熬夜总结了 “HTML5画布” 的知识点（共10条）

var img = new Image();img.src = 'logo.png';img.onload = function() { ctx.drawImage(img,0,0,40,40,0,0,80,80);}

var imageData = ctx.getImageData(x,y,w,h)
返回的是一维数组：[r1,g1,b1,a1,r2,g2,b2,a2...]

ctx.putImageData(imageData,x,y)
把imageData放在(x,y)处

ctx.putImageData(imageData, x, y, dirtyX, dirtyY, dirtyW, dirtyH)
只显示（dirtyX,dirtyY）处的宽dirtyW,dirtyH的区域

context.arc(x,y,radius, starAngle,endAngle, anticlockwise)
圆心(x,y) 半径radius从starAngle到endAngleanticlockwise代表是否逆时针方向

context.quadraticCurveTo(qcpx,qcpy, qx,qy)

context.bezierCurveTo(cp1x,cp1y, cp2x, cp2y, x,y)

ctx.drawImage(canvas,x,y),该方法把canvas绘制在(x,y)处
ctx.drawImage(canvas,x,y, w,h),该方法把canvas绘制在(x,y)处，并缩放为宽w,高h
ctx.drawImage(canvas, sx, sy, sw, sh, dx, dy, dw, dh)，该方法把canvas中（sx, sy）处的宽sw,高sh的区域，绘制到(dx,dy)处，并缩放为宽dw, 高dh

<style>#canva { border: 1px solid red;}</style><div><canvas id="canva" width="200" height="200"></canvas>// 绘制宽高200的canvas</div>

var canvas = document.getElementById("canvas")
可以使用通过标签名称来获取对象的getElementsByTagName方法

var context = canvas.getContext("2d")

context.font="98px 黑体"; // 文字样式context.fillStyle="red"; // 文字颜色context.textAlign = "center"; // 文字对齐方式// 绘制文字context.fillText("达达前端"，100, 123, 234);

drawImage(image, x, y) // 在画布上定位图像// 方法在画布上绘制图像、画布或视频。// 方法也能够绘制图像的某些部分，以及/或者增加或减少图像的尺寸。
drawImage(image, x, y, width, height)// 在画布上定位图像，并规定图像的宽度和高度
drawImage(image, sourceX, sourceY, sourceWidth, sourceHeight, destX, destY, destWidth, destHeight)// 剪切图像，并在画布上定位被剪切的部分

function Draw() { // 获取canvas对象 var canvas = document.getElementById("canvas");  // 获取2d上下文绘图对象 var context = canvas.getContext("2d");  // 使用Image()构造函数创建图像对象 var newImg = new Image();  // 指定图像的文件地址 newImg.src = "../images/dadaqianduan.jpg";  newImg.onload = function () { // 左上角开始绘制图像 context.drawImage(newImg, 0, 0);  context.drawImage(newImg, 250, 100, 150, 200);  context.drawImage(newImg, 90, 80, 100, 100, 0, 0, 120, 120); }}

// canvas 宽高200<canvas id="canvas" width="200" height="200"></canvas><style type="text/css">canvas { border: 2px solid #ccc;}</style><script> // 获取canvas var canvas = document.getElementById("canvas"); var context = canvas.getContext("2d"); // 设置字体 context.font="98px 黑体"; // 填充 context.fillStyle="#036"; // 文本水平位置 context.textAlign="center"; // 执行绘制 context.fillText("达达前端",100, 120, 200);</script>

// 绘制矩形边框strokeRect(x,y, width, height);

// 填充矩形区域fillRect(x,y,width,height);

// 绘制矩形function drawRect() { var canvas = document.getElementById("canvas"); var context = canvas.getContext("2d"); // 描边 context.strokeStyle = "#000"; // 线条宽度 context.lineWidth = 1; // 矩形边框 context.strokeRect(50,50, 150, 100); // 填充 context.fillStyle="#f90"; // 矩形 context.fillRect(50,50,150,100);}window.addEventListener("load",DrawRect,true);

