UIColor Extensions.

UIColor+Extensions.h

@interface UIColor (Extensions)


/**
 Returns a UIColor for a color given in a hexadecimal string format.
 Such as #00FF00.
 */
+ (UIColor *)colorWithHexString:(NSString *)hexString;


/**
 Returns a NSString with a hexadecimal value (HTML/CSS style) of the color.
 Example: "ff8af1".
*/
- (NSString *)hexString;


/**
 Returns a random UIColor.
 */
+ (UIColor *)randomColor;


@end

UIColor+Extensions.m

#import "UIColor+Extensions.h"

@implementation UIColor (Extensions)

/**
 Returns a UIColor for a color given in a hexadecimal string format.
 Such as #00FF00.
 */
+ (UIColor *)colorWithHexString:(NSString *)hexString
{
    unsigned rgbValue = 0;
    
    // Create scanner with given string.
    NSScanner *scanner = [NSScanner scannerWithString:hexString];
    
    // Skip the "#" character (if any).
    [scanner setCharactersToBeSkipped:[NSCharacterSet characterSetWithCharactersInString:@"#"]];
    
    // Get the hex value from string.
    [scanner scanHexInt:&rgbValue];
    
    // Create and return a UIColor.
    return [UIColor colorWithRed:((rgbValue & 0xFF0000) >> 16)/255.0
                           green:((rgbValue & 0xFF00) >> 8)/255.0
                            blue:(rgbValue & 0xFF)/255.0
                           alpha:1.0];
}


/**
 Returns a NSString with a hexadecimal value (HTML/CSS style) of the color.
 Example: "ff8af1".
*/
- (NSString *)hexString
{
    const CGFloat *components = CGColorGetComponents(self.CGColor);
    
    CGFloat r = components[0];
    CGFloat g = components[1];
    CGFloat b = components[2];
    
    return [NSString stringWithFormat:@"%02lX%02lX%02lX",
            lroundf(r * 255),
            lroundf(g * 255),
            lroundf(b * 255)];
}


/**
 Returns a random UIColor.
 */
+ (UIColor *)randomColor
{
    // 0.0 to 1.0
    CGFloat hue = ( arc4random() % 256 / 256.0 );
    
    // 0.5 to 1.0, away from white
    CGFloat saturation = ( arc4random() % 128 / 256.0 ) + 0.5;
    
    // 0.5 to 1.0, away from black.
    CGFloat brightness = ( arc4random() % 128 / 256.0 ) + 0.5;
    
    return [UIColor colorWithHue:hue
                      saturation:saturation
                      brightness:brightness
                           alpha:1];
}


@end