Class CellAreaBox

The column is the column of the model to get a value from, and the attribute is the parameter on cell to be set from the value. So for example if column 2 of the model contains strings, you could have the “text” attribute of a #GtkCellRendererText get its values from column 2.

Events handled by focus siblings can also activate the given focusable renderer.

Whenever the source_property is changed the target_property is updated using the same value. For instance:

  g_object_bind_property (action, "active", widget, "sensitive", 0);

Will result in the "sensitive" property of the widget #GObject instance to be updated with the same value of the "active" property of the action #GObject instance.

If flags contains %G_BINDING_BIDIRECTIONAL then the binding will be mutual: if target_property on target changes then the source_property on source will be updated as well.

The binding will automatically be removed when either the source or the target instances are finalized. To remove the binding without affecting the source and the target you can just call g_object_unref() on the returned #GBinding instance.

Removing the binding by calling g_object_unref() on it must only be done if the binding, source and target are only used from a single thread and it is clear that both source and target outlive the binding. Especially it is not safe to rely on this if the binding, source or target can be finalized from different threads. Keep another reference to the binding and use g_binding_unbind() instead to be on the safe side.

A #GObject can have multiple bindings.

This function is the language bindings friendly version of g_object_bind_property_full(), using #GClosures instead of function pointers.

#GtkBuilder calls this function if a “constructor” has been specified in the UI definition.

For instance, #GtkIconView creates all icons (rows) to have the same width and the cells theirin to have the same horizontal alignments. However each row of icons may have a separate collective height. #GtkIconView uses this to request the heights of each row based on a context which was already used to request all the row widths that are to be displayed.

Implementing #GtkCellArea classes should implement this method to receive and navigate focus in its own way particular to how it lays out cells.

This is necessary for accessors that modify multiple properties to prevent premature notification while the object is still being modified.

This is handy for #GtkCellArea subclasses when handling events, after determining the renderer at the event location it can then chose to activate the focus cell for which the event cell may have been a sibling.

#GtkBuilder sets the name based on the [GtkBuilder UI definition][BUILDER-UI] used to construct the buildable.

area will store some geometrical information in context along the way; when requesting sizes over an arbitrary number of rows, it’s not important to check the minimum_height and natural_height of this call but rather to consult gtk_cell_area_context_get_preferred_height() after a series of requests.

area stores some geometrical information in context along the way while calling gtk_cell_area_get_preferred_width(). It’s important to perform a series of gtk_cell_area_get_preferred_width() requests with context first and then call gtk_cell_area_get_preferred_height_for_width() on each cell area individually to get the height for width of each fully requested row.

If at some point, the width of a single row changes, it should be requested with gtk_cell_area_get_preferred_width() again and then the full width of the requested rows checked again with gtk_cell_area_context_get_preferred_width().

area will store some geometrical information in context along the way; when requesting sizes over an arbitrary number of rows, it’s not important to check the minimum_width and natural_width of this call but rather to consult gtk_cell_area_context_get_preferred_width() after a series of requests.

area stores some geometrical information in context along the way while calling gtk_cell_area_get_preferred_height(). It’s important to perform a series of gtk_cell_area_get_preferred_height() requests with context first and then call gtk_cell_area_get_preferred_width_for_height() on each cell area individually to get the height for width of each fully requested row.

If at some point, the height of a single row changes, it should be requested with gtk_cell_area_get_preferred_height() again and then the full height of the requested rows checked again with gtk_cell_area_context_get_preferred_height().

The value can be:

• an empty #GValue initialized by %G_VALUE_INIT, which will be automatically initialized with the expected type of the property (since GLib 2.60)
• a #GValue initialized with the expected type of the property
• a #GValue initialized with a type to which the expected type of the property can be transformed

In general, a copy is made of the property contents and the caller is responsible for freeing the memory by calling g_value_unset().

Note that g_object_get_property() is really intended for language bindings, g_object_get() is much more convenient for C programming.

