背景图片自适应

<view class="videoBox">
  <view class="videoBox-text">
    <image src="https://xcx.hy720.com/wtt/videobtn.png"></image>
    <text>美食视频</text>
    <view>更多 ></view>
  </view>
  <scroll-view class="image-group" scroll-x="true">
    <view class="dingwei">
      <image class="aa"></image>   <!--背景图片关键代码-->
      <view class="volume">
        <image src="https://xcx.hy720.com/wtt/wzbtn.png" class="tubiao"></image>
        <text>6.8k</text>
      </view>
      <text class="dingwei-title">最走心的同学</text>
    </view>

    <view class="dingwei">
      <image class="aa" ></image> <!--背景图片关键代码-->
      <view class="volume">
        <image src="https://xcx.hy720.com/wtt/wzbtn.png" class="tubiao"></image>
        <text>6.8k</text>
      </view>
      <text class="dingwei-title">最走心的同学</text>
    </view>

    <view class="dingwei">
      <image class="aa" ></image> <!--背景图片关键代码-->
      <view class="volume">
        <image src="https://xcx.hy720.com/wtt/wzbtn.png" class="tubiao"></image>
        <text>6.8k</text>
      </view>
      <text class="dingwei-title">最走心的同学</text>
    </view>   
  </scroll-view>
</view>

page{background-color: #efefef;}
.image-group {
  display: flex;
  white-space: nowrap;
  margin-top: 30rpx;
  border-radius: 15rpx; 
}
.dingwei  {
  width: 240rpx;
  height: 320rpx;
  position: relative;
  display: inline-block;
  margin-right: 20rpx;
}
.aa{
  /* width: 100%;  
  height: 100%; */
  width: 240rpx;
  height: 320rpx;
  margin-right: 20rpx;
  border-radius: 10rpx;
/*背景图片关键代码*/
background: url(https://xcx.hyw.cc/mp/attachment/images/7/2019/08/pCFfAPqi5ii9H9EFe8fEHFHIFEia2c.jpg) no-repeat;
background-size: cover;
background-position: center center;
/*背景图片关键代码*/
}
.volume{display: flex;flex-wrap: wrap;width: 100rpx;height: 35rpx;border-radius: 20rpx;  background-color: rgba(3, 3, 3, 0.4);color: #fff;font-size: 24rpx;position: absolute;z-index: 9999; left: 135rpx; top: 10rpx;}
.volume .tubiao{width: 20rpx;height: 20rpx; margin-left: 10rpx;margin-top: 8rpx;margin-right: 3rpx;}
.volume text{width: 30rpx;height: 35rpx;line-height: 35rpx;}
.dingwei-title{width: 100%;top:270rpx;left: 10rpx; display: block;position: absolute;z-index: 9999;color: #fff;font-size: 24rpx;}
.videoBox{width: 94%;background-color: #fff;margin: 15rpx auto;border-radius: 20rpx;padding: 20rpx;}
.videoBox-text{display: flex;flex-wrap: wrap;padding-top: 10rpx; padding-left: 10rpx;}
.videoBox-text image{width: 50rpx;height: 50rpx;}
.videoBox-text text{width: 550rpx;height: 50rpx;line-height: 50rpx;padding-left: 10rpx;}
.videoBox-text view{width: 90rpx; height: 35rpx;line-height: 35rpx; background-color: #ffdc1c;border-radius: 20rpx;font-size: 20rpx;text-align: center;margin-top: 5rpx;}