函数将颜色转化为图片+16进制色值使用 + 渐变色生成

将颜色转为图片

- (UIImage *)imageWithColor:(UIColor *)color {
    CGRect rect = CGRectMake(0.0f, 0.0f, 1.0f, 1.0f);
    UIGraphicsBeginImageContext(rect.size);
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSetFillColorWithColor(context, [color CGColor]);
    CGContextFillRect(context, rect);    
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

16进制色值使用：

* 宏定义使用
/** 颜色宏定义 */
#define UIColorFromHex(hexValue) [UIColor colorWithRed:((float)((hexValue & 0xFF0000) >> 16))/255.0 green:((float)((hexValue & 0xFF00) >> 8))/255.0 blue:((float)(hexValue & 0xFF))/255.0 alpha:1.0]


* 方法使用
#pragma mark - hex string convert to color object
+ (UIColor *) colorWithHexString:(NSString *)hexString{
    NSString *cString = [[hexString stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] uppercaseString];
    //hexString should six-eight character
    if ([cString length] < 6) {
        return [UIColor clearColor];
    }
    //if hexString has @"0X" prefix
    if ([cString hasPrefix:@"0X"])
        cString = [cString substringFromIndex:2];
    //if hexString has @"#"" prefix
    if ([cString hasPrefix:@"#"])
        cString = [cString substringFromIndex:1];
    // 如果hexString 有@"..FF"后缀...必须是在cString.length长度大于6的情况下
    if (cString.length > 6) {
        if ([cString hasSuffix:@"FF"]) {
            cString = [cString substringToIndex:cString.length-2];
        }
    }
    if ([cString length] != 6)
        return [UIColor clearColor];
    //RGB exchange
    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];
    // unsigned int object
    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];
}

渐变色生成

#pragma mark - gradient color--渐变色生成
/**
 return `CAGradienLayer*`
 [sysView.layer addSublayer:##CAGradientLayer##]; //添加layer
 */
+ (CAGradientLayer *)setGradualChangingColor:(CGRect)gradientLayerFrame fromColor:(NSString *)fromHexColorStr toColor:(NSString *)toHexColorStr {
    
    //    CAGradientLayer类对其绘制渐变背景颜色、填充层的形状(包括圆角)
    CAGradientLayer *gradientLayer = [CAGradientLayer layer];
    gradientLayer.frame = gradientLayerFrame;
    
    //  创建渐变色数组，需要转换为CGColor颜色
    gradientLayer.colors = @[(__bridge id)[self colorWithHexString:fromHexColorStr].CGColor,(__bridge id)[self colorWithHexString:toHexColorStr].CGColor];
    
    //  设置渐变颜色方向，左上点为(0,0), 右下点为(1,1)
    gradientLayer.startPoint = CGPointMake(0, 0);
    gradientLayer.endPoint = CGPointMake(1, 1);
    
    //  设置颜色变化点，取值范围 0.0~1.0
    gradientLayer.locations = @[@0,@1];
    
    return gradientLayer;
}