[X2go-user] X2Go client printing issues if application queries printer parameters

[John A. Sullivan III]

Hello, all.  We are working on a problem for one of our clients where
print margins are not being set properly on a critical financial
application, Timberline.  To save retyping, I'll paste in most of the
contents of our internal GLPI Help Desk
(http://www.glpi-project.org/spip.php?lang=en) ticket:

One of Maryann's critical functions is printing checks. If they print
incorrectly, it is extra critical because of the difficulty of
reprinting them. Maryann eventually figured out that she needed to
override the margin settings of 0,0,0,0 to 0.25,0.25,0,0 to have them
print correctly. However, these defaults were never saved and had to be
re-entered for every check run. That's a problem and prone to human
error.

The call with Timberline was enlightening and may reveal a system design
issue. Unlike reports, check runs do not have custom printer settings.
They draw their margin settings from the physical print device. They can
be overridden which is what Maryann has been doing but there are no
settings to save; they always draw from the print device.

As much as this is working against Maryann, it is probably good design.
It means that the checks will adapt to whichever printer they are sent.

The problem is when a check run is sent to the X2Go printer for printing
to local printers. Now the problem is that two very well designed
"features" interfere with each other and become a problem. Timberline is
trying to adapt to whichever printer is chosen. However, the X2Go
printer is also trying to adapt to whichever printer is chosen to give
users the flexibility to print to whichever local printer happens to be
attached. The problem is that, to do this, the X2Go print driver does
not specify any margins (or it specifies them as 0,0,0,0) as it is
physical printer independent. Now the Timberline check printer queries
the X2Go printer to ask what its margins are (so Timberline can adapt to
the printer) and the X2Go printer says, "I don't have any because I'm
trying to adapt to whatever printer the user connects to me!" This is
why the check runs work perfectly when sent to the network attached
printers - they tell Timberline what their physical margins are.

I can see two ways to solve this problem. Each with distinct advantages
and disadvantages.

The way I think is best is to leave the X2Go printer undefined. The user
receives the PDf file and, when printing, after selecting the target
printer should select "fit to printable area" in the PDF reader print
dialog. This preserves the ability of the X2Go printer to adapt to any
printer the user has, e.g., if Maryann decides she needs to print from
home rather than from the office. The BIG downside is that is still an
extra step and, if Maryann forgets to do it, a check run can be mangled
and we have the problem of reprinting checks. [Note - this is a Windows
client user and thus cannot print directly to the printer from the X2Go
printer dialog]

The other solution is to hack the PPD file for Maryann's X2Go printer
and set fixed margins. I'm not 100% sure how to do that but we can
figure out how. The big advantage is that no user intervention is needed
for the check runs. However, the big disadvantage is that we no longer
adapt to the target printer; the margins are fixed.