LINUX GOODIES - Install and Configure Wacom ArtPad in Fedora Core

INTRO
This documentation is intended for Fedora Core 2 users who want to get a Wacom ArtPad tablet working. If you want to use the Wacom ArtPad in Fedora Core 3 this tutorial is not for you. Fedora Core 2 uses the internal Xorg wacom driver, while Fedora Core 3 features the Wacom driver built by The Linux Wacom Project (package name: linuxwacom). These two driver are different and may have different configuration parameters. I don't know where they differ and how. The linuxwacom supported devices include UD and PenPArtner which are very old tablet, and i guess they use the same protocol as ArtPad. (In fact, Wacom started producing the UD Tablet in 1993 and the ArtPad in 1994...). So I'm quite sure that the ArtPad will work in Fedora Core 3 as well. If you have evidence that this is not correct, please inform me. I will upgrade to Fedora Core 3 soon: then I will try to install the ArtPad in FC3. Since then, I can't help you.

MY TABLET (YOUR TABLET)

The ArtPad tablet was launched in october 1994. One year later the ArtPad is updated with the eraser function. Two years later it is renamed ArtPad II and updated with two sideswitch on the pen. My tablet is the very first ArtPad, without eraser and tilt sesitivity. That's why you will not find any [Option "Type" "eraser"] line in my xorg.conf file. Other specificantions: 2540 lpi (lines per inch), 256 pressure levels. You may think that you don't need a tablet. I can't believe there's someone using The GIMP for photo retouching who doesn't make it with a tablet. It will change your life: it makes working on pictures smoother and more "natural". You will find it useful also when designing with Inkscape: it has grat freehand painting features, so why not giving it a try. You can find these little lovely tablets for a bunch of dollars on Ebay: go there and get one.

MY CONF FILE

Here comes the good part. Every behaviour and functionality of your tablet depends on the wacom driver and the correct configuration lines in the xorg.conf file. If you use Fedora Core 2 with a standard installation your driver is already installed (it's a module, and it "wakes up" when the X Server needs it), so don't worry about it. The X Server configuration file (xorg.conf) resides in the /etc/X11 folder. The following are the important part of my xorg.conf. I will show only the lines concerning the tablet. You can check the my whole file here. WARNING: backup your file before editing it. If you fuck it up, it will be difficult for you to come back (if you are a nerd like me!).

ServerLayout
This is the starting section of xorg.conf, where screen, mouse, keyboard and other input/output devices are named. Note the last line, where we have "pen1": that's the tablet's pen. I will explain the meaning of "AlwaysCore" below.

Section "ServerLayout"
    Identifier     "Anaconda Configured"
    Screen      0 "Screen0" 0 0
    InputDevice    "Mouse0"        "CorePointer"
    InputDevice    "Mouse1"        "SendCoreEvents"
    InputDevice    "Keyboard0"     "CoreKeyboard"
    InputDevice    "ArtpadBrush"   "SendCoreEvents"
EndSection
...

SendCoreEvents: You can have two different kinds of pointer. The Core Pointer is a regular pointer which you can use to operate the GUI (move windows, click buttons, select text...). The Extension mode sends more informations than the Core mode: not only position and click status, but also tilt and pressure informations. This is important if you use the pen in applications like The GIMP, where brushes, eraser and other tools are pressure-sensitive. If you want to use the same pen in both situations, you will just activate/deactivate your device The GIMP's Input Devices dialog.

The Modules' section
This is where X will load the wacom driver. As I said before, it's a module (normally) and it needs to be loaded by the X Server when it starts.

Section "Module"
    Load "dbe"
    Load "extmod"
    Load "fbdevhw"
    Load "dri"
    Load "glx"
    Load "record"
    Load "freetype"
    Load "type1"
    Load "wacom" # Wacom Tablet Driver
EndSection
...

Input devices' section
These are the lines that make the tablet work. This is where we can tweak our options in order to make the tablet going.

