Swift
Swift manual views layouting without auto layout, no magic, pure code, full control. Concise syntax, readable & chainable

PinLayout

Swift manual views layouting without auto layout, no magic, pure code, full control. Concise syntax, readable & chainable.

"No auto-layout constraints attached"

• PinLayout principles and philosophy
• Installation
• Documentation
  • Layout using distances from superview’s edges
  • Anchors
  • Edges
  • Relative positionning
  • Width, height and size
  • Margins
  • Warnings
  • More examples

PinLayout principles and philosophy

Installation

CocoaPods

To integrate PinLayout into your Xcode project using CocoaPods, specify it in your Podfile:

    pod 'PinLayout'

Then, run pod install.

Carthage

To integrate PinLayout into your Xcode project using Carthage, specify it in your Cartfile:

github "mirego/PinLayout"

Then, run carthage update to build the framework and drag the built PinLayout.framework into your Xcode project.

Usage sample

Example:

This example layout an image, a UISegmentedControl and a label.

• Logo image:
  • Its size is set to 100x100
  • The logo is layouted below the UINavigationBar with a margin of 10 pixels all around.
• UISegmentedControl
  • Layout it at the right of the logo
  • Use the remaining horizontal space with a left and right margin of 20 pixels.
• UILabel
  • Layout the label below the UISegmentedControl with a top margin of 10 pixels.
  • Adjust the label's width to match the UISegmentedControl's width.
  • Adjust the label's height to fit its new width. (calls internally UILabel's sizeThatFits() method)

override func layoutSubviews() {
   super.layoutSubviews() 
    
   logo.pin.topLeft().size(100).margin(74, 10, 10)
   segmented.pin.right(of: logo, aligned: .top).right().marginHorizontal(20)
   textLabel.pin.below(of: segmented, aligned: .left).width(of: segmented).pinEdges().marginTop(10).sizeToFit()
}

Documentation

Layout using distances from superview’s edges

Usage Examples:

    view.pin.top(20).left(20)
    view.pin.top(25%).hCenter(0)
    view.pin.left(12).vCenter(100)

Example:

This example layout the view A to fit its superview frame with a margin of 10 pixels. It pins the top, left, bottom and right edges.

    viewA.pin.top(10).left(10).bottom(10).right(10)

Another possible solution using other PinLayout's methods (more details later):

    view.pin.topLeft().bottomRight().margin(10)

Position view directly on superview’s edges

PinLayout also has shorter version that pins a view’s edge directly on its superview's corresponding edge.

Methods:

• top()
  Position the view top edge directly on its superview top edge. Similar to calling top(0)
• left()
  Position the view left edge directly on its superview top edge. Similar to calling left(0)
• bottom()
  Position the view bottom edge directly on its superview top edge. Similar to calling bottom(0)
• right()
  Position the view right edge directly on its superview top edge. Similar to calling right(0)
• hCenter()
  Position the view horizontal center directly on its superview horizontal center. Similar to calling hCenter(0).
• vCenter()
  Position the view vertical center directly on its superview vertical center. Similar to calling vCenter(0).

Usage examples:

	view.pin.top().left()
	view.pin.bottom().right()
	view.pin.hCenter().vCenter()

Example:

This example is similar to the previous example, but pins edges directly on superview’s edges. It will layout the view A to fit its superview frame with a margin of 10 pixels.

    viewA.pin.top().left().bottom().right().margin(10)

Anchors

PinLayout UIView’s anchors

PinLayout add anchors properties to UIViews. These properties are used to reference other view’s anchors.

PinLayout UIView’s anchors:

• UIView.anchor.topLeft
• UIView.anchor.topCenter
• UIView.anchor.topRight
• UIView.anchor.leftCenter
• UIView.anchor.centers
• UIView.anchor.rightCenter
• UIView.anchor.bottomLeft
• UIView.anchor.bottomCenter
• UIView.anchor.bottomRight

Layout using anchors

PinLayout can use anchors to position view’s related to other views.

