/*********************************************************************/
/* pnmflash -  brighten a picture up to total whiteout               */
/* Frank Neumann, August 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 11.10.1993          reads only one line at a time - this     */
/*                          saves LOTS of memory on big picturs      */
/* V1.4 16.11.1993          Rewritten to be NetPBM.programming con-  */
/*                          forming                                  */
/* V1.5 27.11.1999          Promoted from ppmflash to pnmflash.      */
/*********************************************************************/

#include "pnm.h"

/* global variables */
#ifdef AMIGA
static char *version = "$VER: pnmflash 1.5 (27.11.99)";
#endif

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

    /* parse in 'default' parameters */
    pnm_init( &argc, argv );

    argn = 1;

    /* parse in flash factor */
    if (argn == argc)
	    pm_usage(usage);
    if (sscanf(argv[argn], "%lf", &flashfactor) != 1)
	    pm_usage(usage);
    if (flashfactor < 0.0 || flashfactor > 1.0)
	    pm_error("flash 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 to PGM" );
	}
    else
	newformat = format;

    longfactor = (long)(flashfactor * 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 flashing **/
    /* the 'float' parameter for flashing 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(newformat) )
		{
		case PPM_TYPE:
		PPM_ASSIGN(*xP2, PPM_GETR(*xP) + (((maxval - PPM_GETR(*xP)) * longfactor) >> 16),
				 PPM_GETG(*xP) + (((maxval - PPM_GETG(*xP)) * longfactor) >> 16),
				 PPM_GETB(*xP) + (((maxval - PPM_GETB(*xP)) * longfactor) >> 16));
		break;
		default:
		PNM_ASSIGN1(*xP2, PNM_GET1(*xP) + (((maxval - 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);
    pnm_freerow(srcrow);
    pnm_freerow(destrow);

    exit(0);
    }