iOS学习-UIColor

//
//  ViewController.m
//  UIColor详解
//
//  Created by 大欢 on 16/1/18.
//  Copyright © 2016年 bjsxt. All rights reserved.
//

#import "ViewController.h"
#import "UIColor+HEX.h"

#define RGBA(r,g,b,a) [UIColor colorWithRed:(r)/255.f green:(g)/255.f blue:(b)/255.f alpha:(a)];

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor orangeColor];
    
    UIView * v = [[UIView alloc] initWithFrame:CGRectMake(100, 100, 200, 200)];
    
    v.backgroundColor = [UIColor greenColor];
    
//    图片转换color
    //[UIColor colorWithPatternImage:[UIImage imageNamed:@"haha"]];
    
//    saturation饱和度 brightness亮度
    //[UIColor colorWithHue:0.4 saturation:1 brightness:1 alpha:1];
    //[UIColor colorWithHex:0x228942];
    
    //[UIColor colorWithHexString:@"#228942"];
    
    //RGBA(124, 172, 226, 1);
    
//#228942
    
    //区间0 ~ 1
    //[UIColor colorWithRed:124/255.f green:172/255.f blue:226/255.f alpha:1];
    //灰度颜色0 ~ 1
    //[UIColor colorWithWhite:1 alpha:1];
    //[UIColor grayColor];     
    [self.view addSubview:v];
}
@end

//
//  UIColor+HEX.h
//  IOS-Categories
//
//  Created by Jakey on 14/12/15.
//  Copyright (c) 2014年 www.skyfox.org. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface UIColor (HEX)
+ (UIColor *)colorWithHex:(UInt32)hex;
+ (UIColor *)colorWithHex:(UInt32)hex andAlpha:(CGFloat)alpha;
+ (UIColor *)colorWithHexString:(NSString *)hexString;
- (NSString *)HEXString;
@end

//
//  UIColor+HEX.m
//  IOS-Categories
//
//  Created by Jakey on 14/12/15.
//  Copyright (c) 2014年 www.skyfox.org. All rights reserved.
//

#import "UIColor+HEX.h"

CGFloat colorComponentFrom(NSString *string, NSUInteger start, NSUInteger length) {
    NSString *substring = [string substringWithRange:NSMakeRange(start, length)];
    NSString *fullHex = length == 2 ? substring : [NSString stringWithFormat: @"%@%@", substring, substring];
    
    unsigned hexComponent;
    [[NSScanner scannerWithString: fullHex] scanHexInt: &hexComponent];
    return hexComponent / 255.0;
}

@implementation UIColor (HEX)
+ (UIColor *)colorWithHex:(UInt32)hex{
    return [UIColor colorWithHex:hex andAlpha:1];
}
+ (UIColor *)colorWithHex:(UInt32)hex andAlpha:(CGFloat)alpha{
    return [UIColor colorWithRed:((hex >> 16) & 0xFF)/255.0
                           green:((hex >> 8) & 0xFF)/255.0
                            blue:(hex & 0xFF)/255.0
                           alpha:alpha];
}

+ (UIColor *)colorWithHexString:(NSString *)hexString {
    CGFloat alpha, red, blue, green;
    
    NSString *colorString = [[hexString stringByReplacingOccurrencesOfString:@"#" withString:@""] uppercaseString];
    switch ([colorString length]) {
        case 3: // #RGB
            alpha = 1.0f;
            red   = colorComponentFrom(colorString, 0, 1);
            green = colorComponentFrom(colorString, 1, 1);
            blue  = colorComponentFrom(colorString, 2, 1);
            break;
            
        case 4: // #ARGB
            alpha = colorComponentFrom(colorString, 0, 1);
            red   = colorComponentFrom(colorString, 1, 1);
            green = colorComponentFrom(colorString, 2, 1);
            blue  = colorComponentFrom(colorString, 3, 1);
            break;
            
        case 6: // #RRGGBB
            alpha = 1.0f;
            red   = colorComponentFrom(colorString, 0, 2);
            green = colorComponentFrom(colorString, 2, 2);
            blue  = colorComponentFrom(colorString, 4, 2);
            break;
            
        case 8: // #AARRGGBB
            alpha = colorComponentFrom(colorString, 0, 2);
            red   = colorComponentFrom(colorString, 2, 2);
            green = colorComponentFrom(colorString, 4, 2);
            blue  = colorComponentFrom(colorString, 6, 2);
            break;
            
        default:
            return nil;
    }
    return [UIColor colorWithRed:red green:green blue:blue alpha:alpha];
}

- (NSString *)HEXString{
    UIColor* color = self;
    if (CGColorGetNumberOfComponents(color.CGColor) < 4) {
        const CGFloat *components = CGColorGetComponents(color.CGColor);
        color = [UIColor colorWithRed:components[0]
                                green:components[0]
                                 blue:components[0]
                                alpha:components[1]];
    }
    if (CGColorSpaceGetModel(CGColorGetColorSpace(color.CGColor)) != kCGColorSpaceModelRGB) {
        return [NSString stringWithFormat:@"#FFFFFF"];
    }
    return [NSString stringWithFormat:@"#%02X%02X%02X", (int)((CGColorGetComponents(color.CGColor))[0]*255.0),
            (int)((CGColorGetComponents(color.CGColor))[1]*255.0),
            (int)((CGColorGetComponents(color.CGColor))[2]*255.0)];
}
@end