gtkmm: Gtk::Constraint Class Reference

The description of a constraint. More...

#include <gtkmm/constraint.h>

Inheritance diagram for Gtk::Constraint:

Classes
class	Strength_Wrapper
	Wrapper for enum Strength. More...

Public Types
enum class	Attribute { NONE , LEFT , RIGHT , TOP , BOTTOM , START , END , WIDTH , HEIGHT , CENTER_X , CENTER_Y , BASELINE }

enum class	Relation { LE = -1 , EQ , GE }

using	Strength = Strength_Wrapper::Strength
	Strength enumerators are scoped by the wrapper class and can be implicitly converted to int.

Public Member Functions
	Constraint (Constraint &&src) noexcept

Constraint &	operator= (Constraint &&src) noexcept

	~Constraint () noexcept override

GtkConstraint *	gobj ()
	Provides access to the underlying C GObject.

const GtkConstraint *	gobj () const
	Provides access to the underlying C GObject.

GtkConstraint *	gobj_copy ()
	Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs.

Glib::RefPtr< ConstraintTarget >	get_target ()
	Retrieves the Gtk::ConstraintTarget used as the target for the constraint.

Glib::RefPtr< const ConstraintTarget >	get_target () const
	Retrieves the Gtk::ConstraintTarget used as the target for the constraint.

Attribute	get_target_attribute () const
	Retrieves the attribute of the target to be set by the constraint.

Glib::RefPtr< ConstraintTarget >	get_source ()
	Retrieves the Gtk::ConstraintTarget used as the source for the constraint.

Glib::RefPtr< const ConstraintTarget >	get_source () const
	Retrieves the Gtk::ConstraintTarget used as the source for the constraint.

Attribute	get_source_attribute () const
	Retrieves the attribute of the source to be read by the constraint.

Relation	get_relation () const
	The order relation between the terms of the constraint.

double	get_multiplier () const
	Retrieves the multiplication factor applied to the source attribute's value.

double	get_constant () const
	Retrieves the constant factor added to the source attributes' value.

int	get_strength () const
	Retrieves the strength of the constraint.

bool	is_required () const
	Checks whether the constraint is a required relation for solving the constraint layout.

bool	is_attached () const
	Checks whether the constraint is attached to a Gtk::ConstraintLayout, and it is contributing to the layout.

bool	is_constant () const
	Checks whether the constraint describes a relation between an attribute on the property_target() and a constant value.

Glib::PropertyProxy_ReadOnly< Glib::RefPtr< ConstraintTarget > >	property_target () const
	The target of the constraint.

Glib::PropertyProxy_ReadOnly< Attribute >	property_target_attribute () const
	The attribute of the property_target() set by the constraint.

Glib::PropertyProxy_ReadOnly< Relation >	property_relation () const
	The order relation between the terms of the constraint.

Glib::PropertyProxy_ReadOnly< Glib::RefPtr< ConstraintTarget > >	property_source () const
	The source of the constraint.

Glib::PropertyProxy_ReadOnly< Attribute >	property_source_attribute () const
	The attribute of the property_source() read by the constraint.

Glib::PropertyProxy_ReadOnly< double >	property_multiplier () const
	The multiplication factor to be applied to the property_source_attribute().

Glib::PropertyProxy_ReadOnly< double >	property_constant () const
	The constant value to be added to the property_source_attribute().

Glib::PropertyProxy_ReadOnly< int >	property_strength () const
	The strength of the constraint.

Static Public Member Functions
static GType	get_type ()
	Get the GType for this class, for use with the underlying GObject type system.

static Glib::RefPtr< Constraint >	create (const Glib::RefPtr< ConstraintTarget > & target, Attribute target_attribute, Relation relation, const Glib::RefPtr< ConstraintTarget > &source, Attribute source_attribute, double multiplier, double constant, int strength)
	Creates a new Gtk::Constraint representing a relation between a layout attribute on a source and a layout attribute on a target.

static Glib::RefPtr< Constraint >	create (const Glib::RefPtr< ConstraintTarget > & target, Attribute target_attribute, Relation relation, double constant, int strength)
	Creates a new Gtk::Constraint representing a relation between a layout attribute on a target and a constant value.

