Bug 181559 - Problems with highlighting equations
Summary: Problems with highlighting equations
Status: RESOLVED DUPLICATE of bug 407133
Alias: None
Product: okular
Classification: Applications
Component: general (show other bugs)
Version: 0.19.60
Platform: Ubuntu Linux
: NOR normal
Target Milestone: ---
Assignee: Okular developers
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2009-01-22 05:08 UTC by Erik
Modified: 2020-12-20 12:42 UTC (History)
5 users (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


Attachments
example of highlighted equation (36.89 KB, image/jpeg)
2009-01-22 15:48 UTC, Erik
Details

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Description Erik 2009-01-22 05:08:59 UTC
Version:           0.7.3 (using KDE 4.1.3)
OS:                Linux
Installed from:    Ubuntu Packages

Using the highlighting tool on equations in PDF documents (e.g., scientific/engineering documents created in LaTeX) results in an undesired behavior: symbols are all highlighted as they should, however leaving all the spaces in between blank, which is sort of logical if one wanted to highlighted single symbols, however, for most purposes, it looks ugly and makes the equation hard to read. Also, I would imagine most people would mark a complete equation rather than only bits of it.
Comment 1 Pino Toscano 2009-01-22 10:16:00 UTC
Can you please provide a sample document showing the issue?
Comment 2 Erik 2009-01-22 15:48:48 UTC
Created attachment 30510 [details]
example of highlighted equation

I attach a jpg of a document where I highlighted the equations. You can see that the highlighter 'jumps' after certain symbols, like the equal '=' sign. Another issue seems also that it has trouble highlighting fractions. Furthermore, the highlighting tool seems to detect the vertical width of each symbol which yiels some kind of 'stair-case' effect. Perhaps one could just detect the max height, use that for the whole line? But maybe the first issue is to detect when the highlight is within an equation, how long it is etc. I'm glad to help out more, whenever you got to look at this more thoroughly.

You can pull the document that I used for the example from here:
http://arxiv.org/pdf/0809.4048
Comment 3 jordonwii 2011-12-20 04:38:41 UTC
Reproducible on Okular 0.13.3, KDE 4.7.1
Comment 4 Francesco Frassinelli 2013-02-04 20:59:11 UTC
Reproducible on Okular 0.16.0, KDE 4.10.0.
In order to highlight the whole equation I have start from a higher point. It seems like Okular sees them as two different lines.
Comment 5 Albert Astals Cid 2014-05-08 13:34:04 UTC
Yes, it seems two lines, i'm not sure we are actually able to fix this since the pdf file only gives us characters and positions of those characters and we have to infer that it is from that information so for complex layouts like this it's not easy.
Comment 6 Justin Zobel 2020-11-20 03:09:28 UTC
(In reply to Erik from comment #0)
> Version:           0.7.3 (using KDE 4.1.3)
> OS:                Linux
> Installed from:    Ubuntu Packages
> 
> Using the highlighting tool on equations in PDF documents (e.g.,
> scientific/engineering documents created in LaTeX) results in an undesired
> behavior: symbols are all highlighted as they should, however leaving all
> the spaces in between blank, which is sort of logical if one wanted to
> highlighted single symbols, however, for most purposes, it looks ugly and
> makes the equation hard to read. Also, I would imagine most people would
> mark a complete equation rather than only bits of it.

Thanks for the report. Are you able to please upload a sample PDF so we can confirm if this is resolved?
Comment 7 Bug Janitor Service 2020-12-05 04:33:55 UTC
Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least
15 days. Please provide the requested information as soon as
possible and set the bug status as REPORTED. Due to regular bug
tracker maintenance, if the bug is still in NEEDSINFO status with
no change in 30 days the bug will be closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
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If you have already provided the requested information, please
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Comment 8 Bug Janitor Service 2020-12-20 04:34:30 UTC
This bug has been in NEEDSINFO status with no change for at least
30 days. The bug is now closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

Thank you for helping us make KDE software even better for everyone!
Comment 9 Laura David Hurka 2020-12-20 12:42:34 UTC
After all, this is just text entity reordering.

For example, LaTeX documents have letters and symbols in equations in a sensible order, so you can select/highlight them comfortably in other viewers without text entity reordering, e. g. Atril and PDF.js.

*** This bug has been marked as a duplicate of bug 407133 ***