Bug 407438 - Text hinting causes failure to render some texts
Summary: Text hinting causes failure to render some texts
Status: RESOLVED UPSTREAM
Alias: None
Product: okular
Classification: Applications
Component: PDF backend (show other bugs)
Version: 1.6.3
Platform: Kubuntu Linux
: NOR normal
Target Milestone: ---
Assignee: Okular developers
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2019-05-11 21:59 UTC by Lukas Jelinek
Modified: 2021-02-24 21:25 UTC (History)
2 users (show)

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


Attachments
Problematic document (415.29 KB, application/pdf)
2019-05-11 21:59 UTC, Lukas Jelinek
Details

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Description Lukas Jelinek 2019-05-11 21:59:23 UTC
Created attachment 119993 [details]
Problematic document

SUMMARY
When text hinting is enabled, Okular fails to render some texts in some documents.

STEPS TO REPRODUCE
1. Enable text hinting
2. Open a document 
3. Observe rendered texts in the document

OBSERVED RESULT
In some documents, some texts are not rendered.

EXPECTED RESULT
All text are rendered as with text hinting disabled.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 5.15.4
KDE Frameworks Version: 5.56.0
Qt Version: 5.12.2

ADDITIONAL INFORMATION
Kubuntu 19.04
One problematic document is attached.
Comment 1 Christoph Feck 2019-05-30 18:44:50 UTC
Since I can reproduce with qpdfview (using libpoppler version 0.72 and "Splash" backend), I suspect it is a poppler issue.
Comment 2 Laura David Hurka 2019-05-30 19:46:03 UTC
(In reply to Lukas Jelinek from comment #0)
> EXPECTED RESULT
> All text are rendered as with text hinting disabled.

May I ask how the hinting works for the rendered texts?

I enabled hinting in my Okular, and some texts in the attached example document disappeared. I couldn’t see any difference in the rendering of the other text. I would expect them to be hinted...

(Hinting: Vertices of letter outline aligned to nearest pixel boundary, so it looks less smeared. Or does hinting mean something else here?)
Comment 3 jan 2021-02-24 10:21:21 UTC
This is still the case with 20.12.2.
Comment 4 Albert Astals Cid 2021-02-24 21:25:20 UTC
This is something that will never be fixed in Okular since Okular is not involved in how pdf files are rendered. Please report this as a bug in poppler, the library we use for pdf rendering https://gitlab.freedesktop.org/poppler/poppler/-/issues