// 擦除指定的矩形区域context.clearRect(x,y,width,height)

// 为画布设置边框canvas { border: 1px solid #ccc;}// 准备画布，默认是300*150// 设置画布的大小<canvas width="1200" height="800"></canvas>// 准备绘制工具<script>// 获取元素var myCanvas = document.querySelector('canvas');// 获取上下文，绘制工具箱var ctx = myCanvas.getContext('2d');// 移动画笔ctx.moveTo(100,100);// 绘制直线，轨迹ctx.lineTo(200,100);// 描边ctx.stroke()

// 规定元素的 id、宽度和高度<canvas id="myCanvas" width="200" height="100"></canvas>

var grid = 10;// 画多少条x轴方向的线，横向的条数，画布的高度var canvasHeight = myCanvas.heightvar canvasWidth = myCanvas.width// 画布宽高ctx.canvas.widthctx.canvas.height// 网格大小var gridSize = 10;var canvasHeight = ctx.canvas.height;var xLineTotal = canvasHeight / gridSize// 总线条var xLineTotal = Math.floor(canvasHeight / gridSize);for (var i=0; i<=xLineTotal; i++) { ctx.beginPath(); ctx.moveTo(0, i*gridSize-0.5); ctx.lineTo(canvasWidth, i*gridSize-0.5); ctx.strokeStyle='#eee'; ctx.stroke();}// 画多少条y轴方向的线var yLineTotal = canvasWidth / gridSizevar yLineTotal = Math.floor(canvasWidth / gridSize);for (var i=0; i <= yLineTotal; i++) { ctx.beginPath(); ctx.moveTo(i*gridSize-0.5,0); ctx.lineTo(i*gridSize-0.5,canvasHeight); ctx.strokeStyle='#eee'; ctx.stroke();}

// 绘制坐标系var space = 20;var arrowSize = 10;// 画布宽高var canvasWidth = ctx.canvas.width;var canvasHeight = ctx.canvas.height;// 坐标系var x0 = space;var y0 = canvasHeight - space;// 绘制x轴ctx.moveTo(x0,y0);ctx.lineTo(canvasWidth-space, y0);ctx.stroke();// 箭头ctx.lineTo(canvasWidth-space-arrowSize, y0 + arrowSize/2);ctx.lineTo(canvasWidth-space-arrowSize, y0 - arrowSize/2);ctx.lineTo(canvasWidth-space, y0);ctx.fill();ctx.stroke();// 绘制y轴ctx.beginPath();ctx.moveTo(x0, y0);ctx.lineTo(space, space);ctx.stroke();// 箭头ctx.lineTo(space+space-arrowSize/2, space + arrowSize);ctx.lineTo(space-space-arrowSize/2, space - arrowSize);ctx.lineTo(space, space);ctx.fill();ctx.stroke();// 绘制点var coordinate = { x: 146, y: 356}// 点尺寸var dottedSize = 6;ctx.moveTo(coordinate.x - dottedSize/2, coordinate.y - dottedSize/2);ctx.lineTo(coordinate.x + dottedSize/2, coordinate.y - dottedSize/2);ctx.lineTo(coordinate.x + dottedSize/2, coordinate.y + dottedSize/2);ctx.lineTo(coordinate.x - dottedSize/2, coordinate.y + dottedSize/2);ctx.closePath();ctx.fill();

// 圆形context.arc(100,100,30,0,Math.PI*2,true);

function DrawLine() { var canvas = document.getElementById("canvas"); var context = canvas.getContext("2d"); // 创建绘制过程 context.beginPath(); context.moveTo(50,50); context.lineTo(120,120); context.lineTo(120,60); context.closePath(); context.strokeStyle="#000"; // 执行绘制 context.stroke();}

// 圆形，曲线arc(x, y, radius, startAngle, endAngle, counterclockwise);

