share/白板/index.html

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2022-07-15 09:25:31 +00:00
<canvas id=v><script>d=document,d.body.style.margin=0,P="onpointer",c=v.getContext`2d`,v.width=innerWidth,v.height=innerHeight,c.lineWidth=2,f=0,d[P+"down"]=e=>{f=e.pointerId+1;e.preventDefault();c.beginPath();c.moveTo(e.x,e.y)};d[P+"move"]=e=>{f==e.pointerId+1&&c.lineTo(e.x,e.y);c.stroke()},d[P+"up"]=_=>f=0</script></canvas>