Section "InputDevice"
   Identifier    "WacomStylus"
   Driver        "wacom"
   Option        "Type" "stylus"
   Option        "Device" "/dev/ttyS0"
   Option        "Mode" "absolute"
   Option        "Suppress" "2"
   Option        "TopX" "1000"
   Option        "TopY" "1000"
   #Option      "KeepShape" "1"
   Option        "BottomX" "4200"
   Option        "BottomY" "3400"
   Option        "HistorySize" "200"
   Option        "DebugLevel" "5" # quite verbose
EndSection

MODE
"Mode absolute" means that the pointer will use absolute coordinates. A specific position on the tablet always corresponds to a specific pixel on the screen. Te top left corner of the tablet corresponds to the top left pixel of the screen. Mode relative makes the pointer act like a mouse: when you lift the pen and reposition it somewhere else on the tablet, the pointer on the screen will not move to the new (absolute) position.

Option "Mode" "absolute"

SUPPRESS
If you use large resolutions it may become quite difficult to control the pointer in case of little movements. You must have a very firm hand if you don't want to see the pointer tremble all the time. The number you set here is the amount of pixel-movement that will be ignored by the driver before it moves the pointer on the screen. Many use 8 or 10 values. I have a firm hand and with a resolution of 1600x1200 I use "Suppress" "2". If you have larger resolutions you may need a higher number.

Option "Suppress" "2"

COORDINATES and AREA
These parameters are probably the most important: they let you specify which is the active area on your tablet. My tablet is a small A6 one, but I my active area is much smaller: little hand's movements are translated in large pointer movements on the screen. active area in my tablet

I find this useful because when I make some free-hand design i can do even very long lines and traces... When I need more precision, i prefer to zoom closer to the pixels or beziers I'm working at...

Let's take a look at my configuration. I use topX=1000 and topY=1000. This means that the first active point on the tablet is 1000 units form the top and from the left side of the tablet. If you have a Wacom ArtPad you surely know that the maximum active area is delimited by an inset border, that is annoying if you are working near the borders of the screen: it's likely that your pen's tip will "fall" inside this border making you "lose control" of you pen... That's why I've positioned the top left active border off the physical tablet border.

The BottomX and BottomY parameters obviously set the lower right coordinates of your active area. In this case they are BottomX=2400 and BottomY=3200. So, my active area is 3100x2300, and it's a rectangle with almost the same proportions of my 1600×1200 screen. Gives me good feedback while working, that's good for me.

     Option      "TopX"      "1000"
     Option      "TopY"      "1000"
#    Option      "KeepShape" "1"
     Option      "BottomX"   "4200"
     Option      "BottomY"   "3400"

KEEP SHAPE

This option is needed if you want your active area to be proportional with the screen resolution. In my example this line is commented. If you un-comment this line then the following BottomX and BottomY lines will be ignored.

Option "KeepShape" "1"

The result? Your active area will be the largest possible rectangle with the same proportions of your screen's resolution and with the top-left point corresponding to topX/topY coordinates. So, the active area it will reach one or both of the bottom border and right border. As I said before, I want to keep off the border, so I don't use this option. In this picture i make clear how the active area will be if "KeepShape" is used. Note that it reaches the bottom limit.

HERE WE GO (the reason why The GIMP kicks asses!)
Here (left image) is an example of some strokes made with the brush tool and different pressure force on the tablet. That proves that the pressure sensitivity works. In The Gimp you can tweak with some parameters about brush tools pressure effects for Opacity, Hardness, Size and Color.

Another big deal about having two different pointer (CorePointer=mouse, ArtpadBrush=stylus) is that The GIMP is always aware of the one you are using, so it keeps basic informations associated with each of them. Everytime you switch the pointer (by moving the mouse, or pointing the stylus on the tablet) The GIMP will load its own "configurations".

In the picture on the right you can see a little arrow indicating the active pointer. In this case the ArtpadBrush is associated to the Eraser tool, and you can also see the two color swatches for this tool, and also the shape of the brush, the active pattern and gradient. Just grab the mouse and you will switch to the Blur-tool, blue/yellow swatches, "star" brush, new pattern, new gradient. This is a very useful feature: for instance you can use two different brushes, with different colors and shapes...

I don't know about new versions of Photoshop. In my job I use Photoshop 6 and a Wacom Graphire tablet, and this great feature is not there! Nor is available in The GIMP for Windows, so I guess it depends ond the driver and the way Windows manages the "InputDevices" and "CoreEvents"...

This work is licensed under a Creative Commons License.