微信小程序绘制图片发送朋友圈

 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,
      suess: 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,
      suess: 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,
      suess: 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({
      suess: 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',
              suess: 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);
        });
      },
    })
  },