Rainbow Notice for CircuitPython Day 9/9/2020

code - rainbow CircuitPython day.py

import board
import terminalio
import displayio
from adafruit_display_text import bitmap_label as label

def wheel(pos):
    # input a value 0 to 255 to get a color value
    # the colors are a transition r-g-b-back to r.
    if pos < 1 or pos > 255:
        return (0,0,0)
    if pos < 85:
        return (255-pos*3, pos*3, 0)
    if pos < 170:
        pos -=85
        return (0, 255-pos*3, pos *3)
    pos -= 170
    return (pos *3, 0, 255-pos *3)


def increment_palette(target_bitmap, xshift, source_bitmap):
    # copy source_bitmap into the target_bitmap
    # with an offset, including wrap-around
    xshift = xshift % source_bitmap.width
    if xshift <= target_bitmap.width:
        target_bitmap.blit(xshift, 0, source_bitmap)
    target_bitmap.blit(0,0, source_bitmap, x1=(source_bitmap.width-xshift))


if "DISPLAY" not in dir(board):
    # Setup the LCD display with driver
    # You may need to change this to match the display driver for the chipset
    # used on your display
    from adafruit_ili9341 import ILI9341

    displayio.release_displays()

    # setup the SPI bus
    spi = board.SPI()
    tft_cs = board.D9  # arbitrary, pin not used
    tft_dc = board.D10
    tft_backlight = board.D12
    tft_reset = board.D11

    while not spi.try_lock():
        spi.configure(baudrate=32000000)
    spi.unlock()

    display_bus = displayio.FourWire(
        spi,
        command=tft_dc,
        chip_select=tft_cs,
        reset=tft_reset,
        baudrate=32000000,
        polarity=1,
        phase=1,
    )

    # Number of pixels in the display
    DISPLAY_WIDTH = 320
    DISPLAY_HEIGHT = 240

    # create the display
    display = ILI9341(
        display_bus,
        width=DISPLAY_WIDTH,
        height=DISPLAY_HEIGHT,
        rotation=180,  # The rotation can be adjusted to match your configuration.
        auto_refresh=True,
        native_frames_per_second=90,
    )

    # reset the display to show nothing.
    display.show(None)
else:
    # built-in display
    display = board.DISPLAY


# Setup file locations for BDF font files
font_files = [
    'fonts/Helvetica-Bold-16.bdf',
    #'fonts/Fayette-HandwrittenScript-64.bdf',
    #'fonts/Cornerstone-84.bdf',
    'fonts/GothamBlack-54.bdf'
]

print('Preparing for CircuitPython Day...')

font_list = []

for i, font_file in enumerate(font_files):

    from adafruit_bitmap_font import bitmap_font
    this_font = bitmap_font.load_font(font_file)
    font_list.append(this_font)

import time


# create the rainbow text outline

text = "2020"

text_area = label.Label(font_list[1], text=text, 
    color= None, # use transparent text, black background
    background_color=0x000000, background_tight=True,
    anchor_point=(0.5,0.5), 
    max_glyphs=10,
    anchored_position=(display.width/2, display.height/2),
    line_spacing=1.0,
    scale=1
)


bitmap_width=text_area.bounding_box[2]
bitmap_height=text_area.bounding_box[3]

# create a rainbow colored bitmap that will be copied into a bitmap behind the text.
rainbow_bitmap = displayio.Bitmap(255, bitmap_height, 255)
palette=displayio.Palette(255)

for i in range (0,255):
    palette[i]=int(''.join('%02x'%i for i in wheel(i)),16)

for y in range(rainbow_bitmap.height):
    for x in range(rainbow_bitmap.width):
        rainbow_bitmap[x,y]=max(1,(x+1)%255)

# this is the bitmap behind the text
display_bitmap = displayio.Bitmap(bitmap_width, bitmap_height, 255)

display_bitmap.blit(0,0, rainbow_bitmap) # initialize with the rainbow color

# Tilegrid that holds the bitmap behind the text
rainbow_tile=displayio.TileGrid(display_bitmap, pixel_shader=palette, 
                        x=text_area.x+text_area.bounding_box[0], 
                        y=text_area.y+text_area.bounding_box[1])


# create the purple text

text2='CircuitPython Day'
text_area2 = label.Label(font_list[0], text=text2, 
    color= 0xFF00FF,
    background_color=None, background_tight=True,
    anchor_point=(0.5,0.5), 
    max_glyphs=10,
    anchored_position=(display.width/2, display.height/4),
    line_spacing=1.0,
    scale=2
)


text3='09/09/2020'
text_area3 = label.Label(font_list[0], text=text3, 
    color= 0xFF00FF,
    background_color=None, background_tight=True,
    anchor_point=(0.5,0.5), 
    max_glyphs=10,
    anchored_position=(display.width/2, display.height*5/6),
    line_spacing=1.0,
    scale=2
)


my_group=displayio.Group(max_size=4)

my_group.append(rainbow_tile)
my_group.append(text_area)
my_group.append(text_area2)
my_group.append(text_area3)


display.show(my_group)


i=1
while True:

    increment_palette(display_bitmap, (5*i), rainbow_bitmap)
    i += 1