Wrong colors on display with GC9A01 controller

[marsman7]

Display : Waveshare 1.28 inch round LCD modul

I tested this display on an ESP32 with the uDisplay driver and the "displaydesc/GC9A01_display.ini" discriptor file and found that the colors are wrong. In this test the order of the primary colors is not RGB (Red Green Blue) instead it is BGR. I have changed in the discriptor file the lines from

:R,36
:0,C0,00,00,00
:1,A0,00,00,01
:2,00,00,00,02
:3,60,00,00,03

to

:R,36
:0,C8,00,00,00
:1,A8,00,00,01
:2,08,00,00,02
:3,68,00,00,03

Then the colors were displayed as desired. The basis for this is the color table :

https://tasmota.github.io/docs/Displays/#color-indices

Can anyone else confirm this?

Translated with www.DeepL.com/Translator (free version)

[shavkatzh]

Yes. Have same problem for ST7789
The colors under Tasmota work well. Problem found with LVGL settings.

[H3adsho0ot]

Oh wow a :i was in my display ini .... sorry for that. Without it and with your fixed values it shows the correct colors now!

[sydknee]

This seems to have resolved Text but I still have other issues with this.

DisplayMode 1 (useful for testing the connections are correct) I get a white (grey) background and no text. I'm assuming that the text is the same colour so looking for a way to change that.

The display.ini documentation is confusing for us mere mortals and doesn't really explain much around colours for these modes.

I would like to rotate the screen by 180 I can tell from the documentation its the :R,36. I'm assuming 36 is degrees (why not 0) if I put 18 will that work or have I got it totally wrong?

_Just tested the 18 and it worked, strangely the background has now gone black and when I use DisplayText [x120y120Ci2] test -> Red Text I get red text with a white background but the rest of the background stays black. Progress! OK spoke to soon, when rotated the colours go back to blue. Might give the original code a try with :R,18

[sfromis]

The primary way of selecting your rotation is by using the DisplayRotate command, not by modifying display.ini.

As the docs say, the values in :R are opcodes, which is not about degrees, but about commands to the display controller chip. And the next lines :1to :4 again start with a code, with the 4th parameter selecting what to flip (mirror) and if x/y are to be swapped.

[sydknee]

Just trying everything I can, There is something not right about the display.ini for this display and its beyond my abilities.

[H3adsho0ot]

Probably you can find some infos here: #19487