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Glyph Keeper with restricted font embeddability
Marek Ratajczak
Member #18,974
December 2020

Dear Forum Members,

Has anyone an experience with loading and rendering TTF fonts which are marked as "Restricted font embeddability", using Glyph Keeper ? It's Allegro 4, in my case 64bit, but it's not important, and Glyph Keeper 0.32, which works for me incredibly well, except of some fonts, and I realised they are restricted. I'm thinking about such fonts like techic_.ttf, techb___.ttf, techl___.ttf (copyrighted by Payne Loving Trust, and possibly coming with Autocad package or Autodesk DWG viewers etc, but maybe they are also come with regular Windows 10).
Another fonts, also "technical", like isocteui.ttf, isocteur.ttf are working fine, and they are marked as "Installable", another ones like isoct___.ttf, isoct2__.ttf or isoct3__.ttf marked as Restricted don't work. There is no error while loading, but Glyph Keeper doesn't render those fonts, however doesn't crash too.
I understand that restrictions can protect agains embedding fonts in e.g. PDF documents etc, but restricting loading and rendering on the screen seems for me like glitch in rendering package or so.
Any help would be appreciated very much. Those fonts are really good for technical drawings (they were designed for that), and the application in Allegro what I'm implementing TTF fonts both for GUI and drawings is CAD application.

Kind regards,

SiegeLord
Member #7,827
October 2006
avatar

Allegro 5 can load those fonts fine. It uses FreeType, and from what I can see Glyph Keeper uses FreeType as well, but it's bundled version might be too old? Try compiling it with a more up-to-date FreeType perhaps.

"For in much wisdom is much grief: and he that increases knowledge increases sorrow."-Ecclesiastes 1:18
[SiegeLord's Abode][Codes]:[DAllegro5]:[RustAllegro]

Marek Ratajczak
Member #18,974
December 2020

I just compiled Glyph Keeper with very up-to-date FreeType 2 (with just those small changes previously done by Kirill for compatibility with his program) - surprisingly - compiled with success, just adding one extra obj to compile what in the meantime appeared to be necessary, and what is sdf.obj, but when I linked lib with my program, I got the same ::) . It's not rendering glyphs for restricted fonts, however is loading font without error. Also calculating the size of each glyph is wrong (width zero pxl for any character).
Maybe someone could help, it seems to be more than Glyph Keeper...

amarillion
Member #940
January 2001
avatar

Is there a reason you're using Glyph Keeper + Allegro 4 though? What are you using Glyph Keeper for that Allegro 5 can't do out of the box?

Peter Hull
Member #1,136
March 2001

There are programs out there to modify the embeddability of the font file - the first thing I'd do is modify the fonts to confirm that it because the fonts are restricted and not just a coincidence that those fonts have some other feature that G.K. doesn't like. (the embeddability or otherwise is just a flag in one of the file chunks, it's not like the font data is encrypted - see https://docs.microsoft.com/en-us/typography/opentype/spec/os2#fstype)

Then we're looking at maybe fixing a bug in Glyph Keeper - for example zero width glyphs, as you mentioned, maybe do load but render invisibly?

(also - Glyph Keeper is very hard to google for, Magic the Gathering seems have taken over :P )

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