<style>// 画布背景颜色#canvas { background: #000;}</style>// 画布宽度400<canvas id="canvas" width="400" height="400"><script> var canvas = document.getElementById('canvas'); var context= canvas.getContext('2d') // 开始 context.beginPath(); // 绘制圆形 context.arc(100, 100, 50, 0, Math.PI*2, true); // 关闭 context.closePath(); // 填充颜色 context.fillStyle = 'rgb(255,255,255)'; context.fill();</script>

// 设置画布宽度var cx = canvas.width = 400;var cy = canvas.height = 400;

// 获取这个canvas的上下文对象var canvas = document.getElementById('canvas');var context = canvas.getContext('2d');

// 辅助线绘制弧线arcTo(x1, y1, x2, y2, radius)

// 绘制一条弧线function draw() { var canvas = document.getElementById('canvas'); var context = canvas.getContext('2d'); // 开始绘制 context.beginPath(); // 移动点 context.moveTo(80, 120); // 绘制线条 context.lineTo(150, 60); context.lineTo(180, 130); // 描边 context.strokeStyle="rgba(0,0,0,0.4)"; context.lineWidth=2; context.stroke(); context.beginPath(); context.moveTo(80,120); context.arcTo(150,60,180,130,50); context.strolkeStyle="rgba(255,135,0,1)"; context.stroke();}

quadraticCurveTo(cpX, cpY, x, y);// cpX, cpY描述了控制点的坐标，x, y描述了曲线的终点坐标

bezierCurveTo(cp1X, cp1Y, cp2X, cp2Y, x, y);// cp1X, cp1Y 表示第一个控制点的坐标 // cp2X, cp2Y 表示第二个控制点的坐标 // x, y表示曲线的终点坐标

function draw() { // 绘制曲线 var canvas = document..getElementById('canvas'); var context = canvas.getContext('2d'); // 开始绘制 context.beginPath(); // 移动 context.moveTo(100,180); // 连线 context.lineTo(110,80); context.moveTo(260,100); context.lineTo(300,200); // 描边 context.strokeStyle="rgba(0,0,0,0.4)"; // 设置宽度 context.lineWidth=3; context.stroke(); context.beginPath(); context.moveTo(100,180); // 绘制贝济埃曲线 context.bezierCurveTo(110,80,260,100,300,200); // 设置宽度 context.lineWidth = 3; context.strokeStyle="rgba(255,135,0,1)"; context.stroke();}

var canvas = document.getElementById('canvas');var context = canvas.getContext('2d');// 画布宽度200var canX = canvas.width = 200var canY = canvas.height = 200;// 开始绘制context.beginPath();// 四分之一圆context.arc(100, 100, 50, 0, Math.PI*0.5, false);context.strokeStyle="white"context.stroke();
context.beginPath();context.lineTo(200, 200);context.lineTo(200, 100);context.lineTo(100,50);context.strokeStyle = '#fff';context.stroke();

gradient.addColorStop(stop,color)

function draw() { var canvas = document.getElementById('canvas'); var context = canvas.getContext('2d'); // image实例 var newImg = new Image(); newImg.src='../images/dada.jpg' // 指定图像的文件地址 newImg.onload = function(){ // 绘图 context.drawImage(newImg, 0, 0); context.drawImage(newImg, 250,100, 150,200); context.drawImage(newImg, 90,80,100,100,0,0,120,120); }}

