pnm decoding and encoding
| ofs | hex dump | ascii |
|---|---|---|
| 0000 | 50 37 0a 57 49 44 54 48 20 32 30 0a 48 45 49 47 48 54 20 31 35 0a 44 45 50 54 48 20 32 0a 4d 41 | P7.WIDTH.20.HEIGHT.15.DEPTH.2.MA |
| 0020 | 58 56 41 4c 20 32 35 35 0a 54 55 50 4c 54 59 50 45 20 47 52 41 59 53 43 41 4c 45 5f 41 4c 50 48 | XVAL.255.TUPLTYPE.GRAYSCALE_ALPH |
| 0040 | 41 0a 45 4e 44 48 44 52 0a 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | A.ENDHDR........................ |
| 0060 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................................ |
| 0080 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ff | ................................ |
| 00a0 | ff ff ff ff ff ff ff 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................................ |
| 00c0 | 00 00 00 00 00 00 00 ff ff 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................................ |
| 00e0 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ff ff 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................................ |
| 0100 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ff ff ff ff ff ff 00 00 ff ff 00 | ................................ |
| 0120 | 00 ff ff ff ff ff ff ff ff ff ff 00 00 ff ff ff ff ff ff ff ff 00 00 00 00 00 00 00 00 00 00 ff | ................................ |
| 0140 | ff 00 00 00 00 00 00 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 00 00 ff ff 00 00 00 | ................................ |
| 0160 | 00 00 00 00 00 00 00 ff ff 00 00 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 | ................................ |
| 0180 | 00 00 00 ff ff 00 00 00 00 00 00 00 00 00 00 ff ff 00 00 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 | ................................ |
| 01a0 | 00 ff ff 00 00 ff ff 00 00 00 00 ff ff 00 00 00 00 00 00 00 00 00 00 ff ff 00 00 00 00 ff ff 00 | ................................ |
| 01c0 | 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff ff ff ff ff ff ff 00 00 00 00 00 00 00 00 00 00 00 | ................................ |
| 01e0 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ff ff 00 00 00 | ................................ |
| 0200 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................................ |
| 0220 | 00 00 00 ff ff 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................................ |
| 0240 | 00 00 00 00 00 ff ff ff ff ff ff ff ff 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................................ |
| 0260 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................................ |
| 0280 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................................ |
| 02a0 | 00 | . |