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#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include "pm_c_util.h"
#include "shhopt.h"
#include "mallocvar.h"
#include "pam.h"
struct CmdlineInfo {
/* All the information the user supplied in the command line,
in a form easy for the program to use.
*/
unsigned int width;
unsigned int height;
unsigned int maxval;
float sigma;
const char * tupletype;
};
static void
parseCommandLine(int argc, const char ** argv,
struct CmdlineInfo * const cmdlineP) {
/*----------------------------------------------------------------------------
Convert program invocation arguments (argc,argv) into a format the
program can use easily, struct cmdlineInfo. Validate arguments along
the way and exit program with message if invalid.
Note that some string information we return as *cmdlineP is in the storage
argv[] points to.
-----------------------------------------------------------------------------*/
optEntry *option_def;
/* Instructions to OptParseOptions2 on how to parse our options.
*/
optStruct3 opt;
unsigned int tupletypeSpec, maxvalSpec, sigmaSpec;
unsigned int option_def_index;
MALLOCARRAY_NOFAIL(option_def, 100);
option_def_index = 0; /* incremented by OPTENTRY */
OPTENT3(0, "tupletype", OPT_STRING, &cmdlineP->tupletype,
&tupletypeSpec, 0);
OPTENT3(0, "maxval", OPT_UINT, &cmdlineP->maxval,
&maxvalSpec, 0);
OPTENT3(0, "sigma", OPT_FLOAT, &cmdlineP->sigma,
&sigmaSpec, 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, (char **)argv, opt, sizeof(opt), 0);
/* Uses and sets argc, argv, and some of *cmdlineP and others. */
if (!tupletypeSpec)
cmdlineP->tupletype = "";
else {
struct pam pam;
if (strlen(cmdlineP->tupletype)+1 > sizeof(pam.tuple_type))
pm_error("The tuple type you specified is too long. "
"Maximum %u characters.",
(unsigned)sizeof(pam.tuple_type)-1);
}
if (!sigmaSpec)
pm_error("You must specify the -sigma option.");
else if (cmdlineP->sigma <= 0.0)
pm_error("-sigma must be positive. You specified %f",
cmdlineP->sigma);
if (!maxvalSpec)
cmdlineP->maxval = PNM_MAXMAXVAL;
else {
if (cmdlineP->maxval > PNM_OVERALLMAXVAL)
pm_error("The maxval you specified (%u) is too big. "
"Maximum is %u", cmdlineP->maxval, PNM_OVERALLMAXVAL);
if (cmdlineP->maxval < 1)
pm_error("-maxval must be at least 1");
}
if (argc-1 < 2)
pm_error("Need two arguments: width and height.");
else if (argc-1 > 2)
pm_error("Only two arguments allowed: width and height. "
"You specified %d", argc-1);
else {
cmdlineP->width = atoi(argv[1]);
cmdlineP->height = atoi(argv[2]);
if (cmdlineP->width <= 0)
pm_error("width argument must be a positive number. You "
"specified '%s'", argv[1]);
if (cmdlineP->height <= 0)
pm_error("height argument must be a positive number. You "
"specified '%s'", argv[2]);
}
free(option_def);
}
static double
distFromCenter(struct pam * const pamP,
int const col,
int const row) {
return sqrt(SQR(col - pamP->width/2) + SQR(row - pamP->height/2));
}
static double
gauss(double const arg,
double const sigma) {
/*----------------------------------------------------------------------------
Compute the value of the gaussian function with sigma parameter 'sigma'
and mu parameter zero of argument 'arg'.
-----------------------------------------------------------------------------*/
double const pi = 3.14159;
double const coefficient = 1 / (sigma * sqrt(2*pi));
double const exponent = - SQR(arg-0) / (2 * SQR(sigma));
return coefficient * exp(exponent);
}
static double
imageNormalizer(struct pam * const pamP,
double const sigma) {
/*----------------------------------------------------------------------------
Compute the value that has to be multiplied by the value of the
one-dimensional gaussian function of the distance from center in
order to get the value for a normalized two-dimensional gaussian
function. Normalized here means that the volume under the whole
curve is 1, just as the area under a whole one-dimensional gaussian
function is 1.
-----------------------------------------------------------------------------*/
double volume;
unsigned int row;
volume = 0.0; /* initial value */
for (row = 0; row < pamP->height; ++row) {
unsigned int col;
for (col = 0; col < pamP->width; ++col)
volume += gauss(distFromCenter(pamP, col, row), sigma);
}
return 1.0 / volume;
}
int
main(int argc, const char **argv) {
struct CmdlineInfo cmdline;
struct pam pam;
int row;
double normalizer;
tuplen * tuplerown;
pm_proginit(&argc, argv);
parseCommandLine(argc, argv, &cmdline);
pam.size = sizeof(pam);
pam.len = PAM_STRUCT_SIZE(tuple_type);
pam.file = stdout;
pam.format = PAM_FORMAT;
pam.plainformat = 0;
pam.width = cmdline.width;
pam.height = cmdline.height;
pam.depth = 1;
pam.maxval = cmdline.maxval;
strcpy(pam.tuple_type, cmdline.tupletype);
normalizer = imageNormalizer(&pam, cmdline.sigma);
pnm_writepaminit(&pam);
tuplerown = pnm_allocpamrown(&pam);
for (row = 0; row < pam.height; ++row) {
int col;
for (col = 0; col < pam.width; ++col) {
double const gauss1 = gauss(distFromCenter(&pam, col, row),
cmdline.sigma);
tuplerown[col][0] = gauss1 * normalizer;
}
pnm_writepamrown(&pam, tuplerown);
}
pnm_freepamrown(tuplerown);
return 0;
}
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