// 创建线性渐变createLinearGradient()方法
// 创建径向渐变createRadialGradient()方法

addColorStop(offset, color);

function draw() { var canvas = document.getElementById('canvas') var context = canvas.getContext('2d') // 创建渐变对象，线性渐变 var grd = context.createLinearGradient(0,0,300,0) // 设置渐变颜色 grd.addColorStop(0, '#xxx'); // 设置颜色 grd.addColorStop(1, '#xxx'); // 设置颜色 // 将填充样式设置为线性渐变对象 context.fillStyle = grd; context.fillRect(0,0,300,80);}

function draw() { var canvas = document.getElementById('canvas') var context = canvas.getContext('2d') // 径向渐变 var grd = context.createRadialGradient(50,50,0,100,100,90); // 设置渐变颜色以及方式 grd.addColorStop(0,'#xxx'); grd.addColorStop(1,'#xxx'); context.fillStyle = grd; context.beginPath(); // 圆形 context.arc(100,100,90,0,Math.PI*2,true); context.fill();}

butt// 定义了线段没有线帽round// 定义了线段的末端为一个半圆形的线帽square// 定义了线段的末端为一个矩形的线帽

lineJoin = [value];
round // 两条线段的外边缘应该和一个填充的弧结合bevel // 两条线段的外边缘应该和一个填充的三角形相交

createPattern(image, repetitionStyle)

function draw() { var canvas = document.getElementById('canvas') var context = canvas.getContext('2d') var img = new Image();  // 使用Image()构造函数创建图像对象 img.src='../images/xxx'  // 指定图像的文件地址 img.onload = function() { // 绘图模式 var ptrn = context.createPattern(img, 'repeat'); // 填充样式 context.fillStyle = ptrn; // 填充矩形 context.fillReat(0,0,500,200); }}

// 移动translate(dx,dy);// 绘制function draw() { var canvas = document.getElementById('canvas') var context = canvas.getContext('2d') // 设置移动偏移量 context.translate(200, 200); // 绘制一个圆形 ArcFace(context);}// 绘制一个圆形function ArcFace(context) { // 绘制一个圆形边框 context.beginPath(); // 绘制圆形 context.arc(0,0,90,0,Math.PI*2,true); // 线宽 context.lineWidth=5; // 描边 context.strokeStyle='#f90'; context.stroke(); // 绘制 context.beginPath(); context.moveTo(-30, -30); context.lineTo(-30, -20); context.moveTo(30, -30); context.lineTo(30, -20); context.moveTo(-20, 30); // 曲线 context.bezierCurveTo(-20, 44, 20, 30, 30, 20); context.strokeStyle='#000'; context.lineWidth=10; context.lineCap = 'round'; // 笑脸 context.stroke();}

scale(sx, sy);// sx为水平方向上的缩放因子，sy为垂直方向上的缩放因子

// 示例function draw() { var canvas = document.getElementById('canvas') var context = canvas.getContent('2d') // 移动 context.translate(200,200); // 缩放 context.scale(0.5,0.5); ArcFace(context);}

rotate(angle)

// 旋转例子function draw() { var canvas = document.getElementById('canvas'); var context = canvas.getContext('2d') context.translate(200,200); // 旋转 context.rotate(Math.PI/6); context.scale(0.5, 0.5) ArcFace(context)}

transform(m1x,m1y,m2x,m2y,dx,dy); // 移动，缩放，旋转
1. 移动translate (dx, dy)2. 缩放scale (sx,sy)3. 旋转rotate (A)

// 绘制文本示例function draw() { var canvas = document.getElementById('canvas') var context = canvas.getContext('2d') // 填充颜色 context.fillStyle = '#000'; context.font = 'bold 12px impact'; // 绘制文本 context..fillText('达达前端，魔王哪吒', 10, 10); context.strokeStyle = '#000'; context.font = 'bold italic 12px impact'; // 绘制文本 context.strokeText('jeskson', 10, 10);}

measureText(text)

function draw() { var canvas = document.getElementById('canvas'); var context = canvas.getContext('2d'); context.fillStyle='#000'; context.font='bold 10px impact'; // 测量文本的宽度 var tm = context.measureText(txt); context.fillText(txt,10,10); context.fillText(tm.width, tm.width+10, 50); context.strokeStyle = '#000'; context.font = 'bold italic 10px impact'; // 测量文本的宽度 tm = context.measureText(txt); context.strokeText(txt,10,10); context.strokeText(tm.width, tm.width+10, 100);}

