Re: Set number of rows in GtkTreeView

[Tim Müller <zen18864 zen co uk>]

On Wednesday 09 February 2005 13:56, Ken Siersma wrote:

> I want to specify a number of rows to always display in my
> GtkTreeView widget, regardless of how many entities are in my
> GtkListStore.  I'm using the GtkTreeView to display a list of files.
> Sometimes there are no files, sometimes there are 100 files.  I want my
> GtkTreeView to always display 15 rows.
>
> I'm porting code from Motif, and Motif can do this simply by specifying
> the XmNvisibleItemCount property for it's list widget.  I'm looking for
> a simple way to do this in GTK as well.  I've looked through the API,
> but it didn't seem like there were any simple solutions like this.

There isn't really anything as simple as a property. If your rows are all the 
same height, however, you can probably do this in a hackish way, e.g. by 
estimating the height of one row, and then multiplying that height with the 
number of rows you want to be visible, and then call

         gtk_widget_set_size_request (treeview, -1, height) 

The tricky thing is to find out the height of a row of course. If you display 
simple one-line strings or markup, you could do something along these lines:

  guint 
  simple_estimate_row_height (GtkTreeView *tv)
  {
      GtkCellRendererText *cell;
      PangoLayout  *layout;
      guint  row_height, ypad;

      layout = gtk_widget_create_pango_layout (tv, NULL);

      pango_layout_set_markup (layout, "<i>red fox jumps bla</i>", -1);
      pango_layout_get_pixel_extents (layout, NULL, &row_height);

      cell = gtk_cell_renderer_new_text ();
      g_object_get (cell, "ypad", &ypad, NULL);
      g_object_unref (cell);

      g_object_unref (layout);

      return row_height + 2*ypad;
  }

I'm sure there are more accurate and less hackish ways, but this might just do 
anyway. If your treeview is in a scrolled window, you may have to take into 
account the height of the horizontal scroll bar as well (if it's not set to 
be invisible).

Cheers
 -Tim