When possible, eg. when signaling a property change from within the class that registered the property, you should use g_object_notify_by_pspec() instead.

Note that emission of the notify signal may be blocked with g_object_freeze_notify(). In this case, the signal emissions are queued and will be emitted (in reverse order) when g_object_thaw_notify() is called.

This function omits the property name lookup, hence it is faster than g_object_notify().

One way to avoid using g_object_notify() from within the class that registered the properties, and using g_object_notify_by_pspec() instead, is to store the GParamSpec used with g_object_class_install_property() inside a static array, e.g.:

  enum
  {
    PROP_0,
    PROP_FOO,
    PROP_LAST
  };

  static GParamSpec *properties[PROP_LAST];

  static void
  my_object_class_init (MyObjectClass *klass)
  {
    properties[PROP_FOO] = g_param_spec_int ("foo", "Foo", "The foo",
                                             0, 100,
                                             50,
                                             G_PARAM_READWRITE);
    g_object_class_install_property (gobject_class,
                                     PROP_FOO,
                                     properties[PROP_FOO]);
  }

and then notify a change on the "foo" property with:

  g_object_notify_by_pspec (self, properties[PROP_FOO]);

Since GLib 2.56, if GLIB_VERSION_MAX_ALLOWED is 2.56 or greater, the type of object will be propagated to the return type (using the GCC typeof() extension), so any casting the caller needs to do on the return type must be explicit.

In other words, if the object is floating, then this call "assumes ownership" of the floating reference, converting it to a normal reference by clearing the floating flag while leaving the reference count unchanged. If the object is not floating, then this call adds a new normal reference increasing the reference count by one.

Since GLib 2.56, the type of object will be propagated to the return type under the same conditions as for g_object_ref().

Note that cell has already to be packed into cell_layout for this to function properly.

This function should only be called from object system implementations.

This function is used instead of the standard attributes mapping for setting the column value, and should set the value of cell_layout’s cell renderer(s) as appropriate.

func may be %NULL to remove a previously set function.

If the object already had an association with that name, the old association will be destroyed.

Internally, the key is converted to a #GQuark using g_quark_from_string(). This means a copy of key is kept permanently (even after object has been finalized) — so it is recommended to only use a small, bounded set of values for key in your program, to avoid the #GQuark storage growing unbounded.

This is generally called by implementations of #GtkCellAreaClass.focus() or #GtkCellAreaClass.event(), however it can also be used to implement functions such as gtk_tree_view_set_cursor_on_cell().

void
object_add_to_user_list (GObject     *object,
                         const gchar *new_string)
{
  // the quark, naming the object data
  GQuark quark_string_list = g_quark_from_static_string ("my-string-list");
  // retrieve the old string list
  GList *list = g_object_steal_qdata (object, quark_string_list);

  // prepend new string
  list = g_list_prepend (list, g_strdup (new_string));
  // this changed 'list', so we need to set it again
  g_object_set_qdata_full (object, quark_string_list, list, free_string_list);
}
static void
free_string_list (gpointer data)
{
  GList *node, *list = data;

  for (node = list; node; node = node->next)
    g_free (node->data);
  g_list_free (list);
}

Using g_object_get_qdata() in the above example, instead of g_object_steal_qdata() would have left the destroy function set, and thus the partial string list would have been freed upon g_object_set_qdata_full().

If canceled is %TRUE, the currently edited cell renderer will emit the ::editing-canceled signal, otherwise the the ::editing-done signal will be emitted on the current edit widget.

See gtk_cell_area_get_edited_cell() and gtk_cell_area_get_edit_widget().

Duplicate notifications for each property are squashed so that at most one #GObject::notify signal is emitted for each property, in the reverse order in which they have been queued.

It is an error to call this function when the freeze count is zero.

If the pointer to the #GObject may be reused in future (for example, if it is an instance variable of another object), it is recommended to clear the pointer to %NULL rather than retain a dangling pointer to a potentially invalid #GObject instance. Use g_clear_object() for this.