<view class="container">
 <canvas style="box-sizing: border-box; width: 100%; height: 500px;border:1px solid black;position:absolute;top:0px;left:0px;" 
  canvas-id="line"
  disable-scroll="{{true}}"
  bindtouchstart="bindtouchstart"
  bindtouchmove="bindtouchmove"  
  bindtouchend="bindtouchend"
  bindtap="bindtap"
  bindlongpress="bindlongpress"
  ></canvas>
</view>
