Calibration of resistive touchscreens - Revision history

Pzimmermann: Remove headings

2023-10-20T06:39:56Z

Remove headings

← Older revision		Revision as of 08:39, 20 October 2023
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	At our yocto images, we usually use libinput as library for handling input.		At our yocto images, we usually use libinput as library for handling input.

	~~=====~~ Prerequisites ~~=====~~		'''<big>Prerequisites</big>'''

	* Yocto packages ''weston'', ''weston-init'' and ''weston-examples'' have to be installed inside the image.		* Yocto packages ''weston'', ''weston-init'' and ''weston-examples'' have to be installed inside the image.
	* The config file <tt>/etc/xdg/weston/weston.ini</tt> needs the following lines (to enable touchscreen calibration):		* The config file <tt>/etc/xdg/weston/weston.ini</tt> needs the following lines (to enable touchscreen calibration):
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	\|}		\|}

	~~=====~~ Steps for calibration ~~=====~~		'''<big>Steps for calibration</big>'''

	'''1.''' Get the touchscreen device name with weston-touch-calibrator		'''1.''' Get the touchscreen device name with weston-touch-calibrator

Pzimmermann: Change the level of the heading

2023-10-20T06:38:32Z

Change the level of the heading

← Older revision		Revision as of 08:38, 20 October 2023
Line 3:		Line 3:
	At our yocto images, we usually use libinput as library for handling input.		At our yocto images, we usually use libinput as library for handling input.

	==== Prerequisites ====		===== Prerequisites =====
	* Yocto packages ''weston'', ''weston-init'' and ''weston-examples'' have to be installed inside the image.		* Yocto packages ''weston'', ''weston-init'' and ''weston-examples'' have to be installed inside the image.
	* The config file <tt>/etc/xdg/weston/weston.ini</tt> needs the following lines (to enable touchscreen calibration):		* The config file <tt>/etc/xdg/weston/weston.ini</tt> needs the following lines (to enable touchscreen calibration):
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	\|}		\|}

	==== Steps for calibration ====		===== Steps for calibration =====

	'''1.''' Get the touchscreen device name with weston-touch-calibrator		'''1.''' Get the touchscreen device name with weston-touch-calibrator

Pzimmermann: Create page for calibration of touchscreen, it is meant to be included in other pages

2023-10-20T06:31:49Z

Create page for calibration of touchscreen, it is meant to be included in other pages

New page

On devices with resistive touchscreens, the touchscreen has to be calibrated.

At our yocto images, we usually use libinput as library for handling input.

==== Prerequisites ====
* Yocto packages ''weston'', ''weston-init'' and ''weston-examples'' have to be installed inside the image.
* The config file <tt>/etc/xdg/weston/weston.ini</tt> needs the following lines (to enable touchscreen calibration):
[libinput]
touchscreen_calibrator=true
After changing the configuration of weston, weston needs to be restarted:
{| class="wikitable"
|-
| <tt>systemctl restart weston</tt>
|}

==== Steps for calibration ====

'''1.''' Get the touchscreen device name with weston-touch-calibrator
{| class="wikitable"
|-
| <tt>XDG_RUNTIME_DIR=/var/run/user/$(id -u weston) weston-touch-calibrator</tt>
|}

Example result (bold part is needed for next steps):
{| class="wikitable"
|-
| <tt>device "'''/sys/devices/platform/soc/2100000.bus/21a8000.i2c/i2c-2/2-0049/input/input0/event0'''" - head "DPI-1"</tt>
|}

'''2.''' Run weston-touch-calibrator on the device for starting the calibration. With the example part of the last result, the command looks like this (bold part is from the last result):
{| class="wikitable"
|-
| <tt>XDG_RUNTIME_DIR=/var/run/user/$(id -u weston) weston-touch-calibrator -v '''/sys/devices/platform/soc/2100000.bus/21a8000.i2c/i2c-2/2-0049/input/input0/event0'''</tt>
|}

Now you press the highlighted points at the touchscreen to calibrate it. You will now get an output on the console like this (the important part is marked bold):
{| class="wikitable"
|-
| <tt>Calibration values: '''-0.001472 -1.081086 1.033880 -1.135099 0.000319 1.082698'''</tt>
|}

'''3.''' To make the calibration permanent, you need to add a udev rule. Create the file <tt>/etc/udev/rules.d/touchscreen-cal.rules</tt> and use the calibration values there. With the result of the previous example, the file looks like this (bold part is the result of the last example):
SUBSYSTEM=="input", KERNEL=="event[0-9]*", ENV{ID_INPUT_TOUCHSCREEN}=="1", ENV{LIBINPUT_CALIBRATION_MATRIX}="'''-0.001472 -1.081086 1.033880 -1.135099 0.000319 1.082698'''"