static POINTARRAY* ptarray_locate_along(const POINTARRAY *pa, double m, double offset) { int i; POINT4D p1, p2, pn; POINTARRAY *dpa = NULL; /* Can't do anything with degenerate point arrays */ if ( ! pa || pa->npoints < 2 ) return NULL; /* Walk through each segment in the point array */ for ( i = 1; i < pa->npoints; i++ ) { getPoint4d_p(pa, i-1, &p1); getPoint4d_p(pa, i, &p2); /* No derived point? Move to next segment. */ if ( segment_locate_along(&p1, &p2, m, offset, &pn) == LW_FALSE ) continue; /* No pointarray, make a fresh one */ if ( dpa == NULL ) dpa = ptarray_construct_empty(ptarray_has_z(pa), ptarray_has_m(pa), 8); /* Add our new point to the array */ ptarray_append_point(dpa, &pn, 0); } return dpa; }
static LWGEOM* linestring_from_pa(const POINTARRAY *pa, int srid, int start, int end) { int i = 0, j = 0; POINT4D p; POINTARRAY *pao = ptarray_construct(ptarray_has_z(pa), ptarray_has_m(pa), end-start+2); LWDEBUGF(4, "srid=%d, start=%d, end=%d", srid, start, end); for( i = start; i < end + 2; i++ ) { getPoint4d_p(pa, i, &p); ptarray_set_point4d(pao, j++, &p); } return lwline_as_lwgeom(lwline_construct(srid, NULL, pao)); }
static LWGEOM* circstring_from_pa(const POINTARRAY *pa, int srid, int start, int end) { POINT4D p0, p1, p2; POINTARRAY *pao = ptarray_construct(ptarray_has_z(pa), ptarray_has_m(pa), 3); LWDEBUGF(4, "srid=%d, start=%d, end=%d", srid, start, end); getPoint4d_p(pa, start, &p0); ptarray_set_point4d(pao, 0, &p0); getPoint4d_p(pa, (start+end)/2, &p1); ptarray_set_point4d(pao, 1, &p1); getPoint4d_p(pa, end+1, &p2); ptarray_set_point4d(pao, 2, &p2); return lwcircstring_as_lwgeom(lwcircstring_construct(srid, NULL, pao)); }
LWMPOINT * lwmpoint_construct(int srid, const POINTARRAY *pa) { int i; int hasz = ptarray_has_z(pa); int hasm = ptarray_has_m(pa); LWMPOINT *ret = (LWMPOINT*)lwcollection_construct_empty(MULTIPOINTTYPE, srid, hasz, hasm); for ( i = 0; i < pa->npoints; i++ ) { LWPOINT *lwp; POINT4D p; getPoint4d_p(pa, i, &p); lwp = lwpoint_make(srid, hasz, hasm, &p); lwmpoint_add_lwpoint(ret, lwp); } return ret; }
LWGEOM* pta_desegmentize(POINTARRAY *points, int type, int srid) { int i = 0, j, k; POINT4D a1, a2, a3, b; char *edges_in_arcs; int found_arc = LW_FALSE; int current_arc = 1; int num_edges; int edge_type = -1; int start, end; LWCOLLECTION *outcol; /* Die on null input */ if ( ! points ) lwerror("pta_desegmentize called with null pointarray"); /* Null on empty input? */ if ( points->npoints == 0 ) return NULL; /* We can't desegmentize anything shorter than four points */ if ( points->npoints < 4 ) { /* Return a linestring here*/ lwerror("pta_desegmentize needs implementation for npoints < 4"); } /* Allocate our result array of vertices that are part of arcs */ num_edges = points->npoints - 1; edges_in_arcs = lwalloc(num_edges); memset(edges_in_arcs, 0, num_edges); /* We make a candidate arc of the first two edges, */ /* And then see if the next edge follows it */ while( i < num_edges-2 ) { found_arc = LW_FALSE; /* Make candidate arc */ getPoint4d_p(points, i , &a1); getPoint4d_p(points, i+1, &a2); getPoint4d_p(points, i+2, &a3); for( j = i+3; j < num_edges+1; j++ ) { LWDEBUGF(4, "i=%d, j=%d", i, j); getPoint4d_p(points, j, &b); /* Does this point fall on our candidate arc? */ if ( pt_continues_arc(&a1, &a2, &a3, &b) ) { /* Yes. Mark this edge and the two preceding it as arc components */ LWDEBUGF(4, "pt_continues_arc #%d", current_arc); found_arc = LW_TRUE; for ( k = j-1; k > j-4; k-- ) edges_in_arcs[k] = current_arc; } else { /* No. So we're done with this candidate arc */ LWDEBUG(4, "pt_continues_arc = false"); current_arc++; break; } } /* Jump past all the edges that were added to the arc */ if ( found_arc ) { i = j-1; } else { /* Mark this edge as a linear edge */ edges_in_arcs[i] = 0; i = i+1; } } #if POSTGIS_DEBUG_LEVEL > 3 { char *edgestr = lwalloc(num_edges+1); for ( i = 0; i < num_edges; i++ ) { if ( edges_in_arcs[i] ) edgestr[i] = 48 + edges_in_arcs[i]; else edgestr[i] = '.'; } edgestr[num_edges] = 0; LWDEBUGF(3, "edge pattern %s", edgestr); lwfree(edgestr); } #endif start = 0; edge_type = edges_in_arcs[0]; outcol = lwcollection_construct_empty(COMPOUNDTYPE, srid, ptarray_has_z(points), ptarray_has_m(points)); for( i = 1; i < num_edges; i++ ) { if( edge_type != edges_in_arcs[i] ) { end = i - 1; lwcollection_add_lwgeom(outcol, geom_from_pa(points, srid, edge_type, start, end)); start = i; edge_type = edges_in_arcs[i]; } } /* Roll out last item */ end = num_edges - 1; lwcollection_add_lwgeom(outcol, geom_from_pa(points, srid, edge_type, start, end)); /* Strip down to singleton if only one entry */ if ( outcol->ngeoms == 1 ) { LWGEOM *outgeom = outcol->geoms[0]; lwfree(outcol); return outgeom; } return lwcollection_as_lwgeom(outcol); }
LWGEOM* pta_unstroke(const POINTARRAY *points, int type, int srid) { int i = 0, j, k; POINT4D a1, a2, a3, b; POINT4D first, center; char *edges_in_arcs; int found_arc = LW_FALSE; int current_arc = 1; int num_edges; int edge_type; /* non-zero if edge is part of an arc */ int start, end; LWCOLLECTION *outcol; /* Minimum number of edges, per quadrant, required to define an arc */ const unsigned int min_quad_edges = 2; /* Die on null input */ if ( ! points ) lwerror("pta_unstroke called with null pointarray"); /* Null on empty input? */ if ( points->npoints == 0 ) return NULL; /* We can't desegmentize anything shorter than four points */ if ( points->npoints < 4 ) { /* Return a linestring here*/ lwerror("pta_unstroke needs implementation for npoints < 4"); } /* Allocate our result array of vertices that are part of arcs */ num_edges = points->npoints - 1; edges_in_arcs = lwalloc(num_edges + 1); memset(edges_in_arcs, 0, num_edges + 1); /* We make a candidate arc of the first two edges, */ /* And then see if the next edge follows it */ while( i < num_edges-2 ) { unsigned int arc_edges; double num_quadrants; double angle; found_arc = LW_FALSE; /* Make candidate arc */ getPoint4d_p(points, i , &a1); getPoint4d_p(points, i+1, &a2); getPoint4d_p(points, i+2, &a3); memcpy(&first, &a1, sizeof(POINT4D)); for( j = i+3; j < num_edges+1; j++ ) { LWDEBUGF(4, "i=%d, j=%d", i, j); getPoint4d_p(points, j, &b); /* Does this point fall on our candidate arc? */ if ( pt_continues_arc(&a1, &a2, &a3, &b) ) { /* Yes. Mark this edge and the two preceding it as arc components */ LWDEBUGF(4, "pt_continues_arc #%d", current_arc); found_arc = LW_TRUE; for ( k = j-1; k > j-4; k-- ) edges_in_arcs[k] = current_arc; } else { /* No. So we're done with this candidate arc */ LWDEBUG(4, "pt_continues_arc = false"); current_arc++; break; } memcpy(&a1, &a2, sizeof(POINT4D)); memcpy(&a2, &a3, sizeof(POINT4D)); memcpy(&a3, &b, sizeof(POINT4D)); } /* Jump past all the edges that were added to the arc */ if ( found_arc ) { /* Check if an arc was composed by enough edges to be * really considered an arc * See http://trac.osgeo.org/postgis/ticket/2420 */ arc_edges = j - 1 - i; LWDEBUGF(4, "arc defined by %d edges found", arc_edges); if ( first.x == b.x && first.y == b.y ) { LWDEBUG(4, "arc is a circle"); num_quadrants = 4; } else { lw_arc_center((POINT2D*)&first, (POINT2D*)&b, (POINT2D*)&a1, (POINT2D*)¢er); angle = lw_arc_angle((POINT2D*)&first, (POINT2D*)¢er, (POINT2D*)&b); int p2_side = lw_segment_side((POINT2D*)&first, (POINT2D*)&a1, (POINT2D*)&b); if ( p2_side >= 0 ) angle = -angle; if ( angle < 0 ) angle = 2 * M_PI + angle; num_quadrants = ( 4 * angle ) / ( 2 * M_PI ); LWDEBUGF(4, "arc angle (%g %g, %g %g, %g %g) is %g (side is %d), quandrants:%g", first.x, first.y, center.x, center.y, b.x, b.y, angle, p2_side, num_quadrants); } /* a1 is first point, b is last point */ if ( arc_edges < min_quad_edges * num_quadrants ) { LWDEBUGF(4, "Not enough edges for a %g quadrants arc, %g needed", num_quadrants, min_quad_edges * num_quadrants); for ( k = j-1; k >= i; k-- ) edges_in_arcs[k] = 0; } i = j-1; } else { /* Mark this edge as a linear edge */ edges_in_arcs[i] = 0; i = i+1; } } #if POSTGIS_DEBUG_LEVEL > 3 { char *edgestr = lwalloc(num_edges+1); for ( i = 0; i < num_edges; i++ ) { if ( edges_in_arcs[i] ) edgestr[i] = 48 + edges_in_arcs[i]; else edgestr[i] = '.'; } edgestr[num_edges] = 0; LWDEBUGF(3, "edge pattern %s", edgestr); lwfree(edgestr); } #endif start = 0; edge_type = edges_in_arcs[0]; outcol = lwcollection_construct_empty(COMPOUNDTYPE, srid, ptarray_has_z(points), ptarray_has_m(points)); for( i = 1; i < num_edges; i++ ) { if( edge_type != edges_in_arcs[i] ) { end = i - 1; lwcollection_add_lwgeom(outcol, geom_from_pa(points, srid, edge_type, start, end)); start = i; edge_type = edges_in_arcs[i]; } } lwfree(edges_in_arcs); /* not needed anymore */ /* Roll out last item */ end = num_edges - 1; lwcollection_add_lwgeom(outcol, geom_from_pa(points, srid, edge_type, start, end)); /* Strip down to singleton if only one entry */ if ( outcol->ngeoms == 1 ) { LWGEOM *outgeom = outcol->geoms[0]; outcol->ngeoms = 0; lwcollection_free(outcol); return outgeom; } return lwcollection_as_lwgeom(outcol); }
