README.markdown

EGOUICache

Created by enormego

EGOUICache is a collection of functions written on top of EGOCache to cache intensive drawRect: methods. EGOUICache will cache these methods for you, and return a UIImage that you can quickly draw. EGOUICache should not be used in UITableViewCell's with data that is constantly change (like a Twitter app, for example). It's intended to be used in areas where the data is pretty much set, but you need the option for it to change, giving you a dynamically generated, "static" cache.

Methods

EGOUICache is powered by EGOCache, but it's written using C functions since they're faster and speed is what we're trying to achieve here.

• UIImage* EGOUICachedDrawing(id target, SEL selector, CGRect rect, NSString* salt);

  • Caches the selector performed on target, this is the primary function and should be used with UIImage's drawInRect method
  • Parameters
    • target: usually self, target that selector will be performed on
    • selector: selector that will draw the "fresh" content
    • rect: Rect to draw in
    • salt: Unique string for the content in this cached drawing.

• EGOUICacheSetCacheTimeoutInterval(NSTimeInterval cacheTimeoutInterval);

  • This should be called prior to calling EGOUICachedDrawing(), or within it as long as you're not nesting cache calls.
  • Parameters
    • cacheTimeoutInterval number of seconds the cache should persist for
  • Convenience methods
    • EGOUICacheSetCacheTimeoutOneYear();
    • EGOUICacheSetCacheTimeoutOneMonth();
    • EGOUICacheSetCacheTimeoutOneWeek();
    • EGOUICacheSetCacheTimeoutOneDay();
    • EGOUICacheSetCacheTimeoutOneHour();

• EGOUICacheCancel();

  • Cancels one level of caching. This should be called if data hasn't yet loaded or something isn't what it's expected to be. The image returned by EGOUICachedDrawing() will be nil.

Example

Let's say you have a button that gets drawn a bunch of times, that uses intensive blending, and really only needs to be drawn once since the text rarely changes:

- (void)drawRect:(CGRect)rect {
	EGOUICacheSetCacheTimeoutOneMonth();
	[EGOUICachedDrawing(self, @selector(freshDrawRect:), rect, self.currentTitle) drawInRect:rect];
}

- (void)freshDrawRect:(CGRect)rect {
	UIFont* font = [UIFont boldSystemFontOfSize:22.0f];

	CGRect textRect;
	textRect.size = [text sizeWithFont:font];
	textRect.origin.x = floorf((rect.size.width - titleSize.width) / 2);
	textRect.origin.y = floorf((rect.size.height - titleSize.height) / 2) + 1.0f;

	// A bunch of complicated code that draws the text with a gradient, and glow around it, with a 1px shadow
}

The EGOUICachedDrawing() call in drawRect will check to see if it has a cache for the target/selector with the salt being the current title, if it does, it returns the UIImage right away. If it doesn't detect the cache, it calls freshDrawRect:, and then caches and returns an image with the contents drawn in freshDrawRect:.

License

EGOUICache is available under the MIT license:

Copyright (c) 2009-2010 enormego

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.