Image剪裁到指定尺寸

- (UIImage *)clipImage:(UIImage *)image toSize:(CGSize)size {

UIGraphicsBeginImageContextWithOptions(size, YES, [UIScreen mainScreen].scale);

CGSize imgSize = image.size;

CGFloat x = MAX(size.width / imgSize.width, size.height / imgSize.height);

CGSize resultSize = CGSizeMake(x * imgSize.width, x * imgSize.height);

[image drawInRect:CGRectMake(0, 0, resultSize.width, resultSize.height)];

UIImage *finalImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return finalImage;

}