RE: prevent scrolling in GtkText

["Dugas, Alan" <alan dugas analog com>]

Here's How I implement "auto_scrolling" of a gtktext widget... (Note: This
algorithm uses a GLOBAL variable called "auto_scroll" feel free to improve upon
it as you see fit!)

/* Connect to gtktext widget's vertical adjustment - do this during widget
creation */
gtk_signal_connect(GTK_OBJECT(GTK_ADJUSTMENT(GTK_TEXT(text)->vadj)),
"value_changed",
                         GTK_SIGNAL_FUNC(set_scroll_mode), NULL);


...


/* Freezing gtktext widget for updating */
gtk_text_freeze(GTK_TEXT(text));


/* insert text and/or delete text and/or move cursor here */


/* Updating gtktext widget */
gtk_text_thaw(GTK_TEXT(text));


...


/* Setting text to display within text widget */
if ( auto_scroll == TRUE )
        snap_to_bottom(GTK_WIDGET(text), GTK_OBJECT(GTK_TEXT(text)->vadj));



/* Function to set global variable auto_scroll */
void set_scroll_mode(GtkWidget *calling_widget, gboolean state)
{
        if ( GTK_ADJUSTMENT(GTK_TEXT(text)->vadj)->value
                + GTK_ADJUSTMENT(GTK_TEXT(text)->vadj)->page_size
                < GTK_ADJUSTMENT(GTK_TEXT(text)->vadj)->upper )
                auto_scroll = FALSE;
        else
                auto_scroll = TRUE;
}
/* End of set_scroll_mode() */



/* Function to snap text widget to end */
void snap_to_bottom(GtkWidget *calling_widget, GtkObject *vertical_adjustment)
{
        gtk_adjustment_set_value(GTK_ADJUSTMENT(vertical_adjustment),
                                 GTK_ADJUSTMENT(vertical_adjustment)->upper 
                                 - GTK_ADJUSTMENT(vertical_adjustment)->lower
                                 -
GTK_ADJUSTMENT(vertical_adjustment)->page_size);
}
/* End of snap_to_bottom() */

Hope this helps.



                                -- Stupid Genius


> ----------
> From:         Javier Ros Ganuza[SMTP:jros unavarra es]
> Sent:         Tuesday, January 09, 2001 7:27 AM
> To:   Dugas, Alan; gtk-app-devel-list gnome org
> Subject:      Re: prevent scrolling in GtkText
>
> "Dugas, Alan" wrote: 
>
>       Are you inserting your text, and/or moving the cursor, and/or deleting
> text 
>       while frozen?  When I do so, I am able to "auto scroll" by checking if
> the 
>       scrollbar is at it's limit prior to inserting addtional text.  If it is,
>
>       then after thawing the text widget I reset the vertical scrollbar
> adjustment 
>       attached to the gtktext to display the new text at the bottom.
> Otherwise 
>       the text is left alone displaying the same text as it did prior to
> inserting 
>       the addtional text.  Basically do everything while frozen.  Hope this
> helps. 
>
>                                       -- Stupid Genius
>
> Hello :) 
>
> Please , can you be more explicit, I'm inserting text in a freezed gtktex, and
> thawing 
> it doesn't scroll the window towards the insertesd position, so how do you 
>
> '...reset the vertical scrollbar adjustment 
> attached to the gtktext to display the new text ...' 
>
> I suppouse some action over, once the text is unthaw 
>
> GTK_ADJUSTMENT(GTK_TEXT(text)->vadj) 
>
> but which action, 
>
> Also, it is needed to proccess pending events related to insetion, before the
> above 
> described action is performed??? 
>   
>
> Thanks 
> -- 
> Javier Ros Ganuza.
> Dpto. Ingeniería Mecánica.
> Univ. Pública de Navarra. Campus de Arrosadia s/n. 31006 Pamplona.
> Tel. 34 948169307 Fax. 34 948169099
>