Vlib: reduce memory consumption for Vect_snap_lines(_list)()

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@63601 15284696-431f-4ddb-bdfa-cd5b030d7da7

lib/vector/Vlib/snap.c

@@ -21,6 +21,7 @@
 #include <math.h>
 #include <grass/vector.h>
 #include <grass/glocale.h>
+#include <grass/kdtree.h>
 
 /* translate segment to box and back */
 #define X1W 0x01	/* x1 is West, x2 East */
@@ -121,6 +122,14 @@ static int add_item_box(int id, const struct RTree_Rect *rect, void *list)
     return 1;
 }
 
+static void
+Vect_snap_lines_list_rtree(struct Map_info *, const struct ilist *,
+		           double, struct Map_info *);
+
+static void
+Vect_snap_lines_list_kdtree(struct Map_info *, const struct ilist *,
+		            double, struct Map_info *);
+
 /*!
    \brief Snap selected lines to existing vertex in threshold.
    
@@ -161,6 +170,366 @@ void
 Vect_snap_lines_list(struct Map_info *Map, const struct ilist *List_lines,
 		     double thresh, struct Map_info *Err)
 {
+    if (getenv("GRASS_VECTOR_LOWMEM"))
+	Vect_snap_lines_list_rtree(Map, List_lines, thresh, Err);
+    else
+	Vect_snap_lines_list_rtree(Map, List_lines, thresh, Err);
+}
+
+static void
+Vect_snap_lines_list_kdtree(struct Map_info *Map, const struct ilist *List_lines,
+		     double thresh, struct Map_info *Err)
+{
+    struct line_pnts *Points, *NPoints;
+    struct line_cats *Cats;
+    int line, ltype, line_idx;
+    double thresh2;
+
+    int point;			/* index in points array */
+    int nanchors, ntosnap;	/* number of anchors and number of points to be snapped */
+    int nsnapped, ncreated;	/* number of snapped verices, number of new vertices (on segments) */
+    int apoints, npoints, nvertices;	/* number of allocated points, registered points, vertices */
+    XPNT *XPnts;		/* Array of points */
+    NEW *New = NULL;		/* Array of new points */
+    int anew = 0, nnew;		/* allocated new points , number of new points */
+    struct ilist *List;
+    int *Index = NULL;		/* indexes of anchors for vertices */
+    int aindex = 0;		/* allocated Index */
+
+    struct kdtree *KDTree;
+    double c[2];
+    double *kdd;
+    int *kduid, kd_found;
+
+
+    if (List_lines->n_values < 1)
+	return;
+
+    Points = Vect_new_line_struct();
+    NPoints = Vect_new_line_struct();
+    Cats = Vect_new_cats_struct();
+    List = Vect_new_list();
+
+    KDTree = kdtree_create(2, NULL);
+
+    thresh2 = thresh * thresh;
+
+    /* Go through all lines in vector, and add each point to structure of points */
+    apoints = 0;
+    point = 1;			/* index starts from 1 ! */
+    nvertices = 0;
+    XPnts = NULL;
+
+    G_important_message(_("Snap vertices Pass 1: select points"));
+    for (line_idx = 0; line_idx < List_lines->n_values; line_idx++) {
+	int v;
+
+	G_percent(line_idx, List_lines->n_values, 2);
+
+	line = List_lines->value[line_idx];
+
+	G_debug(3, "line =  %d", line);
+	if (!Vect_line_alive(Map, line))
+	    continue;
+
+	ltype = Vect_read_line(Map, Points, Cats, line);
+
+	for (v = 0; v < Points->n_points; v++) {
+	    G_debug(3, "  vertex v = %d", v);
+	    nvertices++;
+
+	    /* coords */
+	    c[0] = Points->x[v];
+	    c[1] = Points->y[v];
+
+	    if (kdtree_insert(KDTree, c, point, 0)) {
+		/* Add to structure */
+		if ((point - 1) == apoints) {
+		    apoints += 10000;
+		    XPnts =
+			(XPNT *) G_realloc(XPnts,
+					   (apoints + 1) * sizeof(XPNT));
+		}
+		XPnts[point].x = Points->x[v];
+		XPnts[point].y = Points->y[v];
+		XPnts[point].anchor = -1;
+		point++;
+	    }
+	}
+    }
+    G_percent(line_idx, List_lines->n_values, 2); /* finish it */
+
+    G_debug(0, "KD Tree depth: %d", (int)KDTree->root->depth);
+    kdtree_optimize(KDTree, 2);
+    G_debug(0, "KD Tree depth: %d", (int)KDTree->root->depth);
+
+    npoints = point - 1;
+
