Astropad, an app for iOS and Mac, transforms your existing iPad into a professional graphics tablet without the need for additional hardware. Having been developed by Matt Ronge and Giovanni Donelli - both former Apple engineers - the app allows for the iPad to act as a extended trackpad as well as work with most third-party styluses.
Ronge and Donelli have named the underlying technology which distinguishes Astropad from other apps claiming to do a similar job LIQUID, which is itself the result of a year's worth of research and development. Having been created specifically to be used over Wi-Fi, it offers a 60fps response time between stylus and screen. In addition, it is accelerated by the Mac's GPU (meaning that computer stays very responsive) and is built with an ARM assembly code on iPad (meaning that the battery life is maintained). Furthermore, it claims to provide better image quality than the highest quality export setting from Adobe Photoshop.