/*********************************************************************/
/* pnmntsc -  make a 'look-alike ntsc' picture from a PNM file       */
/* Frank Neumann, October 1993                                       */
/* V1.2 27.11.1999                                                   */
/*                                                                   */
/* version history:                                                  */
/* V1.0 12.10.1993    first version                                  */
/* V1.1 16.11.1993    Rewritten to be NetPBM.programming conforming  */
/* V1.2 27.11.1999    Promoted from ppmntsc to pnmntsc.              */
/*********************************************************************/

#include "pnm.h"

/* global variables */
#ifdef AMIGA
static char *version = "$VER: pnmntsc 1.2 (27.11.99)"; /* Amiga version identification */
#endif

/**************************/
/* start of main function */
/**************************/
int
main( int argc, char* argv[] )
{
	FILE* ifp;
	int argn, rows, cols, format, newformat, i = 0, j = 0;
	pixel *srcrow, *destrow;
	pixel *xP = NULL, *xP2 = NULL;
	pixval maxval;
	double dimfactor;
	long longfactor;
	char *usage = "dimfactor [pnmfile]\n        dimfactor: 0.0 = total blackness, 1.0 = original picture\n";

	/* parse in 'default' parameters */
	pnm_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 */
	pnm_pbmmaxval = PNM_MAXMAXVAL; /* use larger value for better results */
	pnm_readpnminit(ifp, &cols, &rows, &maxval, &format);

	/* no error checking required here, pnmlib does it all for us */
	srcrow = pnm_allocrow(cols);

	/* Promote PBM files to PGM. */
	if ( PNM_FORMAT_TYPE(format) == PBM_TYPE )  
		{
		newformat = PGM_TYPE;
		pm_message( "promoting from PBM to PGM" );
		}
	else
		newformat = format;

	longfactor = (long)(dimfactor * 65536);

	/* allocate a row of pixel data for the new pixels */
	destrow = pnm_allocrow(cols);

	pnm_writepnminit(stdout, cols, rows, maxval, newformat, 0);

	/** now do the ntsc'ing (actually very similar to pnmdim) **/
	for (i = 0; i < rows; i++)
	{
		pnm_readpnmrow(ifp, srcrow, cols, maxval, format);

		xP = srcrow;
		xP2 = destrow;

		for (j = 0; j < cols; j++)
		{
			/* every alternating row is left in unchanged condition */
			if (i & 1)
			{
				*xP2 = *xP;
			}
			/* and the other lines are dimmed to the specified factor */
			else
			{
				switch ( PNM_FORMAT_TYPE(format) )
				{
					case PPM_TYPE:
					PPM_ASSIGN(*xP2, (PPM_GETR(*xP) * longfactor) >> 16,
							 (PPM_GETG(*xP) * longfactor) >> 16,
							 (PPM_GETB(*xP) * longfactor) >> 16);
					break;
					default:
					PNM_ASSIGN1(*xP2, (PNM_GET1(*xP) * longfactor) >> 16);
					break;
				}
			}
			xP++;
			xP2++;
		}

		/* write out one line of graphic data */
		pnm_writepnmrow(stdout, destrow, cols, maxval, newformat, 0);
	}

	pm_closer(ifp);
	pm_closew(stdout);
	pnm_freerow(srcrow);
	pnm_freerow(destrow);

	exit(0);
}