Protected Member Functions
	Constraint (const Glib::RefPtr< ConstraintTarget > & target, Attribute target_attribute, Relation relation, const Glib::RefPtr< ConstraintTarget > &source, Attribute source_attribute, double multiplier, double constant, int strength)

	Constraint (const Glib::RefPtr< ConstraintTarget > & target, Attribute target_attribute, Relation relation, double constant, int strength)

Related Symbols
(Note that these are not member symbols.)
Glib::RefPtr< Gtk::Constraint >	wrap (GtkConstraint *object, bool take_copy=false)
	A Glib::wrap() method for this object.

Detailed Description

The description of a constraint.

Gtk::Constraint describes a constraint between an attribute on a widget and another attribute on another widget, expressed as a linear equation like:

target.attr1 = source.attr2 × multiplier + constant

Each Constraint is part of a system that will be solved by a Gtk::ConstraintLayout in order to allocate and position each child widget.

A Constraint is immutable once it's created.

Since gtkmm 3.96:

Member Enumeration Documentation

◆ Attribute

enum class Gtk::Constraint::Attribute

strong

Enumerator
NONE	No attribute, used for constant relations.
LEFT	The left edge of a widget, regardless of text direction.
RIGHT	The right edge of a widget, regardless of text direction.
TOP	The top edge of a widget.
BOTTOM	The bottom edge of a widget.
START	The leading edge of a widget, depending on text direction; equivalent to Gtk::Constraint::Attribute::LEFT for LTR languages, and Gtk::Constraint::Attribute::RIGHT for RTL ones.
END	The trailing edge of a widget, depending on text direction; equivalent to Gtk::Constraint::Attribute::RIGHT for LTR languages, and Gtk::Constraint::Attribute::LEFT for RTL ones.
WIDTH	The width of a widget.
HEIGHT	The height of a widget.
CENTER_X	The center of a widget, on the horizontal axis.
CENTER_Y	The center of a widget, on the vertical axis.
BASELINE	The baseline of a widget.

◆ Relation

enum class Gtk::Constraint::Relation

strong

Enumerator
LE	Less than, or equal.
EQ	Equal.
GE	Greater than, or equal.

Constructor & Destructor Documentation

◆ Constraint() [1/3]

Gtk::Constraint::Constraint ( Constraint && src )

noexcept

◆ ~Constraint()

Gtk::Constraint::~Constraint ( )

overridenoexcept

◆ Constraint() [2/3]

Gtk::Constraint::Constraint	(	const Glib::RefPtr< ConstraintTarget > &	target,
		Attribute	target_attribute,
		Relation	relation,
		const Glib::RefPtr< ConstraintTarget > &	source,
		Attribute	source_attribute,
		double	multiplier,
		double	constant,
		int	strength
	)

explicitprotected

◆ Constraint() [3/3]

Gtk::Constraint::Constraint	(	const Glib::RefPtr< ConstraintTarget > &	target,
		Attribute	target_attribute,
		Relation	relation,
		double	constant,
		int	strength
	)

explicitprotected

Member Function Documentation

◆ create() [1/2]

static Glib::RefPtr< Constraint > Gtk::Constraint::create	(	const Glib::RefPtr< ConstraintTarget > &	target,
		Attribute	target_attribute,
		Relation	relation,
		const Glib::RefPtr< ConstraintTarget > &	source,
		Attribute	source_attribute,
		double	multiplier,
		double	constant,
		int	strength
	)

static

Creates a new Gtk::Constraint representing a relation between a layout attribute on a source and a layout attribute on a target.

Parameters

target	A Gtk::ConstraintTarget or an empty Glib::RefPtr.
target_attribute	The attribute of target to be set.
relation	The relation equivalence between target_attribute and source_attribute.
source	A Gtk::ConstraintTarget or an empty Glib::RefPtr.
source_attribute	The attribute of source to be read.
multiplier	A multiplication factor to be applied to source_attribute.
constant	A constant to be added to source_attribute.
strength	The strength of the constraint.

