bug#51385: 29.0.50; PragmataPro wide word ligatures such as [ERR] having the left side cut off in cairo build

bug#51385: 29.0.50; PragmataPro wide word ligatures such as [ERR] having the left side cut off in cairo build

[Patrick Lenihan [sc17pl]]

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When building Emacs with Cairo support, first characters are missing in
many ligatures of PragmataPro. This issue has occurred since Emacs
27.1 but does not occur when building without Cairo. More details:
https://github.com/fabrizioschiavi/pragmatapro/issues/181. The same
occurs regardless of whether prettify-symbols or ligatures.el are
used, although using ligatures.el appears to allow some of these
characters to display correctly. More details on ligatures.el:
https://github.com/mickeynp/ligature.el/issues/33.

Date: Mon, 25 Oct 2021 12:50:34 +0100
Message-ID: <87o87dwcfp.fsf@fedora.mail-host-address-is-not-set>

[https://opengraph.githubassets.com/de761542ce665a33aa3259a68d8c3940fd7fe8528ee7bcc281437fd9f49afc44/mickeynp/ligature.el/issues/33]<https://github.com/mickeynp/ligature.el/issues/33>
Only the right side of wide PragmataPro ligatures are displaying · Issue #33 · mickeynp/ligature.el<https://github.com/mickeynp/ligature.el/issues/33>
On the left is buffer visiting my init file and right is buffer visiting a Python file. Settings are (ligature-set-ligatures &#39;prog-mode &#39;(&quot;[ERROR]&quot; &quot;[DEBUG]&quot; &quot;[INFO...
github.com


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bug#51385: 29.0.50; PragmataPro wide word ligatures such as [ERR] having the left side cut off in cairo build

[Stefan Kangas]

"Patrick Lenihan [sc17pl]" <P.J.Lenihan1@leeds.ac.uk> writes:

> When building Emacs with Cairo support, first characters are missing in
> many ligatures of PragmataPro. This issue has occurred since Emacs
> 27.1 but does not occur when building without Cairo. More details:
> https://github.com/fabrizioschiavi/pragmatapro/issues/181. The same
> occurs regardless of whether prettify-symbols or ligatures.el are
> used, although using ligatures.el appears to allow some of these
> characters to display correctly. More details on ligatures.el:
> https://github.com/mickeynp/ligature.el/issues/33.

Thanks for the bug report.

Could you provide a recipe to reproduce this issue, starting from
"emacs -Q"?

bug#51385: 29.0.50; PragmataPro wide word ligatures such as [ERR] having the left side cut off in cairo build

[Patrick Lenihan [sc17pl]]

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Dear Stefan,

Note that this issue disappears when Emacs is built without Cairo support.


________________________________
From: Patrick Lenihan [sc17pl] <P.J.Lenihan1@leeds.ac.uk>
Sent: 02 November 2021 17:58
To: Stefan Kangas <stefan@marxist.se>
Subject: Re: bug#51385: 29.0.50; PragmataPro wide word ligatures such as [ERR] having the left side cut off in cairo build


  1.  run command "emacs -Q"
  2.  M-:
  3.  (set-frame-font "PragmataPro Mono Liga" nil t)
  4.  C-uC-u<SPC>
  5.  M-x
  6.  insert-char #Xe2c0
  7.  Repeat 4-6 substituting #Xe2c0 for any of the following: #Xe2b0, #Xe2b1, #Xe2b2, #Xe2b3, #Xe2b4, #Xe2b5, #Xe2b6, #Xe2c0, #Xe2c1, #Xe2c2, #Xe2c3, #Xe2c4, #Xe2c5, #Xe2c6, #Xe2c7, #Xe2c8, #Xe2c9, #Xe2ca, #Xe2cb, #Xe2cc, #Xe2cd, #Xe2ce, #Xe2e0, #Xe2e1, #Xe2e2, #Xe2e3, #Xe2e4, #Xe2e5, #Xe2e6, #Xe2e7, #Xe2e8, #Xe2e9, #Xe2ea, #Xe2eb, #Xe2ec, #Xe2ed, #Xe2e  #Xe2f0, #Xe2f1, #Xe2f2, #Xe2f3, #Xe2f4, #Xe2f5, #Xe2f6, #Xe2f7, #Xe2f8, #Xe2f9, #Xe2fa, #Xe2fb, #Xe2fc, #Xe2fd, #Xe2fe

At the moment all are clipped unless Emacs is built without Cairo support.

