[Lazarus] Converting C++ Uint8 to Red,Green,Blue

[Leonardo M. Ramé]

Hi, I'm working with a library that let me get a pointer to an UInt8
array containing the pixels of an image.

To show the image on screen, using Lazarus, I must know the
Red,Green,Blue and Alpha values of each pixel (am I right?), how can I
convert each byte of the UInt8 array to RGBA?

Thanks in advance,
-- 
Leonardo M. Ramé
http://leonardorame.blogspot.com