Returns: The newly created Gtk::Constraint.

◆ create() [2/2]

static Glib::RefPtr< Constraint > Gtk::Constraint::create	(	const Glib::RefPtr< ConstraintTarget > &	target,
		Attribute	target_attribute,
		Relation	relation,
		double	constant,
		int	strength
	)

static

Creates a new Gtk::Constraint representing a relation between a layout attribute on a target and a constant value.

Parameters

target	A Gtk::ConstraintTarget or an empty Glib::RefPtr.
target_attribute	The attribute of target to be set.
relation	The relation equivalence between target_attribute and constant.
constant	A constant to be set on target_attribute.
strength	The strength of the constraint.

Returns: The newly created Gtk::Constraint.

◆ get_constant()

double Gtk::Constraint::get_constant ( ) const

Retrieves the constant factor added to the source attributes' value.

Returns: A constant factor.

◆ get_multiplier()

double Gtk::Constraint::get_multiplier ( ) const

Retrieves the multiplication factor applied to the source attribute's value.

Returns: A multiplication factor.

◆ get_relation()

Relation Gtk::Constraint::get_relation ( ) const

The order relation between the terms of the constraint.

Returns: A relation type.

◆ get_source() [1/2]

Glib::RefPtr< ConstraintTarget > Gtk::Constraint::get_source ( )

Retrieves the Gtk::ConstraintTarget used as the source for the constraint.

If the source is set to nullptr at creation, the constraint will use the widget using the Gtk::ConstraintLayout as the source.

Returns: The source of the constraint.

◆ get_source() [2/2]

Glib::RefPtr< const ConstraintTarget > Gtk::Constraint::get_source ( ) const

Retrieves the Gtk::ConstraintTarget used as the source for the constraint.

If the source is set to nullptr at creation, the constraint will use the widget using the Gtk::ConstraintLayout as the source.

Returns: The source of the constraint.

◆ get_source_attribute()

Attribute Gtk::Constraint::get_source_attribute ( ) const

Retrieves the attribute of the source to be read by the constraint.

Returns: The source's attribute.

◆ get_strength()

int Gtk::Constraint::get_strength ( ) const

Retrieves the strength of the constraint.

Returns: The strength value.

◆ get_target() [1/2]

Glib::RefPtr< ConstraintTarget > Gtk::Constraint::get_target ( )

Retrieves the Gtk::ConstraintTarget used as the target for the constraint.

If the targe is set to nullptr at creation, the constraint will use the widget using the Gtk::ConstraintLayout as the target.

Returns: A Gtk::ConstraintTarget.

◆ get_target() [2/2]

Glib::RefPtr< const ConstraintTarget > Gtk::Constraint::get_target ( ) const

Retrieves the Gtk::ConstraintTarget used as the target for the constraint.

If the targe is set to nullptr at creation, the constraint will use the widget using the Gtk::ConstraintLayout as the target.

Returns: A Gtk::ConstraintTarget.

◆ get_target_attribute()

Attribute Gtk::Constraint::get_target_attribute ( ) const

Retrieves the attribute of the target to be set by the constraint.

Returns: The target's attribute.

◆ get_type()

static GType Gtk::Constraint::get_type ( )

static

Get the GType for this class, for use with the underlying GObject type system.

◆ gobj() [1/2]

GtkConstraint * Gtk::Constraint::gobj ( )

inline

Provides access to the underlying C GObject.

◆ gobj() [2/2]

const GtkConstraint * Gtk::Constraint::gobj ( ) const

inline

Provides access to the underlying C GObject.

◆ gobj_copy()

GtkConstraint * Gtk::Constraint::gobj_copy ( )

Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs.

◆ is_attached()

bool Gtk::Constraint::is_attached ( ) const

Checks whether the constraint is attached to a Gtk::ConstraintLayout, and it is contributing to the layout.

Returns: true if the constraint is attached.

◆ is_constant()

bool Gtk::Constraint::is_constant ( ) const

Checks whether the constraint describes a relation between an attribute on the property_target() and a constant value.

