Bug 112805 - Support for "size" (optical size) OpenType table
Summary: Support for "size" (optical size) OpenType table
Status: NEW
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: LibreOffice (show other bugs)
(earliest affected) release
Hardware: All All
: medium enhancement
Assignee: Not Assigned
Depends on:
Blocks: Font-Rendering
  Show dependency treegraph
Reported: 2017-10-01 21:46 UTC by RGB
Modified: 2018-04-21 00:11 UTC (History)
3 users (show)

See Also:
Crash report or crash signature:

Character properties for Coelacanth font (46.57 KB, image/png)
2017-10-01 21:46 UTC, RGB

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Description RGB 2017-10-01 21:46:19 UTC
Created attachment 136670 [details]
Character properties for Coelacanth font

There are fonts like Latin Modern(1) or the still in development Coelacanth(2) that offers "optical sizes"(3): variants of the font designed to be used for different point sizes (broader, less detailed for small point sizes, taller and with higher contrast for big headings). 

This feature is governed by the "size" OpenType table. Systems like XeTeX automatically pick the right font file to be used on the appropriate size, but it seems that LibreOffice gets confused by that table: not only it do not switch between variants, it's not even possible to select which variant is being used as you can see on the attached screenshot. In fact Coelacanth consist of 37 font files tied together by the "size" OT feature, but LibO only offers a small and rather arbitrary selection.

(1) http://www.gust.org.pl/projects/e-foundry/latin-modern/download
(2) https://github.com/Fuzzypeg/Coelacanth
(3) https://en.wikipedia.org/wiki/Font#Optical_size
Comment 1 Buovjaga 2017-11-02 17:26:08 UTC
Sounds relevant -> NEW
Comment 3 Volga 2018-02-19 17:43:29 UTC
Hi Khaled, 

What do you think about that?
Comment 4 Khaled Hosny 2018-02-19 18:29:15 UTC
(In reply to Volga from comment #3)
> Hi Khaled, 
> What do you think about that?

Patches are welcome.