Add pdf-merge.py script to PDF merging post.

diff --git a/posts/PDF_bookmarks_with_Ghostscript.mdwn b/posts/PDF_bookmarks_with_Ghostscript.mdwn
index af22b97b3a0414ff25fd76c02442032122ea2484..c7fe6da0c4baaa0f84121240bc129fa6eb6fcd22 100644 (file)
--- a/posts/PDF_bookmarks_with_Ghostscript.mdwn
+++ b/posts/PDF_bookmarks_with_Ghostscript.mdwn
@@ -14,9 +14,48 @@ and `pdfmarks` is a text file with contents like:
 
 Nice and easy.
 
+For nested levels, use the `/Count` attribute.  For example:
+
+    [/Count 3 /Title (Chapter 1) /Page 1 /OUT pdfmark
+    [/Count -2 /Title (Section 1.1) /Page 2 /OUT pdfmark
+    [/Title (Section 1.1.1) /Page 3 /OUT pdfmark
+    [/Title (Section 1.1.2) /Page 4 /OUT pdfmark
+    [/Count -1 /Title (Section 1.2) /Page 5 /OUT pdfmark
+    [/Title (Section 1.2.1) /Page 6 /OUT pdfmark
+    [/Title (Section 1.3) /Page 7 /OUT pdfmark
+
+The argument to `/Count` gives the number of immediately subordinate
+bookmarks.  The sign of the argument sets the default display
+(negative for closed, positive for open).
+
+You can also setup the document info dictionary with something like:
+
+    [ /Title (My Test Document)
+      /Author (John Doe)
+      /Subject (pdfmark 3.0)
+      /Keywords (pdfmark, example, test)
+      /DOCINFO pdfmark
+
+If you want more detail, take a look at [Adobe's pdfmark
+reference][reference].
+
+I've bundled the whole pdfmarks-generation bit into a script,
+[[pdf-merge.py]], which generates the pdfmark file and runs
+Ghostscript automatically.  Think of it as a bookmark-preserving
+version of pdftk's `cat`.  The script uses pdftk internally to extract
+bookmark information from the source PDFs.
+
+The script also adds a bit of PostScript to ignore any bookmarks in
+the source PDFs during the Ghostscript run.  The only bookmarks in the
+output will be the ones you specify explicitly in the pdfmarks file.
+If for some reason the automatically generated pdfmarks are not quite
+what you want, the script can pause (via `--ask`) to allow you to
+tweak the pdfmarks manually before running Ghostscript.
+
 [pdftk]: http://www.pdflabs.com/tools/pdftk-the-pdf-toolkit/
 [Ghostscript]: http://ghostscript.com/
 [post]: http://ubuntuforums.org/showthread.php?t=1545064
+[reference]: http://www.adobe.com/content/dam/Adobe/en/devnet/acrobat/pdfs/pdfmark_reference.pdf
 
 [[!tag tags/tools]]
 [[!tag tags/linux]]

diff --git a/posts/PDF_bookmarks_with_Ghostscript/pdf-merge.py b/posts/PDF_bookmarks_with_Ghostscript/pdf-merge.py
new file mode 100755 (executable)
index 0000000..5586e02
--- /dev/null
+++ b/posts/PDF_bookmarks_with_Ghostscript/pdf-merge.py
@@ -0,0 +1,325 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2011 W. Trevor King <wking@drexel.edu>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this program.  If not, see
+# <http://www.gnu.org/licenses/>.
+
+"""Merge PDFs perserving bookmarks.
+"""
+
+import os as _os
+import subprocess as _subprocess
+import sys as _sys
+import tempfile as _tempfile
+
+
+__version__ = '0.1'
+
+
+PDFTK = 'pdftk'
+GS = 'gs'
+
+
+def invoke(args, stdout=None):
+    """
+    >>> invoke(['echo', 'hi', 'there'])
+    'hi there\\n'
+    >>> invoke(['this command does not exist'])
+    Traceback (most recent call last):
+      ...
+    OSError: [Errno 2] No such file or directory
+    """
+    P = _subprocess.PIPE
+    capture_stdout = stdout is None
+    if capture_stdout:
+        stdout = P
+    p = _subprocess.Popen(
+        args, stdin=P, stdout=stdout, stderr=_sys.stderr, shell=False, cwd='.')
