Added a tool to extract pages from a PDF.

asl_rulebook2/utils.py

@@ -4,7 +4,7 @@ import re
 
 # ---------------------------------------------------------------------
 
-def parse_page_numbers( val ):
+def parse_page_numbers( val, offset=0 ):
     """Parse a list of page numbers.
 
     We recognize a list of page numbers, and/or ranges e.g. 1,2,5-9,13.
@@ -17,4 +17,4 @@ def parse_page_numbers( val ):
                 vals.update( range( int(mo.group(1)), int(mo.group(2))+1 ) )
             else:
                 vals.add( int(v) )
-    return vals
+    return [ v+offset for v in vals ]

bin/extract_pages.py

@@ -0,0 +1,49 @@
+#!/usr/bin/env python3
+""" Extract pages from a PDF. """
+
+import click
+from pikepdf import Pdf, Page, OutlineItem, Encryption, make_page_destination
+
+from asl_rulebook2.pdf import PdfDoc
+from asl_rulebook2.utils import parse_page_numbers
+
+# ---------------------------------------------------------------------
+
+@click.command()
+@click.argument( "pdf_file", nargs=1, type=click.Path(exists=True,dir_okay=False) )
+@click.option( "--output","-o","output_fname", required=True, type=click.Path(dir_okay=False), help="Output PDF file" )
+@click.option( "--pages","-p", help="Page(s) to dump (e.g. 2,5,9-15)." )
+def main( pdf_file, output_fname, pages ):
+    """Extract pages from a PDF."""
+
+    # NOTE: This extracts pages from the eASLRB, so we can work on specific parts of it without having to load
+    # the entire document each time. In particular, it maintains the internal PDF strucuture of each page.
+    # The files as small as you might expect (e.g. extracting a single page results in a file only about half
+    # the size), but processing them are significantly faster.
+
+    # process the command-line arguments
+    pages = parse_page_numbers( pages, offset=-1 )
+
+    print( "Loading PDF:", pdf_file )
+    with Pdf.open( pdf_file ) as pdf:
+
+        # delete the TOC
+        print( "Removing the TOC..." )
+        with pdf.open_outline() as outline:
+            while outline.root:
+                del outline.root[-1]
+
+        # extract the specified pages
+        print( "Extracting pages:", ", ".join( str(p) for p in sorted(pages) ) )
+        for page_no in range( len(pdf.pages)-1, -1, -1 ):
+            if page_no not in pages:
+                del pdf.pages[ page_no ]
+
+        # save the new PDF
+        print( "Saving file:", output_fname )
+        pdf.save( output_fname )
+
+# ---------------------------------------------------------------------
+
+if __name__ == "__main__":
+    main() #pylint: disable=no-value-for-parameter

requirements.txt

@@ -1,4 +1,5 @@
 # python 3.8.7
 
 pdfminer.six==20201018
+pikepdf==2.5.2
 click==7.1.2