iPhone - UIImage Leak, ObjectAlloc Building

Question

Alright I am having a world of difficulty tracking down this memory leak. When running this script I do not see any memory leaking, but my objectalloc is climbing. Instruments points to CGBitmapContextCreateImage > create_bitmap_data_provider > malloc, this takes up 60% of my objectalloc.

This code is called several times with a NSTimer.

How do I clear that reUIImage after I return it?

...or How can I make it so that UIImage imageWithCGImage does not build my ObjectAlloc?

    //I shorten the code because no one responded to another post
    //Think my ObjectAlloc is building up on that retUIImage that I am returning
    //**How do I clear that reUIImage after the return?**

-(UIImage) functionname {
    //blah blah blah code
    //blah blah more code

    UIImage *retUIImage = [UIImage imageWithCGImage:cgImage];
            CGImageRelease(cgImage);

            return retUIImage;
    }

Answer 1

this method you use instantiates a UIImage and sets it as autorelease. If you want to cleanup these, you will need to empty the pool periodically

NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
..
..
..
[pool release];

Note that these can be nested:

NSAutoreleasePool *pool1 = [[NSAutoreleasePool alloc] init];
NSAutoreleasePool *pool2 = [[NSAutoreleasePool alloc] init];
..
..
..
[pool2 release];
[pool1 release];

Common practice is to place these around for loops and other methods that make many autoreleased objects.

NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
for (Thing *t in things) {
  [thing doAMethodThatAutoreleasesABunchOfStuff];
}
[pool release]