ppmfade(1) on Linux
The text 326fc1869157, as Debian 13 (Trixie), Debian 12 (Bookworm) shipped it.
generate a transition between two image files using special effects
Flags it lists
-
-base -
-bentley -
-block -
-edge -
-f -
-l -
-mix -
-oil -
-relief -
-shift -
-spread