小程序设置透明背景色不生效

[xxwangkaimin]

trafficstars

<uqrcode ref="qrcode" canvas-id="qrcode" :value="userCode" size="245" :options="{
            backgroundPadding: 1,
            foregroundColor: '#fff',
            foregroundImageWidth: '40',
            foregroundImageHeight: '40',
            foregroundImageSrc: imageBaseUrl + '/logo.png',
            backgroundColor: 'rgba(0,0,0,0)'
          }" :start="false">
            <template v-slot:loading>
              <text style="color: green;">loading...</text>
            </template>
 </uqrcode>

显示效果：