[Bug 1556457] Re: [Resolved Upstream] Demilight (OS/2 weight=350) confuses fontconfig

Mon Mar 14 18:53:53 UTC 2016

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On 2014-07-17T05:57:22+00:00 Kanru-d wrote:

Recently Adobe & Google released a open-source pan-CJK font, Source Han
Sans from Adobe or Noto Sans CJK from Google.

This font family features 7 font weights: ExtraLight, Light, Normal,
Regular, Meidum, Bold, Heavy and their os2 weight are: 100, 300, 350,
400, 500, 700, 900 respectively.

However, in fontconfig, os2 weight class 350 and 400 both maps to weight
80 and I think this makes fontconfig or pango confuse about how to
choose the default font.

In particular in the GktFontChooser user can't choose one of these
fonts. To fix this we probably also have to fix Pango.

This issue is also reported to the source-han-sans project:
https://github.com/adobe-fonts/source-han-sans/issues/5

Reply at:
https://bugs.launchpad.net/ubuntu/+source/fontconfig/+bug/1556457/comments/0

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On 2014-07-19T20:54:16+00:00 Freedesktop wrote:

I believe this is a Pango limitation, not fontconfig.  I'll take a look.

Reply at:
https://bugs.launchpad.net/ubuntu/+source/fontconfig/+bug/1556457/comments/1

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On 2014-07-25T19:05:18+00:00 Freedesktop wrote:

My bad, this *is* a fontconfig issue.  Investigating.

Reply at:
https://bugs.launchpad.net/ubuntu/+source/fontconfig/+bug/1556457/comments/2

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On 2014-07-25T22:09:03+00:00 Freedesktop wrote:

Fontconfig part fixed.  Pango fix needed.

commit ffda7c0e8130eb107ecbb3bdc48043093b12dff9
Author: Behdad Esfahbod <behdad at behdad.org>
Date:   Fri Jul 25 17:59:26 2014 -0400

    Linearly interpolate weight values

    Rest of Part of https://bugs.freedesktop.org/show_bug.cgi?id=81453

    Adds new API:

        FcWeightFromOpenType()
        FcWeightToOpenType()

commit bf9df5ada77469f57101851f6b4e279a4a5ea087
Author: Behdad Esfahbod <behdad at behdad.org>
Date:   Fri Jul 25 18:07:10 2014 -0400

    Change DemiLight from 65 to 55

    Such that Regular is closer to Medium than to DemiLight

commit be6506ca04ccce10868a8cd51d89e586284d149b
Author: Behdad Esfahbod <behdad at behdad.org>
Date:   Fri Jul 25 16:24:26 2014 -0400

    Add FC_WEIGHT_DEMILIGHT

    Part of https://bugs.freedesktop.org/show_bug.cgi?id=81453
    Also hooks up FC_WEIGHT_BOOK to fcfreetype.c.

Reply at:
https://bugs.launchpad.net/ubuntu/+source/fontconfig/+bug/1556457/comments/3

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On 2014-07-25T22:13:35+00:00 Freedesktop wrote:

Tracking pango issue here:
https://bugzilla.gnome.org/show_bug.cgi?id=733764

Reply at:
https://bugs.launchpad.net/ubuntu/+source/fontconfig/+bug/1556457/comments/4

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On 2014-07-26T20:42:43+00:00 Freedesktop wrote:

Pango fixed.  See screenshots here:
https://bugzilla.gnome.org/show_bug.cgi?id=733764

Reply at:
https://bugs.launchpad.net/ubuntu/+source/fontconfig/+bug/1556457/comments/5

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On 2014-08-06T07:09:56+00:00 Daphnediane wrote:

(In reply to comment #3)
> Fontconfig part fixed.  Pango fix needed.
> 
> commit ffda7c0e8130eb107ecbb3bdc48043093b12dff9
> Author: Behdad Esfahbod <behdad at behdad.org>
> Date:   Fri Jul 25 17:59:26 2014 -0400
> 
>     Linearly interpolate weight values
>     
>     Rest of Part of https://bugs.freedesktop.org/show_bug.cgi?id=81453
>     
>     Adds new API:
>     
>         FcWeightFromOpenType()
>         FcWeightToOpenType()

Note that this fix introduced bug 82228 as lerp doesn't handle dy == 0.

Reply at:
https://bugs.launchpad.net/ubuntu/+source/fontconfig/+bug/1556457/comments/6

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On 2016-03-12T04:44:48+00:00 Freedesktop wrote:

*** Bug 94505 has been marked as a duplicate of this bug. ***

Reply at:
https://bugs.launchpad.net/ubuntu/+source/fontconfig/+bug/1556457/comments/7

** Changed in: fontconfig
       Status: Unknown => Fix Released

** Changed in: fontconfig
   Importance: Unknown => Medium

** Bug watch added: GNOME Bug Tracker #733764
   https://bugzilla.gnome.org/show_bug.cgi?id=733764

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https://bugs.launchpad.net/bugs/1556457

Title:
  [Resolved Upstream] Demilight (OS/2 weight=350) confuses fontconfig

Status in Fontconfig:
  Fix Released
Status in fontconfig package in Ubuntu:
  New
Status in fontconfig package in Arch Linux:
  New

Bug description:
  See https://bugs.freedesktop.org/show_bug.cgi?id=81453 and bug
  1468027.

  Fontconfig lacks support for many OpenType/TrueType OS/2 font weight
  values. This causes a bunch of problems, like mixing up Demilight
  (weight=350) and Regular (weight=400).

  Although it's possible to write (dirty?) hacks for deb-packed fonts,
  this still causes problems for otherwise sourced fonts.

  Archlinux: https://bugs.archlinux.org/task/48550

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