bugFree UCS Outline Fonts - Bugs: bug #54911, Bengali top lines misaligned at...


bug #54911: Bengali top lines misaligned at some font sizes

Submitter:  Mahfuzur Rahman <burhandanger>
Submitted:  Mon 29 Oct 2018 06:27:45 AM UTC
Category:  character range Severity:  3 - Normal
Item Group:  letter positioning poor Status:  Fix posted
Privacy:  Public Assigned to:  Stevan_White
Open/Closed:  Open Release:  * development
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Thu 08 Nov 2018 08:34:17 PM UTC, comment #5: 

The only explanation I could come up with was that the font renderer just decided under some circumstances to make a letter a bit taller. 

Since that kind of behavior is related to hinting, and to the PostScript "Blue Values", I tried putting a thin blue value area just above the top line of Bengali. 

This seems to have fixed the problem -- at least, I've experimented with different font sizes in both FreeSans and FreeSerif.

I repeated the fix for the other North Brahmic scripts, and for the other faces with such scripts.

Thanks for pointing this out!

Steve White <Stevan_White>
Group administrator
Thu 08 Nov 2018 08:29:08 PM UTC, comment #4: 

In your original posting, I think you were referring to multiple issues.  I made the title of this report more specific.

The issue is the alignment of the top line, which happens only at certain resolutions, and is most pronounced in FreeSans, but also happens in FreeSerif.  I have confirmed that it does happen.

The picture Pict1.png (attached) you sent me illustrates how to reproduce the problem in Firefox.

Steve White <Stevan_White>
Group administrator
Sat 03 Nov 2018 07:32:42 AM UTC, comment #3: 

It is a matter of finding time to devote to this project.

Steve White <Stevan_White>
Group administrator
Fri 02 Nov 2018 06:56:26 PM UTC, comment #2: 

I built freeserif and it looks ok. Any ETA on release?

Mahfuzur Rahman <burhandanger>
Tue 30 Oct 2018 11:15:17 PM UTC, comment #1: 

Hi Mahfuzur,

Thanks for this!

I see the problems in the samples you posted.  As near as I can tell, newer builds of the font from version control do not have these particular problems.  Have a look at the sample I attach, made with Firefox on my laptop.  The 2012 version of the font was tested with the old Linux font rendering system -- it no longer works properly for Indic faces.

There has not been a release of the font in several years.  The next one should resolve this problem.  However, I know of other problems with the font that preclude a release.

If you would like a build for your own use, let me know!

(file #45331)

Steve White <Stevan_White>
Group administrator
Mon 29 Oct 2018 06:27:45 AM UTC, original submission:  

Referenced Bangla/Bengali font used : SolaimanLipi (widely used in Bangladesh for Bangla)

For page https://www.gnu.org/software/freefont/ranges/Bengali.html.
As shown with freeserif
correct juktoborno use

Parts of page http://www.omniglot.com/babel/bengali.htm opened inside leafpad.(check attached file)

freeserif P1
freeserif P2
SolaimanLipi P1
SolaimanLipi P2

Problematic words are marked with asterisk(*).

Not all Bangla juktoborno is correct in page https://www.gnu.org/software/freefont/ranges/Bengali-cjct.html.
Check http://writebangla.com/juktoborno.html for a relatively better correct list.

[Note: SolaimanLipi may have some font matrics misalignment but overall it's correct]

Mahfuzur Rahman <burhandanger>


(Note: upload size limit is set to 16384 kB, after insertion of the required escape characters.)

Attach Files:

Attached Files
file #45387:  Pic1.png added by Stevan_White (204KiB - image/png - shows misalignment of top line)
file #45331:  testfile.pdf added by Stevan_White (153KiB - application/pdf - made with recent build of font with Firefox)
file #45320:  testfile added by burhandanger (3KiB - application/octet-stream)


Depends on the following items: None found

Items that depend on this one: None found


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  • -email is unavailable- added by Stevan_White (Updated the item)
  • -email is unavailable- added by burhandanger (Submitted the item)

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    Follow 11 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2018-11-08 Stevan_White StatusConfirmed Fix posted
    2018-11-08 Stevan_White Attached File- Added Pic1.png, #45387
        Categoryoverall font problem character range
        Item Groupglyph(s) incorrect letter positioning poor
        StatusWorks for me Confirmed
        Release2012-05-03 development
        SummaryProblem with 'bangla ligatures'(juktoborno) in Bengali Bengali top lines misaligned at some font sizes
    2018-10-30 Stevan_White Attached File- Added testfile.pdf, #45331
        StatusNone Works for me
        Assigned toNone Stevan_White
    2018-10-29 burhandanger Attached File- Added testfile, #45320

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