Mac OS X 10.7 Will Get Overlay Scrollbars and Full-Screen Mode For Apps

As you may know, this Thursday Apple has released a developer preview of Mac OS X Lion and recently we took a sneak peek at its new features. However, the new version of iOS also includes some architectural changes, and we'll talk about it in this post.

Application Persistence

Mac OS X Lion relaunches all the applications that were unclosed when the used decided to Shut Down or Log Out. Moreover, the location and size of apps' window, contents and selections will be also automatically restored.

Multitasking in new Mac OS X now works similar to the one in iOS. Every application behind the scenes may be terminated, if the user doesn't use it and has no currently open windows. However, it may be instantly relaunched if user will access it again.

Some applications may still be manually quitted, but Apple told developers that it is no longer necessary.

Full-Screen Mode for Applications

New NSWindowDelegate protocol and NSApplication and NSWindow classes add full-screen mode support for applications. By default it is off, but it can be turned on with a method call. In that case an app will get an extra "Enter Full Screen" menu item to the "View" menu if it exists or to the "Window" menu.

NSWindow class includes notifications about entering or exiting full-screen mode, window style mask and provides programming interfaces that allow to implement custom animations for entering and exiting that mode.

The NSWindowDelegate protocol gives a window control on the content size and provides with a custom set of presentation options that may be applied when the window becomes primary and full-screen.

Automatic Document Versioning and Saving

New feature in all document-based Cocoa applications now automatically saves every opened document and users are no longer required to be concerned about losing changes and constant saving their documents. Due to the mechanism that writes document data to disk user always sees the data that has been already saved on disk.

Automatic saving feature also allows to browse document version history. It may be accessed via "Browse All Versions" option in the pull-down menu at the right end of the menu bar.

Mac OS X File Coordination

File coordination makes it possible for applications to access directories and files even when these directories and files are being accessed by other processes. With overlapping writes and reads system becomes able to prevent possible inconsistencies.

Overlay Scrollbars

New overlay scrollbars are hidden in the case of normal use. They appear only when the user starts to scroll on the top of the window's content, and stay there for a small amount of time to allow scrollbar dragging.

If there is an external pointing device and it doesn't support scrolling, the scrollbars appears to look and act the same way as in previous versions of Mac OS X. Legacy scrollbars may be also enabled in System Preferences.

If there is no external pointing device, the scrollbar behavior is controlled by the trackpad settings.

Other features

Besides above-mentioned features Mac OS X Lion has new process architecture for Safari, which makes the browser even more stable, responsive and secure, though it does not support WebKit plug-ins no more.

The files and folders in /lost+found and $HOME/LIbrary became hidden.

Stay with us as we post more details about upcoming Mac OS X Lion in the next few hours.