bugThe FreeType Project - Bugs: bug #23669, Hinting problem with Type1 font...

 
 

bug #23669: Hinting problem with Type1 font "Times New Roman"

Submitted by:  Peter Weilbacher <pmw>
Submitted on:  Sat 21 Jun 2008 11:10:52 PM UTC  
 
Severity: 3 - NormalItem Group: Incorrect behaviour
Status: ConfirmedPrivacy: Public
Assigned to: Werner LEMBERG <wl>Open/Closed: Open
Planned Release: None

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Tue 01 Sep 2009 06:02:20 AM UTC, comment #3:

Thanks for the update. Unfortunately, the Type 1 hinting stuff is largely unmaintained, and I don't have time currently to start learning it so that I can fix bugs.

Perhaps David can have a look, but I doubt that he has time.

Werner LEMBERG <wl>
Project AdministratorIn charge of this item.
Thu 20 Aug 2009 02:46:42 PM UTC, comment #2:

I also noticed that between 2.3.5 and 2.3.9 the smallest size "e" of my test program becomes even worse. (The middle horizontal line has completely merged with the top curve.)

(file #18616)

Peter Weilbacher <pmw>
Thu 20 Aug 2009 02:31:11 PM UTC, comment #1:

The same problem still happens with FT 2.3.9.

To make a solution easier I tried to bisect the code between 2.1.9 and 2.3.5 (using the VER-2-1-9 and VER-2-3-5 tags as good and bad base). My first try failed miserably, because I tried to use ftstring. But the current version (or v2.3.5) of the ftstring program cannot be linked to an older FT version and older ft2demos don't run on my Linux machine which I used for the bisecting (something changed in X or they were not 64bit clean?).

Well, now I created a small FreeType+cairo program that creates PNG files. With this I find the first regression to be caused by this checkin:

601aefe4eccd84c8fbca4d43bd8fa68fe6a342d9 is first bad commit
commit 601aefe4eccd84c8fbca4d43bd8fa68fe6a342d9
Author: David Turner <david@freetype.org>
Date: Wed Feb 21 16:47:49 2007 +0000

fix postscript hinter's handling of small and ghost stems

Peter Weilbacher <pmw>
Sat 21 Jun 2008 11:10:52 PM UTC, original submission:

The FreeType Type 1 hinter has a slight problem with the font "Times New Roman" (TNR.PFB). This font is shipped with OS/2 and apparently with the Linux version of Abobe Acrobat Reader v5.

This problem happens with FreeType 2.3.6 and at least with 2.3.5 while it was apparently OK with FreeType 2.1.9. The screenshot I attach compares the rendering through FT 2.1.9 (top) with FT 2.3.5 (bottom). The character 'e' looks almost like a 'c'.

Indepently of my code use this can be reproduced with
ftstring -m eComStation 16 TNR.PFB
and all sizes lower than that.

The same problem appears in other fonts (as reported on the freetype-user list, although I didn't verify that myself):
- MinionPro from acroread 7 at sizes under 13
- URW's NimbusRomanNo9L-Regu in sizes below 14

Peter Weilbacher <pmw>

 

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

Attach File(s):
   
   
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Attached Files
file #18616:  cairo_text_tnr_really_really_bad_VER-2-3-9.png added by pmw (1kB - image/png - even worse display in 2.3.9)
file #18615:  cairo_text_tnr_bad_good4_b68e025c1b888a1d06e3617d768d616d5469f754.png added by pmw (1kB - image/png - cairo test program and bad and good examples)
file #18614:  cairo_text_tnr_bad_bad2_601aefe4eccd84c8fbca4d43bd8fa68fe6a342d9.png added by pmw (1kB - image/png - cairo test program and bad and good examples)
file #18613:  cairo_text.c added by pmw (1kB - application/x-c - cairo test program and bad and good examples)
file #15906:  hinting.png added by pmw (15kB - image/png - demo of hinting problem with 'e' (visible e.g. in "article" or "eComStation"))

 

Depends on the following items: None found

Items that depend on this one: None found

 

Carbon-Copy List
  • -unavailable- added by wl
  • -unavailable- added by wl (Updated the item)
  • -unavailable- added by pmw (Submitted the item)
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    Follow 8 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Tue 01 Sep 2009 06:02:20 AM UTCwlCarbon-Copy-=>Added freetype
    Thu 20 Aug 2009 02:46:42 PM UTCpmwAttached File-=>Added cairo_text_tnr_really_really_bad_VER-2-3-9.png, #18616
    Thu 20 Aug 2009 02:33:04 PM UTCpmwAttached File-=>Added cairo_text.c, #18613
      Attached File-=>Added cairo_text_tnr_bad_good4_b68e025c1b888a1d06e3617d768d616d5469f754.png, #18615
      Attached File-=>Added cairo_text_tnr_bad_bad2_601aefe4eccd84c8fbca4d43bd8fa68fe6a342d9.png, #18614
    Sun 22 Jun 2008 04:50:40 AM UTCwlStatusNone=>Confirmed
      Assigned toNone=>wl
    Sat 21 Jun 2008 11:10:52 PM UTCpmwAttached File-=>Added hinting.png, #15906

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