Using "mgp -o -g <geometry> -D <dir>" works fine as long as you don't
switch to another virtual desktop.  In this case you get errors like:

generating page 16... (full image)X Error of failed request:  BadMatch (invalid parameter attributes)
  Major opcode of failed request:  73 (X_GetImage)
  Serial number of failed request:  4541
  Current serial number in output stream:  4541
(thumbnail)convert: Missing an image file name [No such file or directory].
pnmscale: EOF / read error reading magic number
(html)(txt)
generating page 17...


Obviously mgp is already able do generate its pages not on-screen (see
forward cache).  This mechanism should be used - that would prevent:

1. these X errors
2. display locking when not using -o

retitle 51544 mgp: bad algorithm for image grabbing
thanks

The following demonstrates once more how bad the algorithm for
grabbing images for HTML generation:

$ mgp -g800x600 sample.mgp
[lower window]
$ mgp -D html/ -g800x600 myslides.mgp

As long as the "myslides" window is on foreground (higher than
"sample" window ?), the generated images are taken from the "sample"
window !!!  Lowering "myslides" causes further images to be grabbed
from "myslides".  Raising/lowering further goes on switching back and
forth the source window for grabbing.


I'd expect that the image be written to a pixmap drawable instead of
on-screen, and be grabbed from there.  The current symptoms seem to
tell me grabbing is currently done by an external process, although I
did not look at the code (yet).  Maybe something like ImLib would help ?

You wrote:

Where? I searched around the deity mail archives and the BTS and can't seem
to find a fix documented for this problem.  Will the next release fix
this bug?

Seems like it fits critical since it completely breaks the standard potato
boot-floppies install that relies on apt.

This bug has been forwarded to mgp-users-jp 00662
http://www.mew.org/archive/mgp-users-jp/A/msg00658.html