Re: gtk_text_buffer_delete ?

[Jim Charlton <charltn gmail com>]

On 15-10-07 04:14 AM, Pierre Wieser wrote:
> Hello,
>
> On the application I'm currently working on [1], I want limit the size of the
> text entered in a GtkTextBuffer to those saved in the DBMS, so 4096 chars.
>
> I so connected to the 'changed' signal of the GtkTextBuffer, and the handler
> is :
>
> static void
> on_notes_changed( GtkTextBuffer *buffer, void *empty )
> {
>         static const gchar *thisfn = "my_utils_on_notes_changed";
>         static const gint MAX_LENGTH = 4096;
>         static gboolean in = FALSE;
>         gint count;
>         GtkTextIter start, end;
>
>         /* prevent an infinite recursion */
>         if( !in ){
>                 count = gtk_text_buffer_get_char_count( buffer );
>                 if( count >= MAX_LENGTH ){
>                         /*
>                          * this code works, but emit the following Gtk-Warning:
>                          *
>                          * Invalid text buffer iterator: either the iterator is
>                          * uninitialized, or the characters/pixbufs/widgets in the
>                          * buffer have been modified since the iterator was created.
>                          * You must use marks, character numbers, or line numbers to
>                          * preserve a position across buffer modifications.
>                          * You can apply tags and insert marks without invalidating
>                          * your iterators, but any mutation that affects 'indexable'
>                          * buffer contents (contents that can be referred to by character
>                          * offset) will invalidate all outstanding iterators
>                          */
>                         gtk_text_buffer_get_iter_at_offset( buffer, &start, MAX_LENGTH-1 );
>                         /*gtk_text_iter_backward_char( &start );*/
>                         /*gtk_text_buffer_get_iter_at_offset( buffer, &end, count );*/
>                         gtk_text_buffer_get_end_iter( buffer, &end );
>                         /*gtk_text_iter_backward_char( &end );*/
>                         in = TRUE;
>                         g_debug( "%s: count=%d, start=%d, end=%d",
>                                         thisfn, count, gtk_text_iter_get_offset( &start ), 
> gtk_text_iter_get_offset( &end ));
>                         gtk_text_buffer_delete( buffer, &start, &end );
>                         in = FALSE;
>                 }
>         }
> }
>
> As stated in the comment, the code works (the size if actually limited to 4095 chars),
> but each execution of gtk_text_buffer_delete() triggers the well-known warning
> "Invalid text buffer iterator".
>
> I am a bit stucked here, because I do not understand why this happens, as the buffer
> is not modified between taking the iters and deleting the content...
>
> Can anyone help me in this matter ?
>
> Thanks in advance.
> Regards
> Pierre
> _______________________________________________
> gtk-app-devel-list mailing list
> gtk-app-devel-list gnome org
> https://mail.gnome.org/mailman/listinfo/gtk-app-devel-list
I do not have an answer to the problem as stated, but I have written 
code that achieves the overall purpose of pruning the text buffer.
I work in Gtkmm rather than in GTK3.  Here is a snippet of code.
*************
start = tb1_ptr->begin();
end = tb1_ptr->end();
if (end.get_offset() > 254) end.set_offset(254);
text = tb1_ptr->get_text(start, end, FALSE);
************
where
tb1_ptr = Gtk::TextBuffer::create();
Gtk::TextIter start;
Gtk::TextIter end;
Glib::ustring text;

In your case, rather than using gtk_text_buffer_delete, you would use
gtk_text_iter_get_offset (/|const GtkTextIter 
<https://developer.gnome.org/gtk3/stable/GtkTextIter.html> *iter|/);
and
gtk_text_iter_set_offset (/|GtkTextIter 
<https://developer.gnome.org/gtk3/stable/GtkTextIter.html> *iter|/, 
/|gint 
<https://developer.gnome.org/glib/unstable/glib-Basic-Types.html#gint> 
char_offset|/);

to limit the text buffer to your desired length.

Hope this helps...   Jim...




text = tb1_ptr->get_text(start, end, FALSE);