UIColor contrast additions

UIColor+ContrastAdditions.h

//
//  UIColor+ContrastAdditions
//
//  Created by Brandon Titus (bjtitus.net) on 10/26/12.
//
//

#import <UIKit/UIKit.h>

#import "UIColor-Expanded.h"
//  Clone it from here:
//  http://github.com/ars/uicolor-utilities

@interface UIColor (ContrastAdditions)

//Uses the Hex color values to tell you whether this UIColor contrasts well with black
-(BOOL)contrastsBlack50;

// Converts the color components to YIQ http://en.wikipedia.org/wiki/YIQ and tells you whether this UIColor contrasts well with black
-(BOOL)contrastsBlackYIQ;

@end

UIColor+ContrastAdditions.m

//
//  UIColor+ContrastAdditions.m
//
//  Created by Brandon Titus (bjtitus.net) on 10/26/12.
//
//  Released into the public domain
//  Original idea: http://24ways.org/2010/calculating-color-contrast

#import "UIColor+ContrastAdditions.h"

@implementation UIColor (ContrastAdditions)

-(BOOL)contrastsBlack50
{
    return ([self rgbHex] > 0xffffff/2);
}

-(BOOL)contrastsBlackYIQ
{
    float yiq = (((self.red*256)*299) + ((self.green*256)*587) + ((self.blue*256)*114))/1000;
    return (yiq >=128);
}

@end