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Diffstat (limited to 'Build/source/libs/potrace/potrace-1.12/src/backend_geojson.c')
-rw-r--r--Build/source/libs/potrace/potrace-1.12/src/backend_geojson.c223
1 files changed, 223 insertions, 0 deletions
diff --git a/Build/source/libs/potrace/potrace-1.12/src/backend_geojson.c b/Build/source/libs/potrace/potrace-1.12/src/backend_geojson.c
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+++ b/Build/source/libs/potrace/potrace-1.12/src/backend_geojson.c
@@ -0,0 +1,223 @@
+/* Copyright (C) 2001-2015 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 GeoJSON backend of Potrace. */
+/* Written 2012 by Christoph Hormann <chris_hormann@gmx.de> */
+
+#include <stdio.h>
+#include <stdarg.h>
+#include <string.h>
+#include <math.h>
+
+#include "potracelib.h"
+#include "curve.h"
+#include "main.h"
+#include "backend_geojson.h"
+#include "lists.h"
+#include "auxiliary.h"
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+/* ---------------------------------------------------------------------- */
+/* auxiliary */
+
+/* return a point on a 1-dimensional Bezier segment */
+static inline double bezier(double t, double x0, double x1, double x2, double x3) {
+ double s = 1-t;
+ return s*s*s*x0 + 3*(s*s*t)*x1 + 3*(t*t*s)*x2 + t*t*t*x3;
+}
+
+static char *format = "%f";
+
+/* Convert a floating-point number to a string, using a pre-determined
+ format. The format must be previously set with set_format().
+ Returns one of a small number of statically allocated strings. */
+static char *round_to_unit(double x) {
+ static int n = 0;
+ static char buf[4][100];
+
+ n++;
+ if (n >= 4) {
+ n = 0;
+ }
+ sprintf(buf[n], format, x);
+ return buf[n];
+}
+
+/* Select a print format for floating point numbers, appropriate for
+ the given scaling and info.unit. Note: the format must be so that
+ the resulting number fits into a buffer of size 100. */
+static void set_format(trans_t tr) {
+ double s;
+ int d;
+ static char buf[10];
+
+ s = min(fabs(tr.scalex), fabs(tr.scaley));
+ if (info.unit != 0.0 && s != 0.0) {
+ d = (int)ceil(log(info.unit/s) / log(10));
+ } else {
+ d = 0;
+ }
+ if (d <= 0) {
+ format = "%.0f";
+ } else if (d <= 20) {
+ sprintf(buf, "%%.%df", d);
+ format = buf;
+ } else {
+ format = "%e";
+ }
+}
+
+/* ---------------------------------------------------------------------- */
+/* path-drawing auxiliary functions */
+
+static dpoint_t cur;
+
+static void geojson_moveto(FILE *fout, dpoint_t p, trans_t tr) {
+ dpoint_t q;
+
+ q = trans(p, tr);
+
+ fprintf(fout, "[%s, %s]", round_to_unit(q.x), round_to_unit(q.y));
+
+ cur = q;
+}
+
+static void geojson_lineto(FILE *fout, dpoint_t p, trans_t tr) {
+ dpoint_t q;
+
+ q = trans(p, tr);
+
+ fprintf(fout, ", [%s, %s]", round_to_unit(q.x), round_to_unit(q.y));
+
+ cur = q;
+}
+
+static void geojson_curveto(FILE *fout, dpoint_t p1, dpoint_t p2, dpoint_t p3, trans_t tr) {
+ dpoint_t q1;
+ dpoint_t q2;
+ dpoint_t q3;
+ double step, t;
+ int i;
+ double x, y;
+
+ q1 = trans(p1, tr);
+ q2 = trans(p2, tr);
+ q3 = trans(p3, tr);
+
+ step = 1.0 / 8.0;
+
+ for (i=0, t=step; i<8; i++, t+=step) {
+ x = bezier(t, cur.x, q1.x, q2.x, q3.x);
+ y = bezier(t, cur.y, q1.y, q2.y, q3.y);
+
+ fprintf(fout, ", [%s, %s]", round_to_unit(x), round_to_unit(y));
+ }
+
+ cur = q3;
+}
+
+/* ---------------------------------------------------------------------- */
+/* functions for converting a path to an SVG path element */
+
+static int geojson_path(FILE *fout, potrace_curve_t *curve, trans_t tr) {
+ int i;
+ dpoint_t *c;
+ int m = curve->n;
+
+ fprintf(fout, " [");
+
+ c = curve->c[m-1];
+ geojson_moveto(fout, c[2], tr);
+
+ for (i=0; i<m; i++) {
+ c = curve->c[i];
+ switch (curve->tag[i]) {
+ case POTRACE_CORNER:
+ geojson_lineto(fout, c[1], tr);
+ geojson_lineto(fout, c[2], tr);
+ break;
+ case POTRACE_CURVETO:
+ geojson_curveto(fout, c[0], c[1], c[2], tr);
+ break;
+ }
+ }
+
+ fprintf(fout, " ]");
+
+ return 0;
+}
+
+
+static void write_polygons(FILE *fout, potrace_path_t *tree, trans_t tr, int first) {
+ potrace_path_t *p, *q;
+
+ for (p=tree; p; p=p->sibling) {
+
+ if (!first) fprintf(fout, ",\n");
+
+ fprintf(fout, "{ \"type\": \"Feature\",\n");
+ fprintf(fout, " \"properties\": { },\n");
+ fprintf(fout, " \"geometry\": {\n");
+ fprintf(fout, " \"type\": \"Polygon\",\n");
+ fprintf(fout, " \"coordinates\": [\n");
+
+ geojson_path(fout, &p->curve, tr);
+
+ for (q=p->childlist; q; q=q->sibling) {
+ fprintf(fout, ",\n");
+ geojson_path(fout, &q->curve, tr);
+ }
+
+ fprintf(fout, " ]\n");
+ fprintf(fout, " }\n");
+ fprintf(fout, "}");
+
+ for (q=p->childlist; q; q=q->sibling) {
+ write_polygons(fout, q->childlist, tr, 0);
+ }
+
+ first = 0;
+ }
+}
+
+/* ---------------------------------------------------------------------- */
+/* Backend. */
+
+/* public interface for GeoJSON */
+int page_geojson(FILE *fout, potrace_path_t *plist, imginfo_t *imginfo) {
+
+ trans_t tr;
+
+ /* set up the coordinate transform (rotation) */
+ tr.bb[0] = imginfo->trans.bb[0]+imginfo->lmar+imginfo->rmar;
+ tr.bb[1] = imginfo->trans.bb[1]+imginfo->tmar+imginfo->bmar;
+ tr.orig[0] = imginfo->trans.orig[0]+imginfo->lmar;
+ tr.orig[1] = imginfo->trans.orig[1]+imginfo->bmar;
+ tr.x[0] = imginfo->trans.x[0];
+ tr.x[1] = imginfo->trans.x[1];
+ tr.y[0] = imginfo->trans.y[0];
+ tr.y[1] = imginfo->trans.y[1];
+
+ /* set the print format for floating point numbers */
+ set_format(imginfo->trans);
+
+ /* header */
+ fprintf(fout, "{\n");
+ fprintf(fout, "\"type\": \"FeatureCollection\",\n");
+ fprintf(fout, "\"features\": [\n");
+
+ write_polygons(fout, plist, tr, 1);
+
+ /* write footer */
+ fprintf(fout, "\n]\n");
+ fprintf(fout, "}\n");
+
+ fflush(fout);
+
+ return 0;
+}
+