Friday, September 25, 2009

Genius G-Pen 4500 and Fedora

Just bought a Genius G-Pen 4500 digitizer tablet for myself. Mainly for drawing simple sketches and diagrams. Got it for MYR160 (~=USD50), which is relatively cheap compared to other tablets (Wacom and Genius) I found at LowYat plaza which averages at MYR400-800 (~=USD115-230).



The driver for the tablet is not available in the Fedora and RPMFusion repos, so I had to grab the sources from LinuxGenius GoogleCode page and compile it. (I've put together a RPM here : http://izhar.fedorapeople.org/wizardpen/).

After installation of the driver, a HAL FDI configuration is required for it to work. Here's the default one I'm using for this tablet. (Save it as /etc/hal/fdi/policy/99-wizardpen.fdi)


<?xml version="1.0" encoding="ISO-8859-1" ?>
<deviceinfo version="0.2">
<device>
<!-- This MUST match with the name of your tablet -->
<match key="info.product" contains="UC-LOGIC Tablet WP5540U">
<merge key="input.x11_driver" type="string">wizardpen</merge>
<merge key="input.x11_options.SendCoreEvents" type="string">true</merge>
<merge key="input.x11_options.TopX" type="string">0</merge>
<merge key="input.x11_options.TopY" type="string">0</merge>
<merge key="input.x11_identifier" type="string">stylus</merge>
<merge key="input.x11_options.BottomX" type="string">32739</merge>
<merge key="input.x11_options.BottomY" type="string">32745</merge>
<merge key="input.x11_options.MaxX" type="string">32739</merge>
<merge key="input.x11_options.MaxY" type="string">32745</merge>


(copy paste that or download it here : 99-wizardpen.fdi)

Afterward restart Xorg, and connect the tablet, and it worked quite easily.

Reference: http://digitalbluewave.blogspot.com/2008/10/genius-wizardpen-with-intrepid-ibex.html

Aspect Ratio

By default, the driver utilizes the whole tablet for input, stretching X and Y axis to match the screen shape, thus breaking the aspect ratio. Might still be ok on small screens, but on dualscreen, the ratio stretched too far causing difficulty to draw/write.

Unlike the Wacom driver which have this feature by default, LinuxGenius doesnt have it, but the options in the FDI is enough to allow us to configure it manually. I've written a simple script for this (get it here: wizardpen-ratiocalc.py).

Edit the script and change the resolution value, and run it. The script will output a fdi config that uses the aspect ratio of your screen.

The result?



Sketched on Inkscape.

My initial overall view of this tablet?. Cheap, relatively easy enough to get it working based on my requirement, so I guess this should be good enough for my purposes.

^-^
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