RE: [EXTERNAL] Re: Bug: tt_check_single_notdef function skip spaces

[Dominik Mazgaj]

Hi

>Hmm.  Too bad that Microsoft's PDF driver doesn't strip off tables for 
>embedded bitmaps.  Maybe it makes even sense to write a bug report to
>MS: There shouldn't be any bitmap strikes in fonts part of a PDF.

I can imagine a PDF where someone is using these bitmas in the right size, but 
the space itself can be custom scaled .... And that won't be a bug...

>If you can provide a Merge Request (on gitlab.freedesktop.org) I'm willing to 
>add the functionality you need.

Hmm, with my corporate email, I had trouble signing up here: 
https://gitlab.freedesktop.org/groups/freetype/-/issues

sbits-always-scalable and FT_PARAM_TAG_SBITS_ALWAYS_SCALABLE. That resolve this 
problem, but in my opinion problem is in tt_check_single_notdef (don't see 
glyph at index 3). If I understand correctly this function checking only glyph 
offsets (empty glyph don't have different begin and end offset)? I expected 
some corrections there. Acrobat and FontForge can see that this is a (empty) 
glyph on index 3.

Regards
Dominik Mazgaj

-----Original Message-----
From: Werner LEMBERG <wl@gnu.org> 
Sent: Wednesday, March 16, 2022 12:05 PM
To: Dominik Mazgaj <dominik.mazgaj@bluecrestinc.com>
Cc: freetype-devel@nongnu.org
Subject: Re: [EXTERNAL] Re: Bug: tt_check_single_notdef function skip spaces


> I expressed myself wrong. I know about bitmaps, but in this file our 
> software only needs to render (or get width - depend of scenario) a 
> space.

OK, you have convinced me.

> Original producer: /Producer (Microsoft: Print To PDF)

Hmm.  Too bad that Microsoft's PDF driver doesn't strip off tables for embedded 
bitmaps.  Maybe it makes even sense to write a bug report to
MS: There shouldn't be any bitmap strikes in fonts part of a PDF.

> If you are not going to fix this, please give me some advice on how to 
> modify the tt_check_single_notdef function to recognize empty glyphs?

If you can provide a Merge Request (on gitlab.freedesktop.org) I'm willing to 
add the functionality you need.

* Add a property `sbits-always-scalable` similar to
  `interpreter-version` (file `ttdriver.h`, and structure
  `TT_DriverRec` in file `ttobjs.h`.  You can test for this in
  `tt_face_init`, overriding the decision of `tt_check_single_notdef`.
  This sets a global property.

* Maybe it makes also sense to have a new parameter tag, say,
  `FT_PARAM_TAG_SBITS_ALWAYS_SCALABLE` (see file `ftparams.h`) to have
  a per-face setting.


    Werner

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