[grt-talk] CL-PNG

[Nikodemus Siivola]

Just checked: CL-PNG seems to store images in two-dimensional arrays where
each cell is n-byte integer that is decoded in format dependant manner:

24bit, RGB:

 (setf (ldb (byte 8 0) (aref image i j)) (ppm-value (red x)))
 (setf (ldb (byte 8 8) (aref image i j)) (ppm-value (green x)))
 (setf (ldb (byte 8 16) (aref image i j)) (ppm-value (blue x)))

Or so it seemed. CL-JPEG seemed to want if not the same, then at least
something similar.

Cheers,

  -- Nikodemus