How do I create a mutable array of CGImageRefs?

Question

I want to keep a mutable collection of CGImageRefs. Do I need to wrap them in NSValue, and if so how do I wrap and unwrap them properly? Can I get away with using a C array? If so how do I construct it and how do I add elements to it later? Is it significantly more costly to use UIImages instead of CGImageRefs as the elements of the collection?

Answer 1

You can directly add CGImage to NSMutableArray. You will need to cast to (id) to avoid compiler warnings.

CFType is bridged to NSObject. You can send any message NSObject responds to to any CFType. In particular, -retain and -release work as normal.

Answer 2

2011: just in case someone's still looking You can wrap CGImageRef in NSValues by using

+ (NSValue *)valueWithBytes:(const void *)value objCType:(const char *)type

hence:

CGImageRef cgImage = [self cgImageMethod];
NSValue *cgImageValue = [NSValue valueWithBytes:&cgImage objCType:@encode(CGImageRef)];
[array addObject:cgImageValue];

to retrieve:

CGImageRef retrievedCGImageRef;
[[array objectAtIndex:0] getValue:&retrievedCGImageRef ];

hope this helps somebody