小程序中获取图片主色

let imageSrc = that.swiperList[index].picUrl;

that.setBackgroundColor(imageSrc, index);

setBackgroundColor(imageSrc,index) {
      console.log(imageSrc, 'imageSrc');
      const ctx = wx.createCanvasContext('myCanvas')
      const that = this
      wx.getImageInfo({
        src: imageSrc,
        success: function (res) {
          const poster = res.path
          ctx.drawImage(poster, 0, 0, 150, 100)
          ctx.draw(false, () => {
            wx.canvasToTempFilePath({
              x: 0,
              y: 0,
               150,
              height: 100,
              destWidth: 150,
              destHeight: 100,
              canvasId: "myCanvas",
              success(res) {
                console.log(imageSrc, '11111');
                let tempPath = res.tempFilePath
                // 这种方式获取canvas区域隐含的像素数据
                wx.canvasGetImageData({
                  canvasId: 'myCanvas',
                  x: 0,
                  y: 0,
                   150,
                  height: 100,
                  success(res) {
                    const imageData = res.data
                    // 分区块，可以拓展性的求主要色板，用来做palette
                    let resImageObj = getMainColor(imageData)
                    const { defaultRGB } = resImageObj
                    const { r, g, b } = defaultRGB
                    let resBackground = `rgb(${r}, ${g}, ${b})`; // 图片主色
                    //that.picMainColor.push({
                    //  sort: index,
                    //  background: resBackground
                    //});
                    //wx.setStorageSync("picMainColor", that.picMainColor);
                    //let item = that.picMainColor.find(e=>e.sort == 0);
                    //that.SET_BACKGROUND_COLOR(item ? item.background : 'rgb(80, 135, 203)');
                  },
                })
              },
              fail() {
                console.log('222222');
                throw new Error()
              }
            })
          })
        },
        fail(err) {
          console.log(err, '3333');
        }
      })
    },