+#define column_data "my_column_data"
+
+static void move_row (GtkTreeModel *src,
+ GtkTreeIter *src_iter,
+ GtkTreeModel *dest,
+ GtkTreeIter *dest_iter);
+
+/* Kids, don't try this at home. */
+
+/* Small GtkTreeModel to model columns */
+typedef struct _ViewColumnModel ViewColumnModel;
+typedef struct _ViewColumnModelClass ViewColumnModelClass;
+
+struct _ViewColumnModel
+{
+ GtkListStore parent;
+ GtkTreeView *view;
+ GList *columns;
+ gint stamp;
+};
+
+struct _ViewColumnModelClass
+{
+ GtkListStoreClass parent_class;
+};
+
+static void view_column_model_init (ViewColumnModel *model)
+{
+ model->stamp = g_random_int ();
+}
+
+static gint
+view_column_model_get_n_columns (GtkTreeModel *tree_model)
+{
+ return 2;
+}
+
+static GType
+view_column_model_get_column_type (GtkTreeModel *tree_model,
+ gint index)
+{
+ switch (index)
+ {
+ case 0:
+ return G_TYPE_STRING;
+ case 1:
+ return GTK_TYPE_TREE_VIEW_COLUMN;
+ default:
+ return G_TYPE_INVALID;
+ }
+}
+
+static gboolean
+view_column_model_get_iter (GtkTreeModel *tree_model,
+ GtkTreeIter *iter,
+ GtkTreePath *path)
+
+{
+ ViewColumnModel *view_model = (ViewColumnModel *)tree_model;
+ GList *list;
+ gint i;
+
+ g_return_val_if_fail (gtk_tree_path_get_depth (path) > 0, FALSE);
+
+ i = gtk_tree_path_get_indices (path)[0];
+ list = g_list_nth (view_model->columns, i);
+
+ if (list == NULL)
+ return FALSE;
+
+ iter->stamp = view_model->stamp;
+ iter->user_data = list;
+
+ return TRUE;
+}
+
+static GtkTreePath *
+view_column_model_get_path (GtkTreeModel *tree_model,
+ GtkTreeIter *iter)
+{
+ ViewColumnModel *view_model = (ViewColumnModel *)tree_model;
+ GtkTreePath *retval;
+ GList *list;
+ gint i = 0;
+
+ g_return_val_if_fail (iter->stamp == view_model->stamp, NULL);
+
+ for (list = view_model->columns; list; list = list->next)
+ {
+ if (list == (GList *)iter->user_data)
+ break;
+ i++;
+ }
+ if (list == NULL)
+ return NULL;
+
+ retval = gtk_tree_path_new ();
+ gtk_tree_path_append_index (retval, i);
+ return retval;
+}
+
+static void
+view_column_model_get_value (GtkTreeModel *tree_model,
+ GtkTreeIter *iter,
+ gint column,
+ GValue *value)
+{
+ ViewColumnModel *view_model = (ViewColumnModel *)tree_model;
+
+ g_return_if_fail (column < 2);
+ g_return_if_fail (view_model->stamp == iter->stamp);
+ g_return_if_fail (iter->user_data != NULL);
+
+ if (column == 0)
+ {
+ g_value_init (value, G_TYPE_STRING);
+ g_value_set_string (value, gtk_tree_view_column_get_title (GTK_TREE_VIEW_COLUMN (((GList *)iter->user_data)->data)));
+ }
+ else
+ {
+ g_value_init (value, GTK_TYPE_TREE_VIEW_COLUMN);
+ g_value_set_object (value, ((GList *)iter->user_data)->data);
+ }
+}
+
+static gboolean
+view_column_model_iter_next (GtkTreeModel *tree_model,
+ GtkTreeIter *iter)
+{
+ ViewColumnModel *view_model = (ViewColumnModel *)tree_model;
+
+ g_return_val_if_fail (view_model->stamp == iter->stamp, FALSE);
+ g_return_val_if_fail (iter->user_data != NULL, FALSE);
+
+ iter->user_data = ((GList *)iter->user_data)->next;
+ return iter->user_data != NULL;
+}
+
+static gboolean
+view_column_model_iter_children (GtkTreeModel *tree_model,
+ GtkTreeIter *iter,
+ GtkTreeIter *parent)
+{
+ ViewColumnModel *view_model = (ViewColumnModel *)tree_model;
+
