OC 颜色宏

  平常用的颜色宏大概如下

1
#define RGBHex(rgbValue) [UIColor colorWithRed:((float)((rgbValue & 0xFF0000) >> 16))/255.0 green:((float)((rgbValue & 0xFF00) >> 8))/255.0 blue:((float)(rgbValue & 0xFF))/255.0 alpha:1.0]

  考虑到蓝湖中获得的十六进制颜色值为0xFF0000,手写时需要多写0x,想省略这部分

  C语言宏中’#’称之为字符串化操作符(Stringizing Operator),它将函数宏的实际参数转换为对应的字符串常量。利用这个特点定义如下的颜色宏

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
#define HEXA(COLOR,A) ({ \
char *color = #COLOR;\
NSString *colorString = [NSString stringWithUTF8String:color]; \
colorString = [colorString stringByReplacingOccurrencesOfString:@"#" withString:@""]; \
colorString = [colorString stringByReplacingOccurrencesOfString:@"0x" withString:@""]; \
unsigned int red,green,blue; \
NSRange range; \
range.length = 2; \
range.location = 0; \
[[NSScanner scannerWithString:[colorString substringWithRange:range]] scanHexInt:&red]; \
range.location = 2; \
[[NSScanner scannerWithString:[colorString substringWithRange:range]] scanHexInt:&green]; \
range.location = 4; \
[[NSScanner scannerWithString:[colorString substringWithRange:range]] scanHexInt:&blue]; \
[UIColor colorWithRed:red/255.0f green:green/255.0f blue:blue/255.0f alpha:A]; \
})

#define HEX(COLOR) HEXA(COLOR,1.0)

  支持0xFF0000/#FF0000/FF0000这三种格式