+    stdout_,stderr_ = p.communicate()
+    status = p.wait()
+    assert status == 0, status
+    return stdout_
+
+
+class BookmarkedPDF (object):
+    def __init__(self, filename=None):
+        self.filename = filename
+        if self.filename:
+            self.get_bookmarks()
+
+    def get_bookmarks(self):
+        data = invoke([PDFTK, self.filename, 'dump_data'])
+        self.pages,self.bookmarks = self._parse_dump_data(data)
+
+    @staticmethod
+    def _parse_dump_data(data):
+        """
+        >>> from pprint import pprint
+        >>> data = '\\n'.join([
+        ...     'InfoKey: CreationDate',
+        ...     'InfoValue: D:20080502020302Z',
+        ...     'NumberOfPages: 123',
+        ...     'BookmarkTitle: Chapter 1',
+        ...     'BookmarkLevel: 1',
+        ...     'BookmarkPageNumber: 1',
+        ...     'BookmarkTitle: Section 1.1',
+        ...     'BookmarkLevel: 2',
+        ...     'BookmarkPageNumber: 2',
+        ...     'BookmarkTitle: Section 1.1.1',
+        ...     'BookmarkLevel: 3',
+        ...     'BookmarkPageNumber: 3',
+        ...     'BookmarkTitle: Section 1.1.2',
+        ...     'BookmarkLevel: 3',
+        ...     'BookmarkPageNumber: 4',
+        ...     'BookmarkTitle: Section 1.2',
+        ...     'BookmarkLevel: 2',
+        ...     'BookmarkPageNumber: 5',
+        ...     'PageLabelNewIndex: 1',
+        ...     'PageLabelStart: 316',
+        ...     'PageLabelNumStyle: DecimalArabicNumerals',
+        ...     'PageLabelNewIndex: 2',
+        ...     'PageLabelStart: 317',
+        ...     'PageLabelNumStyle: DecimalArabicNumerals',
+        ...     'PageLabelNewIndex: 3',
+        ...     'PageLabelStart: 318',
+        ...     'PageLabelNumStyle: DecimalArabicNumerals',
+        ...     'PageLabelNewIndex: 4',
+        ...     ])
+        >>> pages,bookmarks = BookmarkedPDF._parse_dump_data(data)
+        >>> pages
+        123
+        >>> pprint(bookmarks)
+        [{'level': 1, 'page': 1, 'title': 'Chapter 1'},
+         {'level': 2, 'page': 2, 'title': 'Section 1.1'},
+         {'level': 3, 'page': 3, 'title': 'Section 1.1.1'},
+         {'level': 3, 'page': 4, 'title': 'Section 1.1.2'},
+         {'level': 2, 'page': 5, 'title': 'Section 1.2'}]
+        """
+        pages = None
+        bookmarks = []
+        bookmark_info = {}
+        bookmark_info_fields = ['title', 'level', 'page']
+        for line in data.splitlines():
+            key,value = line.split(': ', 1)
+            if key == 'NumberOfPages':
+                pages = int(value)
+            elif key.startswith('Bookmark'):
+                k = key[len('Bookmark'):].lower()
+                if k in ['level', 'pagenumber']:
+                    if k == 'pagenumber':
+                        k = 'page'
+                    value = int(value)
+                bookmark_info[k] = value
+                ready_for_bookmark = True
+                for field in bookmark_info_fields:
+                    if field not in bookmark_info:
+                        ready_for_bookmark = False
+                        break
+                if ready_for_bookmark:
+                    bookmarks.append(bookmark_info)
+                    bookmark_info = {}
+        return (pages, bookmarks)
+
+
+def generate_pdfmarks(inputs=(), title=None, author=None, keywords=None):
+    """
+    >>> inputs = []
+    >>> for pages,bookmarks in [
+    ...         (1,
+    ...          [{'level': 1, 'page': 1, 'title': 'Table of Contents'}]),
+    ...         (100,
+    ...          [{'level': 1, 'page': 1, 'title': 'Chapter 1'},
