I'm trying to implement a hotspot with a transparency mask. Klaus wrote that the mask image must have an alpha channel. However, I see he used grayscale jpeg images as mask in his example, and when I open darkmask.jpg in Photoshop CS5, I don't see any alpha channel. But the examples works.

However, when I save my own mask image as a grayscale jpeg, and use it in my own project, krpano does not apply the mask. So it seems to really need an alpha channel.

But Photoshop does not allow me to save the alpha channel for jpeg images. The option "Alpha channels" is grayed out. I tried saving as a TIF instead, but krpano chokes on it.

Would anyone know how to do this?

Hmm, it seems I was looking in the wrong examples folder. I looked in "masks", but apparently I needed "masked-radar-textfield-hotspot", and there the mask is a png file. It does not have an alpha channel as known in Photoshop, but rather simple transparency.

So I figured it out: the part that needs to be transparent, should be transparent in png, and the part that should be there, should be white. So it can even be saved as png-8 with just 2 colors.

It's working nicely now

PS. Jarred, I just posted my own observations a few minutes after you, and didn't read your reply in time, but thanks very much. I had been looking at this for 45 min. already, totally puzzled, so decided to post my cry for help, and then of course I figured it out...