//画像にマスクをかける
+ (UIImage *)mask:(UIImage *)image
         withMask:(UIImage *)maskImage
{
    CGImageRef maskRef = maskImage.CGImage;
    CGImageRef mask = CGImageMaskCreate(CGImageGetWidth(maskRef),
                                        CGImageGetHeight(maskRef),
                                        CGImageGetBitsPerComponent(maskRef),
                                        CGImageGetBitsPerPixel(maskRef),
                                        CGImageGetBytesPerRow(maskRef),
                                        CGImageGetDataProvider(maskRef), NULL, false);
    CGImageRef masked = CGImageCreateWithMask([image CGImage], mask);
    return [UIImage imageWithCGImage:masked];
}

- (void)setMaskedImage
{
    //オリジナル画像
    UIImage *contentImage = [Image resize:[Image getUIImageFromResources:@"Pandora_640_1136" ext:@"jpg"]
                                     rect:CGRectMake(0, 0, 320, 568)];

    //マスク画像
    UIImage *maskImage = [Image resize:[Image getUIImageFromResources:@"mask" ext:@"png"]
                                  rect:CGRectMake(0, 0, 320, 568)];

    //マスク適用
    UIImage *maskedImage = [Image mask:contentImage
                              withMask:maskImage];

    //UIImageViewに格納
    UIImageView *maskedImageView = [[UIImageView alloc] initWithImage:maskedImage];

    //画面に追加
    [self.view addSubview:maskedImageView];
}