Module pbm 

Netpbm P4 (binary PBM) encoder.

PBM stores 1-bit monochrome pixels, MSB first, rows padded to whole bytes. Only Gray8 / Mono8 bitmaps are accepted; 0 maps to white (0 bit), non-zero maps to black (1 bit), per the P4 spec.

Functions

write_pbm

Write bitmap to out as a binary PBM (P4) image.