bugThe FreeType Project - Bugs: bug #46551, Severe colorful subpixel artifacts

 
 

bug #46551: Severe colorful subpixel artifacts

Submitted by:  Alexei Podtelezhnikov <podtelez>
Submitted on:  Fri 27 Nov 2015 02:56:14 AM UTC  
 
Severity: 3 - NormalItem Group: None
Status: FixedPrivacy: Public
Assigned to: NoneOpen/Closed: Closed
Planned Release: None

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Mon 30 Nov 2015 02:46:04 PM UTC, comment #3:

Fixed in git.

Alexei Podtelezhnikov <podtelez>
Project Member
Mon 30 Nov 2015 04:26:06 AM UTC, comment #2:

I think I am onto something. I've managed to segfault ftview just by switching to cyan-on-cyan rendering. I know it is silly as you won't be able to see anything, but I was not expecting to see Segmentation Fault. I cannot find the dumped core file and I do not know how to debug those either. Can you help? These are the steps to reproduce:

1. Apply this patch:

2. Switch to vRGB by pressing [C]. Boom!

Alexei Podtelezhnikov <podtelez>
Project Member
Fri 27 Nov 2015 05:27:26 AM UTC, comment #1:

Some time ago I have noticed an effect similar to this, which comes up from time to time, but i was never able to nail it down so that I could find out what's going on...

Can you work on that? And yes, I also suspect a problem in ft2demos's `graph' library.

Werner LEMBERG <wl>
Project Administrator
Fri 27 Nov 2015 02:56:14 AM UTC, original submission:

I see severe artifacts when testing sub-pixel color blending using freetype2 tools like ftstring. I was able to reproduce it in ftview (modified to use cyan-on-red). It shows up occasionally. In the attached images you will see severe color fringes in just a few glyphs. Interestingly it is not always the same glyphs: other glyphs are affected at different sizes.

I suspect this is a bug in tools rather than library. Because the issue is so severe it should have been noticed before.

Alexei Podtelezhnikov <podtelez>
Project Member

 

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Attach File(s):
   
   
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Attached Files
file #35573:  BlueFringe.png added by podtelez (71KiB - image/png)
file #35572:  YellowFringe.png added by podtelez (17KiB - image/png)

 

Depends on the following items: None found

Items that depend on this one: None found

 

Carbon-Copy List
  • -unavailable- added by wl (Posted a comment)
  • -unavailable- added by podtelez (Submitted the item)
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    Follow 4 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Mon 30 Nov 2015 02:46:04 PM UTCpodtelezStatusNone=>Fixed
      Open/ClosedOpen=>Closed
    Fri 27 Nov 2015 02:56:15 AM UTCpodtelezAttached File-=>Added BlueFringe.png, #35573
    Fri 27 Nov 2015 02:56:14 AM UTCpodtelezAttached File-=>Added YellowFringe.png, #35572

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