需求；鼠标点击下去后确定直线起始点，鼠标移动后直线会随之绵延，鼠标松开则直线绘制完成
源码：
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>动态添加图形和图片并可以拖拽</title>
<meta content="width=device-width;initial-scale=1">
<script type="text/javascript" src="https://cdn.staticfile.org/jquery/1.10.2/jquery.min.js"></script>
<script type="text/javascript" src="d3.min.js"></script>
<script src="svg.min.js"></script>
<script src="svg.draggable.js"></script>
<style>
#drawing {
width: 100%;
height: 500px;
margin: 0;
}
[id^="Svgjs"] {
cursor: move;
}
#img-btn{
background: url("timg.jpg") no-repeat;
border: none;
background-size: 100% 100%;
width: 100px;
height: 40px;
}
#rect-btn{
background-color:#f57518;
width: 100px;
height: 100px;
border: none;
}
#Line-btn{
background-color:pink;
width: 100px;
height: 100px;
border: none;
}
</style>
</head>
<body>
<div id="div1">
</div>
<!--向svg中添加元素-->
<svg id="svg_my" style="border:1px solid #000;width:500px;height:500px" version="1.1" xmlns="http://www.w3.org/2000/svg">
</svg>
</body>
<script>
var Linename =1;
var flag = true; //判断一个直线是否完成
var startLinex1,startLiney1,startLinex2,startLiney2; //直线起始/点
var svgMy = document.getElementById("svg_my")
svgMy.οnmοusedοwn=function(event){
startLinex1 = event.offsetX;
startLiney1 = event.offsetY;
startLinex2 = startLinex1;
startLiney2=startLiney1;
var e,draw = SVG('svg_my');
draw.line(startLinex1,startLiney1, startLinex1, startLiney1).id("Imgline"+Linename).stroke({ width: 1 }).draggable();
flag=true;
}
svgMy.onmousemove = function (event) {
if(flag){
startLinex2 = event.offsetX;
startLiney2 = event.offsetY;
$("#Imgline"+Linename).attr("x2",startLinex2).attr("y2",startLiney2);
}
}
svgMy.onmouseup = function (e) {
$("#Imgline"+Linename).attr("x2",startLinex2).attr("y2",startLiney2);
flag=false;
Linename++;
}
</script>
</html>
