Bug 493490 - Opentype font feature override list is ineffective
Summary: Opentype font feature override list is ineffective
Status: RESOLVED DUPLICATE of bug 499736
Alias: None
Product: systemsettings
Classification: Applications
Component: kcm_fonts (other bugs)
Version First Reported In: 6.1.5
Platform: Other Linux
: NOR normal
Target Milestone: ---
Assignee: Plasma Bugs List
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2024-09-22 15:21 UTC by Andrea Ippolito
Modified: 2025-11-08 19:07 UTC (History)
4 users (show)

See Also:
Latest Commit:
Version Fixed/Implemented In:
Sentry Crash Report:


Attachments
Left: original Inter Display ttf font, Right: my variation with some OpenType features enabled (50.68 KB, image/png)
2024-09-22 15:26 UTC, Andrea Ippolito
Details
my patched version of InterDisplay-Regular with calt, cv05, cv06, cv08, ss01, along with the unpatched font (370.69 KB, application/gzip)
2024-09-22 15:28 UTC, Andrea Ippolito
Details

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Description Andrea Ippolito 2024-09-22 15:21:18 UTC
I was amazed to see, with a recent update, that the fonts System Settings module now allows to specify a comma separated list of OpenType features to enable for the chosen font.

Unfortunately, it's completely ineffective for me.

I have "frozen" some OpenType features for Inter Display and exported the resulting ttf, which is the one I now use as my Plasma variable-width font, and it's called `Inter Display calt, cv05, cv06, cv08, ss01`

One of the most visible changes is cv05 which brings `Lower-case L with tail`

So, I tried to replicate the same aspect by using KDE System Settings' font feature override feature, but nothing changes.

Is this a somewhat beta feature? Does it require some better integration on behalf of my distro?

System info:

Operating System: openSUSE Tumbleweed 20240920
KDE Plasma Version: 6.1.5
KDE Frameworks Version: 6.6.0
Qt Version: 6.7.2
Kernel Version: 6.10.9-1-default (64-bit)
Graphics Platform: Wayland
Processors: 16 × AMD Ryzen 7 7840U w/ Radeon 780M Graphics
Memory: 30.7 GiB of RAM
Graphics Processor: AMD Radeon 780M
Manufacturer: Framework
Product Name: Laptop 13 (AMD Ryzen 7040Series)
System Version: A7
Comment 1 Andrea Ippolito 2024-09-22 15:26:32 UTC
Created attachment 173965 [details]
Left: original Inter Display ttf font, Right: my variation with some OpenType features enabled

The one on the left comes straight from:
https://rsms.me/inter/download/

In the zip, it's under `extras/ttf/InterDisplay-Regular.ttf`

The one on the right is that ttf after having undergone some changes with opentype-feature-freezer: https://github.com/twardoch/fonttools-opentype-feature-freezer

`pyftfeatfreeze -rv -f calt,ss01,cv05,cv06,cv08 -S InterDisplay-Regular.ttf newName.ttf`

I will attach both TTFs for ease of investigation
Comment 2 Andrea Ippolito 2024-09-22 15:28:16 UTC
Created attachment 173966 [details]
my patched version of InterDisplay-Regular with calt, cv05, cv06, cv08, ss01, along with the unpatched font
Comment 3 Andrea Ippolito 2024-09-22 15:30:05 UTC
Also, when I open the font selection popup again, the overrides (comma separated list of features) I had provided are gone.
Comment 4 Akseli Lahtinen 2024-09-24 09:52:01 UTC
I agree this is a bit confusing, but it has not been yet implemented in other apps but Kate for now.

It should be hidden from applications that do not support it yet.
Comment 5 Andrea Ippolito 2024-09-24 09:58:45 UTC
(In reply to Akseli Lahtinen from comment #4)
> I agree this is a bit confusing, but it has not been yet implemented in
> other apps but Kate for now.
> 
> It should be hidden from applications that do not support it yet.

Indeed that seems to be the case. However, even in the Kate font settings, it seems that only the first feature of the list is taken into account
Comment 6 Christoph Cullmann 2025-11-08 19:07:50 UTC
If we fix that bug in KConfig it should work.

*** This bug has been marked as a duplicate of bug 499736 ***