You can calibrate your screen using a few different mechanisms.
These are the four ways you can calibrate touch on your system that include:
- manual: Use the calib as a mode in the scaling configuration file. For more
information, see
calib option.
- direct mapping: This mechanism is useful if the
display has a touchscreen the capability to scale
values on the hardware (e.g., Atmel). For more information,
see
Direct mapping.
- scaled: This is a mechanism that uses the screen resolution and
touch display's maximum X and Y values to calculate
the number of touch coordinates per display
pixel. For more information, see
Scaling calibration.
- user-calibrated: This mechanism is used with the calib-touch
utility. This method is best used for displays that have
resistive screens. This method provides corrections for misaligned
touch displays during the mounting process. For more information,
see
User Calibrated.
Direct mapping
This calibration methods is useful for touch displays that can
scale values on the hardware (e.g., Atmel controller) or if
user-calibrated method is used. Then the driver needs to send raw
events (direct). This calibration mechanism can be used with the
calib-touch utility. For more information about the
calib-touch utility, see the
calib-touch section
in this guide.
To use this method, you do the following:
- Set the mode parameter to direct in
the scaling configuration file (the default
file is at /etc/system/config/scaling.conf).
- For example,if you are using an Atmel touch controller, you
can adjust the maximum X and Y values using the
xrange and yrange values
on the T9 (Gen 3 or earlier) or the
T100 (Generation 4).
Scaled calibration
This calibration method works well with Capacitive-based
touch displays because once they are mounted, the values are
static and don't skew over time.
To use this method, do the following:
-
Set the mode parameter to scale in
the scaling configuration file (the default
file is at /etc/system/config/scaling.conf).
-
In the touch configuration file (the default location is
located at (default is
/etc/system/config/mtouch.conf),
set width and height properties to the maximum X and Y
values of the touchscreen. These X and Y values can be fetched
from slog2info output while in verbose mode.
For example, if you have a touchscreen
that has a maximum X and Y of 4096 with
a display running at 1024x768, here's what your configuration
may look like:
begin mtouch
driver=name_of_your_driver
options=width=4096,height=4096,your_other_options
end mtouch
It's important to mention that this method doesn't correct
misaligned touch displays, but if the origin of isn't in the upper-left
corner of the display, you can use the
invert_x and
invert_y options to reverse the directions of the
coordinates. For more information, see
Settings for various HID displays
in the
mtouch section of this guide.
User Calibrated
This calibration method is useful for resistive screens
that have coordinates that skew over time.
To use this method, do the following:
-
Set the mode parameter to direct in
the scaling configuration file (the default
file is at /etc/system/config/scaling.conf).
-
After the touch driver and Screen
service successfully run, start the
calib-touch utility. After
Screen completes
running, a calibration file is created that's loaded into
Screen's translation matrix. For more information about the
calib-touch utility, see
calib-touch section
in this guide.