From: Behdad Esfahbod <behdad@behdad.org>
To: Eli Zaretskii <eliz@gnu.org>
Cc: Khaled Hosny <dr.khaled.hosny@gmail.com>,
33729@debbugs.gnu.org,
Mohammad Nasirifar <far.nasiri.m@gmail.com>,
kaushal.modi@gmail.com
Subject: bug#33729: 27.0.50; Partial glyphs not rendered for Gujarati with Harfbuzz enabled (renders fine using m17n)
Date: Thu, 20 Dec 2018 15:45:50 -0500 [thread overview]
Message-ID: <CAF63+7VBMXYrnhp9R9ALshoQuYtnsMeScqgzHg3NDgs2qzCDeA@mail.gmail.com> (raw)
In-Reply-To: <8336qsc9fl.fsf@gnu.org>
[-- Attachment #1: Type: text/plain, Size: 3940 bytes --]
Sounds good to me.
On Thu, Dec 20, 2018 at 1:58 PM Eli Zaretskii <eliz@gnu.org> wrote:
> Ping! Could someone on the Harfbuzz team please comment on the
> thoughts below? Khaled, Mohammad, Behdad?
>
> > Date: Mon, 17 Dec 2018 17:55:52 +0200
> > From: Eli Zaretskii <eliz@gnu.org>
> > Cc: dr.khaled.hosny@gmail.com, behdad@behdad.org, 33729@debbugs.gnu.org,
> > far.nasiri.m@gmail.com, kaushal.modi@gmail.com
> >
> > > From: Glenn Morris <rgm@gnu.org>
> > > Cc: far.nasiri.m@gmail.com, dr.khaled.hosny@gmail.com,
> behdad@behdad.org, 33729@debbugs.gnu.org, kaushal.modi@gmail.com
> > > Date: Sun, 16 Dec 2018 19:30:00 -0500
> > >
> > > > After some thinking, my conclusion is that we should import the
> > > > ISO 15924 database from https://unicode.org/iso15924/, use a script
> > > > similar to admin/unidata/blocks.awk to generate an alist from it that
> > > > maps Emacs script names to ISO 15924 tags, and then access that alist
> > > > from uni_script to get the correct script information to Harfbuzz.
> > > >
> > > > Patches implementing that are welcome.
> > >
> > > I live to write awk scripts. I'm not 100% sure what you want, but as a
> > > first example, the following takes
> > > http://www.unicode.org/Public/UCD/latest/ucd/PropertyValueAliases.txt
> > > as input and outputs lines of the form "(gujr . gujarati)".
> > >
> > > The aliases are so that the RHS matches charscript.el.
> > >
> > > If this is not right, please clarify exactly what the inputs and output
> > > should be.
> >
> > Thanks.
> >
> > It turns out I didn't have this figured out completely, and your
> > proposal forced me to dig some more into the relevant parts of Unicode
> > and Emacs. I found a few additional issues and considerations; for at
> > least some of them I'd like to hear the opinions of the Harfbuzz
> > developers.
> >
> > Here are the issues:
> >
> > . Contrary to my original thoughts, I now tend to think that a
> > separate char-table, say char-iso159240tag-table, that maps
> > character codepoints directly to the script tags, is a better
> > solution:
> > - it will allow a faster look up, obviously
> > - the subdivision of characters into scripts, as shown in
> > Unicode's Scripts.txt, is slightly different from what
> > char-script-table does, so a simple mapping from Emacs scripts
> > to ISO 15924 script tag will not do. For example, many
> > characters Emacs puts into 'latin' or 'symbol' scripts are in
> > the Common script according to Scripts.txt, and similarly for
> > the Inherited script. I imagine this is important for
> > Harfbuzz.
> >
> > . Whether to produce the character-to-script-tag mapping using the
> > UCD files, such as Scripts.txt and PropertyValueAliases.txt, or the
> > canonical ISO 15924 tags from https://unicode.org/iso15924/,
> > depends on whether the slight differences mentioned in
> > https://www.unicode.org/reports/tr24/#Relation_To_ISO15924 matter
> > for Harfbuzz. For example, ISO 15924 has separate tags for the
> > Fraktur and Gaelic varieties of the Latin script: does this
> > distinction matter for Harfbuzz?
> >
> > . Does Harfbuzz handle the issues mentioned in
> > https://www.unicode.org/reports/tr24/#Script_Anomalies, and in
> > particular the use case of decomposed characters which yield a
> > different script than their precomposed variants? This use case is
> > quite common in handling of character compositions, so it's
> > important to understand its implications before we decide on the
> > implementation.
