GtkContainer

GtkContainer — Base class for widgets which contain other widgets

Synopsis


#include <gtk/gtk.h>


                    GtkContainer;
#define             GTK_IS_RESIZE_CONTAINER             (widget)
#define             GTK_CONTAINER_WARN_INVALID_CHILD_PROPERTY_ID(object, property_id, pspec)
#define             gtk_container_border_width
void                gtk_container_add                   (GtkContainer *container,
                                                         GtkWidget *widget);
void                gtk_container_remove                (GtkContainer *container,
                                                         GtkWidget *widget);
void                gtk_container_add_with_properties   (GtkContainer *container,
                                                         GtkWidget *widget,
                                                         const gchar *first_prop_name,
                                                         ...);
GtkResizeMode       gtk_container_get_resize_mode       (GtkContainer *container);
void                gtk_container_set_resize_mode       (GtkContainer *container,
                                                         GtkResizeMode resize_mode);
void                gtk_container_check_resize          (GtkContainer *container);
void                gtk_container_foreach               (GtkContainer *container,
                                                         GtkCallback callback,
                                                         gpointer callback_data);
void                gtk_container_foreach_full          (GtkContainer *container,
                                                         GtkCallback callback,
                                                         GtkCallbackMarshal marshal,
                                                         gpointer callback_data,
                                                         GtkDestroyNotify notify);
#define             gtk_container_children
GList*              gtk_container_get_children          (GtkContainer *container);
void                gtk_container_set_reallocate_redraws
                                                        (GtkContainer *container,
                                                         gboolean needs_redraws);
void                gtk_container_set_focus_child       (GtkContainer *container,
                                                         GtkWidget *child);
GtkAdjustment*      gtk_container_get_focus_vadjustment (GtkContainer *container);
void                gtk_container_set_focus_vadjustment (GtkContainer *container,
                                                         GtkAdjustment *adjustment);
GtkAdjustment*      gtk_container_get_focus_hadjustment (GtkContainer *container);
void                gtk_container_set_focus_hadjustment (GtkContainer *container,
                                                         GtkAdjustment *adjustment);
void                gtk_container_resize_children       (GtkContainer *container);
GType               gtk_container_child_type            (GtkContainer *container);
void                gtk_container_child_get             (GtkContainer *container,
                                                         GtkWidget *child,
                                                         const gchar *first_prop_name,
                                                         ...);
void                gtk_container_child_set             (GtkContainer *container,
                                                         GtkWidget *child,
                                                         const gchar *first_prop_name,
                                                         ...);
void                gtk_container_child_get_property    (GtkContainer *container,
                                                         GtkWidget *child,
                                                         const gchar *property_name,
                                                         GValue *value);
void                gtk_container_child_set_property    (GtkContainer *container,
                                                         GtkWidget *child,
                                                         const gchar *property_name,
                                                         const GValue *value);
void                gtk_container_child_get_valist      (GtkContainer *container,
                                                         GtkWidget *child,
                                                         const gchar *first_property_name,
                                                         va_list var_args);
void                gtk_container_child_set_valist      (GtkContainer *container,
                                                         GtkWidget *child,
                                                         const gchar *first_property_name,
                                                         va_list var_args);
void                gtk_container_forall                (GtkContainer *container,
                                                         GtkCallback callback,
                                                         gpointer callback_data);
guint               gtk_container_get_border_width      (GtkContainer *container);
void                gtk_container_set_border_width      (GtkContainer *container,
                                                         guint border_width);
void                gtk_container_propagate_expose      (GtkContainer *container,
                                                         GtkWidget *child,
                                                         GdkEventExpose *event);
gboolean            gtk_container_get_focus_chain       (GtkContainer *container,
                                                         GList **focusable_widgets);
void                gtk_container_set_focus_chain       (GtkContainer *container,
                                                         GList *focusable_widgets);
void                gtk_container_unset_focus_chain     (GtkContainer *container);
GParamSpec*         gtk_container_class_find_child_property
                                                        (GObjectClass *cclass,
                                                         const gchar *property_name);
void                gtk_container_class_install_child_property
                                                        (GtkContainerClass *cclass,
                                                         guint property_id,
                                                         GParamSpec *pspec);
GParamSpec**        gtk_container_class_list_child_properties
                                                        (GObjectClass *cclass,
                                                         guint *n_properties);


