Performance with PNG transparency question

design219

I have no idea how the iPhone handles the rapid math and rendering of transparency, but I'm wondering if a any single pixel transparency is treated the same no matter what the value of adjacent transparent pixel values?

What I'm trying to determine is, would a feathered shadow take more memory / performance hit than a shadow that is not feathered, but consistent in transparency value and the same size.

And does the rendering use just as much processing power if it is totally transparent as opposed to an opacity value? In other words, would a shadow be basically the same as complete transparency?

CodeMonkey

I believe if you have an image with a transparency layer compared to one without one, the one without one would have better performance. But I'll need to get back with you.