path: root/converter/ppm/ppmtoacad.c

/*

      Convert a portable pixmap to an AutoCAD slide or DXB file

    Author:
            John Walker
            Autodesk SA
            Avenue des Champs-Montants 14b
            CH-2074 MARIN
            Switzerland
            Usenet: kelvin@Autodesk.com
            Fax:    038/33 88 15
            Voice:  038/33 76 33

    Permission  to  use, copy, modify, and distribute this software and
    its documentation  for  any  purpose  and  without  fee  is  hereby
    granted,  without any conditions or restrictions.  This software is
    provided "as is" without express or implied warranty.

*/

#include <stdio.h>
#include "ppm.h"

#define TRUE     1
#define FALSE    0

#define EOS     '\0'

#define MAXHIST         32767         /* Color histogram maximum size */

static pixel **pixels;                /* Input pixel map */
static colorhash_table cht;           /* Color hash table */
static int curcol = -1;               /* Current slide output color */
static int polymode = FALSE;          /* Output filled polygons ? */
static int dxbmode = FALSE;           /* Output .dxb format ? */
static int bgcol = -1;                /* Screen background color */
static double aspect = 1.0;           /* Pixel aspect ratio correction */
static int gamut = 256;               /* Output color gamut */

#include "autocad.h"                  /* AutoCAD standard color assignments */

/* prototypes */
static void outrun ARGS((int color, int ysize, int y, int xstart, int xend));
static void slideout ARGS((int xdots, int ydots, int ncolors,
        unsigned char *red, unsigned char *green, unsigned char *blue));


/*  OUTRUN  --  Output a run of pixels. */

static void outrun(color, ysize, y, xstart, xend)
  int color, ysize, y, xstart, xend;
{
    if (color == 0) {
        return;                       /* Let screen background handle this */
    }

    if (curcol != color) {
        if (dxbmode) {
            putchar((char)136);
            (void) pm_writelittleshort(stdout, color);
        } else {
            (void) pm_writelittleshort(stdout, (short) 0xFF00 | color);
        }
        curcol = color;
    }
    if (polymode) {
        int v, yb = (ysize - y) + 1, yspan = 1;

        /* Since  we're emitting filled polygons,  let's scan downward
           in the pixmap and see if we can extend the run on this line
           vertically  as  well.   If  so, emit a polygon that handles
           both the horizontal and vertical run and clear  the  pixels
           in the subsequent lines to the background color. */

        for (v = y + 1; v <= ysize; v++) {
            int j, mismatch = FALSE;

            for (j = xstart; j <= xend; j++) {
                if (PPM_GETR(pixels[y][j]) != PPM_GETR(pixels[v][j])) {
                    mismatch = TRUE;
                    break;
                }
            }
            if (mismatch) {
                break;
            }
            for (j = xstart; j <= xend; j++) {
                PPM_ASSIGN(pixels[v][j], 0, 0, 0);
            }
        }
        yspan = v - y;

        if (dxbmode) {
            putchar(11);              /* Solid */
            (void) pm_writelittleshort(
                stdout, (int) (xstart * aspect + 0.4999));
            (void) pm_writelittleshort(stdout, yb);

            (void) pm_writelittleshort(
                stdout, (int) ((xend + 1) * aspect + 0.4999));
            (void) pm_writelittleshort(stdout, yb);

            (void) pm_writelittleshort(
                stdout, (int) (xstart * aspect + 0.4999));
            (void) pm_writelittleshort(stdout, yb - yspan);

            (void) pm_writelittleshort(
                stdout, (int) ((xend + 1) * aspect + 0.4999));
            (void) pm_writelittleshort(stdout, yb - yspan);
        } else {
            (void) pm_writelittleshort(stdout, (short) 0xFD00); 
              /* Solid fill header */
            (void) pm_writelittleshort(stdout, 4);      
              /* Vertices to follow */
            (void) pm_writelittleshort(stdout, -2);     /* Fill type */

            (void) pm_writelittleshort(stdout, (short)0xFD00); 
              /* Solid fill vertex */
            (void) pm_writelittleshort(stdout, xstart);
            (void) pm_writelittleshort(stdout, yb);

            (void) pm_writelittleshort(stdout, (short) 0xFD00); 
              /* Solid fill vertex */
            (void) pm_writelittleshort(stdout, xend + 1);
            (void) pm_writelittleshort(stdout, yb);

            (void) pm_writelittleshort(stdout, (short) 0xFD00); 
              /* Solid fill vertex */
            (void) pm_writelittleshort(stdout, xend + 1);
            (void) pm_writelittleshort(stdout, yb - yspan);

            (void) pm_writelittleshort(stdout, (short) 0xFD00); 
              /* Solid fill vertex */
            (void) pm_writelittleshort(stdout, xstart);
            (void) pm_writelittleshort(stdout, yb - yspan);

