真的快被 Canvas 跟 Chrome 氣死ㄟ 
掰噗~
說
中肯!!
socket.io/main.js at master · socketio/socket.io
Canvas Free Draw
Canvas Advancement - How to draw a smooth curve? - D...
Realtime collaborative drawing with canvas and WebRT...查超久的筆壓實裝方法，不過我改用 pointer event 比較方便
PointerEvent.pressure - Web APIs | MDN 
How to implement a real eraser in my drawing app?橡皮擦（一樣在畫圖，只是顏色改成透明）
Realtime collaborative drawing with canvas and WebRT...查超久的筆壓實裝方法，不過我改用 pointer event 比較方便PointerEvent.pressure - Web APIs | MDN How to implement a real eraser in my drawing app?橡皮擦（一樣在畫圖，只是顏色改成透明）