Class

GtkLayoutManager

Description [src]

abstract class Gtk.LayoutManager : GObject.Object {
  parent_instance: GObject
}

Layout managers are delegate classes that handle the preferred size and the allocation of a widget.

You typically subclass GtkLayoutManager if you want to implement a layout policy for the children of a widget, or if you want to determine the size of a widget depending on its contents.

Each GtkWidget can only have a GtkLayoutManager instance associated to it at any given time; it is possible, though, to replace the layout manager instance using gtk_widget_set_layout_manager().

Layout properties

A layout manager can expose properties for controlling the layout of each child, by creating an object type derived from GtkLayoutChild and installing the properties on it as normal GObject properties.

Each GtkLayoutChild instance storing the layout properties for a specific child is created through the gtk_layout_manager_get_layout_child() method; a GtkLayoutManager controls the creation of its GtkLayoutChild instances by overriding the GtkLayoutManagerClass.create_layout_child() virtual function. The typical implementation should look like:

static GtkLayoutChild *
create_layout_child (GtkLayoutManager *manager,
                     GtkWidget        *container,
                     GtkWidget        *child)
{
  return g_object_new (your_layout_child_get_type (),
                       "layout-manager", manager,
                       "child-widget", child,
                       NULL);
}

The GtkLayoutChild:layout-manager and GtkLayoutChild:child-widget properties on the newly created GtkLayoutChild instance are mandatory. The GtkLayoutManager will cache the newly created GtkLayoutChild instance until the widget is removed from its parent, or the parent removes the layout manager.

Each GtkLayoutManager instance creating a GtkLayoutChild should use gtk_layout_manager_get_layout_child() every time it needs to query the layout properties; each GtkLayoutChild instance should call gtk_layout_manager_layout_changed() every time a property is updated, in order to queue a new size measuring and allocation.

Hierarchy

hierarchy this GtkLayoutManager ancestor_0 GObject ancestor_0--this

Ancestors

Instance methods

gtk_layout_manager_allocate

Assigns the given width, height, and baseline to a widget, and computes the position and sizes of the children of the widget using the layout management policy of manager.

gtk_layout_manager_get_layout_child

Retrieves a GtkLayoutChild instance for the GtkLayoutManager, creating one if necessary.

gtk_layout_manager_get_request_mode

Retrieves the request mode of manager.

gtk_layout_manager_get_widget

Retrieves the GtkWidget using the given GtkLayoutManager.

gtk_layout_manager_layout_changed

Queues a resize on the GtkWidget using manager, if any.

gtk_layout_manager_measure

Measures the size of the widget using manager, for the given orientation and size.

Methods inherited from GObject (42)

Signals

Signals inherited from GObject (1)

Class structure

struct GtkLayoutManagerClass {
  GtkSizeRequestMode (* get_request_mode) (
    GtkLayoutManager* manager,
    GtkWidget* widget
  );
  void (* measure) (
    GtkLayoutManager* manager,
    GtkWidget* widget,
    GtkOrientation orientation,
    int for_size,
    int* minimum,
    int* natural,
    int* minimum_baseline,
    int* natural_baseline
  );
  void (* allocate) (
    GtkLayoutManager* manager,
    GtkWidget* widget,
    int width,
    int height,
    int baseline
  );
  GType layout_child_type;
  GtkLayoutChild* (* create_layout_child) (
    GtkLayoutManager* manager,
    GtkWidget* widget,
    GtkWidget* for_child
  );
  void (* root) (
    GtkLayoutManager* manager
  );
  void (* unroot) (
    GtkLayoutManager* manager
  );
  
}
Class members
get_request_mode
GtkSizeRequestMode (* get_request_mode) (
    GtkLayoutManager* manager,
    GtkWidget* widget
  )
  No description available.
measure
void (* measure) (
    GtkLayoutManager* manager,
    GtkWidget* widget,
    GtkOrientation orientation,
    int for_size,
    int* minimum,
    int* natural,
    int* minimum_baseline,
    int* natural_baseline
  )
  No description available.
allocate
void (* allocate) (
    GtkLayoutManager* manager,
    GtkWidget* widget,
    int width,
    int height,
    int baseline
  )
  No description available.
layout_child_type
GType
 

The type of GtkLayoutChild used by this layout manager.

create_layout_child
GtkLayoutChild* (* create_layout_child) (
    GtkLayoutManager* manager,
    GtkWidget* widget,
    GtkWidget* for_child
  )
  No description available.
root
void (* root) (
    GtkLayoutManager* manager
  )
  No description available.
unroot
void (* unroot) (
    GtkLayoutManager* manager
  )
  No description available.

Virtual methods

Gtk.LayoutManagerClass.allocate

Assigns the given width, height, and baseline to a widget, and computes the position and sizes of the children of the widget using the layout management policy of manager.

Gtk.LayoutManagerClass.create_layout_child

Create a GtkLayoutChild instance for the given for_child widget.

Gtk.LayoutManagerClass.get_request_mode
No description available.
Gtk.LayoutManagerClass.measure

Measures the size of the widget using manager, for the given orientation and size.

Gtk.LayoutManagerClass.root
No description available.
Gtk.LayoutManagerClass.unroot
No description available.