小程序canvas签字功能

WXML

  <view class="qianzi">
    <view class="paper">
      <canvas class="handWriting" disable-scroll="true" bindtouchstart="touchstart1" bindtouchmove="touchmove1"
        canvas-id="handWriting1">
      </canvas>
    </view>
    <view class="signBtn">
      <button class="btn1" size=""  bindtap="sign1ok">完成签字</button>
      <button class="btn2" size="" bindtap="reSign1">清除签名</button>
    </view>
  </view>

<view class="image" hidden="{{src?false:true}}">
   <image src="{{src}}"></image>
</view>

JS

data: {

    optionsTaskid: '', //接收到的任务id

    orderKey: '',

    context1: null,

    hasDraw: false, //默认没有画

    src: null,

  },

  
touchstart1: function (e) {
    var context1 = this.data.context1;
    context1.moveTo(e.touches[0].x, e.touches[0].y);
    this.setData({
      context1: context1,
      hasDraw: true, //要签字了
    });
  },
  touchmove1: function (e) {
    var x = e.touches[0].x;
    var y = e.touches[0].y;
    var context1 = this.data.context1;
    context1.setLineWidth(3);
    context1.lineTo(x, y);
    context1.stroke();
    context1.setLineCap('round');
    context1.draw(true);
    context1.moveTo(x, y);
  },
  reSign1: function () { //重新画
    var that = this;
    var context1 = that.data.context1;
    context1.draw(); //清空画布
    that.setData({
      hasDraw: false, //没有画
      src: null
    });
  },

  sign1ok: function () {

    var that = this;

    if (!that.data.hasDraw) {

      return app.Tips({

        title: "您还未签名"

      })

    };

  

      var context1 = that.data.context1;

      context1.draw(true, wx.canvasToTempFilePath({

        canvasId: 'handWriting1',

        success(res) {

          console.log("res:", res)

          console.log(res.tempFilePath) //得到了图片下面自己写上传吧

          let Url = getApp().globalData.url,

            header = HEADER;

          console.log("Url:", Url)

          if (getApp().globalData.token) header[TOKENNAME] = 'Bearer ' + getApp().globalData.token;

          wx.uploadFile({

            url: Url + "/api/task/upload/contract",

            filePath: res.tempFilePath,

            name: "file",

            formData: {

              file: "image",

              key: that.data.orderKey

            },

            header: {

              "Content-Type": "multipart/form-data",

              [TOKENNAME]: 'Bearer ' + getApp().globalData.token

            },

            success: function (result) {

              console.log(result)

              var data = JSON.parse(result.data)

              if (data.status == 200) {

                app.Tips({

                  title: data.msg

                });

                setTimeout(function () {

                  wx.redirectTo({

                    url: '/pages/shouerlige/taskOrder_pay/index?key=' + that.data.orderKey + "&taskid=" + that.data.optionsTaskid,

                  })

                }, 1200)

              }else{

                 return app.Tips({title:data.msg})

              }

            },

            fail:function(err){

            }

          })

        }

      }))

  },