To solve the trade-off between better spacing and less hyphenation,
support hyphenation level and its user interface, the hyphenation
slider, like DTP software do.
Add new paragraph property com::sun::star::text::ParaHyphenationLevel
The hyphenation slider is the basic interface of DTP software to adjust
single (or all) paragraphs using better word spacing (i.e. more
hyphenation) or less hyphenation (i.e. worse word spacing). It allows 1)
to choose the best from the near equally good layouts and 2) to solve an
extreme bad layout (caused by words without hyphenation or other corner
cases).
– 50% hyphenation level means disabled hyphenation, if minimum
and maximum word spacing settings allow to break the line within
words (default interoperability value).
– 100% hyphenation level means using extra hyphenation only if that
results better word spacing in the line, than breaking within words.
– Between 50% and 100% hyphenation level, use extra hyphenation only if
its weighted word spacing is better, than breaking the line between
words (weighting grows with the hyphenation level).
– Between 0% and 50% hyphenation level it means disabled hyphenation
with increased desired and maximum word spacing, depending on the
hyphenation level. At %0, the desired word spacing is enlarged to the
original maximum word spacing, while maximum word spacing is enlarged
by a single space.
For example, the original 4-page unit test document with the default 50%
hyphenation level contains 14 hyphenations. 100% hyphenation level
results in 22 hyphenations, while 0% only results in 8 hyphenations.
– sw/qa/extras/layout/data/tdf167648_minimum.fodt,
sw/qa/extras/layout/data/tdf169168_minimum.fodt: set maximum
word-spacing to 100% from 101% to limit the original unit test only
for minimum letter spacing.
More information: LO/COOL Book & Typography projects:
https://www.numbertext.org/typography/https://www.numbertext.org/book/
Follow-up to commit cf104be5cb "tdf#119908
tdf#166113 cool#15973 sw smart justify: fix DOCX hyphenation",
commit d572576dd6
"tdf#119908 cool#15973 sw smart justify: fix "smart" hyphenation",
commit 529755f091
"tdf#166113 sw smart justify: adjust algorithm for interoperability" and
commit 7d08767b89 "tdf#130088 tdf#119908
smart justify: fix DOCX line count + compat opt."
Change-Id: I84b3893ea6c5cd4eff74a73514722285e7071392
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/207545
Reviewed-by: László Németh <nemeth@numbertext.org>
Tested-by: Jenkins
László Németh
5da16bdc79