Apple Explores Using An iPhone, iPad To Power a Laptop (appleinsider.com)
According to the U.S. Patent and Trademark Office, Apple has filed a patent for an "Electronic accessory device." It describes a "thin" accessory that contains traditional laptop hardware like a large display, physical keyboard, GPU, ports and more -- all of which is powered by an iPhone or iPad. The device powering the hardware would fit into a slot built into the accessory. AppleInsider reports: While the accessory can take many forms, the document for the most part remains limited in scope to housings that mimic laptop form factors. In some embodiments, for example, the accessory includes a port shaped to accommodate a host iPhone or iPad. Located in the base portion, this slot might also incorporate a communications interface and a means of power transfer, perhaps Lightning or a Smart Connector. Alternatively, a host device might transfer data and commands to the accessory via Wi-Fi, Bluetooth or other wireless protocol. Onboard memory modules would further extend an iOS device's capabilities. Though the document fails to delve into details, accessory memory would presumably allow an iPhone or iPad to write and read app data. In other cases, a secondary operating system or firmware might be installed to imitate a laptop environment or store laptop-ready versions of iOS apps. In addition to crunching numbers, a host device might also double as a touch input. For example, an iPhone positioned below the accessory's keyboard can serve as the unit's multitouch touchpad, complete with Force Touch input and haptic feedback. Coincidentally, the surface area of a 5.5-inch iPhone 7 Plus is very similar to that of the enlarged trackpad on Apple's new MacBook Pro models. Some embodiments also allow for the accessory to carry an internal GPU, helping a host device power the larger display or facilitate graphics rendering not possible on iPhone or iPad alone. Since the accessory is technically powered by iOS, its built-in display is touch-capable, an oft-requested feature for Mac. Alternatively, certain embodiments have an iPad serving as the accessory's screen, with keyboard, memory, GPU and other operating guts located in the attached base portion. This latter design resembles a beefed up version of Apple's Smart Case for iPad.
1) iOS doesn't support color profiles. While Apple does calibrate the screens, there's no way for users to add their own color profile. No way to add a printer profile. No way to switch to AdobeRGB if/when the iOS devices get OLED screens and you want to edit the full color information captured by your DSLR.
2) iOS relies on a fixed resolution. That's why when they increased resolution on the iPhone and iPad, they had to do it by doubling the resolution. It was the only way to insure that apps written with the old resolution would still display properly. Basically they have the same problem with old apps on high-PPI screens as Windows does. (Ironically, Android does support arbitrary scaling based on PPI. So Android is more more like MacOS and OS X in this respect than iOS is.)
An iOS-based laptop may suit the needs of the casual user (browser, facebook, office apps). But it's totally unsuitable for graphics/photo/video professionals.