            (void) pm_writelittleshort(stdout, (short) 0xFD00); 
              /* Solid fill trailer */
            (void) pm_writelittleshort(stdout, 4); /* Vertices that precede */
            (void) pm_writelittleshort(stdout, -2);     /* Fill type */
        }
    } else {
        (void) pm_writelittleshort(stdout, xstart);     /* Vector:  From X */
        (void) pm_writelittleshort(stdout, ysize - y);  /*          From Y */
        (void) pm_writelittleshort(stdout, xend);       /*          To   X */
        (void) pm_writelittleshort(stdout, ysize - y);  /*          To   Y */
    }
}

/*  SLIDEOUT  --  Write an AutoCAD slide.  */

static void slideout(xdots, ydots, ncolors, red, green, blue)
  int xdots, ydots, ncolors;
  unsigned char *red, *green, *blue;
{
    static char sldhead[18] = "AutoCAD Slide\r\n\32";
    static char dxbhead[20] = "AutoCAD DXB 1.0\r\n\32";
    unsigned char *acadmap;
    int i, xsize, ysize;

    /* If the user has specified a non-black screen background color,
       swap the screen background color into color  index  zero  and
       move  black into the slot previously occupied by the background
       color. */

    if (bgcol > 0) {
        acadcol[0][0] = acadcol[bgcol][0];
        acadcol[0][1] = acadcol[bgcol][1];
        acadcol[0][2] = acadcol[bgcol][2];
        acadcol[bgcol][0] = acadcol[bgcol][1] = acadcol[bgcol][2] = 0;
    }

    acadmap = (unsigned char *) pm_allocrow(ncolors, sizeof(unsigned char));
    xsize = polymode ? xdots : (xdots - 1);
    ysize = polymode ? ydots : (ydots - 1);
    if (dxbmode) {
        fwrite(dxbhead, 19, 1, stdout); /* DXB file header */
        putchar((char)135);                 /* Number mode */
        (void) pm_writelittleshort(stdout, 0);        /* ...short integers */
    } else {
        fwrite(sldhead, 17, 1, stdout); /* Slide file header */
        putchar(86);                  /* Number format indicator */
        putchar(2);                   /* File level number */
        (void) pm_writelittleshort(stdout, xsize); /* Max X co-ordinate value */
        (void) pm_writelittleshort(stdout, ysize); /* Max Y co-ordinate value */
                                      /* Aspect ratio indicator */
        (void) pm_writelittlelong(
            stdout, (long) ((((double) xsize) / ysize) * aspect * 1E7));
        (void) pm_writelittleshort(stdout, 2);        /* Polygon fill type */
        (void) pm_writelittleshort(stdout, 0x1234);   /* Byte order indicator */
    }

    /* Now  build  a  mapping  from  the  image's computed color map
       indices to the closest representation  of  each  color  within
       AutoCAD's color repertoire. */

    for (i = 0; i < ncolors; i++) {
        int best, j;
        long dist = 3 * 256 * 256;

        for (j = 0; j < gamut; j++) {
            long dr = red[i] - acadcol[j][0],
                 dg = green[i] - acadcol[j][1],
                 db = blue[i] - acadcol[j][2];
            long tdist = dr * dr + dg * dg + db * db;

            if (tdist < dist) {
                dist = tdist;
                best = j;
            }
        }
        acadmap[i] = best;
    }

    /* Swoop  over the entire map and replace each  RGB pixel with its
       closest  AutoCAD  color  representation.   We  do  this  in  a
       separate  pass  since it avoids repetitive mapping of pixels as
       we examine them for compression. */

    for (i = 0; i < ydots; i++) {
        int x;

        for (x = 0; x < xdots; x++) {
            PPM_ASSIGN(pixels[i][x],
                acadmap[ppm_lookupcolor(cht, &pixels[i][x])], 0 ,0);
        }
    }

    /* Output a run-length encoded expression of the pixmap as AutoCAD
       vectors. */

    for (i = 0; i < ydots; i++) {
        int x, rx, rpix = -1, nrun = 0;

        for (x = 0; x < xdots; x++) {
            int pix = PPM_GETR(pixels[i][x]);

            if (pix != rpix) {
                if (nrun > 0) {
                    if (rpix > 0) {
                        outrun(rpix, ydots - 1, i, rx, x - 1);
                    }
                }
                rpix = pix;
                rx = x;
                nrun = 1;
            }
        }
        if ((nrun > 0) && (rpix > 0)) {
            outrun(rpix, ydots - 1, i, rx, xdots - 1);
        }
    }
    if (dxbmode) {
        putchar(0);                   /* DXB end sentinel */
    } else {
        (void) pm_writelittleshort(stdout, (short) 0xFC00); 
          /* End of file marker */
    }
    pm_freerow((char *) acadmap);
}