Object Hierarchy


  GObject
   +----GInitiallyUnowned
         +----GtkObject
               +----GtkWidget
                     +----GtkContainer
                           +----GtkBin
                           +----GtkBox
                           +----GtkCList
                           +----GtkFixed
                           +----GtkPaned
                           +----GtkIconView
                           +----GtkLayout
                           +----GtkList
                           +----GtkMenuShell
                           +----GtkNotebook
                           +----GtkSocket
                           +----GtkTable
                           +----GtkTextView
                           +----GtkToolbar
                           +----GtkTree
                           +----GtkTreeView

Implemented Interfaces

GtkContainer implements AtkImplementorIface and GtkBuildable.

Properties


  "border-width"             guint                 : Read / Write
  "child"                    GtkWidget             : Write
  "resize-mode"              GtkResizeMode         : Read / Write

Signals


  "add"                                            : Run First
  "check-resize"                                   : Run Last
  "remove"                                         : Run First
  "set-focus-child"                                : Run First

Description

A GTK+ user interface is constructed by nesting widgets inside widgets. Container widgets are the inner nodes in the resulting tree of widgets: they contain other widgets. So, for example, you might have a GtkWindow containing a GtkFrame containing a GtkLabel. If you wanted an image instead of a textual label inside the frame, you might replace the GtkLabel widget with a GtkImage widget.

There are two major kinds of container widgets in GTK+. Both are subclasses of the abstract GtkContainer base class.

The first type of container widget has a single child widget and derives from GtkBin. These containers are decorators, which add some kind of functionality to the child. For example, a GtkButton makes its child into a clickable button; a GtkFrame draws a frame around its child and a GtkWindow places its child widget inside a top-level window.

The second type of container can have more than one child; its purpose is to manage layout. This means that these containers assign sizes and positions to their children. For example, a GtkHBox arranges its children in a horizontal row, and a GtkTable arranges the widgets it contains in a two-dimensional grid.

To fulfill its task, a layout container must negotiate the size requirements with its parent and its children. This negotiation is carried out in two phases, size requisition and size allocation.

Size Requisition

The size requisition of a widget is it's desired width and height. This is represented by a GtkRequisition.

How a widget determines its desired size depends on the widget. A GtkLabel, for example, requests enough space to display all its text. Container widgets generally base their size request on the requisitions of their children.

The size requisition phase of the widget layout process operates top-down. It starts at a top-level widget, typically a GtkWindow. The top-level widget asks its child for its size requisition by calling gtk_widget_size_request(). To determine its requisition, the child asks its own children for their requisitions and so on. Finally, the top-level widget will get a requisition back from its child.


Size Allocation

When the top-level widget has determined how much space its child would like to have, the second phase of the size negotiation, size allocation, begins. Depending on its configuration (see gtk_window_set_resizable()), the top-level widget may be able to expand in order to satisfy the size request or it may have to ignore the size request and keep its fixed size. It then tells its child widget how much space it gets by calling gtk_widget_size_allocate(). The child widget divides the space among its children and tells each child how much space it got, and so on. Under normal circumstances, a GtkWindow will always give its child the amount of space the child requested.

A child's size allocation is represented by a GtkAllocation. This struct contains not only a width and height, but also a position (i.e. X and Y coordinates), so that containers can tell their children not only how much space they have gotten, but also where they are positioned inside the space available to the container.

Widgets are required to honor the size allocation they receive; a size request is only a request, and widgets must be able to cope with any size.


Child properties

GtkContainer introduces child properties - these are object properties that are not specific to either the container or the contained widget, but rather to their relation. Typical examples of child properties are the position or pack-type of a widget which is contained in a GtkBox.

Use gtk_container_class_install_child_property() to install child properties for a container class and gtk_container_class_find_child_property() or gtk_container_class_list_child_properties() to get information about existing child properties.

