oc代码 创建一个纯白的UIImage

以下是Swift代码：

let size = CGSize(width: 100, height: 100)
UIGraphicsBeginImageContextWithOptions(size, false, 0.0)
UIColor.white.setFill()
UIRectFill(CGRect(origin: CGPoint.zero, size: size))
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()

以下是Objective-C代码：

CGSize size = CGSizeMake(100, 100);
UIGraphicsBeginImageContextWithOptions(size, NO, 0.0);
[[UIColor whiteColor] setFill];
UIRectFill(CGRectMake(0, 0, size.width, size.height));
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();