IOS 画板，手势，涂鸦，能选择图片并对图片进行涂鸦，图片的选择时可以放大缩小旋转，涂鸦结束可以保存到相册-IOS of Sketchpad, gestures, graffiti, graffiti, select a picture and picture and picture selection can zoom rotate, graffiti end can be saved to the album