|SummaSketch tablets are cheap to get, very precise graphics devices, and if you have plenty of space on your desk, they do good work. Although these devices were originally designed for CAD purposes, they are quite usable for vector graphics as well as photo processing. Read on to see how to get them working in X.
Many users have been facing problems with reversed axes or wrong relations between the x- and y- resolutions. Unfortunately the documentation for the xf86summa.so module doesn’t give any hints about these problems, but don’t worry – they are quite easy to fix.
First of all, some basic thoughts about the setup:
- Forget the puck (the clumsy 4-button-thing) as a mouse replacement. It’s ways are too long in absolute mode and you
can not skip between the puck and the pen within a running X-session. You’ll surely prefer using the pen and a seperate mouse instead. Doing things this way you won’t miss the advantages of a wheel mouse in common use, and you can simply lay your mouse aside and grab the pen whenever you want to do some graphics design.
- Switch the tablet on before you start the X-server. It will behave in a weird way if you turn it on later.
- You cannot unplug the pen and plug in the puck (or vice versa) once the tablet is initialized or you’ll face the same unwanted effects as above.
Now let’s add the tablet to /etc/X11/XF86Config-4. In Section "Module", add Load "xf86Summa.so". This should load the driver module for the tablet. Next we define another InputDevice. Assuming the tablet is plugged into the first serial port:
Option "Device" "/dev/ttyS0/index.html"
Option "Resolution" "2540"
Option "MaxY" "12000"
Option "MaxX" "12000"
Option "Mode" "Absolute"
You could also use Option "Mode" "Relative", but this appears to be useful only if you are using the puck as the primary mouse. Starting X now (don’t forget to turn on the tablet first), both your usual mouse and the tablet should work as input devices.
If you start working with the Gimp, you may face another problem: The x-axis seems to be “longer” than the y-axis, which results in drawing an ellipse on the screen when you draw a circle on the tablet. The solution is trivial: Open Gimp’s ‘Dialogs’ => ‘InputDevices’ menu, and change the mode for
“SummaSketch” to “Window”. Now empty your coffee mug (aargh – no sugar!) put it onto the tablet and move the pen around it’s bottom. You should see a perfect circle. Now get some more coffee, and get back to work…