[Bug 21197] New: hinted numerals aren't fixed-width in all sizes of dejavu sans font

http://bugs.freedesktop.org/show_bug.cgi?id=21197

Summary: hinted numerals aren't fixed-width in all sizes of
                    dejavu sans font
           Product: freetype
           Version: unspecified
          Platform: Other
        OS/Version: All
            Status: NEW
          Severity: trivial
          Priority: medium
         Component: general
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]
                CC: [e-mail], fedora-fonts-bugs-
                    [e-mail]

using the default dejavu sans font on fedora 11 snap1 numerals aren't all the
same width when 'full' or 'medium' hinting is enabled.  this leads to a
'jiggling text' effect on ticking clocks.

versions are:
freetype-2.3.9-3.fc11.i586
dejavu-sans-fonts-2.29-2.fc11.noarch

for more details see redhat bug 495820

[Bug 21197] hinted numerals aren't fixed-width in all sizes of dejavu sans font

http://bugs.freedesktop.org/show_bug.cgi?id=21197

--- Comment #1 from Werner Lemberg   2009-04-15 09:02:01 PST ---
Reading the redhat bug description I see that you are not using the TT hinter.

With the autohinter I fear this problem is unavoidable.  It probably has to
be handled on a level higher than FreeType: If you pass a font to the library,
the autohinter simply doesn't know that the digits 0-9 are intended to have the
same width.  As you certainly aware there are fonts containing `old digits'
which intentionally have different widths.

I can imagine that there is an option to `fontconfig' which forces the
same width to all digits if the autohinter is used (probably using the average
value of all digit widths).

[Bug 21197] hinted numerals aren't fixed-width in all sizes of dejavu sans font

http://bugs.freedesktop.org/show_bug.cgi?id=21197

--- Comment #2 from whyoh   2009-04-15 09:20:40 PST ---
thanks for the quick response.

hmm.  can't the library tell that the numerals are all the same width in the
unhinted font?

if so then might there be an option or rule to tell the autohinter: "numerals
are special - don't hint them (much) if they're all the same width in this
font"?

i think that would be enough for me.  but i'm a little hesitant about where (if
at all) it's appropriate to assert the "specialness" of numerals vs hinting.

and what should we say when everyone starts raising "my numerals are fuzzy!!"
bugs?  ;-)

[Bug 21197] hinted numerals aren't fixed-width in all sizes of dejavu sans font

http://bugs.freedesktop.org/show_bug.cgi?id=21197

--- Comment #3 from Werner Lemberg   2009-04-15 22:15:21 PST ---
It's completely irrelevant whether the unhinted numerals have the same width
or not.  In a TrueType font, the hinting instructions modify the advance width
as needed, and this information is not available to the autohinter.

There are two possibilities: Either FreeType gets an option for the autohinting
module to instruct that some glyphs (numerals and probably some others too)
should have the same width, or the library which uses FreeType does this.  IMHO
it should be the latter.

[Bug 21197] hinted numerals aren't fixed-width in all sizes of dejavu sans font

http://bugs.freedesktop.org/show_bug.cgi?id=21197

--- Comment #4 from Behdad Esfahbod   2009-04-15 23:21:01 PST ---
The autohinter already has lots of heuristics based on individual Latin
characters.  I'd rather it also handles the issue at hand (that is, if all
input ASCII glyphs have the same width, they should be hinted to have the same
output width also).  There is no place for this kind of tweak higher in the
stack really.

[Bug 21197] hinted numerals aren't fixed-width in all sizes of dejavu sans font

http://bugs.freedesktop.org/show_bug.cgi?id=21197

--- Comment #5 from Werner Lemberg   2009-04-15 23:28:20 PST ---
Behdad, it's not clear to me what you mean with `all input ASCII glyphs
have the same width'.

[Bug 21197] hinted numerals aren't fixed-width in all sizes of dejavu sans font

http://bugs.freedesktop.org/show_bug.cgi?id=21197

--- Comment #6 from Behdad Esfahbod   2009-04-16 00:29:24 PST ---
(In reply to comment #5)
> Behdad, it's not clear to me what you mean with `all input ASCII glyphs
> have the same width'.

I mean, if the unhinted, design width, of the ASCII digit glyphs are all the
same, the autohinter should ensure that their hinted width is also the same.

[Bug 21197] hinted numerals aren't fixed-width in all sizes of dejavu sans font

http://bugs.freedesktop.org/show_bug.cgi?id=21197

Werner Lemberg  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED

--- Comment #7 from Werner Lemberg   2009-04-27 10:43:15 PST ---
This is now fixed in the FreeType git repository.  Please test.