________________________________
From: Stefan Kangas <stefan@marxist.se>
Sent: 28 October 2021 04:22
To: Patrick Lenihan [sc17pl] <P.J.Lenihan1@leeds.ac.uk>
Cc: 51385@debbugs.gnu.org <51385@debbugs.gnu.org>
Subject: Re: bug#51385: 29.0.50; PragmataPro wide word ligatures such as [ERR] having the left side cut off in cairo build

"Patrick Lenihan [sc17pl]" <P.J.Lenihan1@leeds.ac.uk> writes:

> When building Emacs with Cairo support, first characters are missing in
> many ligatures of PragmataPro. This issue has occurred since Emacs
> 27.1 but does not occur when building without Cairo. More details:
> https://github.com/fabrizioschiavi/pragmatapro/issues/181. The same
> occurs regardless of whether prettify-symbols or ligatures.el are
> used, although using ligatures.el appears to allow some of these
> characters to display correctly. More details on ligatures.el:
> https://github.com/mickeynp/ligature.el/issues/33.

Thanks for the bug report.

Could you provide a recipe to reproduce this issue, starting from
"emacs -Q"?

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bug#51385: 29.0.50; PragmataPro wide word ligatures such as [ERR] having the left side cut off in cairo build

[Eli Zaretskii]

> From: "Patrick Lenihan [sc17pl]" <P.J.Lenihan1@leeds.ac.uk>
> Date: Wed, 3 Nov 2021 12:26:59 +0000
> 
> Note that this issue disappears when Emacs is built without Cairo support.
> 
> ------------------------------------------------------------------------------
> From: Patrick Lenihan [sc17pl] <P.J.Lenihan1@leeds.ac.uk>
> Sent: 02 November 2021 17:58
> To: Stefan Kangas <stefan@marxist.se>
> Subject: Re: bug#51385: 29.0.50; PragmataPro wide word ligatures such as [ERR] having the left side cut
> off in cairo build 
>  
> 1 run command "emacs -Q"
> 2 M-: 
> 3 (set-frame-font "PragmataPro Mono Liga" nil t)
> 4 C-uC-u<SPC>
> 5 M-x 
> 6 insert-char #Xe2c0
> 7 Repeat 4-6 substituting #Xe2c0 for any of the following: #Xe2b0, #Xe2b1, #Xe2b2, #Xe2b3, #Xe2b4,
>  #Xe2b5, #Xe2b6, #Xe2c0, #Xe2c1, #Xe2c2, #Xe2c3, #Xe2c4, #Xe2c5, #Xe2c6, #Xe2c7, #Xe2c8,
>  #Xe2c9, #Xe2ca, #Xe2cb, #Xe2cc, #Xe2cd, #Xe2ce, #Xe2e0, #Xe2e1, #Xe2e2, #Xe2e3, #Xe2e4,
>  #Xe2e5, #Xe2e6, #Xe2e7, #Xe2e8, #Xe2e9, #Xe2ea, #Xe2eb, #Xe2ec, #Xe2ed, #Xe2e  #Xe2f0, #Xe2f1,
>  #Xe2f2, #Xe2f3, #Xe2f4, #Xe2f5, #Xe2f6, #Xe2f7, #Xe2f8, #Xe2f9, #Xe2fa, #Xe2fb, #Xe2fc, #Xe2fd, #Xe2fe
> 
>  At the moment all are clipped unless Emacs is built without Cairo support.

These characters are from the Private Use Area (PUA) of Unicode.  Why
do you expect Emacs to produce anything sensible for them?  To display
such characters, it is not enough to install a font that has glyphs
for PUA codepoints, you need also to tell Emacs what attributes and
properties those codepoints have, because Unicode doesn't define any
properties for those codepoints.

I don't see a bug in this recipe.  Emacs currently doesn't support
display of arbitrary PUA characters.

bug#51385: 29.0.50; PragmataPro wide word ligatures such as [ERR] having the left side cut off in cairo build

[Patrick Lenihan [sc17pl]]

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It's my ignorance. I am a user of ligature packages but don't know how they communicate with the composition table mechanism in Emacs. Perhaps my best effort recipe wasn't a sensible way to display ligatures in Emacs.

