编写的一个canvas工具类，CanvasUtils。目前包含九宫格图片绘制，环形绘制，线条绘制，文本绘制，进度条绘制。使用主要关注传参就好。
效果图
index.html
<!DOCTYPE html><html lang="en"><head><meta charset="UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>Document</title><style>body{background-color: black;}</style></head><body><canvas id="mycanvas"></canvas><canvas id="mycanvas1"></canvas><script type="module">import './index.js'</script></body></html>
index.js
import CanvasUtils from "./canvas.js";import {CircleObj } from "./canvas.js";const mycanvas = document.querySelector("#mycanvas");const mycanvas1 = document.querySelector("#mycanvas1");const canvasInstance = new CanvasUtils(mycanvas, 500, 100);const canvasInstance1 = new CanvasUtils(mycanvas1, 1000, 200);canvasInstance.drawSquaredImg("./img/3.png",10,10,10,10,(res) => {console.log(res.toDataURL("image/png"));},() => {});const circleObj1 = new CircleObj(100,100,50,0.65 * Math.PI,2.35 * Math.PI,5,"#1890FF");const circleObj2 = new CircleObj(100,100,80,0.65 * Math.PI,2.35 * Math.PI,5,"#CCCCCC");canvasInstance1.drawCircle(circleObj1);canvasInstance1.drawCircle(circleObj2);canvasInstance1.drawAnnularProgress(300,100,80,0.65 * Math.PI,2.35 * Math.PI,5,"#FFF","#0FF",0.3,[{font: "16px Verdana",text: "总体进度",colors: [{offset: "0",color: "#FFF",},{offset: "1",color: "#0FF",},],startX: 270,startY: 100,endX: 350,endY: 100,},{font: "16px Verdana",text: "30%",colors: [{offset: "0",color: "#FFFFFF",},{offset: "1",color: "#0FF",},],startX: 290,startY: 120,endX: 330,endY: 120,},]);canvasInstance1.drawProgress(500,80,680,80,10,"#CCC",[{offset: "0",color: "#FFF",},{offset: "1",color: "#0FF",},],0.6,[{font: "16px Verdana",text: "总体进度",colors: [{offset: "0",color: "#FFF",},{offset: "1",color: "#0FF",},],startX: 570,startY: 110,endX: 650,endY: 110,},{font: "16px Verdana",text: "60%",colors: [{offset: "0",color: "#FFFFFF",},{offset: "1",color: "#0FF",},],startX: 590,startY: 140,endX: 630,endY: 140,},]);export {};
canvas.js
/*** @param {Number} x 圆的中心的x坐标* @param {Number} y 圆的中心的y坐标* @param {Number} radius 圆的半径。* @param {Number} startAngle 起始角，以弧度计。（弧的圆形的三点钟位置是 0 度）。* @param {Number} endAngle 结束角，以弧度计。* @param {Number} lineWidth 粗细* @param {string} color 颜色*/export function CircleObj(x,y,radius,startAngle,endAngle,lineWidth,color) {this.x = x;this.y = y;this.radius = radius;this.startAngle = startAngle;this.endAngle = endAngle;this.lineWidth = lineWidth;this.color = color;}/*** @param {String} font* @param {String} text* @param {Number} startX* @param {Number} startY* @param {Number} endX* @param {Number} endY* @param {Array | String} colors*/function TextObj(font = "",text = "",startX = "0",startY = "0",colors = "#1890FF",endX = null,endY = null) {this.font = font;this.text = text;this.startX = startX;this.endX = endX;this.startY = startY;this.endY = endY;this.colors = colors;}class CanvasUtils {/*** @param {HTMLCanvasElement} cDOM* @param {Number} cWidth* @param {Number} cHeight*/constructor(cDOM, cWidth, cHeight) {cDOM.height = cHeight;cDOM.width = cWidth;this.DOM = cDOM;this.ctx = cDOM.getContext("2d");}// 清空画布clear() {this.ctx.clearRect(0, 0, this.DOM.width, this.DOM.height);}/*** 九宫格图片* @param {string} originUrl 图片原地址* @param {number} top 第一条切割线距离原图片顶部的距离* @param {number} bottom 第二条切割线距离原图片底部的距离* @param {number} left 第三条切割线距离原图片左侧的距离* @param {number} right 第四条切割线距离原图片右侧的距离* @param {Function} successCb 成功回调函数，参数为dom* @param {Function} errorCb 失败回调函数，参数为error对象*/drawSquaredImg(originUrl,top = 0,bottom = 0,left = 0,right = 0,successCb = () => {},errorCb = () => {}) {const img = new Image();img.src = originUrl;img.onload = () => {const w = img.naturalWidth;const h = img.naturalHeight;const cw = this.DOM.width;const ch = this.DOM.height;const ctx = this.ctx;// 第一块;ctx.drawImage(img, 