present tense

Using the tablet interface on the HP TC4400 under SUSE Linux
Of course I wanted the tablet interface working as soon as possible. It turned out to be surprisingly easy. No new drivers needed, just a small bit of configuration. See below for the details.

Screen Rotation
Linux can rotate the screen on the fly without any special configuration instructions. However, the tablet coordinates are not automatically rotated.

You can use the xrandr command to rotate the screen:

xrandr -o left ;for a quarter turn counter clockwise
xrandr -o right ;for a quarter turn clockwise
xrandr -o inverted ;to flip the screen upside down
xrandr -o normal ;to restore the screen to its normal laptop position


You can also use the KDR utility KrandrTray (KDR Resize and Rotate Tray applet) to do this with a menu based utility.

The problem with these solutions is that they do not rotate the tablet’s coordinates along with the screen’s coordinates. As a result, if you flip the screen upside down the cursor will travel in the opposite direction from the digital pen.

There is a separate command to rotate the pen coordinates, xsetwacom.

xsetwacom list dev

will list the devices which can be rotated by xsetwacom (typically aliases for your pen and its eraser). Then you can create simple shell scripts like these:

xrandr -o inverted
xsetwacom set Mouse[9] rotate 3
xsetwacom set Mouse[7] rotate 3

I created the four obvious shell scripts and left them on my desktop so I can tap them with the pen when I need to. It’s an ugly hack but it works and it was quick.

A list of better ways to do this, in increasing order of coolness (and difficulty), might be to

1. Modify KRandRTray to also rotate the tablet coordinates. This would free up the wasted screen real estate and keep one from having to access the desktop to rotate the screen.
2. Figure out how to access the soft buttons in the Wacom tablet. One of these is specifically labeled as the screen rotation button. This is what it does under Windows.
3. Improve Xstroke so that you can rotate the screen with a pen gesture.
4. Take advantage of the built-in accelerometer and let the user knock the laptop, gently, on its side, to cause the screen to rotate.

Since I’m sticking primarily to Java programming these days, the best I’m likely to attempt is (2). But most of my tinkering of this kind is driven by real dissatisfaction with something or just an unsatisfied itch caused by seeing wasted capabilities.

Configuring the Tablet Interface

If you haven’t activated the tablet and pen under Linux, here’s how.

1. Fire up YAST. Select Hardware from the left hand list and Graphics Card and Monitor from the icons on the right.

2. This will start the SAX2 configuration utility. Select Tablet from the left hand list. Check Activate This Tablet and select the vendor Wacom and the name ISDV4 Tablet PC (SERIAL).

3. Choose the Port and Mode tab. Setting the Button2 option to 3 will make the pen’s button function as a right click which I have found convenient.

4. Select the Electronic Pens tab. Add both the Pen and the Eraser.

Click OK. Logout and then log back in again. Your pen should be functional.