Homepage: https://github.com/dalanicolai/toc-mode
Author: Daniel Laurens Nicolai
Updated:
Manage outlines/table of contents of pdf and djvu documents
toc-mode.el is a package to create and add a Table of Contents to pdf and djvu documents. It implements features to extract a Table of Contents from the textlayer of a document or via OCR if that last option is necessary or prefered. For 'software generated' PDFs it provides the option to use pdf.tocgen (see URL `https://krasjet.com/voice/pdf.tocgen/'). Subsequently this package implements various features to assist in tidy up the extracted Table of Contents, adjust the pagenumbers and finally parsing the Table of Contents into syntax that is understood by the `pdfoutline' and `djvused' commands that are used to add the table of contents to pdf- and djvu-files respectively. Requirements: To use the pdf.tocgen functionality that software has to be installed (see URL `https://krasjet.com/voice/pdf.tocgen/'). For the remaining functions the package requires the `pdftotext' (part of poppler-utils), `pdfoutline' (part of fntsample) and `djvused' (part of http://djvu.sourceforge.net/) command line utilities to be available. Extraction with OCR requires the tesseract command line utility to be available. Usage: In each step below, check out available shortcuts using C-h m. Additionally you can find available functions by typing the M-x mode-name (e.g. M-x toc-cleanup), or with two dashes in the mode name (e.g. M-x toc--cleanup). Of course if you use packages like Ivy or Helm you just use the fuzzy search functionality. Extraction and adding contents to a document is done in 4 steps: 1 extraction 2 cleanup 3 adjust/correct pagenumbers 4 add TOC to document 1. Extraction For PDFs without TOC pages, with a very complicated TOC (i.e. that require much cleanup work) or with headlines well fitted for automatic extraction (you will have to decide for yourself by trying it) consider to use the pdf.tocgen (URL `https://krasjet.com/voice/pdf.tocgen/') functionality described below. Otherwise, start with opening some pdf or djvu file in Emacs (pdf-tools and djvu package recommended). Find the pagenumbers for the TOC. Then type M-x `toc-extract-pages', or M-x `toc-extract-pages-ocr' if doc has no text layer or text layer is bad, and answer the subsequent prompts by entering the pagenumbers for the first and the last page each followed by RET. For PDF extraction with OCR, currently it is required to view all contents pages once before extraction (toc-mode uses the cached file data). Also the languages used for tesseract OCR can be customized via the `toc-ocr-languages' variable. A buffer with the, somewhat cleaned up, extracted text will open in TOC-cleanup mode. Prefix command with the universal argument (C-u) to omit clean and get the raw text. If the extracted text is of too low quality you either can hack/extend the `toc-extract-pages-ocr' definition, or alternatively you can try to extract the text with the python document-contents-extractor script (see URL `https://pypi.org/project/document-contents-extractor/'), which is more configurable (you are also welcome to hack and improve that script). The documentation at URL `https://tesseract-ocr.github.io/tessdoc/Command-Line-Usage.html' might be useful. For TOC's that are formatted as two columns per page, prepend the `toc-extract-pages-ocr' command with two universal arguments. Then after you are asked for the start and finish pagenumbers, a third question asks you to set the tesseract psm code. For the double column layout it is best (as far as I know) to use psm code '1'. Software-generated PDF's with pdf.tocgen For 'software-generated' (i.e. PDF's not created from scans) PDF-files it is sometimes easier to use `toc-extract-with-pdf-tocgen'. To use this function you first have to provide the font properties for the different headline levels. For that select the word in a headline of a certain level and then type M-x `toc-gen-set-level'. This function will ask which level you are setting, the highest level should be level 1. After you have set the various levels (1,2, etc.) then it is time to run M-x `toc-extract-with-pdf-tocgen'. If a TOC is extracted succesfully, then in the pdftocgen-mode buffer simply press C-c C-c to add the contents to the PDF. The contents will be added to a copy of the original PDF with the filename output.pdf and this copy will be opened in a new buffer. If the pdf-tocgen option does not work well then continue with the steps below. If you merely want to extract text without further processing then you can use the command `toc-extract-only'. 2. TOC-Cleanup In this mode you can further cleanup the contents to create a list where each line has the structure: TITLE (SOME) PAGENUMBER (If the initial TOC looks bad/unusable then try to use then universal argument C-u before extraction in the previous step and/or try the ocr option with or without the universal argument) There can be any number of spaces between TITLE and PAGE. The correct pagenumbers can be edited in the next step. A document outline supports different levels and levels are automatically assigned in order of increasing number of preceding spaces, i.e. the lines with the least amount of preceding spaces are assigned level 0 etc., and lines with equal number of spaces get assigned the same levels. Contents 1 Chapter 1 2 Section 1 3 Section 1.1 4 Chapter 2 5 There are some handy functions to assist in the cleanup. C-c C-j jumps automatically to the next line not ending with a number and joins it with the next line. If the indentation structure of the different lines does not correspond with the levels, then the levels can be set automatically from the number of separatorss in the indices with M-x toc-cleanup-set-level-by-index. The default separators is a . but a different separators can be entered by preceding the function invocation with the universal argument (C-u). Some documents contain a structure like 1 Chapter 1 1 Section 1 2 Here the indentation can be set with M-x replace-regexp ^[^0-9] -> \& (where there is a space character before the \&). Type C-c C-c when finished 3. TOC-tabular (adjust pagenumbers) This mode provides the functionality for easy adjustment of pagenmumbers. The buffer can be navigated with the arrow up/down keys. The left and right arrow keys will shift down/up all the page numbers from the current line and below (combine with SHIFT for setting individual pagenumbers). The TAB key jumps to the pagenumber of the current line, while C-right/C-left will shift all remaining page numbers up/down while jumping/scrolling to the line its page in the document window. to the S-up/S-donw in the tablist window will just scroll page up/down in the document window and, only for pdf, C-up/C-down will scroll smoothly in that window. Type C-c C-c when done. 4. TOC-mode (add outline to document) The text of this buffer should have the right structure for adding the contents to (for pdf’s a copy of) the original document. Final adjusments can be done but should not be necessary. Type C-c C-c for adding the contents to the document. By default, the TOC is simply added to the original file. ONLY FOR PDF’s, if the (customizable) variable toc-replace-original-file is nil, then the TOC is added to a copy of the original pdf file with the path as defined by the variable toc-destination-file-name. Either a relative path to the original file directory or an absolute path can be given. Sometimes the `pdfoutline/djvused' application is not able to add the TOC to the document. In that case you can either debug the problem by copying the used terminal command from the `*messages*' buffer and run it manually in the document's folder, or you can delete the outline source buffer and run `toc--tablist-to-handyoutliner' from the tablist buffer to get an outline source file that can be used with HandyOutliner (see URL `http://handyoutlinerfo.sourceforge.net/') Unfortunately the handyoutliner command does not take arguments, but if you customize the `toc-handyoutliner-path' and `toc-file-browser-command' variables, then Emacs will try to open HandyOutliner and the file browser so that you can drag the files directly into HandyOutliner). Finally, if you just want to extract some text Keybindings all-modes (i.e. all steps) Key Binding Description C-c C-c dispatch (next step) toc-cleanup-mode C-c C-j toc--join-next-unnumbered-lines C-c C-s toc--roman-to-arabic toc-mode (tablist) TAB~ preview/jump-to-page right/left toc-in/decrease-remaining C-right/C-left toc-in/decrease-remaining and view page S-right/S-left in/decrease pagenumber current entry C-down/C-up scroll document other window (if document buffer shown) S-down/S-up full page scroll document other window ( idem ) C-j toc--jump-to-next-entry-by-level