From f43b07b20a416387ebd867774e88e0129ac9f06b Mon Sep 17 00:00:00 2001
From: Elena ``of Valhalla'' Grandi <valhalla@trueelena.org>
Date: Tue, 19 Oct 2021 08:36:06 +0200
Subject: Impose a pdf on an A6 booklet with 16 pages signature

---
 a6_book.py | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100755 a6_book.py

diff --git a/a6_book.py b/a6_book.py
new file mode 100755
index 0000000..189018f
--- /dev/null
+++ b/a6_book.py
@@ -0,0 +1,66 @@
+#!/usr/bin/env python3
+
+import argparse
+import os.path
+import subprocess
+
+
+SIGNATURE = (
+    15, 0, 13, 2,
+    1, 14, 3, 12,
+    11, 4, 9, 6,
+    5, 10, 7, 8,
+)
+
+
+def get_parser():
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "--file", '-f',
+        help="Name of the PDF file",
+    )
+    parser.add_argument(
+        "pagespec",
+        help="Page selection. At the moment only '<start>-<end>' is supported"
+    )
+    return parser
+
+
+def main():
+    parser = get_parser()
+    args = parser.parse_args()
+    pspec = args.pagespec.split('-')
+    try:
+        start = int(pspec[0])
+        end = int(pspec[1])
+    except ValueError:
+        parser.print_usage()
+    except IndexError:
+        parser.print_usage()
+
+    pages = [str(i) for i in range(start, end+1)]
+    if len(pages) % 16 != 0:
+        empty = 16 - len(pages) % 16
+        pages = pages + ["{}"] * empty
+
+    rearranged = []
+    while pages:
+        for i in SIGNATURE:
+            rearranged.append(pages[i])
+        pages = pages[16:]
+
+    base, ext = os.path.splitext(args.file)
+    out_fname = base + '-book' + ext
+
+    subprocess.run([
+       'pdfjam',
+       '--nup', '2x2',
+       #'--no-tidy',
+       '-o', out_fname,
+       args.file,
+       ','.join(rearranged)
+    ])
+
+
+if __name__ == "__main__":
+    main()
-- 
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