What's an efficient way to tell if a bitmap is entirely black?

Question

I\'m wondering if there\'s a super-efficient way of confirming that an Image object references an entirely black image, so every pixel within the bitmap is ARGB(255, 0, 0, 0).

Answer 1

If you knew more about the conditions under which the image would be non-black, it would be easier. For example, what do the edges or center of the image look like when it's non-black. Essentially, what you create is heuristic to guess at a non-black image and sample those areas that will give you the quickest read on it. If your heuristic indicates a all-black image, then you can either decide that it is all-black or do a full check of all pixels. That's heavily dependent on your images, though. If you have to be able to distinguish between an all-black image and one containing a single non-black pixel in a random location, you'll have to check them all.