To set the value of a child property, use gtk_container_child_set_property(), gtk_container_child_set() or gtk_container_child_set_valist(). To obtain the value of a child property, use gtk_container_child_get_property(), gtk_container_child_get() or gtk_container_child_get_valist(). To emit notification about child property changes, use gtk_widget_child_notify().


GtkContainer as GtkBuildable

The GtkContainer implementation of the GtkBuildable interface supports a <packing> element for children, which can contain multiple <property> elements that specify child properties for the child.

Example 45. Child properties in UI definitions

<object class="GtkVBox">
  <child>
    <object class="GtkLabel"/>
    <packing>
      <property name="pack-type">start</property>
    </packing>
  </child>
</object>

Details

GtkContainer

typedef struct _GtkContainer GtkContainer;


GTK_IS_RESIZE_CONTAINER()

#define GTK_IS_RESIZE_CONTAINER(widget) (GTK_IS_CONTAINER (widget) && ((GtkContainer*) (widget))->resize_mode != GTK_RESIZE_PARENT)

widget :


GTK_CONTAINER_WARN_INVALID_CHILD_PROPERTY_ID()

#define             GTK_CONTAINER_WARN_INVALID_CHILD_PROPERTY_ID(object, property_id, pspec)

This macro should be used to emit a standard warning about unexpected properties in set_child_property() and get_child_property() implementations.

object :

the GObject on which set_child_property() or get_child_property() was called

property_id :

the numeric id of the property

pspec :

the GParamSpec of the property

gtk_container_border_width

#define	gtk_container_border_width		gtk_container_set_border_width

Warning

gtk_container_border_width is deprecated and should not be used in newly-written code. Use gtk_container_set_border_width() instead.

Does the same as gtk_container_set_border_width().


gtk_container_add ()

void                gtk_container_add                   (GtkContainer *container,
                                                         GtkWidget *widget);

Adds widget to container. Typically used for simple containers such as GtkWindow, GtkFrame, or GtkButton; for more complicated layout containers such as GtkBox or GtkTable, this function will pick default packing parameters that may not be correct. So consider functions such as gtk_box_pack_start() and gtk_table_attach() as an alternative to gtk_container_add() in those cases. A widget may be added to only one container at a time; you can't place the same widget inside two different containers.

container :

a GtkContainer

widget :

a widget to be placed inside container

gtk_container_remove ()

void                gtk_container_remove                (GtkContainer *container,
                                                         GtkWidget *widget);

Removes widget from container. widget must be inside container. Note that container will own a reference to widget, and that this may be the last reference held; so removing a widget from its container can destroy that widget. If you want to use widget again, you need to add a reference to it while it's not inside a container, using g_object_ref(). If you don't want to use widget again it's usually more efficient to simply destroy it directly using gtk_widget_destroy() since this will remove it from the container and help break any circular reference count cycles.

container :

a GtkContainer

widget :

a current child of container

gtk_container_add_with_properties ()

void                gtk_container_add_with_properties   (GtkContainer *container,
                                                         GtkWidget *widget,
                                                         const gchar *first_prop_name,
                                                         ...);

Adds widget to container, setting child properties at the same time. See gtk_container_add() and gtk_container_child_set() for more details.

container :

a GtkContainer

widget :

a widget to be placed inside container

first_prop_name :

the name of the first child property to set

... :

a NULL-terminated list of property names and values, starting with first_prop_name

gtk_container_get_resize_mode ()

GtkResizeMode       gtk_container_get_resize_mode       (GtkContainer *container);

Returns the resize mode for the container. See gtk_container_set_resize_mode().

container :

a GtkContainer

Returns :

the current resize mode

gtk_container_set_resize_mode ()

void                gtk_container_set_resize_mode       (GtkContainer *container,
                                                         GtkResizeMode resize_mode);

Sets the resize mode for the container.

