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

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

On 3 October 2012 10:19, pra...@gm... <pra...@gm...> wrote:

>
>
> 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.
>

Script to set isFixedPitch bit,
http://git.fedorahosted.org/cgit/liberation-fonts.git/tree/scripts/setisFixedPitch-fonttools.py

Regards,
Pravin Satpute