Issue 41860 - uneven / inaccurate paragraph justification for Thai / CTL
Summary: uneven / inaccurate paragraph justification for Thai / CTL
Alias: None
Product: Writer
Classification: Application
Component: formatting (show other issues)
Version: 680m84
Hardware: All All
: P2 Trivial (vote)
Target Milestone: ---
Assignee: stefan.baltzer
QA Contact: issues@sw
Depends on:
Blocks: 41707
  Show dependency tree
Reported: 2005-02-02 04:04 UTC by samphan
Modified: 2013-08-07 14:41 UTC (History)
5 users (show)

See Also:
Issue Type: DEFECT
Latest Confirmation in: ---
Developer Difficulty: ---

Test document that shows error in Thai justification (8.11 KB, application/vnd.oasis.opendocument.text)
2005-02-02 04:07 UTC, samphan
no flags Details
screenshot from OOo 1.9.84 (29.60 KB, image/gif)
2005-03-21 04:34 UTC, arthit
no flags Details

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Description samphan 2005-02-02 04:04:49 UTC
The right margin of Thai text doesn't line up correctly when full-justified.
This only happen to Thai text, probably due to OOo Thai justification feature
that inserts little bits of space between Thai characters to do
full-justification. This is tested on Windows and Linux.

Test case
- In Writer, load the attached file. The first Thai paragraph contains many
copies of a single word 'à¸à¸' with random spaces in between. The spaces are to
compensate for the bug in issue 41671 by making the lines breakable in many places.
- You will see that the right margin of the Thai paragraph doesn't look
straight. There are a little bit of error at the end of each line. Compare it
with the English paragraph below it.
- You can experiment with the Thai paragraph by deleting or adding spaces
between words. You will see that the amounts of errors change somewhat randomly.
- Adding Thai non-spacing characters like upper/lower vowels and tone marks
doesn't effect the errors. See the second paragraph which is the copy of the
first paragraph with some Thai non-spacing characters added randomly.
Comment 1 samphan 2005-02-02 04:07:13 UTC
Created attachment 22112 [details]
Test document that shows error in Thai justification
Comment 2 frank.meies 2005-02-02 09:34:13 UTC
FME: This happens due to rounding errors if you use a small font (and therefore
have many characters in one line). What happens here is this: If one line has a
remaining space of e.g., 300 twips and you have 102 character clusters in your
line, the first 101 character cluster should get an additional spacing of
300/101=2.97 twips. Unfortunately 300/101 rounds to 2, therefore you have
300-(2*101) = 98 twips of unused space at the end of the line. We have to find a
more stable algorithm for the justification.
Comment 3 jjc 2005-02-13 08:46:38 UTC
This really is an important issue for Thai users.  It means that Thai users
often get an unacceptable result when they print documents using justified
aligment.  There is no way that they can work around this, other than by not
using justified alignment.
Comment 4 arthit 2005-03-21 04:34:46 UTC
Created attachment 24080 [details]
screenshot from OOo 1.9.84
Comment 5 arthit 2005-03-21 04:40:27 UTC
raise Priority to P2,
as this can be considered as "lack of (justification) functionality" for writing
scripts that affected.

from fme's comment,
this could happen with any writing script that has to deal with "cluster".
For instances, any CTL script -- not just Thai.
Comment 6 arthit 2005-03-21 04:43:32 UTC
no workaround available.

fme, does it possible to change the Target milestone to OOo 2.0, please ?

thank you.
Comment 7 arthit 2005-03-21 04:57:40 UTC
changed Target Milestone to OOo 2.0,
please alter this if find inappropriate (e.g. OOo 2.0.1, ...).

thank you.
Comment 8 andreas.martens 2005-03-21 08:20:30 UTC
We have to find a solution but it's too risky to change the algorithmn just now.
So I set the target to OOo2.0.1.
Comment 9 andreas.martens 2005-03-31 14:32:49 UTC
We will investigate to find a solution for OOo2.0
Comment 10 frank.meies 2005-04-01 14:38:26 UTC
FME: Takes some time.
Comment 11 frank.meies 2005-04-06 08:20:03 UTC
Fixed in cws thaiblocksatz.
Comment 12 frank.meies 2005-04-06 15:23:30 UTC
Ready for QA.

re-open issue and reassign to
Comment 13 frank.meies 2005-04-06 15:23:47 UTC
reassign to
Comment 14 frank.meies 2005-04-06 15:24:03 UTC
reset resolution to FIXED
Comment 15 stefan.baltzer 2005-04-11 13:04:38 UTC
SBA: Verified in local build (CWS thaiblocksatz). To be integrated soon into
Set to verified.
Comment 16 stefan.baltzer 2005-05-18 15:45:29 UTC
SBA: OK in 680m103 / OOo 1.9.103. Closed.