84 lines
1.7 KiB
Python
84 lines
1.7 KiB
Python
#!/usr/bin/env python3
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import sys
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import numpy as np
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def lament(*args, **kwargs):
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return print(*args, file=sys.stderr, **kwargs)
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def colorize(x):
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return x * 17 % 256
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def render(row, scale):
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grays = colorize(row)
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if scale > 1:
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grays = np.repeat(grays, scale)
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line = " ".join(str(x) for x in grays)
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for y in range(scale):
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print(line)
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def limit(row): # in-place
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row[row < 0] = 0
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row[row > 15] = 15
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return row
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def initialize(width):
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row = np.zeros(width, int)
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value = 0
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for i in range(width):
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if np.random.randint(8) == 0: # only change values occasionally
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value = np.random.randint(16)
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row[i] = value
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limit(row)
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return row
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name, args = sys.argv[0], sys.argv[1:]
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if len(args) == 0:
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rule_lut = None
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elif len(args) == 16:
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rule_lut = [int(x.strip(",")) for x in args]
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else:
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lament(f"usage: {name}")
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lament(f"usage: {name} {{rules 1 through 16}}")
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sys.exit(1)
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scale = 3
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width, height = 960 // scale, 960 // scale
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if rule_lut is None:
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rule_lut = np.random.randint(-2, 2 + 1, size=(4, 4))
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lament(" ".join(f"{x:+2}" for x in rule_lut.flat))
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else:
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rule_lut = np.array(rule_lut).reshape(4, 4)
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print("P2") # magic code for an ascii Portable GrayMap (PGM) file
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print(width * scale, height * scale)
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print(255) # maximum color value
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row = initialize(width)
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for i in range(height):
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# left, center, right:
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L = np.roll(row, 1)
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C = row.copy()
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R = np.roll(row, -1)
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diffusion = (L + C + C + R + 2) // 4
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# v = [0,1,2,3,1,0,3,2,2,3,0,1,3,2,1,0][V]
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y = (L ^ (L >> 2)) % 4
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x = (R ^ (R >> 2)) % 4
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delta = rule_lut[y, x]
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row = diffusion + delta
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limit(row)
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render(row, scale)
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