File indexing completed on 2024-12-22 04:04:09

 /* Copyright (C) 2001-2019 Peter Selinger.
    This file is part of Potrace. It is free software and it is covered
    by the GNU General Public License. See the file COPYING for details. */
 
 
 /* The PGM backend of Potrace. Here we custom-render a set of Bezier
    curves and output the result as a greymap. This is merely a
    convenience, as the same could be achieved by piping the EPS output
    through ghostscript. */
 
 #ifdef HAVE_CONFIG_H
 #include <config.h>
 #endif
 
 #include <math.h>
 
 #include "backend_pgm.h"
 #include "potracelib.h"
 #include "lists.h"
 #include "greymap.h"
 #include "render.h"
 #include "main.h"
 #include "auxiliary.h"
 #include "trans.h"
 
 #ifndef M_PI
 #define M_PI 3.14159265358979323846
 #endif
 
 static void pgm_path(potrace_curve_t *curve, trans_t t, render_t *rm) {
   dpoint_t *c, c1[3];
   int i;
   int m = curve->n;
   
   c = curve->c[m-1];
   c1[2] = trans(c[2], t);
   render_moveto(rm, c1[2].x, c1[2].y);
   
   for (i=0; i<m; i++) {
     c = curve->c[i];
     switch (curve->tag[i]) {
     case POTRACE_CORNER:
       c1[1] = trans(c[1], t);
       c1[2] = trans(c[2], t);
       render_lineto(rm, c1[1].x, c1[1].y);
       render_lineto(rm, c1[2].x, c1[2].y);
       break;
     case POTRACE_CURVETO:
       c1[0] = trans(c[0], t);
       c1[1] = trans(c[1], t);
       c1[2] = trans(c[2], t);
       render_curveto(rm, c1[0].x, c1[0].y, c1[1].x, c1[1].y, c1[2].x, c1[2].y);
       break;
     }
   }
 }
 
 int page_pgm(FILE *fout, potrace_path_t *plist, imginfo_t *imginfo) {
   potrace_path_t *p;
   greymap_t *gm;
   render_t *rm;
   int w, h;
   trans_t t;
   int mode;
   const char *comment = "created by " POTRACE " " VERSION ", written by Peter Selinger 2001-2019";
 
   t.bb[0] = imginfo->trans.bb[0]+imginfo->lmar+imginfo->rmar;
   t.bb[1] = imginfo->trans.bb[1]+imginfo->tmar+imginfo->bmar;
   t.orig[0] = imginfo->trans.orig[0]+imginfo->lmar;
   t.orig[1] = imginfo->trans.orig[1]+imginfo->bmar;
   t.x[0] = imginfo->trans.x[0];
   t.x[1] = imginfo->trans.x[1];
   t.y[0] = imginfo->trans.y[0];
   t.y[1] = imginfo->trans.y[1];
 
   w = (int)ceil(t.bb[0]);
   h = (int)ceil(t.bb[1]);
 
   gm = gm_new(w, h);
   if (!gm) {
     return 1;
   }
   rm = render_new(gm);
   if (!rm) {
     return 1;
   }
 
   gm_clear(gm, 255); /* white */
 
   list_forall(p, plist) {
     pgm_path(&p->curve, t, rm);
   }
 
   render_close(rm);
 
   /* if negative orientation, make sure to invert effect of rendering */
   mode = imginfo->width * imginfo->height < 0 ? GM_MODE_NEGATIVE : GM_MODE_POSITIVE;
 
   gm_writepgm(fout, rm->gm, comment, 1, mode, info.gamma);
 
   render_free(rm);
   gm_free(gm);
 
   return 0;
 }