UIRotationGestureRecognizer Class
| Inherits from | |
| Conforms to | |
| Framework | /System/Library/Frameworks/UIKit.framework |
| Availability | Available in iOS 3.2 and later. |
| Companion guide | |
| Declared in | UIRotationGestureRecognizer.h |
Overview
UIRotationGestureRecognizer is a concrete subclass of UIGestureRecognizer that looks for rotation gestures involving two touches. When the user moves the fingers opposite each other in a circular motion, the underlying view should rotate in a corresponding direction and speed.
Rotation is a continuous gesture. It begins when two touches have moved enough to be considered a rotation. The gesture changes when a finger moves while the two fingers are down. It ends when both fingers have lifted. At each stage in the gesture, the gesture recognizer sends its action message.
Properties
rotation
The rotation of the gesture in radians.
Discussion
You may set the rotation value to an arbitrary value; however, setting the rotation resets the velocity.
The rotation value is a single value that varies over time. It is not the delta value from the last time that the rotation was reported. Apply the rotation value to the state of the view when the gesture is first recognized—do not concatenate the value each time the handler is called.
Availability
- Available in iOS 3.2 and later.
Declared In
UIRotationGestureRecognizer.hvelocity
The velocity of the rotation gesture in radians per second. (read-only)
Availability
- Available in iOS 3.2 and later.
Declared In
UIRotationGestureRecognizer.h© 2012 Apple Inc. All Rights Reserved. (Last updated: 2012-09-19)