The resize mode of a container determines whether a resize request will be passed to the container's parent, queued for later execution or executed immediately.

container :

a GtkContainer

resize_mode :

the new resize mode

gtk_container_check_resize ()

void                gtk_container_check_resize          (GtkContainer *container);

container :


gtk_container_foreach ()

void                gtk_container_foreach               (GtkContainer *container,
                                                         GtkCallback callback,
                                                         gpointer callback_data);

Invokes callback on each non-internal child of container. See gtk_container_forall() for details on what constitutes an "internal" child. Most applications should use gtk_container_foreach(), rather than gtk_container_forall().

container :

a GtkContainer

callback :

a callback

callback_data :

callback user data

gtk_container_foreach_full ()

void                gtk_container_foreach_full          (GtkContainer *container,
                                                         GtkCallback callback,
                                                         GtkCallbackMarshal marshal,
                                                         gpointer callback_data,
                                                         GtkDestroyNotify notify);

Warning

gtk_container_foreach_full is deprecated and should not be used in newly-written code. Use gtk_container_foreach() instead.

container :

callback :

marshal :

callback_data :

notify :


gtk_container_children

#define gtk_container_children gtk_container_get_children

Warning

gtk_container_children is deprecated and should not be used in newly-written code. Use gtk_container_get_children() instead.

Does the same as gtk_container_get_children().


gtk_container_get_children ()

GList*              gtk_container_get_children          (GtkContainer *container);

Returns the container's non-internal children. See gtk_container_forall() for details on what constitutes an "internal" child.

container :

a GtkContainer

Returns :

a newly-allocated list of the container's non-internal children.

gtk_container_set_reallocate_redraws ()

void                gtk_container_set_reallocate_redraws
                                                        (GtkContainer *container,
                                                         gboolean needs_redraws);

Sets the reallocate_redraws flag of the container to the given value.

Containers requesting reallocation redraws get automatically redrawn if any of their children changed allocation.

container :

a GtkContainer

needs_redraws :

the new value for the container's reallocate_redraws flag

gtk_container_set_focus_child ()

void                gtk_container_set_focus_child       (GtkContainer *container,
                                                         GtkWidget *child);

container :

child :


gtk_container_get_focus_vadjustment ()

GtkAdjustment*      gtk_container_get_focus_vadjustment (GtkContainer *container);

Retrieves the vertical focus adjustment for the container. See gtk_container_set_focus_vadjustment().

container :

a GtkContainer

Returns :

the vertical focus adjustment, or NULL if none has been set.

gtk_container_set_focus_vadjustment ()

void                gtk_container_set_focus_vadjustment (GtkContainer *container,
                                                         GtkAdjustment *adjustment);

Hooks up an adjustment to focus handling in a container, so when a child of the container is focused, the adjustment is scrolled to show that widget. This function sets the vertical alignment. See gtk_scrolled_window_get_vadjustment() for a typical way of obtaining the adjustment and gtk_container_set_focus_hadjustment() for setting the horizontal adjustment.

The adjustments have to be in pixel units and in the same coordinate system as the allocation for immediate children of the container.

container :

a GtkContainer

adjustment :

an adjustment which should be adjusted when the focus is moved among the descendents of container

gtk_container_get_focus_hadjustment ()

GtkAdjustment*      gtk_container_get_focus_hadjustment (GtkContainer *container);

Retrieves the horizontal focus adjustment for the container. See gtk_container_set_focus_hadjustment().

container :

a GtkContainer

Returns :

the horizontal focus adjustment, or NULL if none has been set.

gtk_container_set_focus_hadjustment ()

void                gtk_container_set_focus_hadjustment (GtkContainer *container,
                                                         GtkAdjustment *adjustment);

Hooks up an adjustment to focus handling in a container, so when a child of the container is focused, the adjustment is scrolled to show that widget. This function sets the horizontal alignment. See gtk_scrolled_window_get_hadjustment() for a typical way of obtaining the adjustment and gtk_container_set_focus_vadjustment() for setting the vertical adjustment.

The adjustments have to be in pixel units and in the same coordinate system as the allocation for immediate children of the container.

container :

a GtkContainer

adjustment :

an adjustment which should be adjusted when the focus is moved among the descendents of container

gtk_container_resize_children ()

void                gtk_container_resize_children       (GtkContainer *container);

container :


gtk_container_child_type ()

GType               gtk_container_child_type            (GtkContainer *container);

Returns the type of the children supported by the container.

