JPSDisplayLink provides an easy, block interface to CADisplayLink-based animations.

This is ideal for animating properties that don't support UIView-based animations like font size on a UILabel or UITextView.

Installation

Manually

Important note if your project doesn't use ARC: you must add the -fobjc-arc compiler flag to JPSDisplayLink.m in Target Settings > Build Phases > Compile Sources.

Drag the JPSDisplayLink/JPSDisplayLink folder into your project.

Usage

JPSDisplayLink only has one class method:

typedef void (^JPSDisplayLinkBlock)(CGFloat progress);

+ (void)runDisplayLinkBlock:(JPSDisplayLinkBlock)block duration:(CFTimeInterval)duration;

A JPSDisplayLink object will be created and implicitly retained for the duration specified, then it is automatically released.

Make sure you follow proper block etiquette when using JPSDisplayLinkBlock: for example, avoid retain cycles.

Easing

Add easing to your JPSDisplayLink animations by manipulating the progress parameter in your animation block.

For example, to animate a font size with cubic ease in/out, add AHEasing to your project and use the following code:

[JPSDisplayLink runDisplayLinkBlock:^(CGFloat progress) {
    CGFloat easedProgress = CubicEaseInOut(progress);
    weakLabel.font = [UIFont boldSystemFontOfSize:12.0f + easedProgress*16.0f];
} duration:5.0f];

Demo

See sample Xcode project in /JPSDisplayLinkDemo.

Here's a GIF of the demo app in action. Note that the GIF's framerate is much slower than in reality.

License

This project is under the MIT license.