`display.root_group.hidden = True` causes `RuntimeError: Read-only`

[dhalbert]

display.root_group.hidden = True
has error:

RuntimeError: Read-only

Originally posted by @bh1rio in #2791 (comment)

[dhalbert]

This started happening between 9.0.0-beta.0 and 9.0.0-beta.1.

[dhalbert]

This is due to #8923.

@jepler

display.root_group.hidden = True was previously recommended as a way to hide the terminal. Now that the root group is read-only, it can no longer be made hidden. I can't remember if there is an alternate way to hid the terminal now.

[jepler]

I think it's display.root_group = None

[dhalbert]

@jepler That makes sense, thanks! @bh1rio that should work for you. Please reply if not.

[dhalbert]

More on this: https://forums.adafruit.com/viewtopic.php?p=1019617#p1019617

@tannewt see your comments there.

[bh1rio]

More on this: https://forums.adafruit.com/viewtopic.php?p=1019617#p1019617

@tannewt see your comments there.

en...... set root_group to none, does not have effect

[jepler]

Huh, I tested it here:

Adafruit CircuitPython 9.2.1-21-g7c28ec69cd-dirty on 2024-12-04; Adafruit Floppsy RP2040 with rp2040
>>> import board
>>> board.DISPLAY.root_group = None

After I hit enter on the 2nd line the TFT was set to all black.

I see two things from the forum thread:

• first, you're using an epaper display ("pimoroni badger2040 which has a built in Epaper Display"). circuitpython will defer the refresh of an epaper display for a long time, sometimes minutes, based on the datasheet recommended refresh time/rate
• second, based on the code sample you posted, your code.py finishes right after setting the root group to None (& calling refresh). However, whenever a program exits, the display is set back to the default, i.e., the console. You have to do something like have a loop that runs forever or enter a deep sleep mode to prevent this happening.

[bh1rio]

it have effect in a vm, e.g. code.py.
after it run, display recovery.

if you use thonny, thonny will run help('modules'), and get dir list.
For the 320 * 240 LCD of M5Stack, it will take four to five screens to display all of these contents.

Perhaps it would be better for me to compile a bin with CIRCUITPY_TERMINALIO=0 by myself.

thanks.

[bh1rio]

CIRCUITPY_TERMINALIO=0 is not a perfect solution either. By doing so, both the built-in terminalio and fontio modules will be gone, and there may be other modules that I haven't noticed are missing as well.

[dhalbert]

You can try putting board.DISPLAY.root_group = None in boot.py. In my testing, this produced nothing on the screen when ctrl-C'ing a program, or when using Thonny.

[todbot]

And for future people who discover this thread: you must put board.DISPLAY.root_group = None in both boot.py and code.py as it seems the display gets recreated after boot.py finishes. (at least on an M5Stack Cardputer)

[konsumer]

board.DISPLAY is not defined on RP2040-zero with ssd1306. This worked in boot.py, though:

import supervisor

supervisor.status_bar.display = False
supervisor.status_bar.console = False

[jepler]

board.DISPLAY is a short hand for "the built in display, if this board has one in its board definition". If you create a display object in your code with a line like display = ssd1306(...) then you'd write display instead of board.DISPLAY.