canvas/unpackage/dist/dev/mp-weixin/pages/index/index.wxml

<view class="data-v-1cf27b2a"><block wx:if="{{r0}}"><canvas class="data-v-1cf27b2a" bindtouchstart="{{a}}" bindtouchmove="{{b}}" bindtouchend="{{c}}" style="{{'width:' + d + ';' + ('height:' + e) + ';' + ('transform:' + f)}}" canvas-id="canvas" id="canvas"></canvas></block><image class="data-v-1cf27b2a" src="https://assets.sx25.troyrc.com/sx25/images/events/XBDT.jpg"></image><button class="data-v-1cf27b2a" bindtap="{{g}}">点击绘制圆形</button></view>