UIImageView subclass duplicate the image - iphone

Question

I am working on a subclass of UIImageView and one of the things I require is when the object is initalised with the initWithImage: message a 'copy' is created.
I must be confusing something because I can't see what is not working here..
- (id)initWithImage:(UIImage *)image {
[image retain];
if (self = [super initWithImage:image]) {
if (!maskImage) {
maskImage = [UIImage imageWithCGImage:[image CGImage]];
if (maskImage != nil) {
NSLog(#"Made mask image");
} else {
NSLog(#"Failed");
}
//maskImage = [UIImage imageNamed:#"image.png"];
}
}
[image release];
return self;
}
There are no errors when I build this and the maskimage does appear to be created (i do not get the failure message). However, if I uncomment the line allocating from a png it works.
What am I missing?
Thanks!

Answer 1

You should retain created image, in example like this:
- (id)initWithImage:(UIImage *)image {
if (self = [super initWithImage:image]) {
if (!maskImage) {
maskImage = [[UIImage imageWithCGImage:[image CGImage]] retain];
if (maskImage != nil) {
NSLog(#"Made mask image");
} else {
NSLog(#"Failed");
}
}
}
return self;
}

Answer 2

Try this. Should work.
- (id)initWithImage:(NSString *)image {
if (self = [super initWithImage:image]) {
if (!maskImage) {
img = [UIImage imageNamed:image];
maskImage = CGImageRetain(img.CGImage);
if (maskImage != nil) {
NSLog(#"Made mask image");
} else {
NSLog(#"Failed");
}
}
}
return self;
}
Changes
pass NSString instead of image
no need to retain/release image
need to define img, maskImage in .h
maskImage in .h should have retain property set in #property ( e.g.
#property (nonatomic, retain))

Answer 3

First, you should set maskImage to nil, to make sure it isn't garbage:
self.maskImage=nil;
That may screwing up your line (if not now, then later):
if(!imaskImage)
Then, to make a copy, just implement NSCopying in a UIImage subclass. It's easy to do. Then you can type:
maskImage = [image copy];
Alternatively, you can convert the image to data, archive, then unarchive, then convert back to a UIImage. This gives you a complete copy of the image. It's a little more complex, but its the same method used for making deep copies of an object graph.