A small Clojure(Script) library for reading and writing Netpbm format. Supports plain text formats: p1 (.pbm), p2 (.pgm) and p3 (.ppm).
Good explanation of the format can be found here and here.
Some code samples:
;; read the pbm format
(require '[clj-pnm.core :as pnm])
=> nil
(def pbm
"P1
2
2
1 1
1 1")
=> #'user/pbm
(pnm/read-pnm pbm)
=> {:type :p1, :width 2, :height 2, :map [[1 1] [1 1]]}
;; read the *pgm* format
(def pgm
"P2
3
2
4 # this is the maximum value
1 2 3
4 3 2")
=> #'user/pgm
(pnm/read-pnm pgm)
=> {:type :p2,
:width 3,
:height 2,
:max-value 4,
:map [[1 2 3] [4 3 2]]
:comments ("4 this is the maximum value")} ; prettified
;; read the *ppm* format
(def ppm
"P3
2
2
255
# A ppm comment
255 0 255 128 52 123
0 0 0 45 45 45")
=> #'user/ppm
(pnm/read-pnm ppm)
=> {:type :p3
:width 2
:height 2
:max-value 255
:map [[(255 0 255) (128 52 123)]
[(0 0 0) (45 45 45)]]
:comments ("A ppm comment")} ; prettified
The Clojure version can write Netpbm format to a file:
(pnm/write-pnm {:type :p1 :width 1 :height 1 :map [[1]]} "out.pbm")
=> ...out.pbm file...
(slurp *1)
=> "P1
1
1
1" ;prettified
[Edited 20.06.2023.]
clj-pnm is now available on Clojars.
For more info and more examples check out the repo.