image-access-pixels-to-bgra copies all the pixels in the Image Access object
into the vector
as a sequence of integer values in the range 0-255 for the blue, green, red and alpha components of each pixel. This function is optimized for the case where
has element type
(unsigned-byte 8). If the image has alpha, the values in
are assumed to be premultiplied.
image-access must be an Image Access object returned by make-image-access.
image-access-pixels-to-bgra to modify an image with alpha using colors that came from elsewhere, you need to premultiply them either by hand (multiply the color values by the alpha), or using color-to-premultiplied.
CAPI User Guide and Reference Manual (Unix version) - 25 Feb 2015