tween() without start parameter non-linear fade

[rowlap]

start is an optional parameter to tween(), with the documented default of "the current state".

The problem is the implementation literally assigns a reference to the _values list, without taking a copy. As such, when _values changes during the loop, so does start as they refer to the same list.

Link to code at time of writing.

Steps to reproduce:

from piglow import tween

for _ in range(3):
    tween(2.0, [255] * 18)
    tween(2.0, [0] * 18)

for _ in range(3):
    tween(2.0, start=[0]*18, end=[255]*18)
    tween(2.0, start=[255]*18, end=[0]*18)

What happened:
In the first loop, LEDs fade in/out much faster than the second loop.

What's expected:
Both loops give the same result.

[Gadgetoid]

I wish every issue was this detailed and descriptive. Thank you for reporting and subsequently fixing this.

[Gadgetoid]

Published in release v1.2.5 - https://github.com/pimoroni/piglow/releases/tag/v1.2.5