add optional pixel_buffer and output_buffer args to NeoPixel to pass …

[rhooper]

…in own buffers

Workaround for Issue #65

[tannewt]

Why do we want this? Usually we only have buffers passed in if the object is short lived. Neopixel is long lived so it seems like we don't need this.

[rhooper]

I don't know if we do. There might be something about #65 and what @sta-c0000 is doing that's worth supporting directly in NeoPixel, or if we should document how to use _pixelbuf with neopixel_write directly instead? This PR can be discarded if we don't want to support direct .buf updates (and the https://github.com/adafruit/circuitpython/issues/2502 can also be closed).

[thanpolas]

Hey @rhooper fwiw I tried this patch on my local and i still get the error:

Traceback (most recent call last):
  File "zzz.py", line 6, in <module>
    pixels[0] = (255, 0, 0)
  File "/home/pi/.local/lib/python3.7/site-packages/adafruit_pypixelbuf.py", line 260, in __setitem__
    self.show()
  File "/home/pi/.local/lib/python3.7/site-packages/neopixel.py", line 163, in show
    neopixel_write(self.pin, self.buf)
AttributeError: 'NeoPixel' object has no attribute 'buf'

My code:

import board
import neopixel

pixels = neopixel.NeoPixel(board.D18, 8)

pixels[0] = (255, 0, 0)

pixels.fill((0, 255, 0))

[Maxternight]

Shouldn't you warn the users when you make these kind of changes? Im having the same problem as @thanpolas, I also tried to use the optional_buffer but it says that the init function has no optional_buffer parameter so i don't know what to do. I really wanted to change the color of a certain number of pixels not all like the fill function and I don't know how to do it now. Can you guys help ?

[rhooper]

@Maxternight making things break wasn't intentional. You probably don't want this PR.

You can change arbitrary pixels with something like:

import board
import neopixel

pixels = neopixel.NeoPixel(board.NEOPIXEL, 10)
pixels[0] = (255, 0, 0)
pixels[3:6] = [(255, 0, 0), (0, 0, 255), (255,255,255)]
print(pixels)

which would set the first and 4th, 5th, and 6th pixels

[ladyada]

@Maxternight @thanpolas hi i just pushed a fix, please reinstall adafruit-circuitpython-pypixelbuf (uninstall and reinstall thru pip)

[Maxternight]

@rhooper im sorry for my comment, i know you guys work hard and sometimes some bugs can appear. It all works fine now, thank you @rhooper and @ladyada.