+    /* Go through all registered points and if not yet marked mark it as anchor and assign this anchor
+     * to all not yet marked points in threshold */
+
+    G_important_message(_("Snap vertices Pass 2: assign anchor vertices"));
+
+    nanchors = ntosnap = 0;
+    for (point = 1; point <= npoints; point++) {
+	int i;
+
+	G_percent(point, npoints, 4);
+
+	G_debug(3, "  point = %d", point);
+
+	if (XPnts[point].anchor >= 0)
+	    continue;
+
+	XPnts[point].anchor = 0;	/* make it anchor */
+	nanchors++;
+
+	/* Find points in threshold */
+	c[0] = XPnts[point].x;
+	c[1] = XPnts[point].y;
+
+	Vect_reset_list(List);
+	kd_found = kdtree_dnn(KDTree, c, &kduid, &kdd, thresh, &point);
+	G_debug(4, "  %d points in threshold box", kd_found);
+
+	for (i = 0; i < kd_found; i++) {
+	    int pointb;
+	    double dx, dy, dist2;
+
+	    pointb = kduid[i];
+	    if (pointb == point)
+		continue;
+
+	    dx = XPnts[pointb].x - XPnts[point].x;
+	    dy = XPnts[pointb].y - XPnts[point].y;
+	    dist2 = dx * dx + dy * dy;
+
+	    if (dist2 > thresh2) /* outside threshold */
+		continue;
+		
+	    /* doesn't have an anchor yet */
+	    if (XPnts[pointb].anchor == -1) {
+		XPnts[pointb].anchor = point;
+		ntosnap++;
+	    }
+	    else if (XPnts[pointb].anchor > 0) {   /* check distance to previously assigned anchor */
+		double dist2_a;
+
+		dx = XPnts[XPnts[pointb].anchor].x - XPnts[pointb].x;
+		dy = XPnts[XPnts[pointb].anchor].y - XPnts[pointb].y;
+		dist2_a = dx * dx + dy * dy;
+
+		/* replace old anchor */
+		if (dist2 < dist2_a) {
+		    XPnts[pointb].anchor = point;
+		}
+	    }
+	}
+	if (kd_found) {
+	    G_free(kdd);
+	    G_free(kduid);
+	}
+    }
+
+    /* Go through all lines and: 
+     *   1) for all vertices: if not anchor snap it to its anchor
+     *   2) for all segments: snap it to all anchors in threshold (except anchors of vertices of course) */
+
+    nsnapped = ncreated = 0;
+
+    G_important_message(_("Snap vertices Pass 3: snap to assigned points"));
+
+    for (line_idx = 0; line_idx < List_lines->n_values; line_idx++) {
+	int v, spoint, anchor;
+	int changed = 0;
+	double kddist;
+
+	G_percent(line_idx, List_lines->n_values, 2);
+
+	line = List_lines->value[line_idx];
+
+	G_debug(3, "line =  %d", line);
+	if (!Vect_line_alive(Map, line))
+	    continue;
+
+	ltype = Vect_read_line(Map, Points, Cats, line);
+
+	if (Points->n_points >= aindex) {
+	    aindex = Points->n_points;
+	    Index = (int *)G_realloc(Index, aindex * sizeof(int));
+	}
+
+	/* Snap all vertices */
+	for (v = 0; v < Points->n_points; v++) {
+	    /* Box */
+	    c[0] = Points->x[v];
+	    c[1] = Points->y[v];
+
+	    /* Find point ( should always find one point ) */
+	    Vect_reset_list(List);
+
+	    spoint = -1;
+	    kdtree_knn(KDTree, c, &spoint, &kddist, 1, NULL);
+	    if (spoint == -1)
+		G_fatal_error("Point not in KD Tree");
+
+	    anchor = XPnts[spoint].anchor;
+
+	    if (anchor > 0) {	/* to be snapped */
+		Points->x[v] = XPnts[anchor].x;
+		Points->y[v] = XPnts[anchor].y;
+		nsnapped++;
+		changed = 1;
+		Index[v] = anchor;	/* point on new location */
+	    }
+	    else {
+		Index[v] = spoint;	/* old point */
+	    }
+	}
+
+	/* New points */
+	Vect_reset_line(NPoints);
+
+	/* Snap all segments to anchors in threshold */
+	for (v = 0; v < Points->n_points - 1; v++) {
+	    int i;
+	    double x1, x2, y1, y2, xmin, xmax, ymin, ymax;
+	    double dx, dy;
+	    double kdthresh;
+
+	    G_debug(3, "  segment = %d end anchors : %d  %d", v, Index[v],
+		    Index[v + 1]);
+
+	    x1 = Points->x[v];
+	    x2 = Points->x[v + 1];
+	    y1 = Points->y[v];
+	    y2 = Points->y[v + 1];
+
+	    Vect_append_point(NPoints, Points->x[v], Points->y[v],
+			      Points->z[v]);
+
+	    /* Box */
+	    if (x1 <= x2) {
+		xmin = x1;
+		xmax = x2;
+	    }
+	    else {
+		xmin = x2;
+		xmax = x1;
+	    }