Although my recipe is not well written I do believe there is a bug. The wide PragmataPro ligatures display fine in builds without Cairo, but only the right side is displaying if Cairo is included. Its the same for all ligature packages I've tried.
________________________________
From: Eli Zaretskii <eliz@gnu.org>
Sent: 03 November 2021 14:36
To: Patrick Lenihan [sc17pl] <P.J.Lenihan1@leeds.ac.uk>
Cc: stefan@marxist.se <stefan@marxist.se>; 51385@debbugs.gnu.org <51385@debbugs.gnu.org>
Subject: Re: bug#51385: 29.0.50; PragmataPro wide word ligatures such as [ERR] having the left side cut off in cairo build

> From: "Patrick Lenihan [sc17pl]" <P.J.Lenihan1@leeds.ac.uk>
> Date: Wed, 3 Nov 2021 12:26:59 +0000
>
> Note that this issue disappears when Emacs is built without Cairo support.
>
> ------------------------------------------------------------------------------
> From: Patrick Lenihan [sc17pl] <P.J.Lenihan1@leeds.ac.uk>
> Sent: 02 November 2021 17:58
> To: Stefan Kangas <stefan@marxist.se>
> Subject: Re: bug#51385: 29.0.50; PragmataPro wide word ligatures such as [ERR] having the left side cut
> off in cairo build
>
> 1 run command "emacs -Q"
> 2 M-:
> 3 (set-frame-font "PragmataPro Mono Liga" nil t)
> 4 C-uC-u<SPC>
> 5 M-x
> 6 insert-char #Xe2c0
> 7 Repeat 4-6 substituting #Xe2c0 for any of the following: #Xe2b0, #Xe2b1, #Xe2b2, #Xe2b3, #Xe2b4,
>  #Xe2b5, #Xe2b6, #Xe2c0, #Xe2c1, #Xe2c2, #Xe2c3, #Xe2c4, #Xe2c5, #Xe2c6, #Xe2c7, #Xe2c8,
>  #Xe2c9, #Xe2ca, #Xe2cb, #Xe2cc, #Xe2cd, #Xe2ce, #Xe2e0, #Xe2e1, #Xe2e2, #Xe2e3, #Xe2e4,
>  #Xe2e5, #Xe2e6, #Xe2e7, #Xe2e8, #Xe2e9, #Xe2ea, #Xe2eb, #Xe2ec, #Xe2ed, #Xe2e  #Xe2f0, #Xe2f1,
>  #Xe2f2, #Xe2f3, #Xe2f4, #Xe2f5, #Xe2f6, #Xe2f7, #Xe2f8, #Xe2f9, #Xe2fa, #Xe2fb, #Xe2fc, #Xe2fd, #Xe2fe
>
>  At the moment all are clipped unless Emacs is built without Cairo support.

These characters are from the Private Use Area (PUA) of Unicode.  Why
do you expect Emacs to produce anything sensible for them?  To display
such characters, it is not enough to install a font that has glyphs
for PUA codepoints, you need also to tell Emacs what attributes and
properties those codepoints have, because Unicode doesn't define any
properties for those codepoints.

I don't see a bug in this recipe.  Emacs currently doesn't support
display of arbitrary PUA characters.

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bug#51385: 29.0.50; PragmataPro wide word ligatures such as [ERR] having the left side cut off in cairo build

[Eli Zaretskii]

> From: "Patrick Lenihan [sc17pl]" <P.J.Lenihan1@leeds.ac.uk>
> Date: Wed, 3 Nov 2021 15:08:55 +0000
> 
> It's my ignorance. I am a user of ligature packages but don't know how they communicate with the
> composition table mechanism in Emacs. Perhaps my best effort recipe wasn't a sensible way to display
> ligatures in Emacs.

Why did you use those particular codepoints? where did you see them,
and what glyphs on display they are supposed to show?

> Although my recipe is not well written I do believe there is a bug. The wide PragmataPro ligatures display fine
> in builds without Cairo, but only the right side is displaying if Cairo is included. Its the same for all ligature
> packages I've tried.

I'm not sure I follow: you believe this is a bug because it appears
with Cairo, but not without Cairo?  That's not evidence that there's a
bug in Emacs.  These builds use different libraries to show stuff on
the glass, and each library could have its own peculiarities when PUA
characters are being displayed.