Following methods position the corresponding view anchor on another view’s anchor.

Methods:

• topLeft(to anchor: Anchor)
• topCenter(to anchor: Anchor)
• topRight(to anchor: Anchor)
• leftCenter(to anchor: Anchor)
• center(to anchor: Anchor)
• rightCenter(to anchor: Anchor)
• bottomLeft(to anchor: Anchor)
• bottomCenter(to anchor: Anchor)
• bottomRight(to anchor: Anchor)

📌 These methods can pin a view’s anchor to any other view's anchor, even if don't have the same direct superview! It works with any views that have at some point the same ancestor.

Usage examples:

    view.pin.topCenter(to: view1.anchor.bottomCenter)
    view.pin.topLeft(to: view1.anchor.topLeft).bottomRight(to: view1.anchor.center)

Example:

Layout using an anchors. This example pins the view B topLeft anchor on the view A topRight anchor.

	viewB.pin.topLeft(to: viewA.anchor.topRight)

Example:

Layout using multiple anchors.

It is also possible to combine two anchors to pin the position and the size of a view. The following example will position the view C between the view A and B with horizontal margins of 10px.

	viewC.pin.topLeft(to: viewA.anchor.topRight)
	         .bottomRight(to: viewB.anchor.bottomLeft).marginHorizontal(10)

Layout using superview’s anchors

PinLayout also has a shorter version that pins a view's anchor directly on its corresponding superview’s anchor.

The following methods position the corresponding view's anchor on another view’s anchor.

Methods:

• topLeft()
• topCenter()
• topRight()
• leftCenter()
• center()
• rightCenter()
• bottomLeft()
• bottomCenter()
• bottomRight()

Example:

For example .topRight() will pin the view’s topRight anchor on its superview’s topRight anchor..

	viewA.pin.topRight()

This is equivalent to:

	viewA.pin.topRight(to: superview.pin.topRight)

Edges

PinLayout UIView’s edges

PinLayout adds edges properties to UIViews. These properties are used to reference other view’s edges.

PinLayout UIView’s edges:

• UIView.edge.top
• UIView.edge.left
• UIView.edge.bottom
• UIView.edge.right

Layout using edges

PinLayout has methods to attach a UIView's edge (top, left, bottom or right edge) to another view’s edge.

Methods:

• top(to edge: VerticalEdge)
• left(to: edge: HorizontalEdge)
• bottom(to edge: VerticalEdge)
• right(to: edge: HorizontalEdge)

📌 These methods can pin a view’s edge to any other view's edge, even if don't have the same direct superview! It works with any views that have at some point the same ancestor.

Usage examples:

	view.pin.left(to: view1.edge.right)
	view.pin.left(to: view1.edge.right).top(to: view2.edge.right)

Example:

Layout using an edge.

The following example will layout the view B left edge on the view A right edge. It only change the view B left coordinate

	viewB.pin.left(to: viewA.edge.right)

Relative positionning

Layout using edges relative positioning

PinLayout also has methods to position relative to another view. This is similar to pinning to an edge with a slightly different syntax.

Methods:

• above(of UIView)
  Position the view above the specified view. This method is similar to pinning the view’s bottom edge.
• below(of UIView)
  Position the view below the specified view. This method is similar to pinning the view’s top edge.
• left(of UIView)
  Position the view left of the specified view. This method is similar to pinning the view’s right edge.
• right(of UIView)
  Position the view right of the specified view. This method is similar to pinning the view’s left edge.

📌 These methods can pin a view’s relative to any views, even if don't have the same direct superview! It works with any views that have at some point the same ancestor.

