以下例子是项目中实际用到的。不足之处请大家指正，设计到画线，写文字，填充，文字旋转。
?1 <!DOCTYPE html> ?2 <html> ?3 <head lang="en"> ?4 ????<meta charset="UTF-8"> ?5 ????<title>Canvas绘图</title> ?6 ????<script type="text/javascript" src="../../1_js_plugin/jquery/jquery-2.1.1.min.js"></script> ?7 ????<script type="text/javascript" src="../../1_js_plugin/echarts/echarts.js"></script> ?8 </head> ?9 ?10 <script type="text/javascript"> 11 ?12 ????var oriData = [7533.00, 15508.00, 16780.00, 18737.00, 21155.00, 23769.00, 26302.00, 28504.00, 30178.00, 31197.00, 31513.00, 13 ????????31153.00, 30201.00, 28781.00, 27034.00, 25100.00, 23102.00, 21137.00, 19272.00, 17548.00, 15983.00, 14582.00, 13341.00, 14 ????????12254.00, 11313.00, 10515.00, 9856.00, 9335.00, 8948.00, 8691.00, 8561.00, 8553.00, 8667.00, 8906.00, 9281.00, 9807.00, 15 ????????10503.00, 11389.00, 12478.00, 13778.00, 15283.00, 16977.00, 18837.00, 20830.00, 22919.00, 25064.00, 27211.00, 29298.00, 16 ????????31244.00, 32955.00, 34330.00, 35272.00, 35704.00, 35588.00, 34929.00, 33781.00, 32242.00, 30431.00, 28473.00, 26477.00, 17 ????????24523.00, 22657.00, 20892.00, 19222.00, 17631.00, 16109.00, 14656.00, 13286.00, 12022.00, 10889.00, 9908.00, 9088.00, 18 ????????8426.00, 7905.00, 7499.00, 7177.00, 6910.00, 6671.00, 6442.00, 6214.00, 5981.00, 5745.00, 5510.00, 5278.00, 5055.00, 19 ????????4841.00, 4637.00, 4446.00, 4269.00, 4108.00, 3967.00, 3848.00, 3749.00, 3666.00, 3594.00, 3522.00, 3442.00, 3346.00, 20 ????????3229.00, 3093.00, 2942.00, 2785.00, 2634.00, 2500.00, 2394.00, 2322.00, 2284.00, 2279.00, 2297.00, 2329.00, 2364.00, 21 ????????2392.00, 2406.00, 2404.00, 2388.00, 2362.00, 2332.00, 2303.00, 2281.00, 2266.00, 2256.00, 2249.00, 2239.00, 2223.00, 22 ????????2198.00, 2162.00, 2114.00, 2058.00, 1996.00, 1930.00, 1865.00, 1802.00, 1743.00, 1688.00, 1637.00, 1590.00, 1545.00, 23 ????????1501.00, 1459.00, 1420.00, 1383.00, 1350.00, 1321.00, 1296.00, 1275.00, 1254.00, 1233.00, 1207.00, 1177.00, 1140.00, 24 ????????1097.00, 1049.00, 999.00, 948.00, 899.00, 851.00, 807.00, 766.00, 727.00, 691.00, 657.00, 626.00, 598.00, 574.00, 553.00, 25 ????????536.00, 523.00, 513.00, 505.00, 500.00, 498.00, 497.00, 498.00, 501.00, 503.00, 504.00, 502.00, 497.00, 487.00, 472.00, 26 ????????453.00, 429.00, 403.00, 375.00, 347.00, 321.00, 298.00, 279.00, 266.00, 257.00, 254.00, 253.00, 255.00, 258.00, 261.00, 27 ????????263.00, 264.00, 263.00, 260.00, 255.00, 249.00, 242.00, 233.00, 223.00, 213.00, 202.00, 190.00, 180.00, 170.00, 162.00, 28 ????????157.00, 155.00, 158.00, 164.00, 174.00, 186.00, 200.00, 213.00, 223.00, 231.00, 234.00, 233.00, 229.00, 221.00, 211.00, 29 ????????201.00, 190.00, 180.00, 172.00, 165.00, 159.00, 155.00, 153.00, 151.00, 151.00, 151.00, 151.00, 151.00, 151.00, 150.00, 30 ????????149.00, 148.00, 146.00, 145.00, 144.00, 142.00, 141.00, 140.00, 139.00, 138.00, 136.00, 135.00, 134.00, 133.00, 132.00, 31 ????????130.00, 129.00, 127.00, 124.00, 122.00, 119.00, 117.00, 114.00, 113.00, 111.00, 110.00, 110.00, 110.00, 111.00, 113.00, 32 ????????115.00, 117.00, 120.00, 122.00, 122.00, 122.00, 120.00, 117.00, 113.00, 109.00, 104.00, 100.00, 96.00, 93.00, 91.00, 91.00, 33 ????????90.00, 90.00, 90.00, 90.00, 89.00, 88.00, 86.00, 84.00, 82.00, 79.00, 77.00, 74.00, 72.00, 70.00, 69.00, 69.00, 68.00, 68.00, 34 ????????67.00, 66.00, 65.00, 63.00, 62.00, 60.00, 