这是一个iOS涂鸦Demo，Swift和OC混合开发，功能画笔宽度设置、颜色设置、橡皮擦、截图、清除画板、撤销、保存还原 #This is a mixed development of IOS doodling demo, swift and OC, with functions of fishdoodling demo, brush width setting, color setting, eraser, screenshot, clear palette, undo, save and restore