Usage examples:

	view.pin.above(of: view2)
	view.pin.left(of: view2, aligned: .top)
	view.pin.left(of: view1).above(of: view2).below(of: view3).right(of: view4)

Example:

The following example will position the view C between the view A and B with margins of 10px using relative positioning methods.

	viewC.pin.top().left(of: viewA).right(of: viewB).margin(10)

This is an equivalent solution using edges:

	viewC.pin.top().left(to: viewA.edge.right).right(to: viewB.edge.left).margin(10)

This is also an equivalent solution using relative positioning and alignment explained in the next section:

	viewC.pin.left(of: viewA, aligned: .top).right(of: viewB, aligned: top).marginHorizontal(10)

Layout using relative positioning and alignment

Usage examples:

	view.pin.above(of: view2, aligned: .left)
	view.pin.above(of: view2, aligned: .right)
	view.pin.left(of: view2, aligned: .top)

Example:

The following example layout the view B below the view A aligned on its center.

	viewB.pin.below(of: viewA, aligned: .center)

This is an equivalent solutions using anchors:

	viewB.pin.topCenter(to: viewA.anchor.bottomCenter)

Width, height and size

Adjust view width, height and size

PinLayout has methods to set the view’s height and width.

Methods:

• width(_ width: CGFloat)
  The value specifies the width of the view in pixels. Value must be non-negative.

• width(percent: Percent)
  The value specifies the width of the view in percentage of its superview. Value must be non-negative.

• width(of view: UIView)
  Set the view’s width to match the referenced view’s width.

• height(_ height: CGFloat)
  The value specifies the height of the view in pixels.

• height(percent: Percent)
  The value specifies the height of the view in percentage of its superview. Value must be non-negative.

• height(of view: UIView)
  Set the view’s height to match the referenced view’s height

• size(_ size: CGSize)
  The value specifies the size (width and value) of the view in pixels. Values must be non-negative.

• size(_ percent: Percent)
  The value specifies the width and the height of the view in percentage of its superview. Values must be non-negative.

• size(_ sideLength: CGFloat)
  The value specifies the width and the height of the view in pixels, creating a square view. Values must be non-negative.

• size(of view: UIView)
  Set the view’s size to match the referenced view’s size

Usage examples:

	view.pin.width(50%)
	view.pin.width(100)
	view.pin.width(of: view1)
	
	view.pin.height(100%)
	view.pin.height(200)
	
	view.pin.size(of: view1)
	view.pin.size(50%)
	view.pin.size(250)

Margins

PinLayout's margins

PinLayout has methods to apply margins.

Methods:

• marginTop(_ value: CGFloat)

• marginLeft(_ value: CGFloat)

• marginBottom(_ value: CGFloat)

• marginRight(_ value: CGFloat)

• marginHorizontal(_ value: CGFloat)

• marginVertical(_ value: CGFloat)

• margin(_ value: CGFloat)

• margin(_ vertical: CGFloat, _ horizontal: CGFloat)

• margin(_ top: CGFloat, _ horizontal: CGFloat, _ bottom: CGFloat)

• margin(_ top: CGFloat, _ left: CGFloat, _ bottom: CGFloat, _ right: CGFloat)

• pinEdges()

Usage examples:

	view.pin.topLeft().margin(20)
	view.pin.bottom().marginBottom(20)
	view.pin.left().right().marginHorizontal(20)
	view.pin.topLeft().bottomRight().margin(10, 12, 0, 12)

PinLayout margin rules

The following section explains how CSS/PinLayout margin rules are applied.

When and how horizontal margins are applied in PinLayout?

This table explains how and when left and right margins are applied depending on which view’s attribute has been pinned using PinLayout.

NOTE: - indicates that the margin is not applied.

When and how does vertical margins are applies in PinLayout?

This table explains how and when top and bottom margins are applied depending on which view’s attribute has been pinned using PinLayout.

