Is there anything in the IPP that will accomplish using the Alpha channel of RGBA image to overlay the RGB components onto an RGB image or to a new image? I've taken a look at the ippiAlphaComp() functions, but they do not seem to allow mixing of C4R and C3R.
Basically looking for this:
SourceB = RGB image
SourceO = RGBA image
= (SourceO x SourceO ) + (SourceB)) SourceB x (255 - SourceO = (SourceOx SourceO ) + (SourceB)) SourceB = (SourceO x SourceO) + (SourceB x (255 - SourceO)) x (255 - SourceO
yes, mixing in this case doesn't work. Possible way is to convert C3 image to AC4 (ippiCopy_8u_C3AC4R), fill A channel with "1" and then use ippAlphaOver function that applies aA*A+(1-aA)*aB*B formula. I guess it will be too expensive from the performance point of view and it's better to use the simple loop in your code.
I ended up asking a similar question on stackoverflow, here is the link that will hopefully aid someone else.