IanG on Tap

In Windows 2000, Microsoft introduced a feature called Layered Windows. This introduced desktop composition features that had not been available in previous versions of windows, the most interesting of which was arguably the support for per-pixel transparency. With layered windows, any pixel in a window could be given its own transparency level. This is used for things like the transparent drop shadows you see on some windows, and Outlook uses it to fade new email notifications up and down.

Nice though this feature is, there have been a few limitations. For example, it didn't play nicely with video. If you were to move a semi-transparent window over a window that was playing video, it would all go a bit wrong where the two met. You wouldn't be able to see the video through any semi-transparent bits.

So one of the first things I tried with the Windows Vista beta that came out recently was see if they had fixed this - after all, we're supposed to have a new composition manager, so I wanted to know if that was present in the beta.

And it certainly seems to be:

You can see the translucent title bar of an explorer window of what, despite appearances, is not in fact a video of Alan Davies. (It's a Channel 9 video about the virtual earth project I think. Hard to be sure since I haven't yet got sound drivers working on my Vista machine...)

What may be slightly less obvious is that the translucent title bar is also blurring the video slightly, as it should be - the title bars of Aero Glass windows are not simply transparent. They are slightly blurry, and also have a texture that changes depending on where you put the thing on the screen.