+	    if (y1 <= y2) {
+		ymin = y1;
+		ymax = y2;
+	    }
+	    else {
+		ymin = y2;
+		ymax = y1;
+	    }
+
+	    c[0] = (xmin + xmax) / 2;
+	    c[1] = (ymin + ymax) / 2;
+
+	    dx = xmax - xmin;
+	    dy = ymax - ymin;
+	    kdthresh = sqrt(dx * dx + dy * dy) + thresh;
+
+	    /* Find points */
+	    Vect_reset_list(List);
+	    kd_found = kdtree_dnn(KDTree, c, &kduid, &kdd, kdthresh, NULL);
+
+	    G_debug(3, "  %d points in box", kd_found);
+
+	    /* Snap to anchor in threshold different from end points */
+	    nnew = 0;
+	    for (i = 0; i < kd_found; i++) {
+		double dist2, along;
+
+		spoint = kduid[i];
+		G_debug(4, "    spoint = %d anchor = %d", spoint,
+			XPnts[spoint].anchor);
+
+		if (spoint == Index[v] || spoint == Index[v + 1])
+		    continue;	/* end point */
+		if (XPnts[spoint].anchor > 0)
+		    continue;	/* point is not anchor */
+
+		/* Check the distance */
+		dist2 =
+		    dig_distance2_point_to_line(XPnts[spoint].x,
+						XPnts[spoint].y, 0, x1, y1, 0,
+						x2, y2, 0, 0, NULL, NULL,
+						NULL, &along, NULL);
+
+		G_debug(4, "      distance = %lf", sqrt(dist2));
+
+		if (dist2 <= thresh2) {
+		    G_debug(4, "      anchor in thresh, along = %lf", along);
+
+		    if (nnew == anew) {
+			anew += 100;
+			New = (NEW *) G_realloc(New, anew * sizeof(NEW));
+		    }
+		    New[nnew].anchor = spoint;
+		    New[nnew].along = along;
+		    nnew++;
+		}
+	    }
+	    if (kd_found) {
+		G_free(kduid);
+		G_free(kdd);
+	    }
+	    G_debug(3, "  nnew = %d", nnew);
+	    /* insert new vertices */
+	    if (nnew > 0) {
+		/* sort by distance along the segment */
+		qsort(New, sizeof(char) * nnew, sizeof(NEW), sort_new);
+
+		for (i = 0; i < nnew; i++) {
+		    anchor = New[i].anchor;
+		    /* Vect_line_insert_point ( Points, ++v, XPnts[anchor].x, XPnts[anchor].y, 0); */
+		    Vect_append_point(NPoints, XPnts[anchor].x,
+				      XPnts[anchor].y, 0);
+		    ncreated++;
+		}
+		changed = 1;
+	    }
+	}
+
+	/* append end point */
+	v = Points->n_points - 1;
+	Vect_append_point(NPoints, Points->x[v], Points->y[v], Points->z[v]);
+
+	if (changed) {		/* rewrite the line */
+	    Vect_line_prune(NPoints);	/* remove duplicates */
+	    if (NPoints->n_points > 1 || !(ltype & GV_LINES)) {
+		Vect_rewrite_line(Map, line, ltype, NPoints, Cats);
+	    }
+	    else {
+		Vect_delete_line(Map, line);
+	    }
+	    if (Err) {
+		Vect_write_line(Err, ltype, Points, Cats);
+	    }
+	}
+    }				/* for each line */
+    G_percent(line_idx, List_lines->n_values, 2); /* finish it */
+
+    Vect_destroy_line_struct(Points);
+    Vect_destroy_line_struct(NPoints);
+    Vect_destroy_cats_struct(Cats);
+    G_free(XPnts);
+    G_free(Index);
+    G_free(New);
+    kdtree_destroy(KDTree);
+
+    G_verbose_message(_("Snapped vertices: %d"), nsnapped);
+    G_verbose_message(_("New vertices: %d"), ncreated);
+}
+
+static void
+Vect_snap_lines_list_rtree(struct Map_info *Map, const struct ilist *List_lines,
+		     double thresh, struct Map_info *Err)
+{
     struct line_pnts *Points, *NPoints;
     struct line_cats *Cats;
     int line, ltype, line_idx;
@@ -270,7 +639,7 @@ Vect_snap_lines_list(struct Map_info *Map, const struct ilist *List_lines,
     for (point = 1; point <= npoints; point++) {
 	int i;
 
-	G_percent(point, npoints, 2);
+	G_percent(point, npoints, 4);
 
 	G_debug(3, "  point = %d", point);
 
@@ -581,7 +950,7 @@ Vect_snap_lines(struct Map_info *Map, int type, double thresh,
    \param[in,out] Points line points to snap
    \param[in] thresh threshold in which to snap vertices
    \param[in] with_z 2D or 3D snapping
-   \param[in,out] nsnapped number of snapped verices
+   \param[in,out] nsnapped number of snapped vertices
    \param[in,out] ncreated number of new vertices (on segments)
   
    \return 1 if line was changed, otherwise 0