"></span>);
</p>
<p>context.bezierCurveTo(
<span id="c3"></span>,
<span id="c4"></span>,
<span id="end2"></span>);
</p>
<script>
var $p1,$p2,$codeMove,$codeBez1,$codeBez2;
$(function() {
var canvas=document.getElementById("canvas");
var ctx = canvas.getContext("2d");
$pStart=$(".pStart");
$pEnd=$(".pEnd");
$p1 = $(".p1");
$p2 = $(".p2");
$p3 = $(".p3");
$p4 = $(".p4");
$codeMove=$("code-move");
$codeBez1=$("code-bez1");
$codeBez2=$("code-bez2");
$(".pStart, .pEnd, .p1, .p2, .p3, .p4").draggable({
containment: 'parent',
drag: function(event, ui) { renderWrap(ctx); },
stop: function(){ renderWrap(ctx); }
});
var eyeImage=new Image();
eyeImage.onload=function(){
canvas.width=eyeImage.width*1.5;
canvas.height=eyeImage.height*1.5;
renderWrap(ctx);
}
eyeImage.src="http://i.stack.imgur.com/SbcL4.png";
function renderWrap(ctx) {
var pStart=$pStart.position();
var pEnd=$pEnd.position();
var p1 = $p1.position();
var p2 = $p2.position();
var p3 = $p3.position();
var p4 = $p4.position();
render({x:pStart.left, y:pStart.top}, {x:pEnd.left, y:pEnd.top}, {x:p1.left, y:p1.top}, {x:p2.left, y:p2.top}, {x:p3.left, y:p3.top}, {x:p4.left, y:p4.top} );
};
function render(start, end, p1, p2, p3, p4) {
ctx.clearRect(0,0,canvas.width,canvas.height);
ctx.drawImage(eyeImage,0,0,eyeImage.width,eyeImage.height,0,0,eyeImage.width*1.5,eyeImage.height*1.5);
ctx.beginPath();
ctx.lineWidth = 2;
ctx.strokeStyle = "orange";
// start-->end
ctx.moveTo(start.x,start.y);
ctx.bezierCurveTo(p1.x,p1.y,p2.x,p2.y,end.x,end.y);
ctx.stroke();
// end-->start
ctx.bezierCurveTo(p3.x,p3.y,p4.x,p4.y,start.x,start.y);
ctx.stroke();
ctx.closePath();
// connectors
ctx.beginPath();
ctx.strokeStyle = "#999";
ctx.lineWidth = 1;
connector(start,p1);
connector(end,p2);
connector(end,p3);
connector(start,p4);
ctx.closePath();
// display code
$("#start").html(start.x+","+start.y);
$("#c1").html(p1.x+","+p1.y);
$("#c2").html(p2.x+","+p2.y);
$("#end1").html(end.x+","+end.y);
$("#c3").html(p3.x+","+p3.y);
$("#c4").html(p4.x+","+p4.y);
$("#end2").html(start.x+","+start.y);
}
function connector(pt1,pt2){
ctx.moveTo(pt1.x,pt1.y);
ctx.lineTo(pt2.x,pt2.y);
ctx.stroke();
}
});
</script>
</body>
</html>