Continuous endnotes in Writer

LibreOffice Conference 2024 (https://events.documentfoundation.org/libreoffice-conference-2024/talk/7DVZGZ/), Luxembourg

Video record: https://www.youtube.com/watch?v=_wrlzACWuBI

Transcript

1. Continuous endnotes in Writer Miklos Vajna Software Engineer vmiklos@collabora.com 2024-10-11
2. 2/18 About Miklos • From Hungary • More details: https://www.collaboraonline.com/about-us/ • Google Summer of Code 2010 / 2011 • Rewrite of the Writer RTF import/export • Then a full-time LibreOffice developer for SUSE • Now a contractor at Collabora
3. 3/18 Continuous endnotes in Writer Results so far
4. 4/18 Visual diff: before fixing
5. 5/18 Visual diff: after fixing
6. 6/18 Previous approach • Implemented in 2019 • Tries to map endnotes to footnotes on the last page • Grows from the bottom up, now from to the top to bottom after content • Native Writer behavior: separate endnote page • Collapses with large amount of endnotes • Especially if those are of multiple pages
7. 7/18 The new approach • Introduce a special endnotes section • No backing section node, only exists at a layout level • At the end of the document • No actual content in the section’s body, just hosts a foot/endnote container • Can flow across pages, can handle many notes
8. 8/18 Switch to a section-based layout • Works for simple cases, but the compat flag (to render Word-style endnotes, not Writer-style ones) is just used by DOC files, only in case they have 1 or 2 endnotes • Reverts the changes of the old approach • Creates the layout-level section for endnotes on demand • Handles moving the endnote to a previous or next page
9. 9/18 Enable for all DOC files • See what ‘make check’ finds • What crashtesting has to say • Found problem: trouble if there is a section at the document end already • We tried to insert the section for the endnotes inside that last section from model, fixed
10. 10/18 Enable for DOCX files • Didn’t find more issues instantly • Still had to fix: • Endnote container’s top margin • Endnote separator position • Endnote separator length • DOCX has a per-doc flag to collect endnotes at section end • Import / export of this • Endnote continuation separator length • Writer UI: conditionally hide widgets which won’t work for DOCX
11. 11/18 How is this implemented?
12. 12/18 Document model • sw::DocumentSettingManager stores compat flags • DocumentSettingId::CONTINUOUS_ENDNOTES is the relevant flag here • If true, then layout endnotes like Word does • Otherwise compatible with existing ODF documents
13. 13/18 UNO API • The Writer’s document’s factory can create an instance of the com.sun.star.document.Settings service • Implements beans::XPropertySet • Can set the ContinuousEndnotes property there to true to have the Word behavior
14. 14/18 Layout • The most interesting part • SwFootnoteBossFrame::AppendFootnote() is where the foot/endnote frames are created • A note can go to the end of the current section, to a note page, and now can go to the special new endnote section at the end of the document • The endnote section is created on demand • Moving to the next page works out of the box • Moving to the previous page needs explicit handling in SwFlowFrame::MoveBwd() • Similar to moving sections to the previous page is handled in SwFrame::GetPrevSctLeaf()
15. 15/18 Filters • Remove the restriction to only have continuous endnotes for 1 or 2 endnotes from DOC, have it for all DOC • Also enable it for DOCX • DOCX <w:endnotePr> describes the position of the endnotes in a document • At document end vs at section end • Existing ODF documents stay unchanged
16. 16/18 Tests • Search for stress-test documents in bugzilla • The old approach was reverted for DOCX in the past • It was also restricted to 1-2 endnotes for DOC in the past • Various provided documents to show the old layout was poor • Largest document is 72 endotes, over several pages at the document end • Automated testing: • CppunitTest_sw_core_layout for the actual layout • CppunitTest_sw_writerfilter_dmapper for the DOCX import • CppunitTest_sw_filter_ww8 for the DOCX export • bin/diff-pdf-page.py for the visual diff, based on Laszlo’s idea
17. 17/18 UI: hide not needed widgets for DOCX
18. 18/18 Summary • Section-based endnotes are a new way to layout endnotes at the end of the document, as opposed to layout on a separate endnote page • Compatible with Word • Scales properly: • Many endnotes • Many footnotes • Available for everyone using LibreOffice Technology: LibreOffice desktop, Collabora Online, etc.