Constraint

Object Hierarchy:

Description:

[ CCode ( type_id = "gtk_constraint_get_type ()" ) ]
public sealed class Constraint : Object

`GtkConstraint` describes a constraint between attributes of two widgets, expressed as a linear equation.

The typical equation for a constraint is:

``` target.target_attr = source.source_attr × multiplier + constant ```

Each `GtkConstraint` is part of a system that will be solved by a [class@Gtk.ConstraintLayout] in order to allocate and position each child widget or guide.

The source and target, as well as their attributes, of a `GtkConstraint` instance are immutable after creation.

Namespace: Gtk

Package: gtk4

Content:

Properties:

public double constant { get; construct; }
The constant value to be added to the [property@Gtk.
public double multiplier { get; construct; }
The multiplication factor to be applied to the [property@Gtk.
public ConstraintRelation relation { get; construct; }
The order relation between the terms of the constraint.
public ConstraintTarget source { get; construct; }
The source of the constraint.
public ConstraintAttribute source_attribute { get; construct; }
The attribute of the [property@Gtk.
public int strength { get; construct; }
The strength of the constraint.
public ConstraintTarget target { get; construct; }
The target of the constraint.
public ConstraintAttribute target_attribute { get; construct; }
The attribute of the [property@Gtk.

Creation methods:

public Constraint (ConstraintTarget? target, ConstraintAttribute target_attribute, ConstraintRelation relation, ConstraintTarget? source, ConstraintAttribute source_attribute, double multiplier, double constant, int strength)
Creates a new constraint representing a relation between a layout attribute on a source and a layout attribute on a target.
public Constraint.const (ConstraintTarget? target, ConstraintAttribute target_attribute, ConstraintRelation relation, double constant, int strength)
Creates a new constraint representing a relation between a layout attribute on a target and a constant value.

Methods:

public double get_constant ()
Retrieves the constant factor added to the source attributes' value.
public double get_multiplier ()
Retrieves the multiplication factor applied to the source attribute's value.
public ConstraintRelation get_relation ()
The order relation between the terms of the constraint.
public unowned ConstraintTarget? get_source ()
Retrieves the [iface@Gtk.
public ConstraintAttribute get_source_attribute ()
Retrieves the attribute of the source to be read by the constraint.
public int get_strength ()
Retrieves the strength of the constraint.
public unowned ConstraintTarget? get_target ()
Retrieves the [iface@Gtk.
public ConstraintAttribute get_target_attribute ()
Retrieves the attribute of the target to be set by the constraint.
public bool is_attached ()
Checks whether the constraint is attached to a [class@Gtk.
public bool is_constant ()
Checks whether the constraint describes a relation between an attribute on the [property@Gtk.
public bool is_required ()
Checks whether the constraint is a required relation for solving the constraint layout.

Inherited Members:

All known members inherited from class GLib.Object