Display doesn't update properly unless --invert

[willemOH]

In both vnc and framebuffer (and I think the others but cannot confirm right now), my 3in7 waveshare has this behavior:

1. display color is inverted (or at least always white on black) without the --invert option
2. there is no full refresh (scrub?) after 50 updates (or after any amount specified with --fullevery) -> this may have to do with the fact that the scrub command does not work -> ValueError('Image must be the same dimensions as display required (280x480, got (16x480)
3. the display super ghosts to the point of filling up with garbage within 2 updates and being unreadable
4. using --invert with vnc fixes the super ghosting (its not even a ghost its just solid and not going away if that makes sense)
5. --invert does not invert everything (the i3bar in i3 stays black)

I've been through the edges of the issues reported here to get this far (vncdotool downgrade for one) and feel very close now! I just need to not have inversion of colors and perhaps a refresh (scrub? I haven't seen it in action so I don't know if its the same action) to get everything functional!! Very excited for that moment

[joukos]

I don't have this model to test with and not sure if there's multiple revisions of it like some of the other boards do. But if yours seems to be inverted by default, might be worth trying to override the black/white values in the driver and seeing if that makes a difference, see here

PaperTTY/papertty/drivers/drivers_base.py

Lines 36 to 38 in c2a5d72

	# override these if needed
	white = 255
	black = 0

The --fullevery option would just do a non-partial refresh, not scrubbing (which is another thing that should just be taken out, it's not very useful on well-behaved displays). While the 3.7" display supposedly supports partial refresh, the driver in PaperTTY does not implement that yet and every refresh should thus be a full one.

Adding partial refresh support shouldn't be too much work since Waveshare's own examples do it, but as I don't have the hardware to test with I haven't attempted it.

The 16x480 is a bit weird though... does that happen with VNC or fb or both, and what's the VNC desktop resolution?

[willemOH]

Thanks for responding promptly. It's great to see an author keeping up with a project after some years.

I took override to mean set my own value for black and white. I swapped them (white = 0, black = 255) to no effect.

A new finding is that that --invert works as expected on GUI applications but for rxvt terminal emulator its always white on black inverted or not. Not sure what's up with that. May be a config thing for rxvt to more explicitly select terminal window colors idk.

16x480 only happens with the --scrub command, no others. vnc resolution is 1280x720.

The most glaring issue is that super ghosting I was talking about. It's like its not refreshing and only continuing to add to the e-paper screen. I made sure to put --nopartial since you said partial is not supported for 3in7.

Though as mentioned, adding --invert solves this non-refreshing issue. It's just that everything is of course inverted. So I'd like to have it refreshing and not inverted. Perhaps there's a way to hack it so that using --invert goes through the function but sets the colors to just be normal? That was what I was attempting to do by switching the black and white values but to no avail.

Appreciate your support on this!

EDIT: so strange but as I was typing this response I left the 3in7 running and when I looked back it was actually working. maybe it took a bit for the override to apply. So for anyone else this was my working command:

papertty --driver epd3in7 --nopartial vnc --display 0 --password <pass> --rotate 270

after setting

white = 0
black = 255

p.s does partial update increase response time on the display significantly? If so I might have to send you a 3in7 @joukos ! Or maybe I'll commit myself to understanding the driver code base some time to apply the waveshare partial support myself.

In any case I'm very happy to get this functionally working! I'll update this reply with a pic of my e-paper "laptop" now looking sleek in black on white e-paper!

UPDATE:
the screen was getting messy and dithering was getting fuzzy so I used --invert just because I remembered it all being pretty sharp when I did that. It was went inverted as expected. Then I started --vnc with the above command...and it stayed "inverted" as was the issue originally. I was disappointed since there was no clear way to undo this (same command produced different results).

I retraced my steps to the solution last time and remembered I launched a GUI program (gimp). So I did that and lo and behold after going back to an rxvt terminal window in i3, it was back to black on white. So there's something very strange going on there.

Another question. Should the screen ever flash black and white to refresh the screen like other e-paper devices do? That is not happening and I'm thinking that might be part of the clogging up/dithering noise/some pixels not changing.