UIView Extension Reference


                    
                    
                    constrain(_:to:of:relatedBy:multiplier:constant:priority:isActive:)

Declarative auto-layout. Creates standard NSLayoutConstraint’s but in a declarative way and with fewer lines of code.

Declaration

Swift

@discardableResult
public func constrain(
    _ attr1: NSLayoutConstraint.Attribute,
    to attr2: NSLayoutConstraint.Attribute = .notAnAttribute,
    of view2: Any? = nil,
    relatedBy relation: NSLayoutConstraint.Relation = .equal,
    multiplier: CGFloat = 1,
    constant c: CGFloat = 0,
    priority: UILayoutPriority = .required,
    isActive: Bool = true
) -> NSLayoutConstraint

Parameters

`attr1`	attribute to constrain
`attr2`	second attribute (optional, default `.notAnAttribute`)
`view2`	view for second attribute (optional, default `nil`)
`relation`	relation to evaluate (towards multiplier*attr2 + c) (default `.equal`)
`multiplier`	multiplier to apply (default `1`)
`c`	constant offset amount (default `0`)
`priority`	constraint priority (default `.required`)
`isActive`	whether to activate the constraint or not (default `true`)

Return Value

The created layout constraint


                    
                    
                    XAxisAnchor

Anchors that constrain views along the x-axis

Declaration

Swift

public enum XAxisAnchor


                    
                    
                    YAxisAnchor

Anchors that constrain views along the y-axis

Declaration

Swift

public enum YAxisAnchor


                    
                    
                    DimensionAnchor

Anchors that constrain views along either width or height

Declaration

Swift

public enum DimensionAnchor


                    
                    
                    constrain(_:to:relatedBy:constant:priority:isActive:)

Creates standard NSLayoutConstraint’s using anchor syntax

Declaration

Swift

@discardableResult
public func constrain(
    _ anchorType: XAxisAnchor,
    to otherAnchor: NSLayoutXAxisAnchor,
    relatedBy relation: NSLayoutConstraint.Relation = .equal,
    constant c: CGFloat = 0,
    priority: UILayoutPriority = .required,
    isActive: Bool = true
) -> NSLayoutConstraint

Parameters

`anchorType`	X-axis anchor to constrain
`otherAnchor`	other X-axis anchor
`relation`	relation to evaluate (towards otherAnchor + c) (default `.equal`)
`c`	constant offset amount (default `0`)
`priority`	constraint priority (default `.required`)
`isActive`	whether to activate the constraint or not (default `true`)

Return Value

The created layout constraint


                    
                    
                    constrain(_:to:relatedBy:constant:priority:isActive:)

Creates standard NSLayoutConstraint’s using anchor syntax

Declaration

Swift

@discardableResult
public func constrain(
    _ anchorType: YAxisAnchor,
    to otherAnchor: NSLayoutYAxisAnchor,
    relatedBy relation: NSLayoutConstraint.Relation = .equal,
    constant c: CGFloat = 0,
    priority: UILayoutPriority = .required,
    isActive: Bool = true
) -> NSLayoutConstraint

Parameters

`anchorType`	Y-axis anchor to constrain
`otherAnchor`	other Y-axis anchor
`relation`	relation to evaluate (towards otherAnchor + c) (default `.equal`)
`c`	constant offset amount (default `0`)
`priority`	constraint priority (default `.required`)
`isActive`	whether to activate the constraint or not (default `true`)

Return Value

The created layout constraint


                    
                    
                    constrain(_:relatedBy:constant:priority:isActive:)

Creates standard NSLayoutConstraint’s using anchor syntax

Declaration

Swift

@discardableResult
public func constrain(
    _ anchorType: DimensionAnchor,
    relatedBy relation: NSLayoutConstraint.Relation = .equal,
    constant c: CGFloat,
    priority: UILayoutPriority = .required,
    isActive: Bool = true
) -> NSLayoutConstraint

Parameters

`anchorType`	layout dimension to constrain
`relation`	relation to evaluate (towards otherAnchor + c) (default `.equal`)
`c`	constant offset amount (default `0`)
`priority`	constraint priority (default `.required`)
`isActive`	whether to activate the constraint or not (default `true`)

Return Value

The created layout constraint


                    
                    
                    constrain(_:to:relatedBy:multiplier:constant:priority:isActive:)

Creates standard NSLayoutConstraint’s using anchor syntax

Declaration

Swift

@discardableResult
public func constrain(
    _ anchorType: DimensionAnchor,
    to otherAnchor: NSLayoutDimension,
    relatedBy relation: NSLayoutConstraint.Relation = .equal,
    multiplier: CGFloat = 1,
    constant c: CGFloat = 0,
    priority: UILayoutPriority = .required,
    isActive: Bool = true
) -> NSLayoutConstraint

Parameters

`anchorType`	layout dimension to constrain
`otherAnchor`	other layout dimension anchor
`relation`	relation to evaluate (towards otherAnchor + c) (default `.equal`)
`multiplier`	multiplier to apply (default `1`)
`c`	constant offset amount (default `0`)
`priority`	constraint priority (default `.required`)
`isActive`	whether to activate the constraint or not (default `true`)

Return Value

The created layout constraint


                    
                    
                    constrainAspectRatio(_:offset:relatedBy:priority:isActive:)

Constrain the aspect ratio for the receiving view.

