YACachedLayer

A caching Core Animation layer

About

YACachedLayer is a CALayer subclass that can be used to cache complex draws to disk. It supports preloading on a background thread and caching different states of the same layer.

How to use

Include YACachedLayer in your project and use it as backing for a UIView.

@implementation CachedView

+ (Class)layerClass {
  return [YACachedLayer class];
}

- (id)initWithFrame:(CGRect)frame {
  self = [super initWithFrame:frame];
  if (self) {
    ((YACachedLayer *)self.layer).cacheKey = @"MyCacheKey";
  }
  return self;
}

- (void)drawRect:(CGRect)rect {
  // do some drawing
}

@end

For more complex draws you can subclass it like you would any normal CALayer

@implementation ExampleLayer

- (void)drawInContext:(CGContextRef)context {
  [[UIColor redColor] setFill];
  CGContextFillRect(context, self.bounds);
}

@end

You can also implement formattedValueForKey: to cache multiple states of the layer. Check the source and the example project for more details.

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Made by Johan Nordberg and licensed under the MIT-License