javascript使用canvas实现饼状图效果
(编辑:jimmy 日期: 2024/12/25 浏览:3 次 )
使用canvas写一个饼状图,供大家参考,具体内容如下
代码:
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Document</title> </head> <body> <canvas id='canvas' width='800' height='400' style="border: 1px solid red;"></canvas> <script> let data = [ { title: "服饰1", money: 400 }, { title: "服饰2", money: 300 }, { title: "服饰3", money: 400 }, { title: "服饰4", money: 200 }, { title: "服饰5", money: 500 }, { title: "服饰6", money: 180 }, { title: "服饰7", money: 500 }] /** @type {HTMLCanvasElement} */ let canvas = document.querySelector("#canvas"); let ctx = canvas.getContext("2d"); let r = 100; let money = function (obj, sum) { for (let i = 0; i < obj.length; i++) { sum += data[i].money } return sum; } let totalmoney = money(data, 0); let nowsum = 0; let start = 0; let end = 0; let R = 100; let i=0; data.forEach(function (item) { ctx.beginPath() nowsum += item.money; end = (nowsum / totalmoney) ctx.moveTo(150, 150); ctx.arc(150, 150, R, start*Math.PI*2, end*Math.PI*2) start = end; //产生随机颜色 ctx.fillStyle = '#' + Math.floor(Math.random() * 0xffffff).toString(16); ctx.rect(350,5+(35*i),30,30); ctx.font="14px 黑体" ctx.fillText(item.title,400,25+(35*i)) ctx.strokeStyle = "gray" ctx.fill(); ctx.stroke(); i++; }) </script> </body> </html>
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