bugThe FreeType Project - Bugs: bug #51339, Incorrect rendering of glyphs with...

 
 

bug #51339: Incorrect rendering of glyphs with new FreeType Library

Submitted by:  Vinit Singh <vinitsingh12>
Submitted on:  Thu 29 Jun 2017 07:47:04 AM UTC  
 
Severity:  3 - Normal Item Group:  Incorrect behaviour
Status:  Need Info Privacy:  Public
Assigned to:  Alexei Podtelezhnikov <podtelez> Open/Closed:  Open
Planned Release:  None

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( Jump to the original submission)

Tue 04 Jul 2017 02:20:54 PM UTC, comment #7:

No. This is peculiar to a very corner rcase of specific hinting, stroke width, and monochrome rendering. If you think otherwise, be specific please.

Alexei Podtelezhnikov <podtelez>
Project MemberIn charge of this item.
Tue 04 Jul 2017 11:23:38 AM UTC, comment #6:

I think this change should be part of FreeType Library rather than being a part of ft2demos program.

Are there any plans in future to incorporate such changes in FreeType Library so that the projects who are using FreeType don't face rendering issues like this?

Vinit Singh <vinitsingh12>
Fri 30 Jun 2017 10:55:36 AM UTC, comment #5:

Thanks Alexei for recommending the solution.

I think the corresponding file ftgrid.c is a part of ft2demos(ft2demos-2.8).I am using the windows version of the FreeType library(freetype-2.6.4), I am not able to find ftgrid.c

Meanwhile, I tried to search the FreeType library with similar piece of code which I found in some 4-5 places.

The function in my case responsible is cff_slot_load in cffgload.c. For my case, the hinting was true, so I disabled hinting manually(for checking) and compiled the code with the changes as suggested by you and it worked.

Vinit Singh <vinitsingh12>
Fri 30 Jun 2017 04:27:49 AM UTC, comment #4:

I suspect that this is similar to bug 44121. Also here. The solution was this commit. In other words, I suggest that you shift the outline by 32 (half pixel).

Also, we are at 2.8 now.

Alexei Podtelezhnikov <podtelez>
Project MemberIn charge of this item.
Thu 29 Jun 2017 12:52:19 PM UTC, comment #3:

I'm very sorry, I don't know a place where you can get a binary.

Werner LEMBERG <wl>
Project Administrator
Thu 29 Jun 2017 10:58:23 AM UTC, comment #2:

Can you please redirect me to the windows version of ftview (ft2demos)

Vinit Singh <vinitsingh12>
Thu 29 Jun 2017 08:41:07 AM UTC, comment #1:

[Assigning to Alexei]

Thanks for the report. However, it is insufficient information to do debugging. Can you repeat the problem with the `ftview' demo program? You can call it with

to get a 300dpi resolution; then press key `3' to switch to stroker mode; you can change the radius with keys `r' and `R'.

If you succeed, please send me the problematic font in private mail.

Werner LEMBERG <wl>
Project Administrator
Thu 29 Jun 2017 07:47:04 AM UTC, original submission:

I have updated the FreeType Library that I have been using in my project.

For some reason the glyphs are not rendered properly and there are missing edges for almost all characters.

The problem occurred when I upgraded the FreeType Library version to 2.5.5.0 from 2.3.9.24 some times back.

I have attached the input source file and attached the output file.

The problem is evident at 300 dpi and not at 600 dpi.

In the input source file line width if .240 when converted to radius comes out to be 32 in Freetype space (26.6 metric system) before calling the FT_Stroker_Set.

The problem occurs only when 32 is passes as the radius to FreeType.

Vinit Singh <vinitsingh12>

 

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Attach Files:
   
   
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Attached Files
file #41065:  Input Source File.pdf added by vinitsingh12 (49KiB - application/pdf)
file #41066:  Output File.PDF added by vinitsingh12 (5KiB - application/pdf)

 

Depends on the following items: None found

Items that depend on this one: None found

 

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    Follow 4 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2017-06-29 wl StatusNone => Need Info
        Assigned toNone => podtelez
    2017-06-29 vinitsingh12 Attached File- => Added Input Source File.pdf, #41065
        Attached File- => Added Output File.PDF, #41066

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