Struct gtk::SizeGroup

#[repr(transparent)]
pub struct SizeGroup { /* private fields */ }

SizeGroup provides a mechanism for grouping a number of widgets together so they all request the same amount of space. This is typically useful when you want a column of widgets to have the same size, but you can’t use a Grid widget.

In detail, the size requested for each widget in a SizeGroup 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 SizeGroupExt::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 SizeGroup 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. For example, if you are packing your widgets into a table, you would not include the GTK_FILL flag.

SizeGroup objects are referenced by each widget in the size group, so once you have added all widgets to a SizeGroup, 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 SizeGroupMode::Horizontal or SizeGroupMode::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 SizeGroupMode::Vertical or SizeGroupMode::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 SizeGroupMode::Vertical or SizeGroupMode::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 property::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:

⚠️ The following code is in xml ⚠️

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

Implements

SizeGroupExt, glib::ObjectExt, BuildableExt, BuildableExtManual

Implementations

impl SizeGroup

pub const NONE: Option<&'static SizeGroup> = None

pub fn new(mode: SizeGroupMode) -> SizeGroup

Create a new SizeGroup.

mode

the mode for the new size group.

Returns

a newly created SizeGroup

pub fn builder() -> SizeGroupBuilder

Creates a new builder-pattern struct instance to construct SizeGroup objects.

This method returns an instance of SizeGroupBuilder which can be used to create SizeGroup objects.

Trait Implementations

impl Clone for SizeGroup

fn clone(&self) -> Self

Returns a copy of the value.

const fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for SizeGroup

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for SizeGroup

fn default() -> Self

Returns the “default value” for a type.

impl Display for SizeGroup

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Hash for SizeGroup

fn hash<H>(&self, state: &mut H)where
    H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)where
    H: Hasher,

Feeds a slice of this type into the given Hasher.

impl Ord for SizeGroup

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

const fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

const fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

const fn clamp(self, min: Self, max: Self) -> Selfwhere
    Self: PartialOrd<Self>,

Restrict a value to a certain interval.

impl ParentClassIs for SizeGroup

type Parent = Object

impl<OT: ObjectType> PartialEq<OT> for SizeGroup

fn eq(&self, other: &OT) -> bool

This method tests for self and other values to be equal, and is used by ==.

const fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<OT: ObjectType> PartialOrd<OT> for SizeGroup

fn partial_cmp(&self, other: &OT) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

const fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

const fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

const fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

const fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl StaticType for SizeGroup

fn static_type() -> Type

Returns the type identifier of Self.

impl Eq for SizeGroup

impl IsA<Buildable> for SizeGroup