<template> <view class="backgroundColor"> // 画布 <canvas class="isCan" canvas-id="dadaPoster" :style="{ width: cansWh.cansWidth + 'px', height: cansWh.cansHeight + 'px' }"></canvas> // 效果图 <image class="showImg" mode="aspectFit" v-if="tempImgShow" @longpress="longpress" :src="tempImg"></image> // 按钮 <view v-if="tempImgShow" class="fixedBox flex flex-direction"> <view class="boxTop text-white">长按图片发送给朋友</view> <view class="boxDown"> <button class="flexBtn" hover-class="btnHover" @click="closeCans">关闭</button> </view> </view> </view></template>data() { return { tempImgShow: false, tempImg: '', cansWh: { // 画布宽高 cansWidth: 800, cansHeight: 900, }, qrcode: { // 举例二维码 top: 0.85, left: 0.035, width: 0.23, qrHeight: null, }, ... productImg: { // 产品图 top: 0.1, left: 0.03, width: 1, height: 0.5, }, };},

// 绘制图drawImg(method,param){ return new Promise((resolve, reject)=>{ if(param.url.indexOf('http') === 0){ uni.downloadFile({ url: param.url, success(res) { param.url = res.tempFilePath method(param).then(res=>{ resolve(res) }).catch(err=>{ reject(err) }) }, fail(error) { console.log(error) } }) }else{ method(param).then(res=>{ resolve(res) }).catch(err=>{ reject(err) }) } })}

// 绘制圆形drawCircle(param) {var that = this,x = param.x,y = param.y,r = param.r,url = param.url;return new Promise((resolve, reject) => { x = Math.ceil(that.cansWh.cansWidth * x); y = Math.ceil(that.cansWh.cansHeight * y); r = r > 1 ? r : Math.ceil(that.cansWh.cansWidth * r); that.ctx.save(); var d = 2 * r; var cx = x + r; var cy = y + r; that.ctx.arc(cx, cy, r, 0, 2 * Math.PI); that.ctx.clip(); that.ctx.drawImage(url, x, y, d, d); that.ctx.restore(); that.ctx.draw(true, res=>{ resolve(); });});}

// 绘制图drawPic(item) {return new Promise((resolve, reject) => { let x, y, w, h, r; y = item.sTop <= 1 ? this.cansWh.cansHeight * item.sTop : item.sTop; w = item.sWidth <= 1 ? this.cansWh.cansWidth * item.sWidth : item.sWidth; h = item.sHeight <= 1 ? this.cansWh.cansHeight * item.sHeight : item.sHeight; if (item.sLeft == 'center') { x = item.sWidth <= 1 ? this.cansWh.cansWidth * (0.5 - item.sWidth / 2) : this.cansWh.cansWidth * 0.5 - item.sWidth / 2; } else { x = this.cansWh.cansWidth * item.sLeft; } if (item.r) { r = item.r; this.ctx.save(); if (w < 2 * r) r = w / 2; if (h < 2 * r) r = h / 2; this.ctx.beginPath(); this.ctx.moveTo(x + r, y); this.ctx.arcTo(x + w, y, x + w, y + h, r); this.ctx.arcTo(x + w, y + h, x, y + h, r); this.ctx.arcTo(x, y + h, x, y, r); this.ctx.arcTo(x, y, x + w, y, r); this.ctx.closePath(); this.ctx.clip(); this.ctx.drawImage(item.url, x, y, w, h); this.ctx.restore(); // 返回上一状态 } else { this.ctx.drawImage(item.url, x, y, w, h); } this.ctx.draw(true, res=>{ resolve(); });});}