Note that this may return G_TYPE_NONE to indicate that no more children can be added, e.g. for a GtkPaned which already has two children.

container :

a GtkContainer

Returns :

a GType.

gtk_container_child_get ()

void                gtk_container_child_get             (GtkContainer *container,
                                                         GtkWidget *child,
                                                         const gchar *first_prop_name,
                                                         ...);

Gets the values of one or more child properties for child and container.

container :

a GtkContainer

child :

a widget which is a child of container

first_prop_name :

the name of the first property to get

... :

a NULL-terminated list of property names and GValue*, starting with first_prop_name

gtk_container_child_set ()

void                gtk_container_child_set             (GtkContainer *container,
                                                         GtkWidget *child,
                                                         const gchar *first_prop_name,
                                                         ...);

Sets one or more child properties for child and container.

container :

a GtkContainer

child :

a widget which is a child of container

first_prop_name :

the name of the first property to set

... :

a NULL-terminated list of property names and values, starting with first_prop_name

gtk_container_child_get_property ()

void                gtk_container_child_get_property    (GtkContainer *container,
                                                         GtkWidget *child,
                                                         const gchar *property_name,
                                                         GValue *value);

Gets the value of a child property for child and container.

container :

a GtkContainer

child :

a widget which is a child of container

property_name :

the name of the property to get

value :

a location to return the value

gtk_container_child_set_property ()

void                gtk_container_child_set_property    (GtkContainer *container,
                                                         GtkWidget *child,
                                                         const gchar *property_name,
                                                         const GValue *value);

Sets a child property for child and container.

container :

a GtkContainer

child :

a widget which is a child of container

property_name :

the name of the property to set

value :

the value to set the property to

gtk_container_child_get_valist ()

void                gtk_container_child_get_valist      (GtkContainer *container,
                                                         GtkWidget *child,
                                                         const gchar *first_property_name,
                                                         va_list var_args);

Gets the values of one or more child properties for child and container.

container :

a GtkContainer

child :

a widget which is a child of container

first_property_name :

the name of the first property to get

var_args :

a NULL-terminated list of property names and GValue*, starting with first_prop_name.

gtk_container_child_set_valist ()

void                gtk_container_child_set_valist      (GtkContainer *container,
                                                         GtkWidget *child,
                                                         const gchar *first_property_name,
                                                         va_list var_args);

Sets one or more child properties for child and container.

container :

a GtkContainer

child :

a widget which is a child of container

first_property_name :

the name of the first property to set

var_args :

a NULL-terminated list of property names and values, starting with first_prop_name

gtk_container_forall ()

void                gtk_container_forall                (GtkContainer *container,
                                                         GtkCallback callback,
                                                         gpointer callback_data);

Invokes callback on each child of container, including children that are considered "internal" (implementation details of the container). "Internal" children generally weren't added by the user of the container, but were added by the container implementation itself. Most applications should use gtk_container_foreach(), rather than gtk_container_forall().

container :

a GtkContainer

callback :

a callback

callback_data :

callback user data

gtk_container_get_border_width ()

guint               gtk_container_get_border_width      (GtkContainer *container);

Retrieves the border width of the container. See gtk_container_set_border_width().

container :

a GtkContainer

Returns :

the current border width

gtk_container_set_border_width ()

void                gtk_container_set_border_width      (GtkContainer *container,
                                                         guint border_width);

Sets the border width of the container.

The border width of a container is the amount of space to leave around the outside of the container. The only exception to this is GtkWindow; because toplevel windows can't leave space outside, they leave the space inside. The border is added on all sides of the container. To add space to only one side, one approach is to create a GtkAlignment widget, call gtk_widget_set_size_request() to give it a size, and place it on the side of the container as a spacer.

container :

a GtkContainer

border_width :

amount of blank space to leave outside the container. Valid values are in the range 0-65535 pixels.

gtk_container_propagate_expose ()

void                gtk_container_propagate_expose      (GtkContainer *container,
                                                         GtkWidget *child,
                                                         GdkEventExpose *event);

When a container receives an expose event, it must send synthetic expose events to all children that don't have their own GdkWindows. This function provides a convenient way of doing this. A container, when it receives an expose event, calls gtk_container_propagate_expose() once for each child, passing in the event the container received.

gtk_container_propagate_expose() takes care of deciding whether an expose event needs to be sent to the child, intersecting the event's area with the child area, and sending the event.

