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原生JS实现动态折线图

<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>原生JS实现动态折线图</title>
	</head>
	<body>
	<canvas id="canvas"></canvas>
		<script>
			let N = new CreateMovingLineDiagram();
			//N.SetData.cavaswidth = 800//改变canvas宽度
			N.play();
			
			function CreateMovingLineDiagram() {
				let _this = this;
				//默认参数
				_this.SetData = {
					canvasid: "#canvas",// 画布ID
					canvaswidth: 600,//画布宽度
					canvasheight: 400,//画布高度
					segmentationNum: 50,//分段数,将画布宽度分割成多少分
					MoveSpeed: 100,//移动速度
					IsShowsegmentationBool: true,//是否开启分段显示
					IsCurveBool: true//true使用曲线绘图,false使用直线绘图
				}
				_this.play = function() {
					let canvas = document.querySelector(_this.SetData.canvasid); //获取Canvas元素
					canvas.width = _this.SetData.canvaswidth; //设置画布宽
					canvas.height = _this.SetData.canvasheight; //设置画布高
					
					let context = canvas.getContext("2d"); //使用Context绘画2D
					let segmentation = _this.SetData.segmentationNum //分段数
					let Speed = _this.SetData.MoveSpeed //绘画速度
					let XYAttr = []; //分段坐标数组
					let XZ = canvas.width / segmentation //得到每一段的X坐标
					let XW = 0; //已生成的X坐标
					let IsShowsegmentation = _this.SetData.IsShowsegmentationBool; //是否显示分段线
					let IsCurve = _this.SetData.IsCurveBool; //是否绘画曲线
					
					//进入页面先创建空数组
					for (var i = 0; i < segmentation + 1; i++) {
						XYAttr.push({
							"X": XW,
							"Y": canvas.height / 2
						})
						if (XW != canvas.width) {
							XW += XZ;
						}
					}
					
					setInterval(function() {
						canvas.height = canvas.height; //先清除画布
						if (IsShowsegmentation) {
							for (var i = 0; i < segmentation + 1; i++) {
								//画线
								context.moveTo((i * XZ), 0);
								context.lineTo((i * XZ), canvas.height)
								context.strokeStyle = "#aaa";
								context.stroke();
								context.beginPath();
							}
						}
					
						for (var i = 0; i < XYAttr.length; i++) {
							if (IsCurve) {
								//绘制曲线
								if (i > 0) {
									context.beginPath();
									context.moveTo(XYAttr[i - 1].X, XYAttr[i - 1].Y);
									context.quadraticCurveTo(XYAttr[i - 1].X, XYAttr[i].Y, XYAttr[i].X, XYAttr[i].Y);
					
								}
					
							} else {
								//绘制直线
								if (i > 0) {
									context.beginPath();
									context.moveTo(XYAttr[i - 1].X, XYAttr[i - 1].Y);
									context.lineTo(XYAttr[i].X, XYAttr[i].Y)
								}
							}
					
							context.strokeStyle = "coral";
							context.stroke();
						}
					
						XYAttr.splice(0, 1);
						//随机数据
						round = Math.floor(Math.random() * canvas.height);
					
						for (var i = 0; i < XYAttr.length; i++) {
							XYAttr[i].X = XYAttr[i].X - (XZ * 2)
						}
					
						XYAttr.push({
							"X": XW,
							"Y": round
						})
					
					}, Speed)
				}
			}
			
			
		</script>
	</body>

</html>

请看效果

posted @ 2020-05-20 18:31  LRolinx  阅读(1281)  评论(0编辑  收藏  举报