68 lines
2 KiB
Python
Executable file
68 lines
2 KiB
Python
Executable file
#!/usr/bin/env python3
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import tempfile
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import subprocess
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import dataclasses
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@dataclasses.dataclass
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class Image:
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width: int
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height: int
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data: bytes
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def convert_pdf(pdfname, args=[]):
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with tempfile.NamedTemporaryFile(suffix='.pbm') as pbmfile:
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subprocess.check_call(["pdftoppm", "-mono", "-singlefile"] + args + [pdfname, pbmfile.name.removesuffix('.pbm')])
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header = pbmfile.readline()
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if header.strip() != b'P4':
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raise ValueError("unrecognised image format")
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width_height = pbmfile.readline().decode('ascii')
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data = bytes(x ^ 0xff for x in pbmfile.read())
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width, height = map(int, width_height.strip().split())
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return Image(width, height, data)
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def convert_pdf_scaled(pdfname, max_width, max_height):
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im = convert_pdf(pdfname)
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aspect = im.width / im.height
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max_aspect = max_width / max_height
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if aspect < max_aspect:
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max_width = int(max_height * aspect) - 1
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else:
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# pdftoppm tends to make it 1px too wide
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max_width -= 1
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max_height = int(max_width / aspect)
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args = ['-scale-to-x', str(max_width), '-scale-to-y', str(max_height)]
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im = convert_pdf(pdfname, args)
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assert im.width <= max_width + 1
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assert im.height <= max_height
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return im
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def pdf2tspl(filename, labelwidth_mm=100, labelheight_mm=150, dpi=203):
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labelwidth = int(round(labelwidth_mm / 25.4 * dpi))
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labelheight = int(round(labelheight_mm / 25.4 * dpi))
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image = convert_pdf_scaled(filename, labelwidth, labelheight)
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paste_x = (labelwidth - image.width) // 2
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paste_y = (labelheight - image.height) // 2
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row_bytes = (image.width + 7) // 8
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command = b"\r\n\r\nSIZE %d mm\r\nCLS\r\nBITMAP %d,%d,%d,%d,0," % (labelwidth_mm, paste_x, paste_y, row_bytes, image.height)
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command += image.data
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command += b"\r\nPRINT 1,1\r\n"
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return command
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def print_pdf(filename):
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cmd = pdf2tspl(filename)
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with open("/dev/usb/lp0", "r+b") as prn:
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prn.write(cmd)
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if __name__ == "__main__":
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import sys
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print_pdf(sys.argv[1])
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