Declaration

Swift

@discardableResult
public func constrainAspectRatio(
    _ ratio: CGFloat,
    offset: CGFloat = 0,
    relatedBy relation: NSLayoutConstraint.Relation = .equal,
    priority: UILayoutPriority = .required,
    isActive: Bool = true
) -> NSLayoutConstraint

Parameters

`ratio`	aspect ratio
`offset`	offset to apply (default `.zero`)
`relation`	relation to evaluate (towards ratio) (default `.equal`)
`priority`	constraint priority (default `.required`)
`isActive`	whether to activate the constraint or not (default `true`)

Return Value

the created layout constraint


                    
                    
                    constrain(below:relatedBy:offset:priority:isActive:)

Constrain the receiving view below a sibling view

Declaration

Swift

@discardableResult
public func constrain(
    below sibling: Anchorable,
    relatedBy relation: NSLayoutConstraint.Relation = .equal,
    offset: CGFloat = 0,
    priority: UILayoutPriority = .required,
    isActive: Bool = true
) -> NSLayoutConstraint

Parameters

`sibling`	sibling view to constrain to
`relation`	relation to evaluate (towards sibling) (default `.equal`)
`offset`	the gap between the bottom of sibling and the top of the receiver (default `0`)
`priority`	constraint priority (default `.required`)
`isActive`	whether to activate the constraint or not (default `true`)

Return Value

The created layout constraint


                    
                    
                    constrain(after:relatedBy:offset:priority:isActive:)

Constrain the receiving view to the left of (trailing side of) a sibling view

Declaration

Swift

@discardableResult
public func constrain(
    after sibling: Anchorable,
    relatedBy relation: NSLayoutConstraint.Relation = .equal,
    offset: CGFloat = 0,
    priority: UILayoutPriority = .required,
    isActive: Bool = true
) -> NSLayoutConstraint

Parameters

`sibling`	sibling view to constrain to
`relation`	relation to evaluate (towards sibling) (default `.equal`)
`offset`	the gap between the trailing edge of sibling and the leading edge of the receiver (default `0`)
`priority`	constraint priority (default `.required`)
`isActive`	whether to activate the constraint or not (default `true`)

Return Value

The created layout constraint


                    
                    
                    Center

Center alignment options

Declaration

Swift

public struct Center : OptionSet


                    
                    
                    constrainCenter(_:to:relatedBy:offset:priority:isActive:)

Constrain the center of the receiving view with the center of another view

Declaration

Swift

@discardableResult
public func constrainCenter(
    _ center: Center = .all,
    to view2: Anchorable? = nil,
    relatedBy relation: NSLayoutConstraint.Relation = .equal,
    offset: UIOffset = .zero,
    priority: UILayoutPriority = .required,
    isActive: Bool = true
) -> [NSLayoutConstraint.Attribute: NSLayoutConstraint]

Parameters

`center`	which center attributes to constrain (default `.all`)
`view2`	view or layout guide to constrain to (pass `nil` to constrain to superview)
`relation`	relation to evaluate (towards view2) (default `.equal`)
`offset`	offset to apply relative to view2.center (default `.zero`)
`priority`	constraint priority (default `.required`)
`isActive`	whether to activate the constraints or not (default `true`)

Return Value

dictionary of constraints created, keyed by .centerX, .centerY


                    
                    
                    constrainEdges(_:to:relatedBy:with:priority:isActive:)

Inset the edges of one view to those of another view

Declaration

Swift

@discardableResult
public func constrainEdges(
    _ edges: NSDirectionalRectEdge = .all,
    to view2: Anchorable? = nil,
    relatedBy relation: NSLayoutConstraint.Relation = .equal,
    with insets: NSDirectionalEdgeInsets = .zero,
    priority: UILayoutPriority = .required,
    isActive: Bool = true
) -> [NSLayoutConstraint.Attribute: NSLayoutConstraint]

