It seems to me on Mac OS X it is possible to "zoom" (like a photocamera does) into a region of the screen.
It is handy for example to put at full monitor size a video which would otherwise be limited to be just into a small window (ie. embedded in a web page and not watchable standalone.), obviously losing some quality due to the "zoom".
Do you know of any tool or way to do the same thing on a Linux desktop (with Gnome as desktop manager if it is desktop manager dependent).