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100 lines
2.9 KiB
Python
100 lines
2.9 KiB
Python
#!/usr/bin/env python3
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import cairo
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import math
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from datetime import datetime
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import calendar
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import random
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import colorsys
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# dimensions of the output image
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# how much should the phases be offset?
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WAVE_OFFSET = math.pi / random.choice([1, 2, 4]) # -1.9
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# background black? White otherwise:
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DARK_BG = True
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# precision of the calculation
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PRECISION = 10000
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def get_color_from_date(date: datetime) -> tuple[float, float, float]:
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"""Return a color based on the progress through the year."""
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# a day between 1 and 365 (inclusive)
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today = date.timetuple().tm_yday
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days_in_year = 365 + calendar.isleap(date.year)
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# between 0 and 1, how far through the year are we?
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progress = today / days_in_year
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return colorsys.hsv_to_rgb(progress, 1, 0.9)
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def get_amplitude_from_date(date: datetime, waves) -> float:
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"""Return the amplitude of waves, based on progress through the month."""
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days_in_month = calendar.monthrange(date.year, date.month)[1]
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max_amp = 1 / waves / 2
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return date.day / days_in_month * max_amp
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def create_wpotd(
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width: int, height: int, date: datetime = datetime.now(), dark: bool = True
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) -> cairo.ImageSurface:
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surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, width, height)
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ctx = cairo.Context(surface)
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ctx.scale(width, height) # Normalizing the canvas
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# ctx.set_antialias(cairo.Antialias.BEST)
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lastpoints = [(x / PRECISION, 0) for x in range(PRECISION + 1)]
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frequency = random.randint(10, 40)
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waves = date.month
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amplitude = get_amplitude_from_date(date, waves)
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r, g, b = get_color_from_date(date)
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alpha_step = 1 / waves
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# background color
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if dark:
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ctx.set_source_rgb(0, 0, 0)
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else:
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ctx.set_source_rgb(255, 255, 255)
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ctx.rectangle(0, 0, 1, 1)
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ctx.fill()
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wave_height = 1 / waves
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step_size = 1 / PRECISION
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for wave_index in range(waves + 1):
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points = []
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x = 0
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while x < 1:
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# step along, create points along the wave
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y = amplitude * math.sin(frequency * x + (wave_index * WAVE_OFFSET))
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points.append((x, (y + (0.5 + wave_index) * wave_height)))
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x += step_size
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# print(f'Draw {len(points)} points for curve {num}')
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else:
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# make more transparent toward bottom
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ctx.set_source_rgba(r, g, b, 1 - (alpha_step * wave_index))
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# draw waves
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ctx.move_to(*points[0])
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for p in points[1:]:
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ctx.line_to(*p)
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ctx.set_line_width(0.0004)
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ctx.stroke_preserve()
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for p in reversed(lastpoints):
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ctx.line_to(*p)
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ctx.line_to(*points[0])
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ctx.fill()
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lastpoints = points
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return surface
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# surface.write_to_png(output) # Output to PNG
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def main():
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output = create_wpotd(1920, 1080, dark=False)
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output.write_to_png("out/waves.png")
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if __name__ == "__main__":
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main()
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