CAConstraintLayoutManager Class Reference

Inherits from
Conforms to
Framework
/System/Library/Frameworks/QuartzCore.framework
Availability
Available in OS X v10.5 and later.
Declared in
CAConstraintLayoutManager.h
Companion guides
Related sample code

Overview

The CAConstraintLayoutManager class provides a constraint-based layout manager. You use the shared instance of this object by assigning it to the layoutManager property of any layer objects to which you have added constraints. During a layout update, Core Animation uses the layout manager to update the size and position of the sublayers based on the registered set of constraints.

Constraints let you define a set of geometric relationships between a layer and its sibling layers or between a layer and its superlayer. These relationships are expressed using constraint objects, which are instances of the CAConstraint class. When creating constraints, you can reference a layer by name using that object’s name property. You can also use the special name superlayer to refer to the layer's superlayer.

This class is not meant to be subclassed.

Tasks

Creating the Layout Manager

Class Methods

layoutManager

Returns the shared layout manager object.

+ (id)layoutManager
Return Value

The shared layout manager object.

Discussion

You can assign the returned object to any layers that manage layout using constraints.

Availability
  • Available in OS X v10.5 and later.
Declared In
CAConstraintLayoutManager.h