预期是想在canvas上做一个关闭的小叉，在右上角；

当我用第一种方式写的时候，所有ios出现了定位偏差的问题，安卓没有

一、wxml：

<view class='canvasCon' style="width:670rpx;height:850rpx" catchtap='closecanvas2'>

    <canvas canvas-id="myCanvas" class="canvas">

        <cover-view bindtap='closecanvas' class="canvasView">

            <cover-image class="canvasImg" src="https://cms.hylpz.cn/data/images/common/close.png"/>

        </cover-view>

    </canvas>

    <view class="canvasButton" catchtap='canvasToTempFilePath'>保存图片</view>

</view>

..

wxss：

.page .canvasBox .canvasCon{

    top: 50%;

    left: 50%;

    margin-left: -335rpx;

    margin-top: -500rpx;

    position: relative;

    border-radius: 20rpx;

    z-index: 999;

    background: #fff;

}

.page .canvasBox .canvasCon .canvasView{

    display: block;

    width: 44rpx;

    height: 44rpx;

    position: absolute;

    top:20rpx;

    right: 20rpx;

    z-index: 1000;

}

安卓展示：

ios展示：

于是我想个办法解决这个问题，就是把 <cover-view>拿出来，不放在canvas标签里；

二、wxml：

<view class='canvasCon' style="width:670rpx;height:850rpx" catchtap='closecanvas2'>

    <canvas canvas-id="myCanvas" class="canvas">

    </canvas>

    <view class="canvasButton" catchtap='canvasToTempFilePath'>保存图片</view>

    <cover-view bindtap='closecanva