//将canvas转换为图片保存到本地，然后将图片路径传给image图片的src

  createNewImg() {

    var that = this

    var unit = this.data.screenWidth / 375

    var context = wx.createCanvasContext(‘mycanvas’)

    var path = that.data.qtPaths

    context.drawImage(path, 0, 0, 343 * unit, 220 * unit)

    that.setMoney(context)

    that.setName(context)

    that.setQrcode(context)

    //绘制图片

    context.draw()

    context.save()

    //将生成好的图片保存到本地，需要延迟一会，绘制期间耗时

    setTimeout(() => {

      wx.canvasToTempFilePath({

        canvasId: ‘mycanvas’,

        success: function(res) {

          wx.hideLoading()

          that.setData({

            imagePath: res.tempFilePath

          })

        },

        fail: function(res) {

          console.log(res.errMsg)

        }

      })

    }, 2000)

  },