Multi-page floating tables in Writer

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Miklos Vajna Software Engineer vmiklos@collabora.com 2023-09-22 Multi-page floating tables in Writer

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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

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3 Results so far

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4 Motivation

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5 Selection & dragging of split tables

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6 In-footer floating table

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7 Floating table in a section

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8 Page break before a floating table

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9 Table inside a multi-column section

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10 UI to disable split of a floating table

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11 Chaining enabled, so no split frames

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12 Disabling split of flys at a layout level

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13 Section break directly between tables

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14 Nested tables: the split outer only

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15 Negative vertical offsets

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16 Anhcor text starts with a newline

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17 Hidden anchors

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18 No overlap setting on floating tables

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19 Border rendering problems

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20 Footnote support

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21 How is this implemented?

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22 Document model SwFlyFrameFormat ● Stored in SwDoc::mpSpzFrameFormatTable ● Has an SfxItemSet ● New pool item subclass: SwFormatFlySplit ● Look it up using RES_FLY_SPLIT

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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

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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 :)

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25 Legacy mode for Word <= 2010

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26 Filters ODF + the Word formats ● ODT import + export: ● DOCX: ● 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”

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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

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28 UI

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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

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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