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/******************************************************************************
hdifftopam
*******************************************************************************
This program recovers a PAM image from a horizontal difference images
such as created by Pamtohdiff.
By Bryan Henderson, San Jose, CA 2002.04.15.
******************************************************************************/
#include <string.h>
#include <stdio.h>
#include "pm_c_util.h"
#include "pam.h"
#include "shhopt.h"
#include "nstring.h"
struct cmdlineInfo {
/* All the information the user supplied in the command line,
in a form easy for the program to use.
*/
const char *inputFilespec; /* Filespecs of input files */
unsigned int pnm;
unsigned int verbose;
};
static void
parseCommandLine(int argc, char ** argv,
struct cmdlineInfo * const cmdlineP) {
/*----------------------------------------------------------------------------
Note that the file spec array we return is stored in the storage that
was passed to us as the argv array.
-----------------------------------------------------------------------------*/
optEntry *option_def = malloc( 100*sizeof( optEntry ) );
/* Instructions to pm_optParseOptions3 on how to parse our options.
*/
optStruct3 opt;
unsigned int option_def_index;
option_def_index = 0; /* incremented by OPTENTRY */
OPTENT3(0, "pnm", OPT_FLAG, NULL, &cmdlineP->pnm, 0);
OPTENT3(0, "verbose", OPT_FLAG, NULL, &cmdlineP->verbose, 0);
opt.opt_table = option_def;
opt.short_allowed = FALSE; /* We have no short (old-fashioned) options */
opt.allowNegNum = FALSE; /* We have no parms that are negative numbers */
pm_optParseOptions3(&argc, argv, opt, sizeof(opt), 0);
/* Uses and sets argc, argv, and some of *cmdlineP and others. */
if (argc-1 < 1)
cmdlineP->inputFilespec = "-";
else if (argc-1 == 1)
cmdlineP->inputFilespec = argv[1];
else
pm_error("Too many arguments.");
}
static void
makePnm(struct pam * const pamP) {
switch (pamP->depth) {
case 1:
pamP->format = PGM_FORMAT;
break;
case 3:
pamP->format = PPM_FORMAT;
break;
default:
pm_error("Input depth (%d) does not correspond to a PNM format.",
pamP->depth);
}
}
static void
describeOutput(struct pam const pam) {
pm_message("Output is %d x %d x %d, maxval %u",
pam.width, pam.height, pam.depth, (unsigned int) pam.maxval);
}
int
main(int argc, char *argv[]) {
FILE *ifP;
struct cmdlineInfo cmdline;
struct pam diffpam, outpam;
unsigned int row;
tuple * diffrow;
tuple * outrow;
tuple * prevrow;
pnm_init(&argc, argv);
parseCommandLine(argc, argv, &cmdline);
ifP = pm_openr(cmdline.inputFilespec);
pnm_readpaminit(ifP, &diffpam, PAM_STRUCT_SIZE(tuple_type));
if (diffpam.format != PAM_FORMAT)
pm_error("Input must be a PAM file, not PNM");
else if (!streq(diffpam.tuple_type, "hdiff"))
pm_error("Input tuple type is '%s'. Must be 'hdiff'",
diffpam.tuple_type);
outpam = diffpam;
outpam.file = stdout;
strcpy(outpam.tuple_type, "unhdiff");
if (cmdline.verbose)
describeOutput(outpam);
if (cmdline.pnm)
makePnm(&outpam);
pnm_writepaminit(&outpam);
diffrow = pnm_allocpamrow(&diffpam);
outrow = pnm_allocpamrow(&outpam);
prevrow = pnm_allocpamrow(&diffpam);
pnm_setpamrow(&diffpam, prevrow, 0);
{
unsigned int const bias = diffpam.maxval/2;
for (row = 0; row < diffpam.height; ++row) {
unsigned int col;
pnm_readpamrow(&diffpam, diffrow);
for (col = 0; col < diffpam.width; ++col) {
unsigned int plane;
for (plane = 0; plane < diffpam.depth; ++plane) {
sample const prevSample = prevrow[col][plane];
sample const diffSample = diffrow[col][plane];
outrow[col][plane] =
(-bias + prevSample + diffSample) % (outpam.maxval+1);
prevrow[col][plane] = outrow[col][plane];
}
}
pnm_writepamrow(&outpam, outrow);
}
}
pnm_freepamrow(prevrow);
pnm_freepamrow(outrow);
pnm_freepamrow(diffrow);
exit(0);
}
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