Move polygon parsing into grits-util

[grits] / src / grits-util.c

diff --git a/src/grits-util.c b/src/grits-util.c
index 8ac6a1b93715380a6799702f1fcc5b97588b1d44..ab795f9b15ae41c7e1c86884e2655ca8383371c1 100644 (file)
--- a/src/grits-util.c
+++ b/src/grits-util.c
@@ -70,6 +70,7 @@
 
 #include <glib.h>
 #include <math.h>
+#include <stdio.h>
 
 #include "grits-util.h"
 
@@ -303,3 +304,85 @@ void normd(gdouble *a)
        a[1] = a[1] / total;
        a[2] = a[2] / total;
 }
+
+/**
+ * parse_points:
+ * @string:    String representation of the points
+ * @group_sep: Group separator
+ * @point_sep: Point separator
+ * @coord_sep: Coordinate separator
+ * @bounds:    The bounding box of all the points, or NULL
+ * @center:    The center of the @bounds, or NULL
+ *
+ * Parse a string of the form:
+ *   string -> group [@group_sep group] ...
+ *   group  -> point [@point_sep point] ...
+ *   point  -> latitude @coord_sep longitude [@coord_sep elevation]
+ *
+ * For example
+ *   parse_points("30,-80 30,-120 50,-120 50,-80", "\t", " ", ",");
+ *
+ * Returns: zero-terminated array of groups of points
+ */
+GritsPoints *parse_points(const gchar *string,
+               const gchar *group_sep, const gchar *point_sep, const gchar *coord_sep,
+               GritsBounds *bounds, GritsPoint *center)
+{
+       /* Split and count groups */
+       gchar **sgroups = g_strsplit(string, group_sep, -1);
+       int     ngroups = g_strv_length(sgroups);
+
+       GritsBounds _bounds = {-90, 90, -180, 180};
+       gdouble (**groups)[3] = (gpointer)g_new0(double*, ngroups+1);
+       for (int pi = 0; pi < ngroups; pi++) {
+               /* Split and count coordinates */
+               gchar **scoords = g_strsplit(sgroups[pi], point_sep, -1);
+               int     ncoords = g_strv_length(scoords);
+
+               /* Create binary coords */
+               gdouble (*coords)[3] = (gpointer)g_new0(gdouble, 3*(ncoords+1));
+               for (int ci = 0; ci < ncoords; ci++) {
+                       gdouble lat, lon;
+                       sscanf(scoords[ci], "%lf,%lf", &lat, &lon);
+                       if (bounds || center) {
+                               if (lat > _bounds.n) _bounds.n = lat;
+                               if (lat < _bounds.s) _bounds.s = lat;
+                               if (lon > _bounds.e) _bounds.e = lon;
+                               if (lon < _bounds.w) _bounds.w = lon;
+                       }
+                       lle2xyz(lat, lon, 0,
+                                       &coords[ci][0],
+                                       &coords[ci][1],
+                                       &coords[ci][2]);
+               }
+
+               /* Insert coords into line array */
+               groups[pi] = coords;
+               g_strfreev(scoords);
+       }
+       g_strfreev(sgroups);
+
+       /* Output */
+       if (bounds)
+               *bounds = _bounds;
+       if (center) {
+               center->lat  = (_bounds.n + _bounds.s)/2;
+               center->lon  = lon_avg(_bounds.e, _bounds.w);
+               center->elev = 0;
+       }
+       return groups;
+}
+
+/**
+ * free_points:
+ * @points: Array of points allocated by parse_points()
+ *
+ * Frees all data allocated by parse_points
+ */
+void free_points(GritsPoints *points)
+{
+       gdouble (**_points)[3] = points;
+       for (int i = 0; _points[i]; i++)
+               g_free(_points[i]);
+       g_free(_points);
+}