.TH TOUCHCAL 8.SH NAMEtouchcal \- touch screen calibration.SH SYNOPSIS.B touchcal.SH DESCRIPTION.I Touchcaldraws a cross-hair in each corner of the screen in turn (clockwise from the lower left hand corner),and waits each time for the user to touch the centre of the cross-hair with the stylus.It then prompts with a final cross-hair in the centre of the screen, and waits oncemore for the user to touch its centre with the stylus.The process is repeated until.I touchcalcan calculate a transformation matrix that consistently maps the touch panel to screencoordinates.It then writes corresponding calibration commands for.IR touch (3)on its standard output, whichcan be saved in a file on the device, perhapsprovided in NVRAM by.IR tinyfs (3)or a file system in.IR ftl (3)..PP.I Touchcalcan be used both inside and outside the.IR wm (1)environment,allowing calibration when the system is initialised, and whilstthe window system is running..SH FILES.TF "/dev/touchctl    ".TP.B /dev/touchctlreset or read existing settings.SH SOURCE.B /appl/cmd/touchcal.b.SH SEE ALSO.IR touch (3)