Question

I’m creating an bitmap context, and in my code there is this:

bitmapData = malloc(bitmapByteCount);

context = CGBitmapContextCreate (bitmapData,
                                     pixelsWidth,
                                     pixelsHeight,
                                     8,      // bits per component
                                     bitmapBytesPerRow,
                                     colorSpace,
                                     kCGImageAlphaPremultipliedFirst);

before the method returns the CGContextRef object, I think I must release the bitmapData. Can I safely call free(bitmapData) before I return the context?

Answer 1

The documentation for CGBitmapContextCreate says this:

In iOS 4.0 and later, and Mac OS X
v10.6 and later, you can pass NULL if
you want Quartz to allocate memory for
the bitmap. This frees you from
managing your own memory, which
reduces memory leak issues.

I would suggest you pass NULL instead of a malloc’d pointer and you will be free of worrying about its memory.

However, be mindful that CGBitmapContextCreate has ‘create’ in its name, so by convention you will own the object returned. You will need to release this at some point with CFRelease().