displayio.Bitmap value_count max should be 65536 not 65535

[rimwolf-redux]

CircuitPython version

Adafruit CircuitPython 8.2.6 on 2023-09-12; Adafruit Feather M4 Express with samd51j19

Supplying 65536 as the value_count argument to a displayio.Bitmap constructor yields
an error that value must be 1..65535:

>>> import displayio
>>> bitmap = displayio.Bitmap(160, 120, 65536)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: value_count must be 1-65535
>>>

But in a colorspace like RGB565, all 65536 16-bit values are valid. As for user friendliness, all three of the examples in https://github.com/adafruit/Adafruit_CircuitPython_OV7670/blob/main/examples that use displayio.Bitmap supply 65536 as an argument.

The code in https://github.com/adafruit/circuitpython/blob/main/shared-bindings/displayio/Bitmap.c that calculates the bits (per pixel) from the value_count subtracts 1 from the value_count, so correctly yields 16 for 65536 as well as 65535.

Code/REPL

import displayio
bitmap = displayio.Bitmap(160, 120, 65536)

Behavior

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: value_count must be 1-65535

Description

No response

Additional information

Changing the upper limit to 65536 in the definition of value_count in Bitmap.c (line 67 in the current github version) looks like it would resolve this issue.

[jepler]

I agree! would you be able to submit a pull request to fix this?

[rimwolf-redux]

It's been some time since I've built CircuitPython, but I can give it a shot. This should be against 8.2.x (git checkout 8.2.x) I guess?

[tannewt]

It's been some time since I've built CircuitPython, but I can give it a shot. This should be against 8.2.x (git checkout 8.2.x) I guess?

Yes please. That way it'll get into a stable release more quickly. (We periodically merge it back to main too.)

[rimwolf-redux]

Submitted PR #8434 to fix this issue.

[isacben]

I think this issue is solved. ?

[dhalbert]

Fixed by #8434. Because the PR was not on main, this issue was not closed when that PR was merged.