52 lines
1.5 KiB
Python
52 lines
1.5 KiB
Python
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#!/usr/bin/env python3
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import tempfile
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import subprocess
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from PIL import Image, ImageOps
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def convert_pdf(pdfname, args=[]):
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pbmfile = tempfile.NamedTemporaryFile(suffix='.pbm')
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subprocess.check_call(["pdftoppm", "-mono", "-singlefile"] + args + [pdfname, pbmfile.name.removesuffix('.pbm')])
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return Image.open(pbmfile)
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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.size[0] / im.size[1]
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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.size[0] <= max_width
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assert im.size[1] <= max_height
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return im
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def label_to_command(image, labelwidth=810, labelheight=1200):
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"Centre the image on the label and generate a print command"
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assert im.size[0] <= labelwidth
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assert im.size[1] <= labelheight
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paste_x = (labelwidth - im.size[0]) // 2
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paste_y = (labelheight - im.size[1]) // 2
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row_bytes = (im.size[0] + 7) // 8
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command = b"CLS\r\nBITMAP %d,%d,%d,%d,0," % (paste_x, paste_y, row_bytes, im.size[1])
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command += image.tobytes()
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command += b"\r\nPRINT 1,1\r\nSOUND 3,200\r\n"
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return command
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im = convert_pdf_scaled("test.pdf", 800, 1200)
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cmd = label_to_command(im)
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with open("/dev/usb/lp0", "r+b") as prn:
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prn.write(cmd)
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