General Category > Discussion - EVE
Tag value of an area with content
Rudolph:
--- Quote from: avanti on June 17, 2020, 03:37:04 PM ---
--- Quote from: Rudolph on June 17, 2020, 10:22:24 AM ---Oh, annother thing, avoid tag values below 10, for some reasons these do not give reliable touch events.
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Is this really true!? If so, I have a lot of code to revise.
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I am not quite sure.
I tested this the last time back in January with an EVE3-43G and before that found this behaviour with FT813.
At a tag-value of 1 the value was toggeling between 0 und 1.
At a tag-value of 5 the value was toggeling between 4 und 5.
At a tag-value of 9 the value was toggeling between 8 and 9.
Using other values was stable: 2, 3, 4, 6, 7, 8, 11, 15 and 19.
It was reproduceable, I had seen this before and I got a bug-report regarding this.
I just setup a new test with an EVE3-50G and the value is stable.
It just is freaking stable - as it should be.
No idea why, could not explain it back then either, just reading REG_TOUCH_TAG has a rather low potential for failure.
So well, ignore this, sorry.
darkjezter:
No matter where you touch the display, I'm pretty sure you should get a tag value of some kind. When you clear the display, if you've set the bit to clear the tag, the the entire display will return the tag value determined by CLEAR_TAG which is zero by default. As you draw, tag values are replaced in the region drawn by the current value of TAG (1 to 255 according to the doc, though Rudolph's example also uses zero). Thus, if you draw your scroll region last, then any touches in it should report that tag value. The only exception to this will be when using TAG_MASK, which you don't appear to be.
If you've tried Rudolph's suggestion and as a result are seeing tags of zero for your scrollable region, then it sounds like TAG(0) is supported in spite of the documentation, and you've either failed to set tag again before drawing your scrollable area, or drawn something over top of the scrollable area with TAG still set to zero.
T.Pierret:
Hi,
You are right, the behaviour is not the one I explained. However I often observe a tag value of 0 at the beginning of a sliding movement. Here is some recorded samples of the case:
Event Time Smoothstep Read Tag Pressure"Touch pressed" 18516 172 203 172 203 0 957 "Touch moved" 18521 172 202 473 148 0 1318 "Touch moved" 18526 172 201 501 148 0 1021 "Touch moved" 18531 172 200 534 140 0 899 "Touch moved" 18536 172 199 509 154 16 865 "Touch moved" 18793 237 190 568 150 16 416 "Touch moved" 19078 302 185 568 169 16 479 "Touch moved" 19335 342 187 546 198 16 477 "Touch moved" 19592 375 194 545 234 16 452 "Touch moved" 19849 406 204 565 260 16 564 "Touch moved" 20106 430 215 558 277 16 553 "Touch moved" 20363 449 227 551 293 16 535 "Touch moved" 20620 465 240 547 312 16 529 "Touch moved" 20877 477 256 543 342 16 607 "Touch moved" 21134 487 273 540 363 16 547 "Touch moved" 21391 497 289 548 373 16 556 "Touch released"21648 505 302 32768 32768 16 32767
where the scrollable area (tag value=16) is defined as (80,80) -> (799,479).
Why the first tag values are 0 ? Yet the touch coordinates are well in the 16-tagged area.
Supplementary: why the 1st touch coordinates may be so different of the rest ?
Thanks in advance for any support.
Regards
BRT Community:
Hello,
Can you provide an example display list of how you are tagging the different objects on your screen?
I would like to investigate this behaviour further.
Best Regards,
BRT Community
BRT Community:
--- Quote from: BRT Community on June 18, 2020, 04:01:59 PM ---Hello,
The REG_TOUCH_TAGs default value is 0, however this normally indicates that no touch is detected. It may be that you are reading the register before the frame has fully scanned out.
Can you provide an example display list of how you are tagging the different objects on your screen?
I would like to investigate this behaviour further.
Best Regards,
BRT Community
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