gtk-demo: Add a filter model example

This shows computed columns.

demos/gtk-demo/Makefile.am

@@ -25,6 +25,7 @@ demos_base =					\
 	entry_completion.c			\
 	event_axes.c				\
 	expander.c  				\
+        filtermodel.c				\
 	font_features.c				\
 	gestures.c				\
 	glarea.c				\

demos/gtk-demo/demo.gresource.xml

@@ -131,6 +131,7 @@
     <file>entry_completion.c</file>
     <file>event_axes.c</file>
     <file>expander.c</file>
+    <file>filtermodel.c</file>
     <file>flowbox.c</file>
     <file>font_features.c</file>
     <file>gestures.c</file>

demos/gtk-demo/filtermodel.c

@@ -0,0 +1,160 @@
+/* Tree View/Filter Model
+ *
+ * This example demonstrates how GtkTreeModelFilter can be used
+ * to compute columns that are not actually present in the underlying
+ * model.
+ */
+
+#include <gtk/gtk.h>
+
+enum {
+  WIDTH_COLUMN,
+  HEIGHT_COLUMN,
+  AREA_COLUMN,
+  SQUARE_COLUMN
+};
+
+static void
+format_number (GtkTreeViewColumn *col,
+               GtkCellRenderer   *cell,
+               GtkTreeModel      *model,
+               GtkTreeIter       *iter,
+               gpointer           data)
+{
+  gint num;
+  gchar *text;
+
+  gtk_tree_model_get (model, iter, GPOINTER_TO_INT (data), &num, -1);
+  text = g_strdup_printf ("%d", num);
+  g_object_set (cell, "text", text, NULL);
+  g_free (text);
+}
+
+static void
+filter_modify_func (GtkTreeModel *model,
+                    GtkTreeIter  *iter,
+                    GValue       *value,
+                    gint          column,
+                    gpointer      data)
+{
+  GtkTreeModelFilter *filter_model = GTK_TREE_MODEL_FILTER (model);
+  gint width, height;
+  GtkTreeModel *child_model;
+  GtkTreeIter child_iter;
+
+  child_model = gtk_tree_model_filter_get_model (filter_model);
+  gtk_tree_model_filter_convert_iter_to_child_iter (filter_model, &child_iter, iter);
+
+  gtk_tree_model_get (child_model, &child_iter,
+                      WIDTH_COLUMN, &width,
+                      HEIGHT_COLUMN, &height,
+                      -1);
+
+  switch (column)
+    {
+    case WIDTH_COLUMN:
+      g_value_set_int (value, width);
+      break;
+    case HEIGHT_COLUMN:
+      g_value_set_int (value, height);
+      break;
+    case AREA_COLUMN:
+      g_value_set_int (value, width * height);
+      break;
+    case SQUARE_COLUMN:
+      g_value_set_boolean (value, width == height);
+      break;
+    default:
+      g_assert_not_reached ();
+    }
+}
+
+GtkWidget *
+do_filtermodel (GtkWidget *do_widget)
+{
+  static GtkWidget *window;
+  GtkWidget *tree;
+  GtkListStore *store;
+  GtkTreeModel *model;
+  GtkTreeViewColumn *column;
+  GtkCellRenderer *cell;
+  GType types[4];
+
+  if (!window)
+    {
+      window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
+      gtk_window_set_screen (GTK_WINDOW (window),
+                             gtk_widget_get_screen (do_widget));
+      gtk_window_set_title (GTK_WINDOW (window), "Filter Model");
+      g_signal_connect (window, "destroy",
+                        G_CALLBACK (gtk_widget_destroyed), &window);
+
+      tree = gtk_tree_view_new ();
+      gtk_container_add (GTK_CONTAINER (window), tree);
+
+      column = gtk_tree_view_column_new ();
+      gtk_tree_view_column_set_title (column, "Width");
+      cell = gtk_cell_renderer_text_new ();
+      gtk_tree_view_column_pack_start (column, cell, FALSE);
+      gtk_tree_view_column_set_cell_data_func (column, cell,
+                                               format_number, GINT_TO_POINTER (WIDTH_COLUMN), NULL);
+      gtk_tree_view_append_column (GTK_TREE_VIEW (tree), column);
+
+      column = gtk_tree_view_column_new ();
+      gtk_tree_view_column_set_title (column, "Height");
+      cell = gtk_cell_renderer_text_new ();
+      gtk_tree_view_column_pack_start (column, cell, FALSE);
+      gtk_tree_view_column_set_cell_data_func (column, cell,
+                                               format_number, GINT_TO_POINTER (HEIGHT_COLUMN), NULL);
+      gtk_tree_view_append_column (GTK_TREE_VIEW (tree), column);
+
+      column = gtk_tree_view_column_new ();
+      gtk_tree_view_column_set_title (column, "Area");
+      cell = gtk_cell_renderer_text_new ();
+      gtk_tree_view_column_pack_start (column, cell, FALSE);
+      gtk_tree_view_column_set_cell_data_func (column, cell,
+                                               format_number, GINT_TO_POINTER (AREA_COLUMN), NULL);
+      gtk_tree_view_append_column (GTK_TREE_VIEW (tree), column);
+
+      column = gtk_tree_view_column_new ();
+      gtk_tree_view_column_set_title (column, "Square");
+      cell = gtk_cell_renderer_pixbuf_new ();
+      g_object_set (cell, "icon-name", "object-select-symbolic", NULL);
+      gtk_tree_view_column_pack_start (column, cell, FALSE);
+      gtk_tree_view_column_add_attribute (column, cell, "visible", SQUARE_COLUMN);
+      gtk_tree_view_append_column (GTK_TREE_VIEW (tree), column);
+
+      store = gtk_list_store_new (2, G_TYPE_INT, G_TYPE_INT);
+      store = gtk_list_store_new (2, G_TYPE_INT, G_TYPE_INT);
+      gtk_list_store_insert_with_values (store, NULL, -1,
+                                         WIDTH_COLUMN, 10,
+                                         HEIGHT_COLUMN, 20,
+                                         -1);
+      gtk_list_store_insert_with_values (store, NULL, -1,
+                                         WIDTH_COLUMN, 5,
+                                         HEIGHT_COLUMN, 25,
+                                         -1);
+      gtk_list_store_insert_with_values (store, NULL, -1,
+                                         WIDTH_COLUMN, 15,
+                                         HEIGHT_COLUMN, 15,
+                                         -1);
+
+      types[WIDTH_COLUMN] = G_TYPE_INT;
+      types[HEIGHT_COLUMN] = G_TYPE_INT;
+      types[AREA_COLUMN] = G_TYPE_INT;
+      types[SQUARE_COLUMN] = G_TYPE_BOOLEAN;
+      model = gtk_tree_model_filter_new (GTK_TREE_MODEL (store), NULL);
+      gtk_tree_model_filter_set_modify_func (GTK_TREE_MODEL_FILTER (model),
+                                             G_N_ELEMENTS (types), types,
+                                             filter_modify_func, NULL, NULL);
+
+      gtk_tree_view_set_model (GTK_TREE_VIEW (tree), model);
+    }
+
+  if (!gtk_widget_get_visible (window))
+    gtk_widget_show_all (window);
+  else
+    gtk_widget_destroy (window);
+
+  return window;
+}