小程序 ios真机用canvas画布绘制图片不显示，在开发者工具里显示正常，安卓端真机也显示正常

<camera mode="normal" device-position="{{cardPosition}}" flash="off" style="height:{{ cameraHeight-60 }}px">     <cover-view class="controls" style="width: 100%;height: 100%;">       <!-- 头像面 -->       <cover-image wx:if="{{cardType == 1}}" class="icon-w569-h828" src="/images/icon/take_idcard_a.png" />       <!-- 国徽面 -->       <cover-image wx:elif="{{cardType == 2}}" class="icon-w569-h828" src="/images/icon/take_idcard_b.png" />       <!-- 免冠照 -->       <cover-image wx:else class="icon-w569-h828" src="https://img-blog.csdnimg.cn/20210126144317636.png" />     </cover-view>   </camera> Component({ properties: {     cardType: String,   },   observers:{     'cardType':function(e){       const that = this;       if(e == 1 || e == 2){         that.setData({           cardPosition:'back'         })       }else{         that.setData({           cardPosition:'front'         })       }     }   },   data: {     cameraHeight: wx.getSystemInfoSync().windowHeight,     cameraWidth: wx.getSystemInfoSync().windowWidth,     hide: true,     cardPosition:'back',     myCanvas1_canvas: '',     myCanvas1_ctx: '',   }, ...... });

请求地址 https://api.weixin.qq.com/cgi-bin/changeopenid/?access_token= 返回数据 [图片]