redirecting X11 output to a file

[Werner LEMBERG]

>> I want to compare the graphical output of different versions of a
>> program pixel by pixel.  To do that, I would like to divert the
>> contents of the program's (single) X11 frame directly to a file --
>> a kind of automatic capturing without manual selection of the
>> window.
> 
> xwd is probably what you're looking for. "convert" should then be
> able to convert the dump's content to png or whatever format you
> like.

Thanks.  ImageMagick's `import' command does something similar, and it
directly outputs the right format.


    Werner