ColinKinloch / libwacom

libwacom is a tablet description library

Overview

libwacom is a library to identify Wacom tablets and their model-specific features. It provides easy access to information such as "is this a built-in on-screen tablet", "what is the size of this model", etc.

This functionality is currently used by e.g. GNOME to map built-in tablets to the correct screen.

Debugging libwacom with uinput devices

libwacom by default will not recognise uinput devices. To debug and test, a physical device must be connected.

Custom udev rules are provided to help debug uinput device. Run generate-udev-rules --with-uinput-rules to generate these rules and apply them locally. Devices will then be tagged as required and can be debugged.

Some limitations:

• For these rules to work, the device must be listed in the database
• libwacom will check UINPUT_* properties on the uinput device, if they do not get applied, the device will not be visible

DO NOT USE THESE UINPUT RULES unless you are debugging with uinput devices. Remove the rules once debugging is done.

Adding tablet descriptions to libwacom

A common indicator that a device is not supported by libwacom is that it works normally in a GNOME session, but the device is not correctly mapped to the screen.

Use the libwacom-list-local-devices tool to list all local devices recognized by libwacom. If your device is not listed, but it is available as an event device in the kernel (see /proc/bus/input/devices) and in the X session (see xinput list), the device is missing from libwacom's database.

To add support for a new tablet to libwacom:

1. Create a new tablet definition file. See data/wacom.example in the source for a guideline on how to add a new tablet. For an installed version of libwacom, see the existing data files (e.g. /usr/share/libwacom/cintiq-13hd.tablet)
2. A new tablet description is enabled by adding and installing a new file with a .tablet suffix. Once installed the tablet is part of libwacom's database, no rebuild is neccessary
3. The tablet is then available through libwacom-list-local-devices

The new device should also be added to the udev rule to ensure all required properties are set

• When building from source generate an update ruleset with tools/generate-udev-rules after adding the tablet descripton to
• When updating an installed version of libwacom, add it manually to the existing ruleset (/lib/udev/rules.d/65-libwacom.rules)