Revamped new iTunes 11 user interface hints at future of OS X
New iOS conventions in iTunes
In addition to its touch-friendly navigation menubar and its "iOS Folders" style representation of details within a collection (such as an album or movie), iTunes also borrows two other iOS ideas: Spotlight-style smart search (similar to Safari's integrated search, presenting a live cascade of results) and two timeline based features: "up next" (showing an editable list of songs about to play) and "history" (songs that have played), two new popup menus similar to Notification Center (they even use the same icon).
It's reasonable to think that Apple is likely to recycle some of these evolutions of the interface in OS X, in particular the Finder which shares iTunes' sidebar-orientation as well as its somewhat confusing mix of local and cloud based content.
A Finder focused on search and clean presentation could similarly provide an alternative, "iTunes 11 style" view of the file system that focused on your content, rather than the structure of the file system or the actual location of your documents.
It could also seamlessly integrate iCloud documents with local files, showing each iCloud-registered app library of your documents. This would clarify iCloud's app-centric document storage, a feature that is currently confusing to some users.
Rethinking iTunes' titlebar
Apple's presentation of iTunes 11 also highlighted several other changes to the user interface. Once again, there's now no title bar dedicated to labeling the window as being "iTunes." This was dropped in iTunes 10 two years ago, but reverted along with several other concepts.
This time around, the change is more likely to stick. Since iTunes 10, Apple has also launched the Mac App Store app without a title bar. In a sense, iTunes now has an extended titlebar played by its "virtual LCD panel" display of what's playing. This is what currently shows up in Full Screen mode, and there's no real reason for iTunes to dedicate an entire line of the tool bar just to declare itself.
The title bar still makes sense for document-centric apps (including the Finder, where it plays a navigational role), but for other apps that don't need it, the title bar convention is increasingly likely to be dropped, just as window scroll bars with fixed gutters disappeared in OS X 10.7 Lion.
Rethinking iTunes' window controls
Another element of the iTunes menu bar now in flux: the new Minimize icon next to the Full Screen control. These are slightly odd, because they seeming replicate portions of the standard Close/Dock/Zoom buttons.
Historically, Apple originally presented a Close box and Zoom button (that optimized the size of the window) on the Macintosh. Microsoft's Windows, on the other hand, presented Close, Minimize and Maximize buttons.
At the launch of OS X, Apple added a Dock button that effectively worked similar to Windows' minimize button for shrinking the window out of view (and replacing the "Windowshade" button that reduced a window down to its title bar, but left that visible and in place on the screen). Apple's Zoom never quite duplicated the "take full screen" intention of Windows' Maximize button, a convention mimicking the full screen text modes of MS-DOS.
After releasing the window-free iPad, Apple introduced its own Full Screen mode for OS X, but rather than simply maximizing the window, Apple hid the menu bar and removed the window controls entirely, putting a bit more "max" into its maximizing of the window's content.
Thus, Apple now has three old window controls, and two new ones in iTunes 11, with some overlap (the green zoom button in iTunes 11 is effectively the same as the new Mini Player button). Additionally, in the iTunes 11 mini player, Apple presents a new type of "standard" controls: a grey "X" to close and an grey "O" to zoom (resume normal size).
This indicates Apple may finally get rid of the bright "gumdrop" Aqua window buttons at some point in the future of OS X (they currently have no analog in the windowless iOS), and replace them with "iTunes 11 mini player" style close and open controls that match the new Full Screen buttons that appeared in OS X 10.7 Lion: subtle, simple, grey icons. A variety of monochrome X icons are already used throughout OS X in place of the old Aqua red dot.
iTunes 11 isn't the only app hinting at Apple's future user interface directions as will be expanded upon later. But it does serve as one of the company's most popular places to experiment with user interface ideas. iTunes 11 will likely ship next week, although Apple has only stated that it will launch by the end of October.