// 保存saveCans() {let tempRatio = 1;uni.canvasToTempFilePath({x: 0,y: 0,width: this.cansWh.cansWidth * tempRatio,height: this.cansWh.cansHeight * tempRatio,destWidth: this.cansWh.cansWidth * tempRatio * 2,destHeight: this.cansWh.cansHeight * tempRatio * 2,canvasId: 'dadaPoster',success: (res) => { this.tempImg = res.tempFilePath; setTimeout(() => { this.tempImgShow = true; }, 100); uni.hideLoading();},fail: (res) => { console.log(res); uni.hideLoading();}},);}

// canvas标签的使用<canvas width="100" height="100"></canvas>// 获取canvasvar canvas = document.getElementById('target')if(canvas.getContext) { var ctx = canvas.getContext('2d');}else { alert('该浏览器版本过低，请更换')}
// 矩形fillRect( x , y , width , height) // 填充strokeRect( x , y , width , height) // 空心clearRect( x, y , width , height ) // 清除透明 var grd = ctx.createLinearGradient( x1 ,y1 ,x2 ,y2); //线性渐变var grd = ctx.createRadialGradient(x1 ,y1 ,r1 ,x2 ,y2 ,r2);//径向渐变

<body> <img src="img/bg.png" id="img1" style="display: block" width="1200" height="800" /> <img src="img/dada.png" id="img2" style="display: block" width="100" height="100" /> <img id="img3" /> <button onclick="draw()" id="btn">点击下载</button>  <script> function draw() { var img1 = document.getElementById("img1"), var img2 = document.getElementById("img2"), var img3 = document.getElementById("img3");  var img1.width = 1200; var img1.height = 800; var img2.width = 100; var img2.height = 100;  var canvas = document.createElement("canvas"), context = canvas.getContext("2d"); // 绘制宽度 canvas.width = img1.width; // 绘制高度 canvas.height = img1.height;  /** * context.drawImage(image,x,y,w,h) * var img=new Image(); img.src="url(...)"; * x:绘制图像的x坐标 * y:绘制图像的y坐标 * w:绘制图像的宽度 * h:绘制图像的高度 */  context.drawImage(img1, 0, 0, img1.width, img1.height); // 将 img2 加入画布 context.drawImage(img2, 100, 100, img2.width, img2.height); // 文字填充颜色 context.fillStyle = '#333'; // 文字字体 context.font = 'bold 45px 黑体'; // 设置文字 var name_text = '达达前端，魔王哪吒'; // 获取文字的宽度 var name_width = context.measureText(name_text).width; // 获取除去文本后的一半的宽度 var x = (canvas.width - name_width) / 2;  /** * context.font:设置字体样式 * context.textAlign:水平对齐方式 * context.textBaseline:垂直对齐方式 * context.measureText(text):计算字体长度(px) */ context.fillText(name_text, x, 450); context.fillStyle = '#333'; // 文字填充颜色 context.font = '25px bold 黑体'; var con_1 = 'dadaqianduan'; var con_2 = '达达'; /** * text:要绘制的文字 * x:文字起点的x坐标轴 * y:文字起点的y坐标轴 */ context.fillText(con_1, x, 400); var con_width_2 = context.measureText(con_2).width; context.fillText(con_2, canvas.width - x - con_width_2, 400); context.stroke(); // 将画布内容导出 var src = canvas.toDataURL(); img3.src = src; const a = document.createElement("a"); a.href = src; a.download = '自定义.png'; a.click(); } </script></body>

script引入文件
html2canvas(content, { //content是将要截图的div元素 scale: 2, logging: false, //在console中输出信息 useCORS: true //允许跨域 //proxy: string, //代理地址 //timeout: number //超时时间}).then(function(canvas) { let dataUrl = canvas.toDataURL() console.log(dataUrl)})

