将两张图片重叠后显示为新图片

想要实现两张图片重叠后显示为新突破，但是运行后模拟器什么也没显示

代码如下：

- (void)viewDidLoad
{
    [super viewDidLoad];

    image1 = [[UIImage alloc]init];

    image1 = [UIImage imageNamed:@"iphone.png"];

    imageA = [[UIImageView alloc]initWithImage:image1];


    [self merge];

}

-(void)merge
{
  CGSize size = CGSizeMake(320, 480);
    UIGraphicsBeginImageContext(size);

    CGPoint thumbPoint = CGPointMake(0,0);
    imageview.image = imageA.image;
    [imageA.image drawAtPoint:thumbPoint];

    imageB = [[UIImage alloc]init];

    imageB = [UIImage imageNamed:@"Favorites.png"];

    CGPoint starredPoint = CGPointMake(0, 0);
    [imageB drawAtPoint:starredPoint];

    UIImage *imageC = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    imageview.image = imageC;

    [self.view addSubview:imageview];

}

请高手指点，问题出在哪了？谢谢

把你所有地方merge里面的代码换成下面的：

-(void)merge
{
    CGSize size = CGSizeMake(320, 480);
    UIGraphicsBeginImageContext(size);

    CGPoint point1 = CGPointMake(0,0);
   //两张图像必须有不同点，不然看不来是重叠
    CGPoint point2 = CGPointMake(100,100);

    UIImage *imageOne = [UIImage imageNamed:@"Image1.png"];
    [imageOne drawAtPoint:point1];



    UIImage *imageTwo = [UIImage imageNamed:@"Image2.png"];
  // 如果需要两张图片混搭，可以添加类似如下代码
  //  [imageTwo drawAtPoint:point2 blendMode:kCGBlendModeMultiply alpha:0.5];

    [imageTwo drawAtPoint:point2];


    UIImage *imageC = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    UIImageView *iv = [[UIImageView alloc] initWithFrame:CGRectMake(100,100,200,200)];
    iv.image=imageC;

    [self.view addSubview:iv];


}