Apple has filed an application to patent translucent windows that adjust in opacity as information is updated.

The patent – "graduated visual and manipulative translucency for windows" – is visible on the US Patent & Trademark Office Web site, dated May 13.

In abstract, the patent – news of which was first spotted by MacObserver – reads: "Methods and systems for providing graphical user interfaces are described. Overlaid, information-bearing windows whose contents remain unchanged for a predetermined period of time become translucent. The translucency can be graduated so that, over time, if the window's contents remain unchanged, the window becomes more translucent.

"In addition to visual translucency, windows according to the present invention also have a manipulative translucent quality. Upon reaching a certain level of visual translucency, user input in the region of the window is interpreted as an operation on the underlying objects rather than the contents of the overlaying window."

The patent appears designed to protect the translucent application windows supported by Mac OS X's Quartz imaging layer.

This is vaguely confirmed by the following note accompanying the patent: "The present invention relates generally to graphical user interfaces for computer systems".

Describing the patent as "relating to systems and methods for interfacing users with applications" the notes state the attempt is to "provide for greater flexibility in the operation of both applications and user interfaces".