0, 0, left, top, 0, 0, left, top);// 第二块ctx.drawImage(img,left,0,w - right - left,top,left,0,cw - right - left,top);// 第三块ctx.drawImage(img, w - right, 0, right, top, cw - right, 0, right, top);// 第四块;ctx.drawImage(img,0,top,left,h - top - bottom,0,top,left,ch - bottom - top);// 第五块ctx.drawImage(img,left,top,w - right - left,h - top - bottom,left,top,cw - left - right,ch - top - bottom);// 第六块ctx.drawImage(img,w - right,top,right,h - top - bottom,cw - right,top,right,ch - top - bottom);// 第七块ctx.drawImage(img,0,h - bottom,left,bottom,0,ch - bottom,left,bottom);// 第八块ctx.drawImage(img,left,h - bottom,w - right - left,bottom,left,ch - bottom,cw - left - right,bottom);// 第九块ctx.drawImage(img,w - right,h - bottom,right,bottom,cw - right,ch - bottom,right,bottom);successCb(this.DOM);};img.onerror = (err) => errorCb(err);}/*** @param {CircleObj} circleObj*/drawCircle(circleObj) {const ctx = this.ctx;ctx.beginPath();ctx.arc(circleObj.x,circleObj.y,circleObj.radius,circleObj.startAngle,circleObj.endAngle);//设定曲线粗细度ctx.lineWidth = circleObj.lineWidth;//给曲线着色ctx.strokeStyle = circleObj.color;//连接处样式ctx.lineCap = "round";//给环着色ctx.stroke();ctx.closePath();}createLinearGrad(startX, startY, endX, endY, colors) {const gradient = this.ctx.createLinearGradient(startX, startY, endX, endY);colors.forEach((grd) => {gradient.addColorStop(grd.offset, grd.color);});return gradient;}/*** @param {TextObj} textObj*/drawText(textObj) {const ctx = this.ctx;ctx.font = textObj.font;if (typeof textObj.colors === "object") {ctx.fillStyle = this.createLinearGrad(textObj.startX,textObj.startY,textObj.endX,textObj.endY,textObj.colors);ctx.fillText(textObj.text, textObj.startX, textObj.startY);} else {ctx.fillStyle = textObj.colors;ctx.fillText(textObj.text, textObj.startX, textObj.startY);}}/*** @param {Number} x* @param {Number} y* @param {Number} r* @param {Number} startAngle* @param {Number} endAngle* @param {Number} lineWidth* @param {String } bgColor* @param {String } color* @param {Number} percentage* @param {Array<TextObj>} textConfig*/drawAnnularProgress(x,y,r,startAngle,endAngle,lineWidth,bgColor,color,percentage,textConfig = []) {// 绘制底图const bgCircle = new CircleObj(x,y,r,startAngle,endAngle,lineWidth,bgColor);this.drawCircle(bgCircle);// 绘制进度const perEnd = percentage * (endAngle - startAngle) + startAngle;const perCircle = new CircleObj(x,y,r,startAngle,perEnd,lineWidth,color);this.drawCircle(perCircle);// 绘制文本textConfig.forEach((text) => {this.drawText(text);});}/*** 画线* @param {Number} startX * @param {Number} startY * @param {Number} endX * @param {Number} endY * @param {Number} lineWidth * @param {Array | String} colors */drawLine(startX, startY, endX, endY, lineWidth, colors) {const ctx = this.ctx;ctx.beginPath();ctx.lineCap = "round";if (typeof colors === "string") {ctx.strokeStyle = colors;} else {ctx.strokeStyle = this.createLinearGrad(startX,startY,endX,endY,colors);}ctx.moveTo(startX, startY);ctx.lineTo(endX, endY);ctx.lineWidth = lineWidth;ctx.stroke();}/*** @param {Number} startX 背景起始x* @param {Number} startY 背景起始y* @param {Number} endX 背景结束x* @param {Number} endY 背景结束y* @param {Number} lineWidth 进度条粗细* @param {String | Array} bgColors 背景颜色* @param {String | Array} colors 进度颜色* @param {Number} percentage 进度* @param {Array} textConfig 文本配置*/drawProgress(startX,startY,endX,endY,lineWidth,bgColors,colors,percentage,textConfig = []) {// 绘制底部this.drawLine(startX, startY, endX, endY, lineWidth, bgColors);const perEndY = percentage * (endY - startY) + startY;const perEndX = percentage * (endX - startX) + startX;// 绘制进度this.drawLine(startX, startY, perEndX, perEndY, lineWidth, colors);// 绘制文本textConfig.forEach((text) => {this.drawText(text);});}}export default CanvasUtils;