+    ...           {'level': 2, 'page': 2, 'title': 'Section 1.1'},
+    ...           {'level': 3, 'page': 3, 'title': 'Section 1.1.1'},
+    ...           {'level': 3, 'page': 4, 'title': 'Section 1.1.2'},
+    ...           {'level': 2, 'page': 5, 'title': 'Section 1.2'}]),
+    ...         (100,
+    ...          [{'level': 1, 'page': 1, 'title': 'Chapter 2'},
+    ...           {'level': 2, 'page': 2, 'title': 'Section 2.1'},
+    ...           {'level': 3, 'page': 3, 'title': 'Section 2.1.1'},
+    ...           {'level': 3, 'page': 4, 'title': 'Section 2.1.2'},
+    ...           {'level': 2, 'page': 5, 'title': 'Section 2.2'}]),
+    ...         ]:
+    ...     pdf = BookmarkedPDF()
+    ...     pdf.pages = pages
+    ...     pdf.bookmarks = bookmarks
+    ...     inputs.append(pdf)
+    >>> print(generate_pdfmarks(inputs=inputs, title='My Book',
+    ...     author='Myself', keywords=['fun', 'witty', 'interesting']))
+    [ /Title (My Book)
+      /Author (Myself)
+      /Keywords (fun, witty, interesting)
+      /DOCINFO pdfmark
+    [ /Title (Table of Contents) /Page 1 [/XYZ null null null] /OUT pdfmark
+    [ /Title (Chapter 1) /Page 2 [/XYZ null null null] /Count -2 /OUT pdfmark
+    [ /Title (Section 1.1) /Page 3 [/XYZ null null null] /Count -2 /OUT pdfmark
+    [ /Title (Section 1.1.1) /Page 4 [/XYZ null null null] /OUT pdfmark
+    [ /Title (Section 1.1.2) /Page 5 [/XYZ null null null] /OUT pdfmark
+    [ /Title (Section 1.2) /Page 6 [/XYZ null null null] /OUT pdfmark
+    [ /Title (Chapter 2) /Page 102 [/XYZ null null null] /Count -2 /OUT pdfmark
+    [ /Title (Section 2.1) /Page 103 [/XYZ null null null] /Count -2 /OUT pdfmark
+    [ /Title (Section 2.1.1) /Page 104 [/XYZ null null null] /OUT pdfmark
+    [ /Title (Section 2.1.2) /Page 105 [/XYZ null null null] /OUT pdfmark
+    [ /Title (Section 2.2) /Page 106 [/XYZ null null null] /OUT pdfmark
+    <BLANKLINE>
+    """
+    pdfmarks = []
+    if title or author or keywords:
+        docinfo = []
+        if title:
+            docinfo.append('/Title ({})'.format(title))
+        if author:
+            docinfo.append('/Author ({})'.format(author))
+        if keywords:
+            docinfo.append('/Keywords ({})'.format(', '.join(keywords)))
+        docinfo.append('/DOCINFO pdfmark')
+        pdfmarks.append('[ {}' .format('\n  '.join(docinfo)))
+    bookmarks = []
+    startpage = 0
+    for pdf in inputs:
+        for bookmark in pdf.bookmarks:
+            mark = dict(bookmark)  # shallow copy
+            mark['page'] += startpage
+            bookmarks.append(mark)
+        startpage += pdf.pages
+    for i,bookmark in enumerate(bookmarks):
+        attributes = [
+            '/Title ({})'.format(bookmark['title']),
+            '/Page {}'.format(bookmark['page']),
+            #'[/XYZ null null null]',  # preserve page zoom and viewport
+            ]
+        count = 0
+        for bmk in bookmarks[i+1:]:
+            if bmk['level'] == bookmark['level']:
+                break
+            if bmk['level'] == bookmark['level'] + 1:
+                count += 1
+        if count:
+            attributes.append('/Count -{}'.format(count))
+        pdfmarks.append('[ {} /OUT pdfmark'.format(' '.join(attributes)))
+    pdfmarks.append('')  # terminal newline
+    return '\n'.join(pdfmarks)
+
+
+def _write_pdfmark_noop_file():
+    # By default, Ghostscript will preserve pdfmarks from the sources PDFs
+    fd,filename = _tempfile.mkstemp(prefix='pdfmark-noop-', text=True)
+    # Make `[... /OUT pdfmark` a no-op.
