|Development quick access|
[+] Release todos
This page is on development. See How to enable transparency for user side doc.
The basic concept and power of the Composite Extension is BackingStore (the maintenance of window data even when obscured or otherwise hidden). More precisely, access to the backing store for each window and the ability to dictate how those windows put together.
The basic command for this are XCompositeRedirectSubwindows. It will cause all the window and all its subwindows (everything on a screen if called on the RootWindow) to be redirected.
The automatic flag will ensure that the windows will have an image to access (no need for the client to put the windows together). For the purpose of a pager app (or window capture app), this is perfect. This flag can be used on any window by any amount of programs. For a window that is already redirected (manual or automatic) it acts like a NOOP.
The manual flag causes the window to not be automatically composited onto the screen. For any window, the Manual flag can only be selected once. This allows for the creation of a Composite Manager.
The events for when to update are provided by the Damage Extension (and the data type of Region is provided by Fixes Extension).
What happen if only a few windows were manual redirected? More details on command explanation.
There is some uncommitted patches which enabl XComposite handling.