57 lines
1.6 KiB
Python
57 lines
1.6 KiB
Python
import os
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import sys
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from PIL import Image
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from palette import intensity_to_index
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def convert(image, bpp):
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assert bpp in {8, 4, 2}, bpp
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px_per_byte = 8 // bpp
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px_per_row = 8
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bits_per_byte = 8
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bytes_per_row = (px_per_row // (bits_per_byte // bpp))
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assert image.mode == 'L', image.mode
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width, height = image.size
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buf = bytearray(width * height // px_per_byte)
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for cell_y in range(height//8):
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for cell_x in range(width//8):
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for y in range(8):
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for x in range(8):
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px = im.getpixel((cell_x * 8 + x, cell_y * 8 + y))
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index = intensity_to_index(px)
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buf_ix = x//px_per_byte + (bytes_per_row * (cell_x * 8 + (cell_y * width) + y))
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buf[buf_ix] |= (index << bpp * ((px_per_byte - 1) - (x % px_per_byte)))
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return buf
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def debug(buf, bpp):
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assert bpp in {8, 4, 2}, bpp
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px_per_byte = 8 // bpp
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px_per_row = 8
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bits_per_byte = 8
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bytes_per_row = (px_per_row // (bits_per_byte // bpp))
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bit_mask = (2 ** bpp) - 1
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for row in range(len(buf) // bytes_per_row):
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for x in range(bytes_per_row):
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px = buf[row * bytes_per_row + x]
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for shift in reversed(range(0, px_per_row, bpp)):
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print((px >> shift) & bit_mask, end='')
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print()
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if (row % 8 == 7):
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print()
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in_path = sys.argv[1]
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bpp = int(sys.argv[2])
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out_path = sys.argv[3]
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im = Image.open(in_path)
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buf = convert(im, bpp)
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if 'NBPP_DEBUG' in os.environ:
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debug(buf, bpp)
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with open(out_path, 'wb') as f:
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f.write(buf)
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