By Alejandro Piñeiro Iglesias and Joanmarie Diggs.
Creating tagged PDF documents is easy to do and provides many benefits including reflow for hand-held devices, content extraction with formatting preserved, and accessibility. This presentation will describe and demonstrate the work done thus far to implement this support in Poppler and Evince.
A Beginners Guide to Building a RAG App Using Open Source Milvus
Tag! Your PDF is It! (GUADEC 2013)
1. Tag! Your PDF is It!
Alejandro Piñeiro and Joanmarie Diggs
GUADEC 2013
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Tag! Your PDF is It! - Alejandro Piñeiro & Joanmarie Diggs - GUADEC 2013
Topics
● Tagged PDFs:
– What They Are
– Why We Want Them
– How to Make Them
● Current Status of the Project
● Getting the Code (and what you'll see when you do)
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Tagged PDF > PDF
• Meta-information about page content
• HTMLish tags and IDs for text spans
• Alternative text for images
• Replacement text for symbols
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Why We Want Them
• Enhanced document accessibility
• Through exposure of structural and semantic
information associated with the tags
Thanks (again) Friends of GNOME!!!
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Why We Want Them (cont.)
• Reflow functionality (e.g. for mobile devices)
• Export to other applications with format, layout,
font data, etc.
• Copy and paste to other applications with some
fundamental retention of content format
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Making Tagged PDFs
✘ AbiWord: No
✘ Google Docs: No
✘ LaTeX: No
✘ Scribus: No
✘ PDF Studio: No
✘ python-pisa: No
✔ LibreOffice: Yes
(and it's easy!)
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PDF/A-1a > Tagged PDF
• Objective: Search and repurpose document content
• Includes:
- PDF/A-1b: Reproduce document appearance
- Structure / Hierarchy
- Tagged PDF
- Unicode character maps
- Language specification
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Tagged PDF Support
✔Parse the document structure tree: Poppler
✔Expose the tree and attributes: Poppler GLib
✔Provide tools to examine and verify result: Poppler
● Create parallel object tree with attributes: Evince
● (Expose object tree and attributes via ATK: Evince)
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PDF/A-1a Support
? PDF/A-1b
✔ Tagged PDF
✔ Structure / Hierarchy
? Unicode character maps
✔ Language specification
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What's Next?
• Create parallel object tree with attributes: Evince
• (Expose object tree and attributes via ATK: Evince)
? PDF/A-1b and Unicode character maps
? Adding support to LaTeX, et al.
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Credit Where Credit is Due
• Adrián Pérez: Document Parser Extraordinaire
• Carlos García Campos: Maintains Evince & Poppler
Thanks Guys!!!
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Getting the Code
• git://git.freedesktop.org/git/poppler/poppler
• Today
- Branch: tagged-pdf
- Patches: fdo bugs 64816 and 67710
• Soon: master branch
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Associated Output Tools: Before
• pdfinfo: author, editor, etc.
• pdftotext: content (plain text)
• pdftohtml: content (barely formatted text)
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Associated Output Tools: After
● pdfstructtohtml: like pdftohtml but preserves tags
● pdfinfo's new options:
- hierarchy
- hierarchy along with content of each element
● poppler-glib-demo: new option to display hierarchy
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