8 -- 根据颜色生成图片--16进制颜色

1.给UIImage添加分类

+ (UIImage*)oex_imageWithColor:(UIColor*)color size:(CGSize)size {
UIGraphicsBeginImageContextWithOptions(size, NO, 1);

[color setFill];
UIRectFill(CGRectMake(0, 0, 1, 1));

UIImage* result = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return result;
}

+ (UIImage*)oex_imageWithColor:(UIColor*)color {
return [self oex_imageWithColor:color size:CGSizeMake(1, 1)];
}

2.给UIColor添加分类--16进制颜色

- (id)initWithRGBHex:(uint32_t)value alpha:(CGFloat)alpha {
CGFloat r = ((value >> 16) & 0xFF) / 255.;
CGFloat g = ((value >> 8) & 0xFF) / 255.;
CGFloat b = (value & 0xFF) / 255.;
self = [self initWithRed:r green:g blue:b alpha:alpha];
return self;
}


+ (UIColor *) colorWithHexString: (NSString *)color
{
NSString *cString = [[color stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] uppercaseString];

// String should be 6 or 8 characters
if ([cString length] < 6) {
    return [UIColor clearColor];
}

// strip 0X if it appears
if ([cString hasPrefix:@"0X"])
    cString = [cString substringFromIndex:2];
if ([cString hasPrefix:@"#"])
    cString = [cString substringFromIndex:1];
if ([cString length] != 6)
    return [UIColor clearColor];

// Separate into r, g, b substrings
NSRange range;
range.location = 0;
range.length = 2;

//r
NSString *rString = [cString substringWithRange:range];

//g
range.location = 2;
NSString *gString = [cString substringWithRange:range];

//b
range.location = 4;
NSString *bString = [cString substringWithRange:range];

// Scan values
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];
}