Returns: true if the constraint is a constant relation.

◆ is_required()

bool Gtk::Constraint::is_required ( ) const

Checks whether the constraint is a required relation for solving the constraint layout.

Returns: true if the constraint is required.

◆ operator=()

Constraint & Gtk::Constraint::operator= ( Constraint && src )

noexcept

◆ property_constant()

Glib::PropertyProxy_ReadOnly< double > Gtk::Constraint::property_constant ( ) const

The constant value to be added to the property_source_attribute().

Default value: 0

Returns: A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.

◆ property_multiplier()

Glib::PropertyProxy_ReadOnly< double > Gtk::Constraint::property_multiplier ( ) const

The multiplication factor to be applied to the property_source_attribute().

Default value: 1

Returns: A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.

◆ property_relation()

Glib::PropertyProxy_ReadOnly< Relation > Gtk::Constraint::property_relation ( ) const

The order relation between the terms of the constraint.

Default value: Gtk::Constraint::Relation::EQ

Returns: A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.

◆ property_source()

Glib::PropertyProxy_ReadOnly< Glib::RefPtr< ConstraintTarget > > Gtk::Constraint::property_source ( ) const

The source of the constraint.

The constraint will set the property_target_attribute() property of the target using the property_source_attribute() property of the source.

Returns: A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.

◆ property_source_attribute()

Glib::PropertyProxy_ReadOnly< Attribute > Gtk::Constraint::property_source_attribute ( ) const

The attribute of the property_source() read by the constraint.

Default value: Gtk::Constraint::Attribute::NONE

Returns: A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.

◆ property_strength()

Glib::PropertyProxy_ReadOnly< int > Gtk::Constraint::property_strength ( ) const

The strength of the constraint.

The strength can be expressed either using one of the symbolic values of the Gtk::ConstraintStrength enumeration, or any positive integer value.

Default value: 1001001000

Returns: A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.

◆ property_target()

Glib::PropertyProxy_ReadOnly< Glib::RefPtr< ConstraintTarget > > Gtk::Constraint::property_target ( ) const

The target of the constraint.

The constraint will set the property_target_attribute() property of the target using the property_source_attribute() property of the source widget.

Returns: A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.

◆ property_target_attribute()

Glib::PropertyProxy_ReadOnly< Attribute > Gtk::Constraint::property_target_attribute ( ) const

The attribute of the property_target() set by the constraint.

Default value: Gtk::Constraint::Attribute::NONE

Returns: A PropertyProxy_ReadOnly that allows you to get the value of the property, or receive notification when the value of the property changes.

Friends And Related Symbol Documentation

◆ wrap()

Glib::RefPtr< Gtk::Constraint > wrap	(	GtkConstraint *	object,
		bool	take_copy = `false`
	)

A Glib::wrap() method for this object.

Parameters

object	The C instance.
take_copy	False if the result should take ownership of the C instance. True if it should take a new copy or ref.

Returns: A C++ instance that wraps this C instance.

Classes

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Related Symbols

Detailed Description

Member Enumeration Documentation

◆ Attribute

◆ Relation

Constructor & Destructor Documentation

◆ Constraint() [1/3]

◆ ~Constraint()

◆ Constraint() [2/3]

◆ Constraint() [3/3]

Member Function Documentation

◆ create() [1/2]

◆ create() [2/2]

◆ get_constant()

◆ get_multiplier()

◆ get_relation()

◆ get_source() [1/2]

◆ get_source() [2/2]

◆ get_source_attribute()

◆ get_strength()

◆ get_target() [1/2]

◆ get_target() [2/2]

◆ get_target_attribute()

◆ get_type()

◆ gobj() [1/2]

◆ gobj() [2/2]

◆ gobj_copy()

◆ is_attached()

◆ is_constant()

◆ is_required()

◆ operator=()

◆ property_constant()

◆ property_multiplier()

◆ property_relation()

◆ property_source()

◆ property_source_attribute()

◆ property_strength()

◆ property_target()

◆ property_target_attribute()

Friends And Related Symbol Documentation

◆ wrap()