Wayland's Weston Getting New Touchscreen Calibrator

With Wayland appearing in more places from automobile in-vehicle infotainments to planes to smartphones, having a good touchscreen calibration system is certainly important. Collabora developers have been working on a new touchscreen calibrator and new protocol extension for Weston.

Pekka Paalanen today sent out a set of 25 patches providing a new touchscreen calibrator for Wayland's Weston reference compositor. This new calibrator and new protocol extension for touchscreen calibration are intended to solve problems with Weston's current touchscreen calibration support.

This new tool and extension allows picking a physical touch device to calibrate, assurances that touch events come from a particular device, the calibration window will be mapped to the correct output with the right coordinates, unambiguously calibrate multiple touchscreens that are cloned, support for a libinput-style calibration matrix, and support for loading a new calibration into the compositor without needing to restart it or other shortcuts.

Thanks to libinput and usin its calibration matrix, this new approach also allows calibrating the touchscreen(s) once under Weston and then switching over to any other Wayland compositor and allowing the calibrated device to still behave as expected.

But these patches do not yet enforce any rules about how a Wayland client is authorized to use the touchscreen calibration controls, upload new calibrations for a device, etc.

Those interested in Wayland on touchscreens can learn more about the tool update and new weston_touch_calibration protocol via wayland-devel.