+ /* this is a list, nodes have no children */
+ if (parent)
+ return FALSE;
+
+ /* but if parent == NULL we return the list itself as children of the
+ * "root"
+ */
+
+ if (view_model->columns)
+ {
+ iter->stamp = view_model->stamp;
+ iter->user_data = view_model->columns;
+ return TRUE;
+ }
+ else
+ return FALSE;
+}
+
+static gboolean
+view_column_model_iter_has_child (GtkTreeModel *tree_model,
+ GtkTreeIter *iter)
+{
+ return FALSE;
+}
+
+static gint
+view_column_model_iter_n_children (GtkTreeModel *tree_model,
+ GtkTreeIter *iter)
+{
+ return g_list_length (((ViewColumnModel *)tree_model)->columns);
+}
+
+static gint
+view_column_model_iter_nth_child (GtkTreeModel *tree_model,
+ GtkTreeIter *iter,
+ GtkTreeIter *parent,
+ gint n)
+{
+ ViewColumnModel *view_model = (ViewColumnModel *)tree_model;
+
+ if (parent)
+ return FALSE;
+
+ iter->stamp = view_model->stamp;
+ iter->user_data = g_list_nth ((GList *)view_model->columns, n);
+
+ return (iter->user_data != NULL);
+}
+
+static gboolean
+view_column_model_iter_parent (GtkTreeModel *tree_model,
+ GtkTreeIter *iter,
+ GtkTreeIter *child)
+{
+ return FALSE;
+}
+
+static void
+view_column_model_tree_model_init (GtkTreeModelIface *iface)
+{
+ iface->get_n_columns = view_column_model_get_n_columns;
+ iface->get_column_type = view_column_model_get_column_type;
+ iface->get_iter = view_column_model_get_iter;
+ iface->get_path = view_column_model_get_path;
+ iface->get_value = view_column_model_get_value;
+ iface->iter_next = view_column_model_iter_next;
+ iface->iter_children = view_column_model_iter_children;
+ iface->iter_has_child = view_column_model_iter_has_child;
+ iface->iter_n_children = view_column_model_iter_n_children;
+ iface->iter_nth_child = view_column_model_iter_nth_child;
+ iface->iter_parent = view_column_model_iter_parent;
+}
+
+static gboolean
+view_column_model_drag_data_get (GtkTreeDragSource *drag_source,
+ GtkTreePath *path,
+ GtkSelectionData *selection_data)
+{
+ if (gtk_tree_set_row_drag_data (selection_data,
+ GTK_TREE_MODEL (drag_source),
+ path))
+ return TRUE;
+ else
+ return FALSE;
+}
+
+static gboolean
+view_column_model_drag_data_delete (GtkTreeDragSource *drag_source,
+ GtkTreePath *path)
+{
+ /* Nothing -- we handle moves on the dest side */
+
+ return TRUE;
+}
+
+static gboolean
+view_column_model_row_drop_possible (GtkTreeDragDest *drag_dest,
+ GtkTreePath *dest_path,
+ GtkSelectionData *selection_data)
+{
+ GtkTreeModel *src_model;
+
+ if (gtk_tree_get_row_drag_data (selection_data,
+ &src_model,
+ NULL))
+ {
+ if (src_model == left_tree_model ||
+ src_model == top_right_tree_model ||
+ src_model == bottom_right_tree_model)
+ return TRUE;
+ }
+
+ return FALSE;
+}
+
+static gboolean
+view_column_model_drag_data_received (GtkTreeDragDest *drag_dest,
+ GtkTreePath *dest,
+ GtkSelectionData *selection_data)
+{
+ GtkTreeModel *src_model;
+ GtkTreePath *src_path = NULL;
+ gboolean retval = FALSE;
+
+ if (gtk_tree_get_row_drag_data (selection_data,
+ &src_model,
+ &src_path))
+ {
+ GtkTreeIter src_iter;
+ GtkTreeIter dest_iter;
+ gboolean have_dest;
+
+ /* We are a little lazy here, and assume if we can't convert dest
+ * to an iter, we need to append. See gtkliststore.c for a more
+ * careful handling of this.
