[Bug 2095039] [NEW] Can't get full hinting working

[Oleg Moiseichuk]

Public bug reported:

I can't enable full hinting on fresh Kubuntu 24.04.1 install.
Previously I removed symlink 10-hinting-slight.conf in /etc/fonts/conf.d and placed 10-hinting-full.conf symlink there and that was sufficient.
Now this action doesn't produce any result - font hinting remains slight. When I open Font applet in KDE System Settings, the previews of Slight, Medium and Full Hinting look absolutely the same.

What other things I tried:
Compiling older versions of libfreetype from 20.04 and 22.04 - former doesn't work at all in 24.04, the latter shows no difference with the one shipped with 24.04.
Adding environment variable FREETYPE_PROPERTIES="truetype:interpreter-version=35" - I noticed only slight differences in diacritics, hinting remained the same.
Changing lcdfilter doesn't produce any result.
Changing mode="append" to more strict mode="assign" in hintstyle rule - no result.

In the same time if I run 'xrdb -q', I see the next output:
Xft.antialias:  1
Xft.hinting:    1
Xft.hintstyle:  hintfull
Xft.rgba:       rgb
So it seems that hinting style is set properly after all, but it doesn't work as intended.

The sole way I managed to activate it is to add 10-autohint.conf symlink, which enables auto-hinter. But it isn't the desired result, as auto-hinter works appropriately with very few fonts, the rest are rendered subpar when full hinting is activated.
How can I enable full hinting with the native hinter, avoiding auto-hinter usage?

Freetype library is provided by libfreetype6 (2.13.2+dfsg-1build3)
package.

** Affects: freetype (Ubuntu)
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/2095039

Title:
  Can't get full hinting working

Status in freetype package in Ubuntu:
  New

Bug description:
  I can't enable full hinting on fresh Kubuntu 24.04.1 install.
  Previously I removed symlink 10-hinting-slight.conf in /etc/fonts/conf.d and placed 10-hinting-full.conf symlink there and that was sufficient.
  Now this action doesn't produce any result - font hinting remains slight. When I open Font applet in KDE System Settings, the previews of Slight, Medium and Full Hinting look absolutely the same.

  What other things I tried:
  Compiling older versions of libfreetype from 20.04 and 22.04 - former doesn't work at all in 24.04, the latter shows no difference with the one shipped with 24.04.
  Adding environment variable FREETYPE_PROPERTIES="truetype:interpreter-version=35" - I noticed only slight differences in diacritics, hinting remained the same.
  Changing lcdfilter doesn't produce any result.
  Changing mode="append" to more strict mode="assign" in hintstyle rule - no result.

  In the same time if I run 'xrdb -q', I see the next output:
  Xft.antialias:  1
  Xft.hinting:    1
  Xft.hintstyle:  hintfull
  Xft.rgba:       rgb
  So it seems that hinting style is set properly after all, but it doesn't work as intended.

  The sole way I managed to activate it is to add 10-autohint.conf symlink, which enables auto-hinter. But it isn't the desired result, as auto-hinter works appropriately with very few fonts, the rest are rendered subpar when full hinting is activated.
  How can I enable full hinting with the native hinter, avoiding auto-hinter usage?

  Freetype library is provided by libfreetype6 (2.13.2+dfsg-1build3)
  package.

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