Re: [Fontforge-users] Regenerated font does not recognize as a Monospace in Windows

[<pra...@gm...>]

On 1 October 2012 18:51, Khaled Hosny <kha...@eg...> wrote:

> On Mon, Oct 01, 2012 at 04:48:16PM +0530, pra...@gm... wrote:
> >
> >
> > On 1 October 2012 15:02, pra...@gm... <pra...@gm...>
> wrote:
> >
> >
> >
> >     On 29 September 2012 16:08, Khaled Hosny <kha...@eg...>
> wrote:
> >
> >         On Sat, Sep 29, 2012 at 11:52:33AM +0530, pra...@gm...wrote:
> >         > Hi,
> >         >
> >         >   I have downloaded
> https://googlefontdirectory.googlecode.com/hg/ofl
> >         /cousine/
> >         > Cousine-Regular.ttf and saved as .sfd and regenerated ttf from
> it.
> >         But
> >         > regenerated font does not get recognized as a Monospace in
> Windows
> >         http://
> >         > www.chiark.greenend.org.uk/~sgtatham/putty/download.htmlPutty.exe
> >         >   While the original downloaded font get recognized there
> properly.
> >         >
> >         >   What might be going wrong while saving it as .sfd and
> regenerating
> >         .ttf?
> >         >
> >         >   Regenerated font
> http://pravins.fedorapeople.org/Test-Cousine.ttf
> >
> >         The original font has the isFixedPitch bit in post table set
> which it
> >         seems used by some application to recognise monospace fonts
> (though
> >         this, arguably, is wrong, there is no requirement that all
> monnospace
> >         fonts set it). Per the spec, isFixedPitch is only set when all
> glyphs
> >         in
> >         the font have the same width, but the font has a zero width
> ".null"
> >         glyph, so FontForge does not set isFixedPitch when generating
> the font
> >         (which is the right thing to do, some applications is know to
> behave
> >         wrongly with such a font).
> >
> >         Removing that glyph (which seems to serve no purpose and was
> probably
> >         auto inserted by the tool generating the font), should do the
> trick.
> >
> >
> >     Converting Cousine-Regular.ttf to .sfd and
> >
> >     $cat Cousine.sfd |grep "Width: 0"|wc -l
> >     267
> >
> >     We have lots of Zero width characters in Cousine-Regular fonts and
> removing
> >     them looks not good solution.
> >
> >     Do we have any other alternative to Set isFixedPitch bit?
> >
> >
> > While more analysis i found that 0 width is assigned to most of the marks
> > characters.
> > 1. In my humble opinion it is valid. We can not assign equal Width same
> as Base
> > characters to Marks character.
> > Font with "Decided Fixed width" or "0 Width" characters should be
> considered as
> > a Monospace.
> > 2. Other reasons is compatibility with other font editors.
>
> The isFixedPitch bit is carried on from Type1 fonts where it really
> meant all glyphs with no exception have the same width so
> implementations can just check the width of any glyph, cache it, and
> assume all other glyphs have the same width, as a form of optimisation
> in the olden days. Many implementation still does so, now if the font
> have a zero width glyph and it happens to be the glyph that the
> implementation checked first, all other glyphs will be treated as if
> they are zero width, which is not something you want¹.
>

It is clear to me now, Fontforge's behaviour is as per standard. As said by
Paul it will be good to Document this somewhere since looks like other
proprietary editors do not follow it.


>
> Now if you don’t care about all of this, you can use fontTools python
> library (or its command line ttx tool) to post process the font and
> manually set the bit.
>

I do care for standards but for the time being will use fontTools. But in
Long Term i will do necessary changes.

Thanks to all helped to clear my doubts.

Regards,
Pravin Satpute