> >
> > To summarize, unless the Harfbuzz guys advise differently, I'd prefer
> > processing Scripts.txt and PropertyValueAliases.txt into a list
> > similar to the one we produce in charscript.el, then generate a
> > char-table from that list.
> >
> > Thanks again for working on this.
> >
> >
> >
> >
>
--
behdad
http://behdad.org/
[-- Attachment #2: Type: text/html, Size: 6215 bytes --]
next prev parent reply other threads:[~2018-12-20 20:45 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-13 20:20 bug#33729: 27.0.50; Partial glyphs not rendered for Gujarati with Harfbuzz enabled (renders fine using m17n) Kaushal Modi
2018-12-13 20:25 ` Kaushal Modi
2018-12-13 20:31 ` Khaled Hosny
2018-12-13 20:43 ` Kaushal Modi
2018-12-13 20:53 ` Khaled Hosny
2018-12-13 21:04 ` Kaushal Modi
2018-12-14 5:57 ` Eli Zaretskii
2018-12-14 7:48 ` Eli Zaretskii
2018-12-14 7:50 ` Khaled Hosny
2018-12-14 10:03 ` Eli Zaretskii
2018-12-14 11:03 ` Khaled Hosny
2018-12-14 13:42 ` Eli Zaretskii
2018-12-14 15:25 ` Eli Zaretskii
2018-12-17 0:30 ` Glenn Morris
2018-12-17 15:55 ` Eli Zaretskii
2018-12-20 18:58 ` Eli Zaretskii
2018-12-20 20:45 ` Behdad Esfahbod [this message]
2018-12-22 8:54 ` Khaled Hosny
2018-12-22 9:06 ` Khaled Hosny
2018-12-22 10:11 ` Eli Zaretskii
2018-12-22 15:15 ` Khaled Hosny
2018-12-22 15:27 ` Behdad Esfahbod
2018-12-22 15:42 ` Khaled Hosny
2018-12-22 15:42 ` Eli Zaretskii
2018-12-22 15:49 ` Khaled Hosny
2018-12-22 16:33 ` Eli Zaretskii
2018-12-22 19:38 ` Eli Zaretskii
2018-12-22 20:59 ` Khaled Hosny
2018-12-23 3:34 ` Eli Zaretskii
2018-12-23 13:51 ` Khaled Hosny
2018-12-23 16:00 ` Eli Zaretskii
2018-12-24 2:08 ` Khaled Hosny
2018-12-24 4:12 ` Kaushal Modi
2018-12-24 16:10 ` Eli Zaretskii
2018-12-24 17:37 ` Khaled Hosny
2018-12-24 18:07 ` Eli Zaretskii
2019-01-05 21:15 ` Khaled Hosny
2019-01-06 16:03 ` Eli Zaretskii
2019-01-27 17:12 ` Eli Zaretskii
2019-01-29 22:25 ` Khaled Hosny
2018-12-29 14:49 ` Eli Zaretskii
2019-01-05 20:53 ` Khaled Hosny
2019-01-05 21:04 ` Khaled Hosny
2019-01-06 17:54 ` Eli Zaretskii
2019-01-27 17:12 ` Eli Zaretskii
2019-01-29 22:33 ` Khaled Hosny
2019-01-06 15:50 ` Eli Zaretskii
2019-01-29 22:29 ` Khaled Hosny
2022-04-29 12:47 ` Lars Ingebrigtsen
2022-04-29 13:24 ` Eli Zaretskii
2019-01-27 17:09 ` Eli Zaretskii
2018-12-24 17:38 ` Benjamin Riefenstahl
2018-12-14 22:47 ` Khaled Hosny
2018-12-16 14:47 ` Benjamin Riefenstahl
2018-12-14 6:45 ` Paul Eggert
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: https://www.gnu.org/software/emacs/
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAF63+7VBMXYrnhp9R9ALshoQuYtnsMeScqgzHg3NDgs2qzCDeA@mail.gmail.com \
--to=behdad@behdad.org \
--cc=33729@debbugs.gnu.org \
--cc=dr.khaled.hosny@gmail.com \
--cc=eliz@gnu.org \
--cc=far.nasiri.m@gmail.com \
--cc=kaushal.modi@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://git.savannah.gnu.org/cgit/emacs.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).