iOS中替UIColor创建类别 其中添加了几个常用的方法

//  UIColor+UIColor_HexConvert.h

#import

@interface UIColor (HexConvert)

+(UIColor *)colorFromHexString:(NSString*)colorString;

+(NSString*)stringFromColor:(UIColor*)color;

-(void)getRGBComponents:(CGFloat [3])components;

@end

//  UIColor+UIColor_HexConvert.m

#import "UIColor+HexConvert.h"

@implementation UIColor (HexConvert)

+(UIColor *)colorFromHexString:(NSString *)colorString

{

    NSString *cString = [[colorString stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] uppercaseString];

    

    

    if ([cString length] < 6)

        return [UIColor whiteColor];

    if ([cString hasPrefix:@"#"])

        cString = [cString substringFromIndex:1];

    if ([cString length] != 6)

        return [UIColor whiteColor];

    

    NSRange range;

    range.location = 0;

    range.length = 2;

    NSString *rString = [cString substringWithRange:range];

    

    range.location = 2;

    NSString *gString = [cString substringWithRange:range];

    

    range.location = 4;

    NSString *bString = [cString substringWithRange:range];

    

    

    unsigned int r, g, b;

    [[NSScanner scannerWithString:rString] scanHexInt:&r];

    [[NSScanner scannerWithString:gString] scanHexInt:&g];

    [[NSScanner scannerWithString:bString] scanHexInt:&b];

    

    return [UIColor colorWithRed:((float) r / 255.0f)

                           green:((float) g / 255.0f)

                            blue:((float) b / 255.0f)

                           alpha:1.0f];

}

+(NSString *)stringFromColor:(UIColor *)color

{

    const CGFloat *cs=CGColorGetComponents(color.CGColor);

    

    

    NSString *r = [NSString stringWithFormat:@"%@",[self  ToHex:cs[0]*255]];

    NSString *g = [NSString stringWithFormat:@"%@",[self  ToHex:cs[1]*255]];

    NSString *b = [NSString stringWithFormat:@"%@",[self  ToHex:cs[2]*255]];

    return [NSString stringWithFormat:@"#%@%@%@",r,g,b];

}

+(NSString *)ToHex:(int)tmpid

{

    NSString *endtmp=@"";

    NSString *nLetterValue;

    NSString *nStrat;

    int ttmpig=tmpid%16;

    int tmp=tmpid/16;

    switch (ttmpig)

    {

        case 10:

            nLetterValue =@"A";break;

        case 11:

            nLetterValue =@"B";break;

        case 12:

            nLetterValue =@"C";break;

        case 13:

            nLetterValue =@"D";break;

        case 14:

            nLetterValue =@"E";break;

        case 15:

            nLetterValue =@"F";break;

        default:nLetterValue=[[NSString alloc]initWithFormat:@"%i",ttmpig];

            

    }

    switch (tmp)

    {

        case 10:

            nStrat =@"A";break;

        case 11:

            nStrat =@"B";break;

        case 12:

            nStrat =@"C";break;

        case 13:

            nStrat =@"D";break;

        case 14:

            nStrat =@"E";break;

        case 15:

            nStrat =@"F";break;

        default:nStrat=[[NSString alloc]initWithFormat:@"%i",tmp];

            

    }

    endtmp=[[NSString alloc]initWithFormat:@"%@%@",nStrat,nLetterValue];

    return endtmp;

}

- (void)getRGBComponents:(CGFloat [3])components

{

    CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();

    unsigned char resultingPixel[4];

    CGContextRef context = CGBitmapContextCreate(&resultingPixel,

                                                 1,

                                                 1,

                                                 8,

                                                 4,

                                                 rgbColorSpace,

                                                 (CGBitmapInfo)kCGImageAlphaNoneSkipLast);

    CGContextSetFillColorWithColor(context, [self CGColor]);

    CGContextFillRect(context, CGRectMake(0, 0, 1, 1));

    CGContextRelease(context);

    CGColorSpaceRelease(rgbColorSpace);

    

    for (int component = 0; component < 3; component++) {

        components[component] = resultingPixel[component] / 255.0f;

    }

}

@end