Calibration Evdevtouch for EGLFS platform

tictactoe

Hi
I write a QT program for raspberry PI . I use QT on EGLFS platform . I have a problem with touchscreen (Resistive touch) . The driver for reading points from touch is eGalax . Touchscreen is working but it is not good performance. I have a problem in the touching some buttons on the top and the bottom of the screen . It was touching by finger so hardly .
I read this link
[link text] (https://wiki.qt.io/Native_Build_of_Qt_5.4.1_on_a_Raspberry_Pi)
after installing new Tslib from github I read "Readme.md" from tslib directory and optimize my environment variable like below.

export QT_DEBUG_PLUGINS="1"
export QT_QPA_EGLFS_DISABLE_INPUT="1"
export QT_QPA_EVDEV_TOUCHSCREEN_PARAMETERS="/dev/input/event0:rotate=90"
export QT_QPA_GENERIC_PLUGINS="evdevtouch:/dev/input/event0"

Some button that is designed by QT on the different place of the touchscreen is touched so hardly.for example I cant touch some button with finger and I must use pen for touching some points in the button for touching. I think it was not calibrate correctly. How can I calibrate touchscreen for better response.
What can I do for it?

Regards

tictactoe

I can calibrate using ts_calibrate and save pointer in the file.But I could not use tslib.
As you see I am using touch with Evdev . But it is not good and doesnt have good response.
How can I calibrate Evdev for touch screen?

Regards