hpoj reference: xojpanel
xojpanel is a graphical application that continuously displays
the contents of the LCD (liquid crystal display) on the device's front
panel, for devices which support readback of this information.
See the xojpanel column on the
Supported devices page
for the most up-to-date information about which models support this feature.
Syntax:
xojpanel devname &
Where devname is the PTAL device name.
Notes
xojpanel should work with most recent 1.x and 2.x versions of the
QT library from Trolltech. If you
don't have QT installed on your system, then the hpoj ./configure
script should disable compilation of xojpanel.
xojpanel will not run if the device doesn't support LCD readback,
or if there's a communication problem, for example, if the device is
powered off or disconnected or the low-level I/O daemon
(ptal-mlcd) isn't running.
Also, xojpanel will exit if a communication problem occurs later.
xojpanel mimics the look of a typical LCD with the font and
foreground/background colors. It currently has two lines and is 20
characters wide. If the text on either line is too long, then it scrolls
the text from right to left.
Advanced users may wish to hack the xojpanel source code to
customize various compile-time options, such as font, colors, scroll
speeds, poll rates, etc. See the xojpanel.cpp and xojpanel.h
files in the hpoj source package's apps/xojpanel directory for
more information.
Several models have quirks related to xojpanel and
"ptal-hp display" that are worth
mentioning here:
- Many models, such as the OfficeJet G series and later models,
occasionally display non-standard characters, such as a filled-triangle
right arrow (0x81) and a filled circle (0x83). Depending on the font
used on your display, these characters may display as question marks,
spaces, or square bullets. A future release will include the ability
to remap some of them to printable ASCII characters.
- The LaserJet 3200 series incorrectly formats the information it
returns when there are leading or trailing spaces on either line.
For example (dots indicate spaces for clarity):
READY...........AUTO
JUL-27-2001...4:20AM
on the device is correctly returned to the PC, but
.....MAIN MENU......
...FAX JOB STATUS...
on the device is incorrectly returned to the PC as
MAIN MENUFAX JOB STA
TUS.................
Unfortunately, it doesn't appear to be feasible to fix or work around
this problem in software.
- The LaserJet 1220, which doesn't even have a physical LCD,
displays the string "DOCUMENT LOADED" most of the time, even
when no document is loaded, due to the way its scanner subsystem works.
Joe Piolunek is the current
maintainer of the xojpanel application. He has a
web page
dedicated to this effort and related efforts, such as a larger
xhpcontrol application.