微信小程序涂鸦功能的实现

<view class="container">
 <!--画布区域-->
 <view class="canvas_area">
 <!--注意：同一页面中的 canvas-id 不可重复，如果使用一个已经出现过的 canvas-id，该 canvas 标签对应的画布将被隐藏并不再正常工作-->
 <canvas canvas-id="myCanvas" class="myCanvas"
 disable-scroll="false"
 bindtouchstart="touchStart"
 bindtouchmove="touchMove"
 bindtouchend="touchEnd">
 </canvas>
 </view>
 <!--画布工具区域-->
 <view class="canvas_tools">
 <view class="box box1" bindtap="penSelect" data-param="5"></view>
 <view class="box box2" bindtap="penSelect" data-param="15"></view>
 <view class="box box3" bindtap="colorSelect" data-param="#cc0033"></view>
 <view class="box box4" bindtap="colorSelect" data-param="#ff9900"></view>
 <view class="box box5" bindtap="clearCanvas"></view>
 </view>
</view>