ppmfade
Generate a transition between two PPM images.
TLDR
Generate a transition between two PPM images ([f]irst and [l]ast) using the specified effect
$ ppmfade -f [path/to/image1.ppm] -l [path/to/image2.ppm] -[mix|spread|shift|relief|oil|...]
Generate a transition starting with the specified image and ending in a solid black image
$ ppmfade -f [path/to/image.ppm] -[mix|spread|shift|relief|oil|...]
Generate a transition starting with a solid black image and ending with the specified image
$ ppmfade -l [path/to/image.ppm] -[mix|spread|shift|relief|oil|...]
Store the resulting images in files named base.NNNN.ppm where NNNN is a increasing number
$ ppmfade -f [path/to/image1.ppm] -l [path/to/image2.ppm] -[mix|spread|shift|relief|oil|...] -base [base]