hpoj reference: CWxojpanel

xojpanel [devname] [options...] &

CWxojpanel 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 CWxojpanel column on the hpoj Supported devices page for the most up-to-date information about which models support this feature.

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CWCIdevnameCW is the optional PTAL device name

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options... is zero or more of:

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CW-caption "CItextCW" Text to be displayed in titlebar

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CW-notrans Disables translation of nonprintable characters

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CW-hidedevname Hides device name from titlebar

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CW& Runs CWxojpanel in the background

CWxojpanel should work with most recent 1.x, 2.x, and 3.x versions of the QT library from Trolltech. If you don't have QT installed on your system, then the hpoj CW./configure script should disable compilation of CWxojpanel. CWxojpanel refuses to start, or exits if it has already started, upon any of the following conditions:

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The device doesn't support LCD readback (returns an error on the display PML objects).

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The device is disconnected or powered off.

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The low-level I/O daemon for locally-connected devices (CWptal-mlcd) isn't running, presumably because "CWptal-init start" has not been run.

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There is some other problem communicating with the device.

CWxojpanel 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 CWxojpanel source code to customize various compile-time options, such as font, colors, scroll speeds, poll rates, etc. See the CWxojpanel.cpp and CWxojpanel.h files in the hpoj source package's CWapps/xojpanel directory for more information. Some models have a color LCD for previewing and adjusting photos before printing. It is not possible for CWxojpanel to retrieve graphical information from such displays.

Several models have quirks related to CWxojpanel and "CWptal-hp display" that are worth mentioning here:

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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). By default, CWxojpanel translates non-standard characters to reasonable printable equivalents if possible or spaces otherwise. The CW-notrans command-line option disables this behavior.

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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................. It is not feasible to fix or work around this problem in software.

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The LaserJet 1220, which doesn't even have a physical LCD, displays the string "CWDOCUMENT LOADED" most of the time, even when no document is loaded, due to the way its scanner subsystem works.

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Some models answer queries of the display PML objects but return an empty string.

Andreas Fester originally wrote CWxojpanel, but Joe Piolunek wrote most of the code that is in the current version of CWxojpanel.