The important part here is that Emacs doesn't currently support
display of PUA characters, even if the default font has glyphs for
those characters.

bug#51385: 29.0.50; PragmataPro wide word ligatures such as [ERR] having the left side cut off in cairo build

[Patrick Lenihan [sc17pl]]

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These codepoints correspond to ligatures intended to highlight import messages in command line like [FIXME], [TODO], [WARNING], #FIXME #TODO #ERROR, and their ligatures are a bit wide. These can be viewed on the font authors website at https://fsd.it/wp-content/uploads/command_line_messages_ligatures.png, or on the font authors Github at https://github.com/fabrizioschiavi/pragmatapro/blob/master/showcase/PragmataPro%200.829/PragmataPro-0829-ligatures.png. I found the code points at https://github.com/fabrizioschiavi/pragmatapro/blob/master/emacs_snippets/pragmatapro-prettify-symbols-v0.829.el, which is also in the font author's Github.
[https://repository-images.githubusercontent.com/10056929/68a59700-d314-11e9-9fae-babbbabbc40b]<https://github.com/fabrizioschiavi/pragmatapro/blob/master/emacs_snippets/pragmatapro-prettify-symbols-v0.829.el>
pragmatapro/pragmatapro-prettify-symbols-v0.829.el at master · fabrizioschiavi/pragmatapro<https://github.com/fabrizioschiavi/pragmatapro/blob/master/emacs_snippets/pragmatapro-prettify-symbols-v0.829.el>
PragmataPro font is designed to help pros to work better - pragmatapro/pragmatapro-prettify-symbols-v0.829.el at master · fabrizioschiavi/pragmatapro
github.com


[https://fsd.it/wp-content/uploads/command_line_messages_ligatures.png]

You understood me correctly regarding these PUA characters not displaying in the Cairo build. If Emacs doesn't support them at all then perhaps this is a feature request and not a bug. Thanks for your work on Emacs.
________________________________
From: Eli Zaretskii <eliz@gnu.org>
Sent: 03 November 2021 17:17
To: Patrick Lenihan [sc17pl] <P.J.Lenihan1@leeds.ac.uk>
Cc: 51385@debbugs.gnu.org <51385@debbugs.gnu.org>
Subject: Re: bug#51385: 29.0.50; PragmataPro wide word ligatures such as [ERR] having the left side cut off in cairo build

> From: "Patrick Lenihan [sc17pl]" <P.J.Lenihan1@leeds.ac.uk>
> Date: Wed, 3 Nov 2021 15:08:55 +0000
>
> It's my ignorance. I am a user of ligature packages but don't know how they communicate with the
> composition table mechanism in Emacs. Perhaps my best effort recipe wasn't a sensible way to display
> ligatures in Emacs.

Why did you use those particular codepoints? where did you see them,
and what glyphs on display they are supposed to show?

> Although my recipe is not well written I do believe there is a bug. The wide PragmataPro ligatures display fine
> in builds without Cairo, but only the right side is displaying if Cairo is included. Its the same for all ligature
> packages I've tried.

I'm not sure I follow: you believe this is a bug because it appears
with Cairo, but not without Cairo?  That's not evidence that there's a
bug in Emacs.  These builds use different libraries to show stuff on
the glass, and each library could have its own peculiarities when PUA
characters are being displayed.

The important part here is that Emacs doesn't currently support
display of PUA characters, even if the default font has glyphs for
those characters.

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bug#51385: 29.0.50; PragmataPro wide word ligatures such as [ERR] having the left side cut off in cairo build

[Lars Ingebrigtsen]

"Patrick Lenihan [sc17pl]" <P.J.Lenihan1@leeds.ac.uk> writes:

> You understood me correctly regarding these PUA characters not
> displaying in the Cairo build. If Emacs doesn't support them at all
> then perhaps this is a feature request and not a bug.

(I'm going through old bug reports that unfortunately weren't resolved
at the time.)

Skimming this bug report, it's not clear to me whether there's anything
that can be usefully done on the Emacs side.  Eli?

bug#51385: 29.0.50; PragmataPro wide word ligatures such as [ERR] having the left side cut off in cairo build

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: Eli Zaretskii <eliz@gnu.org>,  "51385@debbugs.gnu.org"
>  <51385@debbugs.gnu.org>
> Date: Wed, 14 Sep 2022 20:31:32 +0200
> 
> Skimming this bug report, it's not clear to me whether there's anything
> that can be usefully done on the Emacs side.  Eli?

No, I don't think so.  Closing.