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/*********************************************************************/
/* ppmtv - make a 'look-alike ntsc' picture from a PPM file */
/* Frank Neumann, October 1993 */
/* V1.1 16.11.1993 */
/* */
/* version history: */
/* V1.0 12.10.1993 first version */
/* V1.1 16.11.1993 Rewritten to be NetPBM.programming conforming */
/*********************************************************************/
#include "ppm.h"
/**************************/
/* start of main function */
/**************************/
int main(argc, argv)
int argc;
char *argv[];
{
FILE* ifp;
int argn, rows, cols, format, i = 0, j = 0;
pixel *srcrow, *destrow;
pixel *pP = NULL, *pP2 = NULL;
pixval maxval;
double dimfactor;
long longfactor;
const char * const usage = "dimfactor [ppmfile]\n dimfactor: 0.0 = total blackness, 1.0 = original picture\n";
/* parse in 'default' parameters */
ppm_init(&argc, argv);
argn = 1;
/* parse in dim factor */
if (argn == argc)
pm_usage(usage);
if (sscanf(argv[argn], "%lf", &dimfactor) != 1)
pm_usage(usage);
if (dimfactor < 0.0 || dimfactor > 1.0)
pm_error("dim factor must be in the range from 0.0 to 1.0 ");
++argn;
/* parse in filename (if present, stdin otherwise) */
if (argn != argc)
{
ifp = pm_openr(argv[argn]);
++argn;
}
else
ifp = stdin;
if (argn != argc)
pm_usage(usage);
/* read first data from file */
ppm_readppminit(ifp, &cols, &rows, &maxval, &format);
/* no error checking required here, ppmlib does it all for us */
srcrow = ppm_allocrow(cols);
longfactor = (long)(dimfactor * 65536);
/* allocate a row of pixel data for the new pixels */
destrow = ppm_allocrow(cols);
ppm_writeppminit(stdout, cols, rows, maxval, 0);
/** now do the ntsc'ing (actually very similar to ppmdim) **/
for (i = 0; i < rows; i++)
{
ppm_readppmrow(ifp, srcrow, cols, maxval, format);
pP = srcrow;
pP2 = destrow;
for (j = 0; j < cols; j++)
{
/* every alternating row is left in unchanged condition */
if (i & 1)
{
PPM_ASSIGN(*pP2, PPM_GETR(*pP), PPM_GETG(*pP), PPM_GETB(*pP));
}
/* and the other lines are dimmed to the specified factor */
else
{
PPM_ASSIGN(*pP2, (PPM_GETR(*pP) * longfactor) >> 16,
(PPM_GETG(*pP) * longfactor) >> 16,
(PPM_GETB(*pP) * longfactor) >> 16);
}
pP++;
pP2++;
}
/* write out one line of graphic data */
ppm_writeppmrow(stdout, destrow, cols, maxval, 0);
}
pm_close(ifp);
ppm_freerow(srcrow);
ppm_freerow(destrow);
exit(0);
}
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