<script>var code_model = '<div id="qrcode" style="position: fixed; opacity: 0;"></div>', // 放置二维码 canvas_model = '<canvas width="1200" height="800" style="position: fixed;opacity:0;" id="myCanvas"></canvas>', // 放置canvas poster_model = '<div class="poster_container"><div class="poster"><img src="" alt="" class="poster_img"><p class="save_poster">长按保存图片至手机相册</p><p style="margin-top: 0.5rem" class="aaaa"></p></div></div>'; //poster_model为效果图$("body").append(code_model, canvas_model, poster_model);$.ajax({ url: "/photo/dada", data: { id: id }, success: function (res) { $.hideLoading(); if (res.e = "1111") { if (!res.data.is_buy) { location.href = res.data.jump_url; return false; } $(".poster").show();  var data_base = res.data.poster_info; new QRCode('qrcode', { text: data_base.url, width: 100, height: 100, colorDark: '#000000', colorLight: '#ffffff', correctLevel: QRCode.CorrectLevel.H }); var c = document.getElementById("myCanvas"),  cxt = c.getContext("2d"); var img = new Image(), imgUrl, personName = data_base.name; //跨域问题 img.crossOrigin = 'anonymous'; img.src = data_base.image; img.onload = function () { //图片加载为异步加载 cxt.drawImage(img, 0, 0); cxt.save(); cxt.beginPath(); cxt.arc(100, 200, 33, 0, 2 * Math.PI, true); cxt.strokeStyle = '#fff'; cxt.stroke(); cxt.clip(); var img_head = new Image(); img_head.crossOrigin = 'anonymous'; var avatar_height = data_base.avatar_height, avatar_width = data_base.avatar_width; img_head.src = data_base.avatar; img_head.onload = function () { cxt.drawImage(img_head, 0, 0, avatar_height, avatar_width, 54, 520, 80, 80); cxt.restore(); var img_code = new Image(); img_code.crossOrigin = 'anonymous'; cxt.lineWidth = "4"; cxt.strokeStyle = '#FFF'; cxt.rect(80, 80, 400, 400); cxt.stroke(); setTimeout(function () { img_code.src = $("#qrcode").find("img").attr("src"); img_code.onload = function () { cxt.drawImage(img_code, 0, 0, 100, 100, 450, 450, 80, 80); cxt.font = '21px 黑体'; cxt.fillStyle = "#000"; cxt.fillText(personName, 250, 520); imgUrl = c.toDataURL("image/png", 1); $(".poster_img").attr("src", imgUrl); $(".poster_container").show(); }; }, 0); }; }; } else { $.toast(res.m, "text"); } }});</script>

<view class="photoCan"> <canvas style="width: 375px; height: 612px; position:fixed; top:9999px; left:0; z-index:223;" canvas-id="mycanvas"></canvas> <image src="{{imagePath}}" mode="widthFix"></image></view>

const app = getApp()const setText = (context, fs, color, x, y, c) => { context.setFontSize(fs); context.setFillStyle(color); context.setTextAlign('left'); context.fillText(c, x, y); context.restore();};
Page({ data: { imagePath:'' }, onLoad(){ var that=this; wx.downloadFile({ url: 'https://xxxx.com/image', success: function (res) { that.setData({ path: res.tempFilePath }) } }) var ctx = wx.createCanvasContext('mycanvas'); var c_avatar = '../image/timg2.jpg'; var wechat = '../image/wechat.png'; var path = that.data.path; ctx.fillStyle = "#ffe200"; ctx.fillRect(0, 0, 375, 612); setText(ctx, 16, '#xxx', 90, 45, '达达); // 绘制画报背景图 ctx.drawImage(path, 30, 95, 400, 500); //头像 ctx.arc(45, 45, 25, 0, 2 * Math.PI) ctx.strokeStyle = "#fff"; ctx.clip(); ctx.drawImage(c_avatar, 20, 20, 50, 50); // 绘制生成画报 ctx.draw(true, setTimeout(function () { // 保存 wx.canvasToTempFilePath({ canvasId: 'mycanvas', success: function (res) { console.log(res) var tempFilePath = res.tempFilePath; that.setData({ imagePath: tempFilePath }); }, fail: function (res) { console.log(res); } }) }, 1000)); }})