added usage info

README.md

@@ -1,2 +1,7 @@
-# asn-barcodes
+# ASN-Barcodes
 
+This tool can be used to generate ASN Barcodes for paperless-ngx. Usage:
+
+```sh
+python asn-barcodes.py POSITION COUNT
+```

asn-barcodes.py

@@ -0,0 +1,74 @@
+try:
+    import sys
+    import argparse
+    import barcode
+    from barcode import Code128
+    from io import BytesIO
+    from reportlab.lib.pagesizes import A4
+    from reportlab.lib.units import mm
+    from reportlab.pdfgen import canvas
+    from reportlab.lib.utils import ImageReader
+except:
+    print("Unable to load libraries. Install them with 'pip install python-barcode reportlab'")
+    sys.exit(1)
+
+# Define arguments
+
+def check_positive(value):
+    try:
+        value = int(value)
+        if value <= 0:
+            raise argparse.ArgumentTypeError("{} is not a positive integer".format(value))
+    except:
+        raise argparse.ArgumentTypeError("{} is not an integer".format(value))
+    return value
+
+parser = argparse.ArgumentParser(prog="asn-barcodes.py", description="This tool can be used to generate ASN Barcodes for paperless-ngx.")
+parser.add_argument('--version', action='version', version='%(prog)s 1.0')
+parser.add_argument("position", help="Number of the first ASN-Barcode to generate", metavar="POSITION", type=check_positive)
+parser.add_argument("count", help="Number of ASN-Barcodes to generate", metavar="COUNT", type=check_positive)
+parser.add_argument("-o", "--output", default="asn-barcodes", dest="output", help="Destination file name", metavar="")
+args = parser.parse_args()
+
+start = int(args.position)
+end = int(args.position) + int(args.count)
+
+# Generate barcodes
+barcodes = []
+for i in range(start, end):
+    barcode_value = 'ASN' + str(i).zfill(4)
+    barcode_image = Code128(barcode_value, writer=barcode.writer.ImageWriter()).render()
+    barcodes.append((barcode_value, barcode_image))
+
+# Create PDF document with barcodes formatted for Avery L7871 Labels
+pdf_file = args.output + ".pdf"
+c = canvas.Canvas(pdf_file, pagesize=A4)
+width, height = A4
+page_left_margin = 16.1 * mm
+page_bottom_margin = 13.5 * mm
+label_width = 25.4 * mm
+label_height = 10 * mm
+horizontal_gap = 0.25 * mm
+vertical_gap = 0 * mm
+rows = 27
+columns = 7
+x = page_left_margin
+y = height - page_bottom_margin
+for i, (barcode_value, barcode_image) in enumerate(barcodes):
+    if i > 0 and i % (rows * columns) == 0:
+        c.showPage()
+        x = page_left_margin
+        y = height - page_bottom_margin
+    # Convert barcode image to BytesIO object
+    barcode_image_file = BytesIO()
+    barcode_image.save(barcode_image_file, format='PNG')
+    barcode_image_file.seek(0)
+    # Draw barcode image on label
+    img = ImageReader(barcode_image_file)
+    c.drawImage(img, x, y - label_height, width=label_width, height=label_height)
+    x += label_width + horizontal_gap
+    if i % columns == columns - 1:
+        x = page_left_margin
+        y -= label_height + vertical_gap
+c.save()
+print(f"Generated {i + 1} barcodes with ASN from {start} to {end-1} in ./{pdf_file}")