59.00, 58.00, 57.00, 56.00, 56.00, 55.00, 55.00, 53.00, 52.00, 50.00, 48.00, 46.00, 35 ????????45.00, 43.00, 41.00, 40.00, 39.00, 37.00, 36.00, 35.00, 34.00, 33.00, 32.00, 32.00, 33.00, 33.00, 33.00, 32.00, 32.00, 31.00, 36 ????????30.00, 30.00, 29.00, 29.00, 29.00, 29.00, 29.00, 28.00, 27.00, 26.00, 25.00, 24.00, 23.00, 21.00, 20.00, 20.00, 19.00, 19.00, 37 ????????19.00, 18.00, 18.00, 18.00, 18.00, 18.00, 18.00, 18.00, 17.00, 17.00, 17.00, 17.00, 16.00, 16.00, 15.00, 14.00, 13.00, 12.00, 38 ????????12.00, 11.00, 10.00, 9.00, 9.00, 9.00, 8.00, 8.00, 8.00, 8.00, 7.00, 7.00, 7.00, 6.00, 6.00, 6.00, 6.00, 5.00, 5.00, 5.00, 5.00, 39 ????????5.00, 5.00, 5.00, 5.00, 5.00, 5.00, 5.00, 4.00, 4.00, 4.00, 4.00, 4.00, 3.00, 3.00, 3.00, 3.00, 3.00, 2.00, 2.00, 2.00, 2.00, 40 ????????2.00, 2.00, 2.00, 2.00, 2.00, 2.00, 2.00, 2.00, 2.00, 2.00, 2.00, 2.00, 2.00, 2.00, 2.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 41 ????????1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 1.00, 0.00, 42 ????????0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 43 ????????0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 44 ????????0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00, 0.00] ????// 原始数据 45 ????var max = {xMax: 0, yMax: 0}; ??// 横坐标与纵坐标的最值 46 ????var dataNum = 512; ?????// 绘图点的个数 47 ????var data = {xData: [], yData: []}; ?// 坐标值 48 ????// 分割点的x坐标与索引 49 ????var segArr = [ 50 ????????{x: 0, index: Math.round(0 * dataNum)}, 51 ????????{x: 0.04, index: Math.round(0.04 * dataNum), color: "gray"}, 52 ????????{x: 0.15, index: Math.round(0.15 * dataNum), color: "red"}, 53 ????????{x: 0.4, index: Math.round(0.4 * dataNum), color: "green"}, 54 ????????{x: 1, index: Math.round(1 * dataNum)} 55 ????]; 56 ?57 ????$(function () { 58 ????????dealData(); 59 ????????draw(); 60 ????}) 61 ?62 ????/** 63 ?????* @function：数据处理，获取x与y 64 ?????* @author： 65 ?????* @date：2018-05-29 07:48 66 ?????*/ 67 ????function dealData() { 68 ????????var STEP = 1 / 512; 69 ?70 ????????var xMax = 0; 71 ????????var yMax = 0; 72 ????????var x_data = []; 73 ????????var y_data = []; 74 ?75 ????????// x坐标及最值 76 ????????x_data.push(0); 77 ????????for (var i = 1; i <= 512; i++) { 78 ????????????x_data.push(Math.round((x_data[i - 1] + STEP) * 10000) / 10000); 79 ????????????xMax = xMax < x_data[i] ? x_data[i] : xMax; 80 ????????} 81 ????????max.xMax = xMax; 82 ????????data.xData = x_data; 83 ?84 ????????// y坐标及最值 85 ????????for (var i = 0; i < oriData.length; i++) { 86 ????????????y_data.push(oriData[i] / 1000 / 1000); 87 ????????????yMax = yMax < y_data[i] ? y_data[i].toFixed(3) : yMax; 88 ????????} 89 ????????max.yMax = yMax; 90 ????????data.yData = y_data; 91 ????} 92 ?93 ????/** 94 ?????* @function：绘图 95 ?????* @author： 96 ?????* @date：2018-05-29 19:18 97 ?????*/ 98 ????function draw() { 99 ????????// 坐标轴矩形的宽高100 ????????var retWidth = 680;101 ????????var retHeight = 460;102 103 ????????// 坐标轴矩形的左上角坐标104 ????????var ret_leftTop_x = 80;105 ????????var ret_leftTop_y = 80;106 107 ????????// 坐标轴矩形的左下角坐标108 ????????var ret_leftBottom_y = ret_leftTop_y + retHeight;109 110 ????????// 坐标轴的分割数目111 ????????var xSeg = 4;112 ????????var ySeg = 5;113 114 ????????// 坐标刻度短轴长度115 ????????var axis = 5;116 117 ????????