Parameters

`edges`	which edges to constrain (default `.all`)
`view2`	view or layout guide to constrain to (pass `nil` to constrain to superview)
`relation`	relation to evaluate (towards view2) (default `.equal`)
`insets`	insets to apply to each edge (default `.zero`)
`priority`	constraint priority (default `.required`)
`isActive`	whether to activate the constraints or not (default `true`)

Return Value

dictionary of constraints created, keyed by .top, .leading, .bottom, .trailing


                    
                    
                    constrainEdges(_:to:relatedBy:outsets:priority:isActive:)

Outset the edges of one view relative to those of another

Declaration

Swift

@discardableResult
public func constrainEdges(
    _ edges: NSDirectionalRectEdge = .all,
    to view2: UIView? = nil,
    relatedBy relation: NSLayoutConstraint.Relation = .equal,
    outsets: NSDirectionalEdgeInsets,
    priority: UILayoutPriority = .required,
    isActive: Bool = true
) -> [NSLayoutConstraint.Attribute: NSLayoutConstraint]

Parameters

`edges`	which edges to constrain (default `.all`)
`view2`	view to constraint to (pass `nil` to constrain to superview)
`relation`	relation to evaluate (towards view2) (default `.equal`)
`outsets`	outsets to apply to each edge (default `.zero`)
`priority`	constraint priority (default `.required`)
`isActive`	whether to activate the constraints or not (default `true`)

Return Value

dictionary of constraints created, keyed by .top, .leading, .bottom, .trailing


                    
                    
                    constrainEdgesToMargins(_:to:relatedBy:with:priority:isActive:)

Inset the edges of one view to the layout margins of another view

Declaration

Swift

@discardableResult
public func constrainEdgesToMargins(
    _ edges: NSDirectionalRectEdge = .all,
    to view2: UIView? = nil,
    relatedBy relation: NSLayoutConstraint.Relation = .equal,
    with insets: NSDirectionalEdgeInsets = .zero,
    priority: UILayoutPriority = .required,
    isActive: Bool = true
) -> [NSLayoutConstraint.Attribute: NSLayoutConstraint]

Parameters

`edges`	which edges to constrain (default `.all`)
`view2`	view whose layout margins will be used to constrain the receiver (pass `nil` to constrain to superview.layoutMarginsGuide)
`relation`	relation to evaluate (towards view2) (default `.equal`)
`insets`	insets to apply to each edge (default `.zero`)
`priority`	constraint priority (default `.required`)
`isActive`	whether to activate the constraints or not (default `true`)

Return Value

dictionary of constraints created, keyed by .top, .leading, .bottom, .trailing


                    
                    
                    constrainSize(_:relatedBy:priority:isActive:)

Constrain the receiving view with given size

Declaration

Swift

@discardableResult
public func constrainSize(
    _ size: CGSize,
    relatedBy relation: NSLayoutConstraint.Relation = .equal,
    priority: UILayoutPriority = .required,
    isActive: Bool = true
) -> [NSLayoutConstraint.Attribute: NSLayoutConstraint]

Parameters

`size`	size of view to constrain to
`relation`	relation to evaluate (towards size) (default `.equal`)
`priority`	constraint priority (default `.required`)
`isActive`	whether to activate the constraint or not (default `true`)

Return Value

dictionary of constraints created, keyed by .width, .height


                    
                    
                    constrainSize(width:height:relatedBy:priority:isActive:)

Constrain the receiving view with width and height

Declaration

Swift

@discardableResult
public func constrainSize(
    width: CGFloat,
    height: CGFloat,
    relatedBy relation: NSLayoutConstraint.Relation = .equal,
    priority: UILayoutPriority = .required,
    isActive: Bool = true
) -> [NSLayoutConstraint.Attribute: NSLayoutConstraint]

Parameters

`width`	width of view to constrain to
`height`	height of view to constrain to
`relation`	relation to evaluate (towards width and height) (default `.equal`)
`priority`	constraint priority (default `.required`)
`isActive`	whether to activate the constraint or not (default `true`)

Return Value

dictionary of constraints created, keyed by .width, .height


                    
                    
                    constrainSize(_:relatedBy:priority:isActive:)

Constrain the receiving view with given dimension applied to both width and height.

Declaration

Swift

@discardableResult
public func constrainSize(
    _ dimension: CGFloat,
    relatedBy relation: NSLayoutConstraint.Relation = .equal,
    priority: UILayoutPriority = .required,
    isActive: Bool = true
) -> [NSLayoutConstraint.Attribute: NSLayoutConstraint]

Parameters

`dimension`	dimension of view to constrain to
`relation`	relation to evaluate (towards dimension) (default `.equal`)
`priority`	constraint priority (default `.required`)
`isActive`	whether to activate the constraint or not (default `true`)

Return Value

dictionary of constraints created, keyed by .width, .height