这种生成图片的效果是很常见的，实现起来也不难，跟原生js的差不多。需要注意的就是canvas标签上不要加太多的css，后果呢就是导致canvas不显示，还有呢就是canvas组件的优先级是最高的，所以会覆盖掉下面的所有内容，解决方法呢就是使用：
onLoad: function(options) { var grade = options.grade; this.setData({ grade: grade }) this.loading(); }, //检测，网络图片是否下载完成 loading: function() { var _this = this; wx.showLoading({ title: '生成中...', }) timer = setInterval(function() { var avatarUrl = _this.data.avatarUrl; var qc_code = _this.data.qc_code; if (avatarUrl != null && qc_code != null) { wx.hideLoading(); clearInterval(timer); _this.draw(); } }, 500) }, //保存到相册 saveImage: function() { var imagePath = this.data.imagePath; wx.saveImageToPhotosAlbum({ filePath: imagePath, success: function(res) { console.log(res) }, fail: function(res) { console.log(res) } }) }, //将用户头像下载为本地路径 downImage: function(img) { var _this = this; wx.getImageInfo({ src: img, success: function(res) { console.log(res.path) _this.setData({ avatarUrl: res.path }) } }) }, //下载小程序二维码 downImage2: function (img) { var _this = this; wx.getImageInfo({ src: img, success: function (res) { console.log(res.path) _this.setData({ qc_code: res.path }) } }) }, //生成canvas图片 draw: function() { var _this = this; var context = wx.createCanvasContext('firstCanvas'); var userInfo = wx.getStorageSync('userInfo'); var award ; // 性别 var gender = userInfo.gender; //背景图片 var bg = '../../images/icon-cj.png'; //得分 var grade = 0 ^ _this.data.grade; var width; var height; if (grade >= 0 && grade <= 30) { if(gender == 2){ award = '../../images/zbzxlp.png'; }else{ award = '../../images/zbzxlg.png'; } }else if(grade >= 31 && grade <= 60){ if (gender == 2) { award = '../../images/zklp.png'; } else { award = '../../images/zklg.png'; } } else if (grade >= 61 && grade <= 80){ if (gender == 2) { award = '../../images/zmlp.png'; } else { award = '../../images/whlg.png'; } }else{ if (gender == 2) { award = '../../images/wmlp.png'; } else { award = '../../images/wmlg.png'; } } if (award == '../../images/zbzxlp.png' || award == '../../images/zbzxlg.png'){ width = 156; height= 25; }else{ width = 103; height = 25; } //二维码 var qc_code = _this.data.qc_code; // 用户头像 var avatarUrl = _this.data.avatarUrl; //获取设备的基本信息 wx.getSystemInfo({ success: function(res) { //绘制背景图 context.drawImage(bg, 0, 0, 350, 468); // 绘制奖项 context.drawImage(award,180 - (width / 2),212 - (height / 2),width,height); //绘制二维码 context.drawImage(qc_code, 175 - (92 / 2), 385 - (108 / 2), 92, 107); //绘制得分 context.setFontSize(28); //字体大小 context.fillStyle = '#4fc089'; context.setTextAlign('center') context.fillText(grade, 177, 48) // 绘制姓名 context.setFontSize(16); context.fillStyle = '#000000'; context.setTextAlign('center') context.fillText(userInfo.nickName, 167, 180); // 绘制头像 context.drawImage(avatarUrl, 72, 157, 33, 33); context.draw(false, function() { setTimeout(function() { wx.canvasToTempFilePath({ width: 350, height: 468, destWidth: 700, destHeight: 936, canvasId: 'firstCanvas', success: function(res) { var tempFilePath = res.tempFilePath; console.log("图片"+tempFilePath); _this.setData({ imagePath: tempFilePath, isCanvas: true }); _this.upload(tempFilePath); }, fail: function(res) { console.log(res); } }); }, 1000); }); }, }) }, 因为我的项目需要，我上面做个很多判断，那些东西不需要管，重点就是，绘制图片drawimage方法 和绘制文字的方法，我的绘制方法是让他们根据canvas上的一个坐标点居中绘制的，这个可以看一下。