// 实际有效的绘图数目118 ????????var validDataNum = 205;119 120 ????????var fdCanvas = document.getElementById("frequencyDomainChart");121 ????????var ctx = fdCanvas.getContext("2d");122 ????????var tip = fdCanvas.getContext("2d");123 124 ????????// canvas的宽高125 ????????var canvasWidth = fdCanvas.width;126 127 ????????// title128 ????????tip.font = "18px Arial";129 ????????tip.fillText("RR Spectrum", 20, 30, 100); ??// fillText(text,x,y,maxWidth)130 131 ????????// 坐标轴132 ????????ctx.lineWidth = 1;133 ????????ctx.rect(ret_leftTop_x, ret_leftTop_y, retWidth, retHeight); ???// rect(x,y,width,height)134 ????????ctx.stroke();135 136 ????????// x轴及坐标137 ????????ctx.beginPath();138 ????????for (var i = 0; i <= xSeg; i++) {139 ????????????ctx.moveTo(ret_leftTop_x + retWidth / xSeg * i, ret_leftBottom_y - axis);140 ????????????ctx.lineTo(ret_leftTop_x + retWidth / xSeg * i, ret_leftBottom_y);141 ????????????ctx.stroke();142 ????????????ctx.fillText(i/10, ret_leftTop_x - 20 / 2 + retWidth / xSeg * i, ret_leftBottom_y + 20, 20);143 ????????}144 ????????ctx.closePath();145 ????????tip.font = "15px Arial";146 ????????tip.fillText("Frequency(Hz)", canvasWidth / 2 - 40, ret_leftBottom_y + 50, 100); ??// fillText(text,x,y,maxWidth)147 148 ????????// y轴及坐标149 ????????ctx.beginPath();150 ????????for (var i = 0; i <= ySeg; i++) {151 ????????????ctx.moveTo(ret_leftTop_x, ret_leftTop_y + retHeight / ySeg * i);152 ????????????ctx.lineTo(ret_leftTop_x + axis, ret_leftTop_y + retHeight / ySeg * i);153 ????????????ctx.stroke();154 ????????????ctx.fillText((max.yMax - max.yMax / ySeg * i).toFixed(3), ret_leftTop_x - 35, ret_leftTop_y + retHeight / ySeg * i + 5, 30);155 ????????}156 ????????ctx.closePath();157 158 ????????// 画曲线159 ????????for (var t = 0; t < segArr.length - 2; t++) {160 ????????????ctx.beginPath();161 ????????????ctx.lineWidth = 2;162 ????????????ctx.moveTo(retWidth / validDataNum * segArr[t].index + ret_leftTop_x, retHeight - retHeight * data.yData[segArr[t].index] / max.yMax + ret_leftTop_y);163 ????????????for (var i = segArr[t].index + 1; i <= segArr[t + 1].index; i++) {164 ????????????????ctx.lineTo(retWidth / validDataNum * i + ret_leftTop_x, retHeight - retHeight * data.yData[i] / max.yMax + ret_leftTop_y);165 ????????????}166 ????????????console.log(segArr[t + 1].x);167 ????????????ctx.lineTo(ret_leftTop_x + segArr[t + 1].x * retWidth/(xSeg*1.0/10), ret_leftBottom_y);168 ????????????ctx.lineTo(ret_leftTop_x + segArr[t].x * retWidth/(xSeg*1.0/10), ret_leftBottom_y);169 ????????????ctx.closePath();170 ????????????ctx.stroke();171 ????????????if (t != segArr.length - 1) {172 ????????????????ctx.fillStyle = segArr[t + 1].color;173 ????????????????ctx.fill();174 ????????????}175 ????????}176 177 ????????// 纵轴单位178 ????????tip.font = "15px Arial";179 ????????tip.fillStyle = "black";180 ????????tip.translate(ret_leftTop_x - 50,ret_leftTop_y + retHeight/2); ?????//重新映射画布上的 (0,0) 位置181 ????????tip.rotate( 270* Math.PI/180); ?????//旋转当前的绘图，以弧度计182 ????????tip.fillText("PSD(s^2/Hz)", 0, 0, 100);183 184 ????}185 186 </script>187 188 <style type="text/css">189 ????#frequencyDomainChart {190 ????????border: 1px solid #000000;191 ????}192 </style>193 194 <body>195 <canvas id="frequencyDomainChart" height="600px" width="800px"></canvas>196 </body>197 </html>最终效果（重点是文字旋转，文字旋转必选放到最后；还有画一段连续的线条时，只需第一次moveTo，然后剩下的lineTo即可）：
Html5使用canvas作图
原文地址：https://www.cnblogs.com/DDgougou/p/9112714.html