bugThe FreeType Project - Bugs: bug #30908, Stray pixel from...


bug #30908: Stray pixel from FT_Outline_Get_Bitmap()

Submitted by:  Ian Britten <britten>
Submitted on:  Mon 30 Aug 2010 04:10:54 PM UTC  
Severity:  3 - Normal Item Group:  Incorrect behaviour
Status:  Confirmed Privacy:  Public
Assigned to:  Werner LEMBERG <wl> Open/Closed:  Open
Planned Release:  None

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Tue 31 Aug 2010 11:11:56 AM UTC, comment #2: 

No, you need 2.3.10 or newer.

However, I've identified the problem but it's hard to fix quickly.  It is deeply rooted in the used drop-out algorithm (or rather, the improvements I've added), and good rendering of the test case provided by Ian needs an additional constraint.

As soon as time permits I'll post a complete description of the problem on the freetype-devel mailing list.

Werner LEMBERG <wl>
Project AdministratorIn charge of this item.
Tue 31 Aug 2010 10:22:00 AM UTC, comment #1: 

example3.cpp can be built with freetype-2.3.9?

suzuki toshiya <mpsuzuki>
Project Administrator
Mon 30 Aug 2010 04:10:54 PM UTC, original submission:  

Attached is a modified version of example3.cpp (And screenshot) that reproduces a test case that results in a stray pixel being rendered, as first reported at http://lists.nongnu.org/archive/html/freetype/2010-08/msg00000.html

I believe I'm seeing a regression between 2.3.9 and 2.3.11 when
rendering monochrome text, resulting in a stray pixel being
rendered - See the attached screenshots.  Note that I feel this
is a regression since the 2.3.11 version looks wrong, while the
older 2.3.9 looks correct.  This is on a 64-bit Mandriva 2010.0
system (GCC 4.4.1).  Note that no problems are seen when the
text is rendered using AA.  Also, hinting is disabled.

As mentioned in that mail thread, the problem was eventually tracked down to changes made to Horizontal_Sweep_Drop()...

Ian Britten <britten>


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Attach Files:

Attached Files
file #21353:  example3.cpp added by britten (5KiB - application/octet-stream)
file #21354:  ft_2.3.11.png added by britten (1KiB - image/png)


Depends on the following items: None found

Items that depend on this one: None found


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    Follow 5 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2010-08-31 wl StatusNone => Confirmed
        Assigned toNone => wl
    2010-08-31 mpsuzuki Carbon-Copy- => Added mpsuzuki
    2010-08-30 britten Attached File- => Added example3.cpp, #21353
        Attached File- => Added ft_2.3.11.png, #21354

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