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Python

#!/usr/bin/env python3
import cairo
import math
from datetime import datetime
import calendar
import random
import colorsys
from utils import random_color
# dimensions of the output image
WIDTH, HEIGHT = 1920, 1080
# how much should the phases be offset?
WAVE_OFFSET = math.pi / random.choice([1, 2, 4]) #-1.9
# amplitude of the sine wave
#AMPLITUDE = 9
# only 1 color with shades?
MONOCHROME = True
# works only if monochrome is set - uses todays date as base for the color
DATE_BASED_COLOR = True
DATE_BASED_AMPLITUDE = True
DATE_BASED_COUNT = True
# background black? White otherwise:
DARK_BG = True
# precision of the calculation
PRECISION = 10000
def days_color(date: datetime) -> tuple[float, float, float]:
'''Return a color based on the progress through the year.'''
# a day between 1 and 365 (inclusive)
today = date.timetuple().tm_yday
days_in_year = 365 + calendar.isleap(date.year)
# between 0 and 1, how far through the year are we?
progress = today/days_in_year
return colorsys.hsv_to_rgb(progress, 1, 0.9)
def days_amp(date: datetime, waves) -> float:
'''Return the amplitude of waves, based on progress through the month.'''
days_in_month = calendar.monthrange(date.year, date.month)[1]
max_amp = 1/waves/2
return date.day/days_in_month * max_amp
def create_wpotd(width: int, height: int):
#TODO: return a `file`-like object
surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, width, height)
ctx = cairo.Context(surface)
ctx.scale(width, height) # Normalizing the canvas
#ctx.set_antialias(cairo.Antialias.BEST)
lastpoints = [(x/PRECISION, 0) for x in range(PRECISION+1)]
date = datetime.today()
frequency = random.randint(10, 40)
if DATE_BASED_COUNT:
# generate as many waves as the number of the current month
waves = date.month
else:
waves = 12
if DATE_BASED_AMPLITUDE:
amplitude = days_amp(date, waves)
else:
amplitude = 25
if MONOCHROME:
if DATE_BASED_COLOR:
r, g, b = days_color(date) #datetime.datetime.now())
else:
r, g, b = random_color()
alpha_step = 1/waves
if DARK_BG:
# make bg black
ctx.rectangle(0, 0, 1, 1)
ctx.set_source_rgb(0, 0, 0)
ctx.fill()
wave_height = 1/waves
step_size = 1/PRECISION
for wave_index in range(waves+1):
if not MONOCHROME:
r, g, b = random_color()
points = []
x = 0
while x < 1:
# step along, create points along the wave
y = amplitude * math.sin(frequency * x + (wave_index * WAVE_OFFSET))
points.append((x, (y + (0.5 + wave_index)*wave_height)))
x += step_size
#print(f'Draw {len(points)} points for curve {num}')
if not MONOCHROME:
ctx.set_source_rgb(r, g, b)
else:
# make more transparent toward bottom
ctx.set_source_rgba(r, g, b, 1 - (alpha_step * wave_index))
# draw waves
ctx.move_to(*points[0])
for p in points[1:]:
ctx.line_to(*p)
ctx.set_line_width(0.0004)
ctx.stroke_preserve()
for p in reversed(lastpoints):
ctx.line_to(*p)
ctx.line_to(*points[0])
ctx.fill()
lastpoints = points
return surface
#surface.write_to_png(output) # Output to PNG
def main():
output = create_wpotd(1920, 1080)
output.write_to_png('out/waves.png')
if __name__ == '__main__':
main()