Multi-page floating tables in Writer

LibreOffice conference 2023 (https://events.documentfoundation.org/libreoffice-conference-2023/talk/Q7PLSS/), Bucharest (remote)
Video record: https://www.youtube.com/watch?v=KXE6OSkWOYs

Transcript

1. Miklos Vajna Software Engineer vmiklos@collabora.com 2023-09-22 Multi-page floating tables in Writer
2. 2 About Miklos • From Hungary • More details: • https://www.collaboraoffice.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 Results so far
4. 4 Motivation
5. 5 Selection & dragging of split tables
6. 6 In-footer floating table
7. 7 Floating table in a section
8. 8 Page break before a floating table
9. 9 Table inside a multi-column section
10. 10 UI to disable split of a floating table
11. 11 Chaining enabled, so no split frames
12. 12 Disabling split of flys at a layout level
13. 13 Section break directly between tables
14. 14 Nested tables: the split outer only
15. 15 Negative vertical offsets
16. 16 Anhcor text starts with a newline
17. 17 Hidden anchors
18. 18 No overlap setting on floating tables
19. 19 Border rendering problems
20. 20 Footnote support
21. 21 How is this implemented?
22. 22 Document model SwFlyFrameFormat • Stored in SwDoc::mpSpzFrameFormatTable • Has an SfxItemSet • New pool item subclass: SwFormatFlySplit • Look it up using RES_FLY_SPLIT
23. 23 UNO API SwXTextFrame • SwXTextDocument has a getTextFrames() • The text frame supports XPropertySet • A new IsSplitAllowed property there • So a floating table is a fly frame that’s allowed to split • And only contains exactly one inner table
24. 24 Layout representation 1 2 3 4 5 3 3 4 5 Frame height is automatic At-paragraph anchored text frame Top left of anchor frames Content flows around the frame on the last page Vertical offset is only rendered on the first page 1 2 #libreoffice-dev_20170512.log:12:44 < mst_> vmiklos: now we only need a flyframe that is also a flowframe and we'd have floating tables :)
25. 25 Legacy mode for Word <= 2010
26. 26 Filters ODF + the Word formats • ODT import + export: <draw:frame loext:may-break-between- pages="true"> • DOCX: <w:tblpPr> • DOC: sprmTPc, and 6 others for positioning • RTF: very similar to DOC, just not binary • Separate markup for doc-level “no split” and frame-level “don’t overlap”
27. 27 Testing Various testing types • Load a Word document, assert layout result from cppunit • Build an SwDoc from C++ code, assert the layout result • UITest for the UI part • Crashtesting • Watching the sanitizers tinderbox
28. 28 UI
29. 29 Specification Just an optional new boolean attribute • Where to put it? Frame? Frame style? • Should it be a property of the inner text box? • Settled down on frame-as-direct-format, similar to ZOrder • No-overlap for frames: reuse markup from shapes • “Don’t split” per-document setting → settings.xml
30. 30 Summary Originally requested in 2013, multi-page floating tables are coming to Writer • COOL 23.05 / LibreOffice (perhaps) 7.6 • Status: 50%+ done, but you can already try it out • How it interacts with headers/footers, orphan/widow control, minimal row height, compatibility modes, change tracking, etc. – is complex, but we’re working on it • Defaulting to the way today’s Word (>= 2013) does it, but also have a legacy mode for older documents