Constraint

open class Constraint : GLibObject.Object, ConstraintProtocol

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 [classGtk.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.

The Constraint type acts as a reference-counted owner of an underlying GtkConstraint instance. It provides the methods that can operate on this data type through ConstraintProtocol conformance. Use Constraint as a strong reference or owner of a GtkConstraint instance.

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  • Designated initialiser from the underlying `C` data type.

    This creates an instance without performing an unbalanced retain i.e., ownership is transferred to the Constraint instance.

    Declaration

    Swift

    @inlinable
public init(_ op: UnsafeMutablePointer<GtkConstraint>)

    Parameters

    op

    pointer to the underlying object
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  • Designated initialiser from a constant pointer to the underlying C data type. This creates an instance without performing an unbalanced retain i.e., ownership is transferred to the Constraint instance.

    Declaration

    Swift

    @inlinable
public init(_ op: UnsafePointer<GtkConstraint>)

    Parameters

    op

    pointer to the underlying object
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  • Optional initialiser from a non-mutating gpointer to the underlying C data type. This creates an instance without performing an unbalanced retain i.e., ownership is transferred to the Constraint instance.

    Declaration

    Swift

    @inlinable
override public init!(gpointer op: gpointer?)

    Parameters

    op

    gpointer to the underlying object
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  • Optional initialiser from a non-mutating gconstpointer to the underlying C data type. This creates an instance without performing an unbalanced retain i.e., ownership is transferred to the Constraint instance.

    Declaration

    Swift

    @inlinable
override public init!(gconstpointer op: gconstpointer?)

    Parameters

    op

    pointer to the underlying object
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  • Optional initialiser from a constant pointer to the underlying C data type. This creates an instance without performing an unbalanced retain i.e., ownership is transferred to the Constraint instance.

    Declaration

    Swift

    @inlinable
public init!(_ op: UnsafePointer<GtkConstraint>?)

    Parameters

    op

    pointer to the underlying object
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  • Optional initialiser from the underlying C data type. This creates an instance without performing an unbalanced retain i.e., ownership is transferred to the Constraint instance.

    Declaration

    Swift

    @inlinable
public init!(_ op: UnsafeMutablePointer<GtkConstraint>?)

    Parameters

    op

    pointer to the underlying object
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  • Designated initialiser from the underlying C data type. Will retain GtkConstraint. i.e., ownership is transferred to the Constraint instance.

    Declaration

    Swift

    @inlinable
public init(retaining op: UnsafeMutablePointer<GtkConstraint>)

    Parameters

    op

    pointer to the underlying object
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  • Reference intialiser for a related type that implements ConstraintProtocol Will retain GtkConstraint.

    Declaration

    Swift

    @inlinable
public init<T>(constraint other: T) where T : ConstraintProtocol

    Parameters

    other

    an instance of a related type that implements ConstraintProtocol
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  • Unsafe typed initialiser. Do not use unless you know the underlying data type the pointer points to conforms to ConstraintProtocol.

    Declaration

    Swift

    @inlinable
override public init<T>(cPointer p: UnsafeMutablePointer<T>)

    Parameters

    cPointer

    pointer to the underlying object
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  • Unsafe typed, retaining initialiser. Do not use unless you know the underlying data type the pointer points to conforms to ConstraintProtocol.

    Declaration

    Swift

    @inlinable
override public init<T>(retainingCPointer cPointer: UnsafeMutablePointer<T>)

    Parameters

    cPointer

    pointer to the underlying object
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  • Unsafe untyped initialiser. Do not use unless you know the underlying data type the pointer points to conforms to ConstraintProtocol.

    Declaration

    Swift

    @inlinable
override public init(raw p: UnsafeRawPointer)

    Parameters

    p

    raw pointer to the underlying object
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  • Unsafe untyped, retaining initialiser. Do not use unless you know the underlying data type the pointer points to conforms to ConstraintProtocol.

    Declaration

    Swift

    @inlinable
override public init(retainingRaw 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 ConstraintProtocol.

    Declaration

    Swift

    @inlinable
public required init(raw p: UnsafeMutableRawPointer)

    Parameters

    p

    mutable raw pointer to the underlying object
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  • Unsafe untyped, retaining initialiser. Do not use unless you know the underlying data type the pointer points to conforms to ConstraintProtocol.

    Declaration

    Swift

    @inlinable
required public init(retainingRaw raw: UnsafeMutableRawPointer)

    Parameters

    raw

    mutable raw pointer to the underlying object
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  • Unsafe untyped initialiser. Do not use unless you know the underlying data type the pointer points to conforms to ConstraintProtocol.

    Declaration

    Swift

    @inlinable
override public init(opaquePointer p: OpaquePointer)

    Parameters

    p

    opaque pointer to the underlying object
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  • Unsafe untyped, retaining initialiser. Do not use unless you know the underlying data type the pointer points to conforms to ConstraintProtocol.

    Declaration

    Swift

    @inlinable
override public init(retainingOpaquePointer p: OpaquePointer)

    Parameters

    p

    opaque pointer to the underlying object
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  • Creates a new constraint representing a relation between a layout attribute on a source and a layout attribute on a target.

    Declaration

    Swift

    @inlinable
public init<ConstraintTargetT>(target: ConstraintTargetT?, targetAttribute: GtkConstraintAttribute, relation: GtkConstraintRelation, source: ConstraintTargetT?, sourceAttribute: GtkConstraintAttribute, multiplier: CDouble, constant: CDouble, strength: Int) where ConstraintTargetT : ConstraintTargetProtocol
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  • Creates a new constraint representing a relation between a layout attribute on a target and a constant value.

    Declaration

    Swift

    @inlinable
public init<ConstraintTargetT>(constant target: ConstraintTargetT?, targetAttribute: GtkConstraintAttribute, relation: GtkConstraintRelation, constant: CDouble, strength: Int) where ConstraintTargetT : ConstraintTargetProtocol
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  • Creates a new constraint representing a relation between a layout attribute on a target and a constant value.

    Declaration

    Swift

    @inlinable
public static func new<ConstraintTargetT>(constant target: ConstraintTargetT?, targetAttribute: GtkConstraintAttribute, relation: GtkConstraintRelation, constant: CDouble, strength: Int) -> Constraint! where ConstraintTargetT : ConstraintTargetProtocol
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