The cropmask.XXX file provides a mask for cropped lev1
images with image configuration id XXX.  The mask is
a 1D byte array containing a zero at addresses corresponding
to pixels outside the crop radius and a one otherwise.  (The
pixel addresses start with zero at the lower left corner of
the image.)

The code below reads a lev0 crop table on stdin and writes
the lev1 cropmask on stdout.  It is for 4-port read-out,
two-row and two-column overscan configurations only; minor
changes will be needed for other configurations.


============= /home/kehcheng/work/hmicomp/makecropmask.c ==============

#include <stdio.h>

char mask[16777216];

main()
{
    int cropid, width, height, skip, take, i, j;

    memset(mask,0,16777216);

    scanf("%d", &cropid);
    scanf("%d", &width);
    scanf("%d", &height);

    for (i=0; i< 2048; ++i) {
	scanf("%d %d", &skip, &take);
	for (j=0; j<take; ++j)
	    mask[i*4096l+skip+j]=1;
    }
    for (i=0; i< 2048; ++i) {
	scanf("%d %d", &skip, &take);
	for (j=0; j<take; ++j)
	    mask[i*4096l+4095-skip-j]=1;
    }
    for (i=0; i< 2048; ++i) {
	scanf("%d %d", &skip, &take);
	for (j=0; j<take; ++j)
	    mask[(4095-i)*4096l+4095-skip-j]=1;
    }
    for (i=0; i< 2048; ++i) {
	scanf("%d %d", &skip, &take);
	for (j=0; j<take; ++j)
	    mask[(4095-i)*4096l+skip+j]=1;
    }

    fwrite(mask,1,16777216,stdout);
}