ConstraintRef

public struct ConstraintRef : ConstraintProtocol, GWeakCapturing

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 ConstraintRef type acts as a lightweight Swift reference to an underlying GtkConstraint instance. It exposes methods that can operate on this data type through ConstraintProtocol conformance. Use ConstraintRef only as an unowned reference to an existing GtkConstraint instance.

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ptr
```
Untyped pointer to the underlying `GtkConstraint` instance.
```
For type-safe access, use the generated, typed pointer constraint_ptr property instead.
Declaration
Swift

public let ptr: UnsafeMutableRawPointer!
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Constraint Class

init(_:)
Designated initialiser from the underlying C data type
Declaration
Swift

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

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

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

@inlinable init!(_ maybePointer: UnsafePointer<GtkConstraint>?)
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init(gpointer:)
Conditional initialiser from an optional gpointer
Declaration
Swift

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

@inlinable init!(gconstpointer g: gconstpointer?)
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init(_:)
Reference intialiser for a related type that implements ConstraintProtocol
Declaration
Swift

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

@inlinable static func unowned<T>(_ other: T) -> ConstraintRef where T : ConstraintProtocol
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init(cPointer:)
Unsafe typed initialiser. Do not use unless you know the underlying data type the pointer points to conforms to ConstraintProtocol.
Declaration
Swift

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

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

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

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

@inlinable init(opaquePointer: OpaquePointer)
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                    init(target:targetAttribute:relation:source:sourceAttribute:multiplier:constant:strength:)

Creates a new constraint representing a relation between a layout

attribute on a source and a layout attribute on a target.

Declaration

Swift

@inlinable
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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                    init(constant:targetAttribute:relation:constant:strength:)

Creates a new constraint representing a relation between a layout attribute on a target and a constant value.

Declaration

Swift

@inlinable
init<ConstraintTargetT>(constant target: ConstraintTargetT?, targetAttribute: GtkConstraintAttribute, relation: GtkConstraintRelation, constant: CDouble, strength: Int) where ConstraintTargetT : ConstraintTargetProtocol

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                    new(constant:targetAttribute:relation:constant:strength:)

Creates a new constraint representing a relation between a layout attribute on a target and a constant value.

Declaration

Swift

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

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