bwrect — extract a rectangle from a black and white bw file
Bwrect extracts a rectangular region from a black and white bw(5) format file. The program prompts for the area to extract in x and y pixels, the scanline length of the input file in pixels, and the origin in the input file from which to extract. First quadrant coordinates and file storage format are used.
We ought to allow the questions to be answered on the command line so that shell scripts, etc., could use this.