Status of the Writer import/export filters

LibreOffice Conference 2013 (http://conference.libreoffice.org/2013/en/program/development-1/status-of-the-writer-import-export-filters), Milan
Video record: https://vimeo.com/80676221 (original: http://www.ustream.tv/recorded/39220616, from 0:36:55)

Transcript

1. Status of the Writer
   import/export filters
   Miklós Vajna
   2013­09­25
   

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2. Introduction
   

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3. 3 / 25 LibreOffice Conference 2013 | Miklós Vajna
   How to measure an import filter?
   ● Target is to handle every feature that the given
   format can describe
   ● We want numbers
   ● Number of … handled:
   ● XML tags
   ● Single PRoperty Modifiers
   ● Control words
   ● Shape properties
   

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4. 4 / 25 LibreOffice Conference 2013 | Miklós Vajna
   How to measure an export filter?
   ● Target is to handle every Writer feature
   ● Checklist, e.g. vmiklos01_rtf_status.ods
   ● UNO filter unhandled properties
   →
   ● Internal filter unhandled SfxPoolItems
   →
   ● Word export unimplemented methods
   →
   

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5. 5 / 25 LibreOffice Conference 2013 | Miklós Vajna
   Is this optimal?
   ● No, because:
   ● Even if pictures and tables are handled,
   possibly pictures inside tables need explicit
   support
   ● Not every item (XML tag, SPRM, etc.) are
   equally important
   ● Still better than having no numbers at all
   ● Scripts used: swfilters­loconf­milan­2k13.txt
   

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6. Status of the ODT / ODF filter
   

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7. 7 / 25 LibreOffice Conference 2013 | Miklós Vajna
   ODF import status
   ● ODF is XML­based, so has a schema
   ● Almost everything is imported
   ● As ODF was OOoXML before, with little
   differences
   ● No domain problems
   ● Writer and ODF concepts are really close to each
   other
   ● Main task is to keep it up to date
   

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8. 8 / 25 LibreOffice Conference 2013 | Miklós Vajna
   ODF export status
   ● Simplified architecture:
   ● Iterates over paragraphs, text portions, properties
   ● If something is not exported unhandled property
   →
   ● Current status is near perfect (apart from occasional
   bugs)
   ● Keep it up to date
   ● In an ideal case a new property is 3 lines to handle
   

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9. 9 / 25 LibreOffice Conference 2013 | Miklós Vajna
   LibreOffice­specific extensions
   ● When we add new features, we serialize
   those from/to ODF, see
   ODF_Implementer_Notes
   ● Each such commit is turned into an ODF
   proposal before we hit a release
   ● Still, a slow process
   ● ODF 1.2 is not yet an ISO standard e.g.
   

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10. 10 / 25 LibreOffice Conference 2013 | Miklós Vajna
    Intentional OOo/LO­specific data
    ● settings.xml's
    ● e.g. ooo:configuration­settings
    ● Contains application­specific configuration
    – e.g. Writer layout compat settings
    ● Macros: script:language="ooo:StarBasic" …>
    

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11. 11 / 25 LibreOffice Conference 2013 | Miklós Vajna
    Summary of ODF filter status
    ● Export is lossless
    ● Modulo the reported bugs in Bugzilla ;­)
    ● What we export is imported lossless as well
    ● Other: reasonably
    ● If only the above would be true for other
    filters as well
    

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12. Status of DOCX / OOXML filter
    

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13. 13 / 25 LibreOffice Conference 2013 | Miklós Vajna
    Introduction
    ● OOXML may mean lots of things, here:
    ● OOXML, as in what Word does (there is also an
    ISO version)
    ● OOXML is DOCX, XLSX, PPTX, drawingml, VML,
    etc. – here: wordprocessingml
    ● Import is older, from­scratch
    ● Export is newer (only in LO), re­using the
    DOC export
    

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14. 14 / 25 LibreOffice Conference 2013 | Miklós Vajna
    OOXML import
    ● Two parts: tokenizer and domain mapper
    ● Problems to be solved by tokenizer:
    ● XML element token
    →
    ● RTF control word token
    →
    ● Problems to be solved by the domain
    mapper:
    ● Section Page style
    →
    

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15. 15 / 25 LibreOffice Conference 2013 | Miklós Vajna
    OOXML export
    ● Shared Word export: reused domain
    mapper
    ● Still not perfect due to domain problems
    ● e.g. textframes: writer and draw textframes ↔
    Word old­style frames and rectangle shapes
    

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16. 16 / 25 LibreOffice Conference 2013 | Miklós Vajna
    OOXML numbers
    ● # of XML elements in OfficeOpenXML­
    XMLSchema­Strict.zip / wml.xsd: 546
    ● # of at least tokenized elements: 461
    ● # of unhandled elements: 85
    ● Looks pretty good, but remember: this
    does not measure the coverage of
    element attributes, combinations, etc.
    

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17. Status of DOC / WW8 filter
    

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18. 18 / 25 LibreOffice Conference 2013 | Miklós Vajna
    Introduction
    ● DOC is usually WW8 (Word 97­2003)
    ● Probably the oldest Writer filter
    ● What's possible wrt. Writer Word (up to
    ↔
    2003) handling is mostly already done
    ● Still, not as up to date as it could be
    ● e.g. commented text ranges are not handled
    

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19. 19 / 25 LibreOffice Conference 2013 | Miklós Vajna
    Import / export status
    ● Import:
    ● Could measure unhandled FIB entries – rare problem
    ● Can measure SPRM's – more useful
    ● Export:
    ● The export framework is from the WW8 filter
    ● All methods are implemented, not useful to check
    ● Unhandled SfxPoolItems – better to measure this
    

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20. 20 / 25 LibreOffice Conference 2013 | Miklós Vajna
    WW8 numbers
    ● Specification has character (85),
    paragraph (93), table (80), section (59)
    and picture (8) SPRM's 325 in total
    →
    ● Number of handled SPRMS: 318
    ● Handling of some may be still problematic,
    but again – looks pretty good
    

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21. Status of the RTF filter
    

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22. 22 / 25 LibreOffice Conference 2013 | Miklós Vajna
    What to measure in import
    ● RTF has control words:
    ● A control word can be a flag, a destination, a
    symbol, a toggle or a value
    ● Shape import is Writer­specific as well
    (unlike ODF/OOXML/WW8)
    ● Same for math import
    

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23. 23 / 25 LibreOffice Conference 2013 | Miklós Vajna
    What to measure in export
    ● Uses the shared Word exporter can
    →
    check unimplemented methods (almost
    none)
    ● Control words: as useful as XML tags in the
    OOXML case
    ● Checklist
    

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24. 24 / 25 LibreOffice Conference 2013 | Miklós Vajna
    RTF numbers
    ● # of control words from the spec: 1821
    ● # of LO­specific RTF control words: 4
    ● obsolete, only there for compatibility reasons
    ● # of handled control words on import: 575
    ● Does not cover e.g. shape properties
    ● # of handled control words on export: 368
    ● Math status is on par with OOXML
    ● Easier, due to 1:1 mapping
    

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25. 25 / 25 LibreOffice Conference 2013 | Miklós Vajna
    Questions?
    ● Anyone?
    Slides: http://vmiklos.hu/odp
    

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