/*********************************************************************/
/* ppmdim -  dim a picture down to total blackness                   */
/* Frank Neumann, October 1993                                       */
/* V1.4 16.11.1993                                                   */
/*                                                                   */
/* 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                                  */
/*********************************************************************/

#include "ppm.h"

/* global variables */
#ifdef AMIGA
static char *version = "$VER: ppmdim 1.4 (16.11.93)"; /* Amiga version identification */
#endif

/**************************/
/* 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 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++)
        {
                ppm_readppmrow(ifp, srcrow, cols, maxval, format);

                pP = srcrow;
                pP2 = destrow;

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