File indexing completed on 2024-12-22 04:04:15

 /* 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. */
 
 /* calculations with coordinate transformations and bounding boxes */
 
 #ifdef HAVE_CONFIG_H
 #include <config.h>
 #endif
 
 #include <math.h>
 #include <string.h>
 
 #include "trans.h"
 #include "bbox.h"
 
 /* rotate the coordinate system counterclockwise by alpha degrees. The
    new bounding box will be the smallest box containing the rotated
    old bounding box */
 void trans_rotate(trans_t *r, double alpha) {
   double s, c, x0, x1, y0, y1, o0, o1;
   trans_t t_struct;
   trans_t *t = &t_struct;
 
   memcpy(t, r, sizeof(trans_t));
 
   s = sin(alpha/180*M_PI);
   c = cos(alpha/180*M_PI);
 
   /* apply the transformation matrix to the sides of the bounding box */
   x0 = c * t->bb[0];
   x1 = s * t->bb[0];
   y0 = -s * t->bb[1];
   y1 = c * t->bb[1];
 
   /* determine new bounding box, and origin of old bb within new bb */
   r->bb[0] = fabs(x0) + fabs(y0);
   r->bb[1] = fabs(x1) + fabs(y1);
   o0 = - min(x0,0) - min(y0,0);
   o1 = - min(x1,0) - min(y1,0);
 
   r->orig[0] = o0 + c * t->orig[0] - s * t->orig[1];
   r->orig[1] = o1 + s * t->orig[0] + c * t->orig[1];
   r->x[0] = c * t->x[0] - s * t->x[1];
   r->x[1] = s * t->x[0] + c * t->x[1];
   r->y[0] = c * t->y[0] - s * t->y[1];
   r->y[1] = s * t->y[0] + c * t->y[1];
 }
 
 /* return the standard cartesian coordinate system for an w x h rectangle. */
 void trans_from_rect(trans_t *r, double w, double h) {
   r->bb[0] = w;
   r->bb[1] = h;
   r->orig[0] = 0.0;
   r->orig[1] = 0.0;
   r->x[0] = 1.0;
   r->x[1] = 0.0;
   r->y[0] = 0.0;
   r->y[1] = 1.0;
   r->scalex = 1.0;
   r->scaley = 1.0;
 }
 
 /* rescale the coordinate system r by factor sc >= 0. */
 void trans_rescale(trans_t *r, double sc) {
   r->bb[0] *= sc;
   r->bb[1] *= sc;
   r->orig[0] *= sc;
   r->orig[1] *= sc;
   r->x[0] *= sc;
   r->x[1] *= sc;
   r->y[0] *= sc;
   r->y[1] *= sc;
   r->scalex *= sc;
   r->scaley *= sc;
 }
 
 /* rescale the coordinate system to size w x h */
 void trans_scale_to_size(trans_t *r, double w, double h) {
   double xsc = w/r->bb[0];
   double ysc = h/r->bb[1];
 
   r->bb[0] = w;
   r->bb[1] = h;
   r->orig[0] *= xsc;
   r->orig[1] *= ysc;
   r->x[0] *= xsc;
   r->x[1] *= ysc;
   r->y[0] *= xsc;
   r->y[1] *= ysc;
   r->scalex *= xsc;
   r->scaley *= ysc;
   
   if (w<0) {
     r->orig[0] -= w;
     r->bb[0] = -w;
   }
   if (h<0) {
     r->orig[1] -= h;
     r->bb[1] = -h;
   }
 }
 
 /* adjust the bounding box to the actual vector outline */
 void trans_tighten(trans_t *r, potrace_path_t *plist) {
   interval_t i;
   dpoint_t dir;
   int j;
   
   /* if pathlist is empty, do nothing */
   if (!plist) {
     return;
   }
 
   for (j=0; j<2; j++) {
     dir.x = r->x[j];
     dir.y = r->y[j];
     path_limits(plist, dir, &i);
     if (i.min == i.max) {
       /* make the extent non-zero to avoid later division by zero errors */
       i.max = i.min+0.5;
       i.min = i.min-0.5;
     }
     r->bb[j] = i.max - i.min;
     r->orig[j] = -i.min;
   }
 }