/*  Main program.  */

int main(argc, argv)
  int argc;
  char* argv[];
{
    FILE *ifp;
    int argn, rows, cols, ncolors, i;
    int aspectspec = FALSE;
    pixval maxval;
    colorhist_vector chv;
    unsigned char *Red, *Green, *Blue;
    const char * const usage =
        "[-poly] [-dxb] [-white] [-background <col>]\n\
                  [-aspect <f>] [-8] [ppmfile]";


    ppm_init(&argc, argv);

    argn = 1;
    while (argn < argc && argv[argn][0] == '-' && argv[argn][1] != EOS) {
        if (pm_keymatch(argv[argn], "-dxb", 2)) {
            dxbmode = polymode = TRUE;
        } else if (pm_keymatch(argv[argn], "-poly", 2)) {
            polymode = TRUE;
        } else if (pm_keymatch(argv[argn], "-white", 2)) {
            if (bgcol >= 0) {
                pm_error("already specified a background color");
            }
            bgcol = 7;
        } else if (pm_keymatch(argv[argn], "-background", 2)) {
            if (bgcol >= 0) {
                pm_error("already specified a background color");
            }
            argn++;
            if ((argn == argc) || (sscanf(argv[argn], "%d", &bgcol) != 1))
                pm_usage(usage);
            if (bgcol < 0) {
                pm_error("background color must be >= 0 and <= 255");
            }
        } else if (pm_keymatch(argv[argn], "-aspect", 2)) {
            if (aspectspec) {
                pm_error("already specified an aspect ratio");
            }
            argn++;
            if ((argn == argc) || (sscanf(argv[argn], "%lf", &aspect) != 1))
                pm_usage(usage);
            if (aspect <= 0.0) {
                pm_error("aspect ratio must be greater than 0");
            }
            aspectspec = TRUE;
        } else if (pm_keymatch(argv[argn], "-8", 2)) {
            gamut = 8;
        } else {
            pm_usage(usage);
        }
        argn++;
    }

    if (argn < argc) {
        ifp = pm_openr(argv[argn]);
        argn++;
    } else {
        ifp = stdin;
    }

    if (argn != argc) {
        pm_usage(usage);
    }

    pixels = ppm_readppm(ifp, &cols, &rows, &maxval);

    pm_close(ifp);

    /* Figure out the colormap.  Logic for squeezing depth to limit the
       number of colors in the image was swiped from ppmquant.c. */

    while (TRUE) {
        int row, col;
        pixval newmaxval;
        pixel *pP;

        pm_message("computing colormap...");
        chv = ppm_computecolorhist(pixels, cols, rows, MAXHIST, &ncolors);
        if (chv != (colorhist_vector) 0)
            break;
        newmaxval = maxval / 2;
        pm_message(
        "scaling colors from maxval=%d to maxval=%d to improve clustering...",
                   maxval, newmaxval );
        for (row = 0; row < rows; ++row) {
            for (col = 0, pP = pixels[row]; col < cols; ++col, ++pP) {
                PPM_DEPTH(*pP, *pP, maxval, newmaxval);
            }
        }
        maxval = newmaxval;
    }
    pm_message("%d colors found", ncolors);

    /* Scale the color map derived for the PPM file into one compatible
       with AutoCAD's convention of 8 bit intensities. */

    if (maxval != 255) {
        pm_message("maxval is not 255 - automatically rescaling colors");
    }
    Red = (unsigned char *) pm_allocrow(ncolors, sizeof(unsigned char));
    Green = (unsigned char *) pm_allocrow(ncolors, sizeof(unsigned char));
    Blue = (unsigned char *) pm_allocrow(ncolors, sizeof(unsigned char));

    for (i = 0; i < ncolors; ++i) {
        if ( maxval == 255 ) {
            Red[i] = PPM_GETR(chv[i].color);
            Green[i] = PPM_GETG(chv[i].color);
            Blue[i] = PPM_GETB( chv[i].color );
        } else {
            Red[i] = ((int) PPM_GETR(chv[i].color) * 255) / maxval;
            Green[i] = ((int) PPM_GETG(chv[i].color) * 255) / maxval;
            Blue[i] = ((int) PPM_GETB(chv[i].color) * 255) / maxval;
        }
    }

    /* And make a hash table for fast lookup. */

    cht = ppm_colorhisttocolorhash(chv, ncolors);
    ppm_freecolorhist(chv);

    slideout(cols, rows, ncolors, Red, Green, Blue);
    pm_freerow((char *) Red);
    pm_freerow((char *) Green);
    pm_freerow((char *) Blue);
    exit(0);
}