Re: Distinguish column header from normal button

[Federico Mena Quintero <federico ximian com>]

On Tue, 2005-09-13 at 23:45 +0200, Richard Stellingwerff wrote:

> To distinguish Column headers from normal buttons, I check if its
> parent is a GtkTreeView or a GtkCList. A horrible way, but afaik the
> only way.
> In order to properly distinguish a column header from a normal button,
> I was thinking about setting a name on the column header button, using
> gtk_widget_set_name. Perhaps something like "Header:First",
> "Header:Middle", and "Header:Last".

The right way to do it is to add a private API to GtkButton, so that the
tree view can tell the button which hint to pass to the gtk_paint_*()
functions.  The theme engine will then use this hint to draw the proper
box type for the tree column's buttons.

> a) Where do I set the names of these widgets. It needs to be done when
> a column is added, removed, moved, or its visibility is toggled. Which
> function catches these events, or do I need to add them myself?

You want to change the hints in the buttons whenever the tree view emits
the "columns-changed" signal.

Grep for "COLUMNS_CHANGED" (note the underscore) in gtktreeview.c;
you'll find three emissions thereof.  That's where you want to do
something like

GList *l;

for (l = tree_view->priv->columns; l; l = l->next)
  {
    GtkTreeViewColumn *col;
    const char *hint;

    col = l->data;

    if (l->prev == NULL)
      {
        if (l->next == NULL)
          hint = "gtk-treeview-header-left-right";
        else
          hint = "gtk-treeview-header-left";
      }
    else if (l->next == NULL)
      hint = "gtk-treeview-header-right";
    else
      hint = "gtk-treeview-header-middle";

    _gtk_button_set_hint (col->button, hint);
  }

Making that work in RTL mode is left as an exercise for the reader.

Speaking of Clearlooks... currently, the hints that get passed to the
gtk_paint*() functions are totally undocumented.  Theme authors have to
dig in the GTK+ sources to see how each widget draws itself.  It would
be *fantastic* if you could cook a list of the hints for each widget,
and leave it as a reference for other theme authors :)

Good luck, and keep up the sexy,

  Federico