Margin examples

Example 1:

In this example, only the left margin is applied

	view.pin.left().margin(10)

Example 2:

In this example, only the right margin is applied

	view.pin.right().width(100).marginHorizontal(10)

Example 3:

In this example, the left and right margins are applied

	view.pin.left().right().margin(10)

Example 4:

In this example, left, right and top margins are applied. Note that the view’s width has been reduced to apply left and right margins.

	view.pin.topLeft().right().height(100).margin(10)

Example 5:

In this example, left, right, top and bottom margins are applied.

	view.pin.topLeft().bottomRight().margin(10)

pinEdges()

The pinEdges() method pins the four edges (top, left, bottom and right edges) before applying margins.

This method is useful in situations where the width and/or the height attributes have been pinned. This method is an add-on, there is no equivalent in CSS.

Example without pinEdges

Without pinEdges() margins rules would be applied and the view would be moved to the left.

	view.pin.left().width(percent: 100).marginHorizontal(20)

Example with pinEdges

With pinEdges() the left and right margins are applied even if only the left and width has been set. The reason is the call to pinEdges() has pinned the two horizontal edges at their position before applying margins.

	view.pin.left().width(percent: 100).pinEdges().marginHorizontal(20)

NOTE: In that in that particular situation, the same results could have been achieved differently too:

	view.pin.left().right().marginHorizontal(20)

Warnings

PinLayout's warnings

In debug, PinLayout will display warnings when pin rules cannot be applied.

Warning reasons

• The newly pinned attributes conflict with other already pinned attributes.
  Example:
  view.pin.left(10).right(10).width(200)
  👉 Layout Conflict: width(200) won't be applied since it conflicts with the following already set properties: left: 0, right: 10.

• The newly pinned attributes have already been set to another value.
  Example:
  view.pin.width(100).width(200)
  👉 Layout Conflict: width(200) won't be applied since it value has already been set to 100.

• The view being layout hasn’t been added yet into a superview
  Example:
  view.pin.width(100)
  👉 Layout Warning: width(100) won't be applied, the view must be added as a sub-view before being layouted using this method.

• A view is used as a reference, either directly or using its anchors or its edges, but hasn’t been added yet to a superview.
  Example:
  view.pin.left(of: view2)
  👉 Layout Warning: left(of: view2) won't be applied, the view must be added as a sub-view before being used as a reference.

• The width and the height must be non negative values.
  Example:
  view.pin.width(-100)
  👉 Layout Warning: The width (-100) must be greater or equal to 0.

Disabling warnings

Warnings can be disabled in debug mode too by setting the boolean PinLayoutLogConflicts to false.

More examples

Adjust to container size

The following examples show how PinLayout can be used to adjust views size and position to the size of their container. in this case containers are cells.

Cell A:

• A1 is left aligned with a width of 50px
• A2 fills the remaining space

	a1.pin.topLeft().bottom().width(50)
	a2.pin.right(of: a1, aligned: .top).bottomRight().marginLeft(10)

Cell B:

• B2 is right aligned with a fixed width of 50px
• B1 fills the remaining space

	b2.pin.topRight().bottom().width(50)
	b1.pin.left(of: b2, aligned: .top).bottomLeft().marginRight(10)

Cell C:

• C2 is centered with a fixed width of 50px
• C1 fills the remaining left space
• C3 fills the remaining right space

	c2.pin.topCenter().width(50).bottom()
	c1.pin.left(of: c1, aligned: .top).bottomLeft().marginRight(10)
	c3.pin.right(of: c2, aligned: .top).bottomRight().marginLeft(10)

Cell D:

• D1 takes 25% of its container width
• D2 takes 50% of its container width
• D3 fills the remaining space

	d1.pin.topLeft().bottom().width(25%)
	d2.pin.right(of: d1, aligned: .top).bottom().width(50%).marginLeft(10)
	d3.pin.right(of: d2, aligned: .top).bottomRight().marginLeft(10)

Contributing

1. Fork it!
2. Create your feature branch: git checkout -b my-new-feature
3. Commit your changes: git commit -am 'Add some feature'
4. Push to the branch: git push origin my-new-feature
5. Submit a pull request :D

License

BSD 3-Clause License