In most cases, a container can simply either simply inherit the "expose" implementation from GtkContainer, or, do some drawing and then chain to the ::expose implementation from GtkContainer.

container :

a GtkContainer

child :

a child of container

event :

a expose event sent to container

gtk_container_get_focus_chain ()

gboolean            gtk_container_get_focus_chain       (GtkContainer *container,
                                                         GList **focusable_widgets);

Retrieves the focus chain of the container, if one has been set explicitly. If no focus chain has been explicitly set, GTK+ computes the focus chain based on the positions of the children. In that case, GTK+ stores NULL in focusable_widgets and returns FALSE.

container :

a GtkContainer

focusable_widgets :

location to store the focus chain of the container, or NULL. You should free this list using g_list_free() when you are done with it, however no additional reference count is added to the individual widgets in the focus chain.

Returns :

TRUE if the focus chain of the container has been set explicitly.

gtk_container_set_focus_chain ()

void                gtk_container_set_focus_chain       (GtkContainer *container,
                                                         GList *focusable_widgets);

Sets a focus chain, overriding the one computed automatically by GTK+.

In principle each widget in the chain should be a descendant of the container, but this is not enforced by this method, since it's allowed to set the focus chain before you pack the widgets, or have a widget in the chain that isn't always packed. The necessary checks are done when the focus chain is actually traversed.

container :

a GtkContainer

focusable_widgets :

the new focus chain

gtk_container_unset_focus_chain ()

void                gtk_container_unset_focus_chain     (GtkContainer *container);

Removes a focus chain explicitly set with gtk_container_set_focus_chain().

container :

a GtkContainer

gtk_container_class_find_child_property ()

GParamSpec*         gtk_container_class_find_child_property
                                                        (GObjectClass *cclass,
                                                         const gchar *property_name);

Finds a child property of a container class by name.

cclass :

a GtkContainerClass

property_name :

the name of the child property to find

Returns :

the GParamSpec of the child property or NULL if class has no child property with that name.

gtk_container_class_install_child_property ()

void                gtk_container_class_install_child_property
                                                        (GtkContainerClass *cclass,
                                                         guint property_id,
                                                         GParamSpec *pspec);

Installs a child property on a container class.

cclass :

a GtkContainerClass

property_id :

the id for the property

pspec :

the GParamSpec for the property

gtk_container_class_list_child_properties ()

GParamSpec**        gtk_container_class_list_child_properties
                                                        (GObjectClass *cclass,
                                                         guint *n_properties);

Returns all child properties of a container class.

cclass :

a GtkContainerClass

n_properties :

location to return the number of child properties found

Returns :

a newly allocated NULL-terminated array of GParamSpec*. The array must be freed with g_free().

Property Details

The "border-width" property

  "border-width"             guint                 : Read / Write

The width of the empty border outside the containers children.

Allowed values: <= G_MAXINT

Default value: 0


The "child" property

  "child"                    GtkWidget             : Write

Can be used to add a new child to the container.


The "resize-mode" property

  "resize-mode"              GtkResizeMode         : Read / Write

Specify how resize events are handled.

Default value: GTK_RESIZE_PARENT

Signal Details

The "add" signal

void                user_function                      (GtkContainer *container,
                                                        GtkWidget    *widget,
                                                        gpointer      user_data)      : Run First

container :

the object which received the signal.

widget :

user_data :

user data set when the signal handler was connected.

The "check-resize" signal

void                user_function                      (GtkContainer *container,
                                                        gpointer      user_data)      : Run Last

container :

the object which received the signal.

user_data :

user data set when the signal handler was connected.

The "remove" signal

void                user_function                      (GtkContainer *container,
                                                        GtkWidget    *widget,
                                                        gpointer      user_data)      : Run First

container :

the object which received the signal.

widget :

user_data :

user data set when the signal handler was connected.

The "set-focus-child" signal

void                user_function                      (GtkContainer *container,
                                                        GtkWidget    *widget,
                                                        gpointer      user_data)      : Run First

container :

the object which received the signal.

widget :

user_data :

user data set when the signal handler was connected.