Preferred configuration for resistive touch with Universal Touch

[s-hadinger]

@gemu2015 I started using the Universal Touch driver, awesome work!

I got back my Lolin TFT that uses the XPT2046 driver. It worked fine except that the x was reversed. The SCL opcode does not make it very friendly to reverse the scale, it needs some extra calculation.

I already did the ts_calibrate.be app to help easy calibration of resistive touchscreen that generates the :M line. I see that this still works with universal touch.

My question: don't you think it would be easier for calibration to use a combination of :UTI and :M, instead of just using SCL directive?

Im my case is would be:

:M,3931,378,185,3813           <- use previous :M section
:UTI,XPT2046,S1,27,-1,-1
CPR 00
RT
:UTT
XPT 300
RT
:UTX
MV 0 2            <- no SCL
RT
:UTY
MV 2 2            <- no SCL
RT
#

instead of the example in the doc:

:UTI,XPT2046,S1,21,-1,22
CPR 00
RT
:UTT
XPT 300
RT
:UTX
MV 0 2
;DBG 1
SCL 460 0.0930233
LIM 319
RT
:UTY
MV 2 2
SCL 300 0.0695652
LIM 239
RT
#

[gemu2015]

yes you can use the M: as usual,
but i have a display that can not be made working with the M: parameters.
therefore i created the SCL opcode which allows any combination.

we should use M: when possible and only use SCL when M: does not fit.