lineCap:设置线条两端的形状
lineCap的属性值:butt(默认)、round、square。
var canvas=document.getElementById("canvas");
var context=canvas.getContext("2d");
canvas.width=1024;
canvas.height=768;
context.strokeStyle="#cccccc";
context.lineWidth=20;
context.beginPath();
context.moveTo(100,100);
context.lineTo(400,100);
context.lineCap="butt"; //默认
context.stroke();
context.beginPath();
context.moveTo(100,150);
context.lineTo(400,150);
context.lineCap="square"; //两端方头
context.stroke();
context.beginPath();
context.moveTo(100,200);
context.lineTo(400,200);
context.lineCap="round"; //两端圆头
context.stroke();