"Full screen" mode existed before Lion (10.7), but prior to 10.6 the API did not exist. There are actually three ways to do full-screen in OS X:
1) Use Core Graphics to capture the display,
2) Manipulate window properties to get the result you want, or
3) Send the toggleFullscreen message to a window (10.6+ only).
Let's ignore option #1. It's primarily useful when you need to change the screen resolution without affecting other applications.
You say that the feature was deleted from Quicktime, but that's not what happened. Quicktime 7 and Quicktime X have different code bases. Quicktime 7's fullscreen functionality predate the current fullscreen API, and so there's a chunk of code in the Quicktime 7 player itself to futz around with window levels, types, desktop modes, and animate the whole thing. The Quicktime X application uses a different framework for video AND a different framework for the GUI, I doubt that you could bring much code from Quicktime 7 to Quicktime X.
Quicktime 7 used the old Quicktime library with Carbon. (So the API it was using to go fullscreen is even deprecated!)
Quicktime X uses the new Quicktime framework with Cocoa.
I myself have implemented the "nice" fullscreen technique, it requires some extra code but allows you to decide whether to allow other applications above yours.
I don't care if the feature broke because QT 7 and QT X have completely different code bases or because they removed the correctly functioning code. Either way it's broken and it's really fucking annoying.
1) Use Core Graphics to capture the display,
2) Manipulate window properties to get the result you want, or
3) Send the toggleFullscreen message to a window (10.6+ only).
Let's ignore option #1. It's primarily useful when you need to change the screen resolution without affecting other applications.
You say that the feature was deleted from Quicktime, but that's not what happened. Quicktime 7 and Quicktime X have different code bases. Quicktime 7's fullscreen functionality predate the current fullscreen API, and so there's a chunk of code in the Quicktime 7 player itself to futz around with window levels, types, desktop modes, and animate the whole thing. The Quicktime X application uses a different framework for video AND a different framework for the GUI, I doubt that you could bring much code from Quicktime 7 to Quicktime X.
Quicktime 7 used the old Quicktime library with Carbon. (So the API it was using to go fullscreen is even deprecated!)
Quicktime X uses the new Quicktime framework with Cocoa.
I myself have implemented the "nice" fullscreen technique, it requires some extra code but allows you to decide whether to allow other applications above yours.