### Class

# GtkSizeGroup

#### Description [src]

    final class Gtk.SizeGroup : GObject.Object
      implements Gtk.Buildable {
      /* No available fields */
    }

`GtkSizeGroup` groups widgets together so they all request the same size.

This is typically useful when you want a column of widgets to have the same size, but you can’t use a `GtkGrid`.

In detail, the size requested for each widget in a `GtkSizeGroup` is the maximum of the sizes that would have been requested for each widget in the size group if they were not in the size group. The mode of the size group (see `gtk_size_group_set_mode()`) determines whether this applies to the horizontal size, the vertical size, or both sizes.

Note that size groups only affect the amount of space requested, not the size that the widgets finally receive. If you want the widgets in a `GtkSizeGroup` to actually be the same size, you need to pack them in such a way that they get the size they request and not more.

`GtkSizeGroup` objects are referenced by each widget in the size group, so once you have added all widgets to a `GtkSizeGroup`, you can drop the initial reference to the size group with g_object_unref(). If the widgets in the size group are subsequently destroyed, then they will be removed from the size group and drop their references on the size group; when all widgets have been removed, the size group will be freed.

Widgets can be part of multiple size groups; GTK will compute the horizontal size of a widget from the horizontal requisition of all widgets that can be reached from the widget by a chain of size groups of type `GTK_SIZE_GROUP_HORIZONTAL` or `GTK_SIZE_GROUP_BOTH`, and the vertical size from the vertical requisition of all widgets that can be reached from the widget by a chain of size groups of type `GTK_SIZE_GROUP_VERTICAL` or `GTK_SIZE_GROUP_BOTH`.

Note that only non-contextual sizes of every widget are ever consulted by size groups (since size groups have no knowledge of what size a widget will be allocated in one dimension, it cannot derive how much height a widget will receive for a given width). When grouping widgets that trade height for width in mode `GTK_SIZE_GROUP_VERTICAL` or `GTK_SIZE_GROUP_BOTH`: the height for the minimum width will be the requested height for all widgets in the group. The same is of course true when horizontally grouping width for height widgets.

Widgets that trade height-for-width should set a reasonably large minimum width by way of `GtkLabel:width-chars` for instance. Widgets with static sizes as well as widgets that grow (such as ellipsizing text) need no such considerations.

# GtkSizeGroup as GtkBuildable

Size groups can be specified in a UI definition by placing an `<object>` element with `class="GtkSizeGroup"` somewhere in the UI definition. The widgets that belong to the size group are specified by a `<widgets>` element that may contain multiple `<widget>` elements, one for each member of the size group. The ”name” attribute gives the id of the widget.

An example of a UI definition fragment with `GtkSizeGroup`:

    <object class="GtkSizeGroup">
      <property name="mode">horizontal</property>
      <widgets>
        <widget name="radio1"/>
        <widget name="radio2"/>
      </widgets>
    </object>

#### Hierarchy

#### Ancestors

- GObject

#### Implements

- GtkBuildable

#### Constructors

###### gtk_size_group_new

Create a new `GtkSizeGroup`.

#### Instance methods

###### gtk_size_group_add_widget

Adds a widget to a `GtkSizeGroup`.

###### gtk_size_group_get_mode

Gets the current mode of the size group.

###### gtk_size_group_get_widgets

Returns the list of widgets associated with `size_group`.

###### gtk_size_group_remove_widget

Removes a widget from a `GtkSizeGroup`.

###### gtk_size_group_set_mode

Sets the `GtkSizeGroupMode` of the size group.

##### Methods inherited from GObject (43)

Please see GObject for a full list of methods.

##### Methods inherited from GtkBuildable (1)

###### gtk_buildable_get_buildable_id

Gets the ID of the `buildable` object.

#### Properties

###### Gtk.SizeGroup:mode

The direction in which the size group affects requested sizes.

#### Signals

##### Signals inherited from GObject (1)

###### GObject::notify

The notify signal is emitted on an object when one of its properties has its value set through g_object_set_property(), g_object_set(), et al.