color.py

from tree import Tree
from colorzero import Color

tree = Tree(25, mosi_pin=12, clock_pin=25)

while True:
    try:
        txt = input('Enter a colour name: ')
        c = Color(txt)
        print(c)
        tree.color = c
    except ValueError:
        print("Invalid colour")

gradient.py

from tree import Tree
from colorzero import Color
from time import sleep

tree = Tree(25, mosi_pin=12, clock_pin=25)

y = Color('yellow')
r = Color('red')
while True:
    for c in y.gradient(r, steps=20):
        print(c)
        tree.color = c
        sleep(0.01)

rgb.py

from tree import Tree
from time import sleep

tree = Tree(25, mosi_pin=12, clock_pin=25)

while True:
    for c in ((1, 0, 0), (0, 1, 0), (0, 0, 1)):
        print(c)
        tree.color = c
        sleep(0.1)

tree.py

from gpiozero import SPIDevice
from colorzero import Color, Hue

class Tree(SPIDevice):
    def __init__(self, pixels, brightness=0.5, *args, **kwargs):
        super(Tree, self).__init__(*args, **kwargs)
        self._pixels = pixels
        self._value = [(0, 0, 0)] * pixels
        self.brightness = brightness
        self.off()

    @property
    def color(self):
        return None

    @color.setter
    def color(self, c):
        r, b, g = c
        self.value = ((r, g, b),) * self._pixels

    @property
    def brightness(self):
        return self._brightness

    @brightness.setter
    def brightness(self, brightness):
        max_brightness = 31
        self._brightness_bits = int(brightness * max_brightness)
        self._brightness = brightness
        self.value = self.value

    @property
    def value(self):
        return self._value

    @value.setter
    def value(self, value):
        start_of_frame = [0]*4
        end_of_frame = [0]*5
                     # SSSBBBBB (start, brightness)
        brightness = 0b11100000 | self._brightness_bits
        pixels = [[int(255*v) for v in p] for p in value]
        pixels = [[brightness, b, g, r] for r, g, b in pixels]
        pixels = [i for p in pixels for i in p]
        data = start_of_frame + pixels + end_of_frame
        self._spi.transfer(data)
        self._value = value

    def on(self):
        self.value = ((1, 1, 1),) * self._pixels

    def off(self):
        self.value = ((0, 0, 0),) * self._pixels

    def close(self):
        self.off()
        super(Tree, self).close()