iOS开发将颜色(UIColor)转为图片(UIImage)

Objective-c 版本

- (nullable UIImage *)imageFromColor: (nonnull UIColor *)color withSize:(CGSize)size {
    
    CGRect rect = CGRectMake(0, 0, size.width, size.height);
    
    UIGraphicsBeginImageContextWithOptions(rect.size, NO, [UIScreen mainScreen].scale);
    
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSetFillColorWithColor(context,color.CGColor);
    CGContextFillRect(context, rect);
    
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    
    return image;
}

Swift 版本

extension UIColor {
    
    func asImage(_ size: CGSize) -> UIImage? {
        
        var resultImage: UIImage? = nil
        let rect = CGRect(x: 0, y: 0, width: size.width, height: size.height)
        UIGraphicsBeginImageContextWithOptions(rect.size, false, UIScreen.main.scale)
        
        guard let context = UIGraphicsGetCurrentContext() else {
            
            return resultImage
        }
        
        context.setFillColor(self.cgColor)
        context.fill(rect)
        resultImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        
        return resultImage
    }
}

使用

let colorImage = UIColor.black.asImage(CGSize(width: 100, height: 100));