SizeGroupRef

public struct SizeGroupRef : SizeGroupProtocol, GWeakCapturing

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 [methodGtk.SizeGroup.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 [propertyGtk.Label: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:

&lt;object class="GtkSizeGroup"&gt;
  &lt;property name="mode"&gt;horizontal&lt;/property&gt;
  &lt;widgets&gt;
    &lt;widget name="radio1"/&gt;
    &lt;widget name="radio2"/&gt;
  &lt;/widgets&gt;
&lt;/object&gt;

The SizeGroupRef type acts as a lightweight Swift reference to an underlying GtkSizeGroup instance. It exposes methods that can operate on this data type through SizeGroupProtocol conformance. Use SizeGroupRef only as an unowned reference to an existing GtkSizeGroup instance.

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  • ptr 
    Untyped pointer to the underlying `GtkSizeGroup` instance.

    For type-safe access, use the generated, typed pointer size_group_ptr property instead.

    Declaration

    Swift

    public let ptr: UnsafeMutableRawPointer!
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SizeGroup Class

  • Designated initialiser from the underlying C data type

    Declaration

    Swift

    @inlinable
init(_ p: UnsafeMutablePointer<GtkSizeGroup>)
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  • Designated initialiser from a constant pointer to the underlying C data type

    Declaration

    Swift

    @inlinable
init(_ p: UnsafePointer<GtkSizeGroup>)
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  • Conditional initialiser from an optional pointer to the underlying C data type

    Declaration

    Swift

    @inlinable
init!(_ maybePointer: UnsafeMutablePointer<GtkSizeGroup>?)
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  • Conditional initialiser from an optional, non-mutable pointer to the underlying C data type

    Declaration

    Swift

    @inlinable
init!(_ maybePointer: UnsafePointer<GtkSizeGroup>?)
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  • Conditional initialiser from an optional gpointer

    Declaration

    Swift

    @inlinable
init!(gpointer g: gpointer?)
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  • Conditional initialiser from an optional, non-mutable gconstpointer

    Declaration

    Swift

    @inlinable
init!(gconstpointer g: gconstpointer?)
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  • Reference intialiser for a related type that implements SizeGroupProtocol

    Declaration

    Swift

    @inlinable
init<T>(_ other: T) where T : SizeGroupProtocol
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  • This factory is syntactic sugar for setting weak pointers wrapped in GWeak<T>

    Declaration

    Swift

    @inlinable
static func unowned<T>(_ other: T) -> SizeGroupRef where T : SizeGroupProtocol
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  • Unsafe typed initialiser. Do not use unless you know the underlying data type the pointer points to conforms to SizeGroupProtocol.

    Declaration

    Swift

    @inlinable
init<T>(cPointer: UnsafeMutablePointer<T>)
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  • Unsafe typed initialiser. Do not use unless you know the underlying data type the pointer points to conforms to SizeGroupProtocol.

    Declaration

    Swift

    @inlinable
init<T>(constPointer: UnsafePointer<T>)
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  • Unsafe untyped initialiser. Do not use unless you know the underlying data type the pointer points to conforms to SizeGroupProtocol.

    Declaration

    Swift

    @inlinable
init(mutating raw: UnsafeRawPointer)
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  • Unsafe untyped initialiser. Do not use unless you know the underlying data type the pointer points to conforms to SizeGroupProtocol.

    Declaration

    Swift

    @inlinable
init(raw: UnsafeMutableRawPointer)
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  • Unsafe untyped initialiser. Do not use unless you know the underlying data type the pointer points to conforms to SizeGroupProtocol.

    Declaration

    Swift

    @inlinable
init(opaquePointer: OpaquePointer)
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  • Create a new GtkSizeGroup.

    Declaration

    Swift

    @inlinable
init(mode: GtkSizeGroupMode)
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