+ */
+ have_dest = gtk_tree_model_get_iter (GTK_TREE_MODEL (drag_dest), &dest_iter, dest);
+
+ if (gtk_tree_model_get_iter (src_model, &src_iter, src_path))
+ {
+ if (src_model == left_tree_model ||
+ src_model == top_right_tree_model ||
+ src_model == bottom_right_tree_model)
+ {
+ move_row (src_model, &src_iter, GTK_TREE_MODEL (drag_dest),
+ have_dest ? &dest_iter : NULL);
+ retval = TRUE;
+ }
+ }
+
+ gtk_tree_path_free (src_path);
+ }
+
+ return retval;
+}
+
+static void
+view_column_model_drag_source_init (GtkTreeDragSourceIface *iface)
+{
+ iface->drag_data_get = view_column_model_drag_data_get;
+ iface->drag_data_delete = view_column_model_drag_data_delete;
+}
+
+static void
+view_column_model_drag_dest_init (GtkTreeDragDestIface *iface)
+{
+ iface->drag_data_received = view_column_model_drag_data_received;
+ iface->row_drop_possible = view_column_model_row_drop_possible;
+}
+
+static void
+view_column_model_class_init (ViewColumnModelClass *klass)
+{
+}
+
+G_DEFINE_TYPE_WITH_CODE (ViewColumnModel, view_column_model, GTK_TYPE_LIST_STORE,
+ G_IMPLEMENT_INTERFACE (GTK_TYPE_TREE_MODEL, view_column_model_tree_model_init)
+ G_IMPLEMENT_INTERFACE (GTK_TYPE_TREE_DRAG_SOURCE, view_column_model_drag_source_init)
+ G_IMPLEMENT_INTERFACE (GTK_TYPE_TREE_DRAG_DEST, view_column_model_drag_dest_init))
+
+static void
+update_columns (GtkTreeView *view, ViewColumnModel *view_model)
+{
+ GList *old_columns = view_model->columns;
+ gint old_length, length;
+ GList *a, *b;
+
+ view_model->columns = gtk_tree_view_get_columns (view_model->view);
+
+ /* As the view tells us one change at a time, we can do this hack. */
+ length = g_list_length (view_model->columns);
+ old_length = g_list_length (old_columns);
+ if (length != old_length)
+ {
+ GtkTreePath *path;
+ gint i = 0;
+
+ /* where are they different */
+ for (a = old_columns, b = view_model->columns; a && b; a = a->next, b = b->next)
+ {
+ if (a->data != b->data)
+ break;
+ i++;
+ }
+ path = gtk_tree_path_new ();
+ gtk_tree_path_append_index (path, i);
+ if (length < old_length)
+ {
+ view_model->stamp++;
+ gtk_tree_model_row_deleted (GTK_TREE_MODEL (view_model), path);
+ }
+ else
+ {
+ GtkTreeIter iter;
+ iter.stamp = view_model->stamp;
+ iter.user_data = b;
+ gtk_tree_model_row_inserted (GTK_TREE_MODEL (view_model), path, &iter);
+ }
+ gtk_tree_path_free (path);
+ }
+ else
+ {
+ gint i;
+ gint m = 0, n = 1;
+ gint *new_order;
+ GtkTreePath *path;
+
+ new_order = g_new (int, length);
+ a = old_columns; b = view_model->columns;
+
+ while (a->data == b->data)
+ {
+ a = a->next;
+ b = b->next;
+ if (a == NULL)
+ return;
+ m++;
+ }
+
+ if (a->next->data == b->data)
+ {
+ b = b->next;
+ while (b->data != a->data)
+ {
+ b = b->next;
+ n++;
+ }
+ for (i = 0; i < m; i++)
+ new_order[i] = i;
+ for (i = m; i < m+n; i++)
+ new_order[i] = i+1;
+ new_order[i] = m;
+ for (i = m + n +1; i < length; i++)
+ new_order[i] = i;
+ }
+ else
+ {
+ a = a->next;
+ while (a->data != b->data)
+ {
+ a = a->next;
+ n++;
+ }
+ for (i = 0; i < m; i++)
+ new_order[i] = i;
+ new_order[m] = m+n;
+ for (i = m+1; i < m + n+ 1; i++)
+ new_order[i] = i - 1;
+ for (i = m + n + 1; i < length; i++)
+ new_order[i] = i;
+ }
+
+ path = gtk_tree_path_new ();
+ gtk_tree_model_rows_reordered (GTK_TREE_MODEL (view_model),
+ path,
+ NULL,
+ new_order);
+ gtk_tree_path_free (path);
+ g_free (new_order);
+ }
+ if (old_columns)
+ g_list_free (old_columns);
+}
+
+static GtkTreeModel *
+view_column_model_new (GtkTreeView *view)
+{
+ GtkTreeModel *retval;
+
+ retval = g_object_new (view_column_model_get_type (), NULL);
+ ((ViewColumnModel *)retval)->view = view;
+ ((ViewColumnModel *)retval)->columns = gtk_tree_view_get_columns (view);
+
+ g_signal_connect (view, "columns_changed", G_CALLBACK (update_columns), retval);
+
+ return retval;
+}
+
+/* Back to sanity.
+ */
+