Re: GtkScrolledWindow containing GtkTextView containing a TextBuffer can't keep at bottom of Buffer

[Colomban Wendling <lists ban herbesfolles org>]

Hi,

Le 10/06/2013 12:26, Thomas A. Moulton a écrit :
> On 06/09/2013 05:21 PM, Thomas A. Moulton wrote:
> > Ok here is a single file example of my code... it works the same way
> > it does in my larger project
> >
> > Any suggestions would be GREATLY appreciated!
> >
> > tom
> What happens is when you enter enough lines of text to fill the window
> the scrolled window does not scroll up
> when the "eob" mark is not visible (eob=last line of text buffer)

The problem you have is that you insert the TextView in the
ScrolledWindow through a Viewport.  This results in a widget hierarchy
like this:

...
+ GtkScrolledWindow
  + GtkViewport
    + GtkTextView

This means that the TextView doesn't get to control the ScrolledWinodw,
its the Viewport that does.  So when you ask scroll_to_mark() the
ScrolledWindow won't get the request, and so won't scroll.

What you need it NOT to add a Viewport, so you get a hierarchy like this:

...
+ GtkScrolledWindow
  + GtkTextView

Like this, the thing that gets scrolled is the TextView, not a kind of
proxy.  GtkViewport is only useful if you want to add a non-scrollable
widget (e.g. boxes, grids, etc) to a scrolled window: it acts as a proxy
that implements the scrolling.  On the other hand, if the widget you
want to add IS scrollable (implement the GtkScrollable interface), it
must NOT be in a Viewport: if it does, it will expect scrolling requests
and alike, but never get them since its the Viewport that gets them.

In practice, just replace

        gtk_scrolled_window_add_with_viewport(scroll, GTK_WIDGET(text));

with

        gtk_container_add(GTK_CONTAINER(scroll), GTK_WIDGET(text));

and it will work as you expect.  Not that
gtk_scrolled_window_add_with_viewport() is even deprecated nowadays,
simply adding a child to a ScrolledWindow is enough (it will
automatically add a Viewport for you if required -- which is NOT the
case for GtkTextViews).

Regards,
Colomban


PS:

you do:

        char line[512];
        const gchar *cmd;

        cmd = gtk_entry_get_text(entry);
        strcpy(line, cmd);
        gtk_entry_set_text(entry, "");

        ...
        gtk_text_buffer_insert_with_tags(buf, ..., line, -1, ...);

Why do you copy the line in a static buffer (that might be too small,
and cause a crash since strcpy() doesn't have a max size parameter)?
You could just put the line into the buffer:

        
        const gchar *line;

        line = gtk_entry_get_text(entry);
        ...
        gtk_text_buffer_insert_with_tags(buf, ..., line, -1, ...);
        gtk_entry_set_text(entry, "");