canvas轨迹回放功能实现

这篇文章主要介绍了canvas轨迹回放功能实现过程以及相关的代码整理，跟着小编一起学习下吧。

本文通过json机构，HTML代码以及JS代码详细给大家分析了canvas轨迹回放功能实现的过程，以下是全部内容。

json结构

 [ { "path": [ { "x": 82, "y": 43 }, { "x": 83, "y": 43 }, { "x": 84, "y": 45 }, { "x": 86, "y": 47 }, { "x": 86, "y": 49 }, { "x": 86, "y": 54 }, { "x": 86, "y": 59 }, { "x": 86, "y": 64 }, { "x": 86, "y": 69 }, { "x": 86, "y": 74 }, { "x": 86, "y": 78 }, { "x": 86, "y": 83 }, { "x": 86, "y": 87 }, { "x": 86, "y": 89 }, { "x": 86, "y": 91 }, { "x": 86, "y": 92 }, { "x": 86, "y": 93 }, { "x": 86, "y": 94 }, { "x": 86, "y": 95 } ] }, { "path": [ { "x": 129, "y": 36 }, { "x": 129, "y": 39 }, { "x": 129, "y": 44 }, { "x": 129, "y": 49 }, { "x": 129, "y": 54 }, { "x": 129, "y": 59 }, { "x": 128, "y": 65 }, { "x": 127, "y": 73 }, { "x": 125, "y": 78 }, { "x": 125, "y": 81 }, { "x": 124, "y": 88 }, { "x": 123, "y": 91 }, { "x": 123, "y": 94 }, { "x": 123, "y": 96 }, { "x": 123, "y": 97 }, { "x": 123, "y": 98 }, { "x": 123, "y": 99 }, { "x": 122, "y": 100 } ] } ]

html

将json作为js文件引入，并将其赋值给全局变量testPath(引入方式按照实际项目要求来)

  *{margin:0; padding:0;} #test{border:1px solid #ccc; background: #eee; margin:20px 30px;} 
start

js

 $('#start').click(function(event) { var lineIndex = 0,pointIndex = 0,line2; var obj = document.getElementById('test'); var cxt = obj.getContext('2d'); cxt.lineWidth = 1; cxt.strokeStyle = 'red'; cxt.lineCap = 'round'; cxt.clearRect(0,0,600,200); function drawBegin(){ cxt.beginPath(); pointIndex=0; var intervalHandle = window.setInterval(function () { line2 = testPath[lineIndex].path[pointIndex]; if (!line2) { window.clearInterval(intervalHandle); if (lineIndex <testPath.length - 1) { lineIndex = lineIndex + 1; drawBegin(); } }else{ if (pointIndex == 0) { cxt.moveTo(line2.x, line2.y); } pointIndex = pointIndex + 1; cxt.lineTo(line2.x, line2.y); cxt.stroke(); } },0); } drawBegin(); });

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