Does iPhone support per pixel alpha?

Question

I am finding a way to draw image with per pixel alpha using UIView on iphone, any one have tried that?

Answer 1

This is possible. I'm assuming you are using a UIImageView to display the image? Just make sure that the background colour of your view is set to clear and that Opaque is set to false.

Answer 2

Yes.

You can back an UIView with an RGBA bitmap of the same size where every pixel has it's own 8 bits of alpha channel.

Unless you specify otherwise (by scaling or using a transform, etc.), a generic UIView uses a CALayer backed by such a bitmap.