bugThe FreeType Project - Bugs: bug #39295, "TeX Gyre Heros" (CFF)...

 
 

bug #39295: "TeX Gyre Heros" (CFF) gets hinted badly

Submitted by:  None
Submitted on:  Wed 19 Jun 2013 11:56:49 PM UTC  
 
Severity: 3 - NormalItem Group: Incorrect behaviour
Status: FixedPrivacy: Public
Assigned to: Werner LEMBERG <wl>Open/Closed: Closed
Planned Release: 2.5.1

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Sun 29 Sep 2013 02:22:40 PM UTC, comment #6:

Dave Arnold has now fixed this. Please read the extensive comment in the ChangeLog entry

http://git.savannah.gnu.org/cgit/freetype/freetype2.git/commit/?id=3a2cb0f881e7dc20b7714d2051254310471edee0

together with

http://mail.math.utah.edu/pipermail/tex-fonts/2013-August/001420.html

which explains why there are still distortions (due to a bug in the font).

Werner LEMBERG <wl>
Project AdministratorIn charge of this item.
Thu 26 Sep 2013 05:22:51 PM UTC, comment #5:

The Cantarell Bold issue was brought to the attention of their developers, and was subsequently fixed:

https://bugzilla.gnome.org/show_bug.cgi?id=704084

Jan Steffens <heftig>
Thu 26 Sep 2013 05:17:52 PM UTC, comment #4:

The second issue is about overshoot. For glyphs controlled by alignment zones, curved tops and bottoms are designed to slightly exceed those with flat tops and bottoms. This improves the visual appearance at large sizes. At small sizes, CFF has a mechanism to suppress this overshoot and make curves and flats align to the same pixel. The size below which overshoot is suppressed is controlled by the BlueScale value in the font. For TexGyreHeros-Regular, this size is 39.63 px. The "rust" sample is just above this size, so overshoot is allowed.

The example of Cantarell Bold is different. Here, the alignment zone for digits extends from 694 to 701 in font units. The curved top digits (0,2,8) are designed with the top of the curve at 703. So, they miss the alignment zone and are not controlled. This is a font problem.

Dave Arnold <darnold>
Project Member
Thu 11 Jul 2013 01:31:12 AM UTC, comment #3:

About the second issue (hinting the "rust" word): I've also seen it in other fonts, e.g. in Gnome's "Cantarell Bold 16px", the digit 0 gains height and the digit 1 loses height, so numbers look uneven.

Jan Steffens <heftig>
Wed 26 Jun 2013 05:47:07 PM UTC, comment #2:

And here are snapshots of ftgrid (from current git) which shows the rendering with the old FreeType and the Adobe engine.

(file #28428, file #28429)

Werner LEMBERG <wl>
Project AdministratorIn charge of this item.
Thu 20 Jun 2013 05:29:30 AM UTC, comment #1:

I can confirm this. To repeat with ftview, simply say

ftview -m "Sp" 25 texgyreheros-regular.otf

We'll have a look soon.

Werner LEMBERG <wl>
Project AdministratorIn charge of this item.
Wed 19 Jun 2013 11:56:49 PM UTC, original submission:

Looking for a free Helvetica replacement, I stumbled upon TeX Gyre Heros:
http://www.gust.org.pl/projects/e-foundry/tex-gyre/heros/index_html

However, when rendered with Freetype 2.5.0.1 and hinting enabled, some glyphs are unpleasantly distorted (note lower-right bulging of the "S" and "p" glyphs), while others have size and baseline issues (note "rust" word).

Unhinted text looks fine. I don't know whether this is a renderer issue or a font issue.

Images generated with:
pango-view --font="TeX Gyre Heros 25px" --backend=ft2 --markup -t 'Sp <span font="bold 40px">rust</span>' -o hinted.png

pango-view --font="TeX Gyre Heros 25px" --backend=ft2 --markup -t 'Sp <span font="bold 40px">rust</span>' --hinting=none -o unhinted.png

Anonymous

 

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Attached Files
file #28358:  hinted.png added by None (1kB - image/png)
file #28359:  unhinted.png added by None (1kB - image/png)

 

Depends on the following items: None found

Items that depend on this one: None found

 

Carbon-Copy List
  • -unavailable- added by darnold (Posted a comment)
  • -unavailable- added by heftig (Posted a comment)
  • -unavailable- added by heftig (Submitter)
  • -unavailable- added by wl (Posted a comment)
  • -unavailable- added by wl
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    Follow 11 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Sun 29 Sep 2013 02:22:40 PM UTCwlStatusConfirmed=>Fixed
      Open/ClosedOpen=>Closed
      Planned ReleaseNone=>2.5.1
    Wed 26 Jun 2013 05:47:07 PM UTCwlAttached File-=>Added texgyreheros-regular-S-25px-FreeType.png, #28428
      Attached File-=>Added texgyreheros-regular-S-25px-Adobe.png, #28429
    Sat 22 Jun 2013 09:43:21 PM UTCheftigCarbon-Copy-=>Added heftig
    Thu 20 Jun 2013 05:29:30 AM UTCwlStatusNone=>Confirmed
      Assigned toNone=>wl
      Carbon-Copy-=>Added -unavailable-
    Wed 19 Jun 2013 11:56:49 PM UTCNoneAttached File-=>Added hinted.png, #28358
      Attached File-=>Added unhinted.png, #28359

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