Re: Pango delete/backspace best practices

[Emmanuele Bassi <ebassi gmail com>]

On 1 September 2017 at 12:41, Jeffrey Sheen
<jeffrey sheen00 alumni imperial ac uk> wrote:
> Thank you Emmanuele,
>
> I received similar feedback from another member of the list.
>
> I will take a look at the suggested source code in GtkTextView and GtkEntry
> (I am unfamiliar, as I am not using the upper libraries in the GTK stack).

If you're going to implement text editing, you're probably going to
need much more than Pango alone. GTK+ has a lot of code dealing with
text editing — both in single line and multi-line contexts.

On top of that, there are two whole libraries for text editing widgets
based on top of that code:

  - GtkSourceView: https://git.gnome.org/browse/gtksourceview
  - Tepl: https://git.gnome.org/browse/tepl/

> A suggestion of a more suitable mailing list would be appreciated as well. I
> do not want to clutter an inappropriate group.

You probably want gtk-devel-list, but mailing lists are kind of high
latency and not everyone familiar with Pango reads them.

You may want to join the #gtk+ IRC channel, on irc.gnome.org.

Ciao,
 Emmanuele.

> On 1 September 2017 at 12:34, Emmanuele Bassi <ebassi gmail com> wrote:
> > Or, more likely, you sent the email to the wrong list. You probably
> > want to talk to the developers of text editors based on GtkTextView
> > and Pango.
> >
> > Additionally, you may want to look at GtkTextView itself.
> >
> > Ciao,
> >  Emmanuele.
> >
> >
> > On 1 September 2017 at 12:14, Jeffrey Sheen
> > <jeffrey sheen00 alumni imperial ac uk> wrote:
> > > Dear list,
> > >
> > > As there has not been a response to my query about Unicode deletion-key
> > > interrupts, one of the following must be true:
> > >
> > > My question does not make sense, as I have made an incorrect assumption
> > > No-one on the list has written code for a text editor widget
> > > No-one wishes to share their experience writing code for a text editor
> > > widget
> > >
> > > The first reason is most likely, but I would appreciate a brief
> > > explanation.
> > >
> > > Deletion-key interrupts are a fundamental use-case of creating an
> > > application with interactive text, so I think this is an important
> > > talking
> > > point.
> > >
> > > Jeff.
> > >
> > > On 22 July 2017 at 12:45, Jeffrey Sheen
> > > <jeffrey sheen00 alumni imperial ac uk> wrote:
> > > > Dear list,
> > > >
> > > > I would like to leverage your experience with the Pango API.
> > > >
> > > > I am currently using "pango_layout_move_cursor_visually" to handle
> > > > arrow-key presses. This establishes the byte index that the cursor
> > > > should be
> > > > moved to, visually skipping whole grapheme clusters.
> > > >
> > > > However, I understand that there are more states are required when
> > > > handling the delete and backspace keys, depending on the text's
> > > > language.
> > > >
> > > > i.e. it is possible to press a deletion key, and the grapheme cluster
> > > > be
> > > > altered, but not reduce the number of grapheme clusters in the string.
> > > >
> > > > Reading the Pango API documentation, this aspect appears to be
> > > > represented
> > > > with the "PangoLogAttr.backspace_deletes_character" member variable.
> > > >
> > > > However, unlike "pango_layout_move_cursor_visually",
> > > > "pango_get_log_attrs"
> > > > operates below the level of a PangoLayout object, requiring a
> > > > PangoLanguage*
> > > > to be passed.
> > > >
> > > > Must I manually store the language that a block of text is written in
> > > > and
> > > > convert this to a PangoLanguage object?
> > > >
> > > > What is the best practice when handling a delete/backspace key press?
> > > >
> > > > Cheers,
> > > >
> > > > Jeff.
> > >
> > >
> > >
> > > _______________________________________________
> > > gtk-list mailing list
> > > gtk-list gnome org
> > > https://mail.gnome.org/mailman/listinfo/gtk-list
> >
> >
> >
> > --
> > https://www.bassi.io
> > [@] ebassi [@gmail.com]
>
>
>
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