+    _os.write(fd, """
+% store the original pdfmark
+/originalpdfmark { //pdfmark } bind def
+
+% replace pdfmark with a wrapper that ignores OUT
+/pdfmark
+{
+  {  % begin loop
+
+      { counttomark pop }
+    stopped
+      { /pdfmark errordict /unmatchedmark get exec stop }
+    if
+
+    dup type /nametype ne
+      { /pdfmark errordict /typecheck get exec stop }
+    if
+
+    dup /OUT eq
+      { (Skipping OUT pdfmark\n) print cleartomark exit }
+    if
+
+    originalpdfmark exit
+
+  } loop
+} def
+""")
+    _os.close(fd)
+    return filename
+
+def _write_pdfmark_restore_file():
+    fd,filename = _tempfile.mkstemp(prefix='pdfmark-restore-', text=True)
+    # Restore the default `[... /Out pdfmark` behaviour
+    _os.write(fd, '/pdfmark { originalpdfmark } bind def\n')
+    _os.close(fd)
+    return filename
+
+def _write_markfile(pdfmarks, pause_for_manual_tweaking=False):
+    fd,filename = _tempfile.mkstemp(prefix='pdfmarks-', text=True)
+    if pdfmarks:
+        _os.write(fd, pdfmarks)
+    _os.close(fd)
+    if pause_for_manual_tweaking:
+        print('edit {} as you see fit, and press enter when ready'.format(
+                filename))
+        _sys.stdin.readline()
+    return filename
+
+def merge_pdfs(inputs, output, pdfmarks=None, pause_for_manual_tweaking=False):
+    args = [GS, '-dBATCH', '-dNOPAUSE', '-sDEVICE=pdfwrite']
+    if output:
+        args.append('-sOutputFile={}'.format(output))
+    else:
+        args.extend(['-sOutputFile=-', '-q'])
+    if pdfmarks:
+        mark_noop = _write_pdfmark_noop_file()
+        args.append(mark_noop)
+    args.extend([pdf.filename for pdf in inputs])
+    if pdfmarks:
+        mark_restore = _write_pdfmark_restore_file()
+        args.append(mark_restore)
+    markfile = _write_markfile(
+        pdfmarks=pdfmarks, pause_for_manual_tweaking=pause_for_manual_tweaking)
+    args.append(markfile)
+    print('preparing to execute: {}'.format(args))
+    invoke(args, stdout=_sys.stdout)
+    if pdfmarks:
+        _os.unlink(mark_noop)
+        _os.unlink(mark_restore)
+    _os.unlink(markfile)
+
+
+if __name__ == '__main__':
+    import argparse
+
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument('input', metavar='PDF', nargs='+',
+                        help='an input PDF to merge')
+    parser.add_argument('--ask', dest='pause_for_manual_tweaking',
+                        action='store_const', const=True,
+                        help='pause for manual pdfmark tweaking')
+    parser.add_argument('--output', dest='output',
+                        help='name of the output PDF')
+    parser.add_argument('--title', dest='title',
+                        help='title of output PDF')
+    parser.add_argument('--author', dest='author',
+                        help='author of output PDF')
+    parser.add_argument('--keywords', dest='keywords',
+                        help='keywords for the output PDF')
+    parser.add_argument('--pdftk', dest='pdftk', default=PDFTK,
+                        help='path to the pdftk executable')
+    parser.add_argument('--gs', dest='gs', default=GS,
+                        help='path to the gs (Ghostscript) executable')
+
+    args = parser.parse_args()
+
+    PDFTK = args.pdftk
+    GS = args.gs
+
+    inputs = []
+    for filename in args.input:
+        inputs.append(BookmarkedPDF(filename))
+    pdfmarks = generate_pdfmarks(
+        inputs, title=args.title, author=args.author, keywords=args.keywords)
+    merge_pdfs(inputs=inputs, pdfmarks=pdfmarks, output=args.output,
+               pause_for_manual_tweaking=args.pause_for_manual_tweaking)