/*********************************************************************/
/* pnmdim -  dim a picture down to total blackness                   */
/* Frank Neumann, October 1993                                       */
/* V1.5 27.11.1999                                                   */
/*                                                                   */
/* version history:                                                  */
/* V1.0 ~ 15.August 1993    first version                            */
/* V1.1 03.09.1993          uses ppm libs & header files             */
/* V1.2 03.09.1993          integer arithmetics instead of float     */
/*                          (gains about 50 % speed up)              */
/* V1.3 10.10.1993          reads only one line at a time - this     */
/*                          saves LOTS of memory on big pictures     */
/* V1.4 16.11.1993          Rewritten to be NetPBM.programming con-  */
/*                          forming                                  */
/* V1.5 27.11.1999          Promoted from ppmdim to pnmdim.          */
/*********************************************************************/

#include "pnm.h"

/* global variables */
#ifdef AMIGA
static char *version = "$VER: pnmdim 1.5 (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;
	xel *srcrow, *destrow;
	xel *xP = NULL, *xP2 = NULL;
	xelval 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 xel data for the new xels */
	destrow = pnm_allocrow(cols);

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

	/** now do the dim'ing **/
	/* the 'float' parameter for dimming is sort of faked - in fact, we */
	/* convert it to a range from 0 to 65536 for integer math. Shouldn't */
	/* be something you'll have to worry about, though. */

	for (i = 0; i < rows; i++)
	{
		pnm_readpnmrow(ifp, srcrow, cols, maxval, format);

		xP = srcrow;
		xP2 = destrow;

		for (j = 0; j < cols; j++)
		{
			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);
}