Updates to pixelbuf API - Addresses #884

[rhooper]

This work-in-progress still requires some thorough testing. It switches over _pixelbuf to the same string based API as pypixelbuf.

Early feedback would be highly welcome, @dhalbert @tannewt

Also thoughts on what a good test suite looks like would help me.

[tannewt]

Looking good here! Just a couple comments. I'm a bit torn about having the constants for every order still but it does give us the ability to change it later.

[ladyada]

@rhooper hi - what are ya currently blocking on for this PR - we can get some help to wrap up this PR.

[rhooper]

@ladyada

From the top of my head, these are the remaining tasks:

• Free up time somehow!
• Sort out making it so native method calls can call python subclass overrides (specifically so the native .fill() can call .show() on the python subclass). This is needed for auto_write to work properly with the native .fill(). We could skip native .fill() for now.
• Finish writing pypixelbuf so that implementations without pixelbuf work
• Test and merge the neopixel changes that work with pixelbuf (and pypixelbuf)
• Test and merge adafruit_dotstar changes that work with pixelbuf (and pypixelbuf)
• Test Test Test
• Update which neopixel and dotstar libs are frozen in

[ladyada]

@rhooper would it be ok for other folks to implement/test some of these TODOs?

[rhooper]

@ladyada absolutely fine with me. the more people that know the changes the better!
all i’d ask is that work be coordinated so i don’t spend time doing something someone else is working on.

[ladyada]

sure, they'll post here in this thread

[rhooper]

I worked around the native .fill() method being unable to call .show() on subclasses using a helper function in _pixelbuf instead.

[rhooper]

Dotstar and Neopixel changes appear to work, but I need some assistance gathering up examples to test compatibility.

adafruit/Adafruit_CircuitPython_NeoPixel#59
adafruit/Adafruit_CircuitPython_DotStar#42

[rhooper]

Pypixelbuf has had some testing done - seems to work - but needs the same kind of testing as the Dotstar and NeoPixel PR. It also needs putting in pypi so that the Dotstar and Neopixel builds can pass.

adafruit/Adafruit_CircuitPython_Pypixelbuf#3

[tannewt]

Really really close. The show stuff looks fine except the name. Another questions about unused param but good otherwise.

[tannewt]

This looks good to me! Thank you for your incredible persistence. @dhalbert you will need to approve as well or at least dismiss your review.

[dhalbert]

👍 Thank you for all this work!!

[ladyada]

💯 💯 🔥 🏅 💯 💯 to everyone who helped get this over the finish line - you are heros! many glowy projects will thank u :)

[siddacious]

:🎉🎉🎉Whoooo🎉🎉🎉🥳

Awesome contribution, thank you! Much glow will be had