another displayio demo

bubbles.py

# SPDX-FileCopyrightText: Copyright (c) 2021 Randall Bohn (dexter)
#
# SPDX-License-Identifier: MIT
"""Bubbles"""
# circup install adafruit_display_shapes
# circup install adafruit_fancyled
import random
import time
import displayio
import framebufferio
import videocore

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

# broadcom HDMI display on raspberry pi zero 2 W
displayio.release_displays()
fb = videocore.Framebuffer(1920//2, 1080//2)
display = framebufferio.FramebufferDisplay(fb)
#display.rotation=270

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

hotwheel = [
    fancy.CRGB(32,0,0),
    fancy.CRGB(240,0,0),
    fancy.CRGB(240,240,0),
    fancy.CRGB(24,24,255),
    fancy.CRGB(128,255,240)]

ncolors=64
spectrum = displayio.Palette(ncolors)
for c in range(ncolors):
    color = fancy.palette_lookup(hotwheel, c/ncolors)
    spectrum[c] = color.pack()
bitmap = displayio.Bitmap(ncolors,24, ncolors)
for x in range(ncolors):
    for y in range(24):
        bitmap[x,y]=x
tg = displayio.TileGrid(bitmap, pixel_shader=spectrum)
splash.append(tg)

bubbles = displayio.Group()
for _ in range(24):
    x = random.randrange(128,256)
    y = random.randrange(0,display.height)
    r = random.randrange(8,24)
    color=random.choice(spectrum)
    #bubbles.append(Circle(x,y,r,fill=0,stroke=1,outline=color))
    bubbles.append(Circle(x,y,r,fill=color))

splash.append(bubbles)

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(-5,0)
        if shape.y < -9: shape.y = display.height + 6

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