<view style="width: 100%;height: 100%;position: relative;">
<canvas type="2d" class='canvas' id='scannerCanvas' canvas-id='scannerCanvas' disable-scroll="true" style="width: 100%; height: 100%;"/>
<cover-view class="flex-row-center-container" style="width: 100px;height: 50px;background-color: aquamarine;position: absolute;left: 0;bottom: 100px;display: flex;">
<cover-view style="width: 50%;text-align: center;" catchtap="amplification">放大</cover-view>
<cover-view style="width: 50%;text-align: center;" catchtap="narrow">缩小</cover-view>
</cover-view>
</view>
请具体描述问题出现的流程,并提供能复现问题的简单代码片段(https://developers.weixin.qq.com/miniprogram/dev/devtools/minicode.html)。