bugGNU roff - Bugs: bug #58718, font file should allow kern pairs...


bug #58718: font file should allow kern pairs with space as first element

Submitter:  Dave <barx>
Submitted:  Tue 07 Jul 2020 09:43:10 AM UTC
Category:  Font - others/general Severity:  1 - Wish
Item Group:  Feature change Status:  None
Privacy:  Public Assigned to:  None
Open/Closed:  Open Planned Release:  None
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Fri 11 Aug 2023 02:31:38 PM UTC, comment #5: 

OK, for reals this time: the savannah bug has been fixed, so soliciting Peter's input on comment #2.

Dave <barx>
Group Member
Wed 09 Aug 2023 06:08:25 PM UTC, comment #4: 

Conclusion: continuing to misdeliver to Peter.

As a further test, along with this comment I'm adding the savannah handle "gbranden" to this bug's cc to see whether the savannah problem is specific to Peter's account.  (http://savannah.gnu.org/users/PTPi shows his longtime and valid email address, so there's nothing obviously misconfigured in his account.)

If this email goes to Branden's correct address, I'll delete the cc immediately after this (he can certainly add himself if he wants to be cc:ed here).  If it goes to a bogus one, I'll leave it, as it won't be cluttering his mailbox.

Sorry for the extra noise in this bug report.

Dave <barx>
Group Member
Wed 09 Aug 2023 12:16:41 PM UTC, comment #3: 

comment #2:

> I'm looping in Peter

Rather, I tried to loop him in, but sr #110918 thwarted me.  This comment serves to test whether it was only upon the initial add to the cc list that savannah used the wrong address for him, or whether it will continue to do so on all subsequent autogenerated emails.

Dave <barx>
Group Member
Mon 07 Aug 2023 05:07:02 PM UTC, comment #2: 

Further, the width of ordinary spaces is under the control of the user (via .ss), and spaces are stretchable in fully justified text.  Thus, kerning them raises an additional question that other kerned characters need not address: is the amount of kerning always that specified in the kernpairs section, or does it scale based on these other factors?

Also, it seems that a kerning amount specified for "a space" should apply to all of " ", "\ ", and "\~".  Is there any reason to give the user the ability to kern each of these types of spaces separately?  I can't think of one, but I'm looping in Peter, who originally proposed the idea (and who has far more typesetting experience than I do), to see if he can.

Dave <barx>
Group Member
Mon 07 Aug 2023 08:33:43 AM UTC, comment #1: 

Bug #64519 observes that a hyphen likewise cannot be the first element of a kern pair.

Arguably these are two examples of the same limitation.  (There may be others; I did not test every character.)  But I feel #64519 is the easier to solve because it doesn't require any font file syntax change: it's already possible to specify a kern pair that starts with a hyphen, but groff ignores such a pair.  Specifying a space as an element of a kern pair requires a different syntax, since currently spaces in the kernpair section are delimiters.  So to me this justifies filing them as separate bug reports.

Dave <barx>
Group Member
Tue 07 Jul 2020 09:43:10 AM UTC, original submission:  

Back in 2014, Peter Schaffter wrote, "Something I've never figured out is whether it's possible to set up kern pairs in groff font files that have 'space' as the first element of the pair.  I pipe my files through sed(1) to catch space-W, space-T, etc and kern them, but it would be great to have these pairs included in the kerning tables."

Werner Lemberg replied "This is not possible" and later in the thread suggested this enhancement request be added to the bug tracker.  If it ever was, I can't find it, so here it is.

Dave <barx>
Group Member


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Carbon-Copy List
  • -email is unavailable- added by barx (originally suggested the enhancement)
  • -email is unavailable- added by barx (Submitted the item)

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    Follow 4 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2023-08-09 barx Carbon-CopyRemoved gbranden -
    2023-08-09 barx Carbon-Copy- Added gbranden
    2023-08-07 barx Carbon-Copy- Added ptpi
    2021-06-04 barx Severity3 - Normal 1 - Wish

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