Corrupted XImage retrieved from a Window area

[Thomas Lübking]

On Sun, Jul 31, 2016 at 07:51:08AM +0000, Fabien Lelaquais wrote:
>Thanks a lot for your answer.
>Unfortunately I may not be able to rely of the Composite extension (app would be deployed in environments I don't control).
>
>Regarding the XGetImage documentation, that I've read ten times:
>My drawable (mainWindow) is indeed a viewable window.
>It has no inferior, and an overlapping window on its center. The specified rectangle that I provide, which is the center part of the source window, is both fully visible on the screen and wholly contained in mainWindow.
>I have no X error.

Ahh, sorry - my bad. I had interpreted it vv.
Your demo code works fine here - my guess would be

> options:    backing-store NO, save-unders NO
            ^^^^^^^^^^^^^^^^^^^^^

this one to be the troublemaker - enable the backing store (set "WHEN
MAPPED" here) and try again.

> Option "BackingStore" "on"

in the screen section - or pass +bs to Xorg

Unfortunately I don't know whether the BackingStore is a hard condition
or things are supposed to work anyway (ie. this would be a bug in the
server)

Cheers and sorry for the fuzz,
Thomas