iOS UIImageView图片自动拉伸功能

- (void)viewDidLoad

{

  [super viewDidLoad];

  UIImage *smallImage = [UIImage imageNamed:@"hc_03.png"]; 

  UIImageView *imageView = [[UIImageView alloc] initWithImage:smallImage];

  [imageView setFrame:CGRectMake(0, 20, 320, 44)];

  imageView.contentMode = UIViewContentModeScaleToFill;

  [self.view addSubview:imageView];

  [imageView release];

}