another displayio demo

snowflakes.py

# SPDX-FileCopyrightText: Copyright (c) 2021 Randall Bohn (dexter)
#
# SPDX-License-Identifier: MIT
"""snowflakes"""
# like bubbles but they fall from they sky
# circup install adafruit_display_shapes
# circup install adafruit_fancyled
import random
import time
import displayio

from adafruit_display_shapes.circle import Circle
import adafruit_fancyled.adafruit_fancyled as fancy

import board
display = board.DISPLAY

splash = displayio.Group()
display.show(splash)

september = [fancy.CRGB(255,0,0), fancy.CRGB(255,240,0), fancy.CRGB(128,255,0)]
ice = [fancy.CRGB(255,255,255), fancy.CRGB(240,240,240), 
    fancy.CRGB(255,255,255), fancy.CRGB(128,255,255)]
snow = ice[:2]
ncolors=64

def fill_palette(palette, gradient):
    n = len(palette)
    for c in range(n):
        color = fancy.palette_lookup(gradient, c/n)
        palette[c] = color.pack()
    return palette

palette = displayio.Palette(ncolors)
fill_palette(palette, snow)

def stripe(palette, width, height):
    n = len(palette)
    bitmap = displayio.Bitmap(width, height, n)
    for x in range(width):
        for y in range(height):
            bitmap[x,y] = int(n * x/width)
    return bitmap
    
bitmap = stripe(palette, display.width, 16)
tg = displayio.TileGrid(bitmap, pixel_shader=palette)

bubbles = displayio.Group()
for _ in range(24):
    x = random.randrange(12,display.width-12)
    y = random.randrange(0,display.height)
    r = random.randrange(2,4)
    color=random.choice(palette)
    #bubbles.append(Circle(x,y,r,fill=0,stroke=1,outline=color))
    bubbles.append(Circle(x,y,r,fill=color))

splash.append(bubbles)
splash.append(tg)

def herd(group):
    for shape in group:
        shape.x += random.randint(-2,2)
        if shape.x < 9: shape.x = display.width - 18
        if shape.x > display.width - 9: shape.x = 18
        shape.y += random.randint(0,5)
        if shape.y > display.height + 6: shape.y = -12

from supervisor import runtime as RT
while not RT.serial_bytes_available:
    time.sleep(0.05)
    herd(bubbles)