/** * Segmentize an arc * * Does not add the final vertex * * @param to POINTARRAY to append segmentized vertices to * @param p1 first point defining the arc * @param p2 second point defining the arc * @param p3 third point defining the arc * @param tol tolerance, semantic driven by tolerance_type * @param tolerance_type see LW_LINEARIZE_TOLERANCE_TYPE * @param flags LW_LINEARIZE_FLAGS * * @return number of points appended (0 if collinear), * or -1 on error (lwerror would be called). * */ static int lwarc_linearize(POINTARRAY *to, const POINT4D *p1, const POINT4D *p2, const POINT4D *p3, double tol, LW_LINEARIZE_TOLERANCE_TYPE tolerance_type, int flags) { POINT2D center; POINT2D *t1 = (POINT2D*)p1; POINT2D *t2 = (POINT2D*)p2; POINT2D *t3 = (POINT2D*)p3; POINT4D pt; int p2_side = 0; int clockwise = LW_TRUE; double radius; /* Arc radius */ double increment; /* Angle per segment */ double angle_shift = 0; double a1, a2, a3, angle; POINTARRAY *pa = to; int is_circle = LW_FALSE; int points_added = 0; int reverse = 0; LWDEBUG(2, "lwarc_linearize called."); p2_side = lw_segment_side(t1, t3, t2); /* Force counterclockwise scan if SYMMETRIC operation is requsested */ if ( p2_side == -1 && flags & LW_LINEARIZE_FLAG_SYMMETRIC ) { /* swap p1-p3 */ t1 = (POINT2D*)p3; t3 = (POINT2D*)p1; p1 = (POINT4D*)t1; p3 = (POINT4D*)t3; p2_side = 1; reverse = 1; } radius = lw_arc_center(t1, t2, t3, ¢er); LWDEBUGF(2, " center is POINT(%.15g %.15g) - radius:%g", center.x, center.y, radius); /* Matched start/end points imply circle */ if ( p1->x == p3->x && p1->y == p3->y ) is_circle = LW_TRUE; /* Negative radius signals straight line, p1/p2/p3 are colinear */ if ( (radius < 0.0 || p2_side == 0) && ! is_circle ) return 0; /* The side of the p1/p3 line that p2 falls on dictates the sweep direction from p1 to p3. */ if ( p2_side == -1 ) clockwise = LW_TRUE; else clockwise = LW_FALSE; if ( tolerance_type == LW_LINEARIZE_TOLERANCE_TYPE_SEGS_PER_QUAD ) {{ int perQuad = rint(tol); // error out if tol != perQuad ? (not-round) if ( perQuad != tol ) { lwerror("lwarc_linearize: segments per quadrant must be an integer value, got %.15g", tol, perQuad); return -1; } if ( perQuad < 1 ) { lwerror("lwarc_linearize: segments per quadrant must be at least 1, got %d", perQuad); return -1; } increment = fabs(M_PI_2 / perQuad); LWDEBUGF(2, "lwarc_linearize: perQuad:%d, increment:%g (%g degrees)", perQuad, increment, increment*180/M_PI); }} else if ( tolerance_type == LW_LINEARIZE_TOLERANCE_TYPE_MAX_DEVIATION ) {{ double halfAngle; if ( tol <= 0 ) { lwerror("lwarc_linearize: max deviation must be bigger than 0, got %.15g", tol); return -1; } halfAngle = acos( -tol / radius + 1 ); increment = 2 * halfAngle; LWDEBUGF(2, "lwarc_linearize: maxDiff:%g, radius:%g, halfAngle:%g, increment:%g (%g degrees)", tol, radius, halfAngle, increment, increment*180/M_PI); }} else if ( tolerance_type == LW_LINEARIZE_TOLERANCE_TYPE_MAX_ANGLE ) { increment = tol; if ( increment <= 0 ) { lwerror("lwarc_linearize: max angle must be bigger than 0, got %.15g", tol); return -1; } } else { lwerror("lwarc_linearize: unsupported tolerance type %d", tolerance_type); return LW_FALSE; } /* Angles of each point that defines the arc section */ a1 = atan2(p1->y - center.y, p1->x - center.x); a2 = atan2(p2->y - center.y, p2->x - center.x); a3 = atan2(p3->y - center.y, p3->x - center.x); LWDEBUGF(2, "lwarc_linearize A1:%g (%g) A2:%g (%g) A3:%g (%g)", a1, a1*180/M_PI, a2, a2*180/M_PI, a3, a3*180/M_PI); if ( flags & LW_LINEARIZE_FLAG_SYMMETRIC ) {{ /* Calculate total arc angle, in radians */ double angle = clockwise ? a1 - a3 : a3 - a1; if ( angle < 0 ) angle += M_PI * 2; LWDEBUGF(2, "lwarc_linearize SYMMETRIC requested - total angle %g deg", angle * 180 / M_PI); if ( flags & LW_LINEARIZE_FLAG_RETAIN_ANGLE ) {{ /* Number of steps */ int steps = trunc(angle / increment); /* Angle reminder */ double angle_reminder = angle - ( increment * steps ); angle_shift = angle_reminder / 2.0; LWDEBUGF(2, "lwarc_linearize RETAIN_ANGLE operation requested - " "total angle %g, steps %d, increment %g, reminder %g", angle * 180 / M_PI, steps, increment * 180 / M_PI, angle_reminder * 180 / M_PI); }} else {{ /* Number of segments in output */ int segs = ceil(angle / increment); /* Tweak increment to be regular for all the arc */ increment = angle/segs; LWDEBUGF(2, "lwarc_linearize SYMMETRIC operation requested - " "total angle %g degrees - LINESTRING(%g %g,%g %g,%g %g) - S:%d - I:%g", angle*180/M_PI, p1->x, p1->y, center.x, center.y, p3->x, p3->y, segs, increment*180/M_PI); }} }} /* p2 on left side => clockwise sweep */ if ( clockwise ) { LWDEBUG(2, " Clockwise sweep"); increment *= -1; angle_shift *= -1; /* Adjust a3 down so we can decrement from a1 to a3 cleanly */ if ( a3 > a1 ) a3 -= 2.0 * M_PI; if ( a2 > a1 ) a2 -= 2.0 * M_PI; } /* p2 on right side => counter-clockwise sweep */ else { LWDEBUG(2, " Counterclockwise sweep"); /* Adjust a3 up so we can increment from a1 to a3 cleanly */ if ( a3 < a1 ) a3 += 2.0 * M_PI; if ( a2 < a1 ) a2 += 2.0 * M_PI; } /* Override angles for circle case */ if( is_circle ) { a3 = a1 + 2.0 * M_PI; a2 = a1 + M_PI; increment = fabs(increment); clockwise = LW_FALSE; } LWDEBUGF(2, "lwarc_linearize angle_shift:%g, increment:%g", angle_shift * 180/M_PI, increment * 180/M_PI); if ( reverse ) {{ const int capacity = 8; /* TODO: compute exactly ? */ pa = ptarray_construct_empty(ptarray_has_z(to), ptarray_has_m(to), capacity); }} /* Sweep from a1 to a3 */ if ( ! reverse ) { ptarray_append_point(pa, p1, LW_FALSE); } ++points_added; if ( angle_shift ) angle_shift -= increment; LWDEBUGF(2, "a1:%g (%g deg), a3:%g (%g deg), inc:%g, shi:%g, cw:%d", a1, a1 * 180 / M_PI, a3, a3 * 180 / M_PI, increment, angle_shift, clockwise); for ( angle = a1 + increment + angle_shift; clockwise ? angle > a3 : angle < a3; angle += increment ) { LWDEBUGF(2, " SA: %g ( %g deg )", angle, angle*180/M_PI); pt.x = center.x + radius * cos(angle); pt.y = center.y + radius * sin(angle); pt.z = interpolate_arc(angle, a1, a2, a3, p1->z, p2->z, p3->z); pt.m = interpolate_arc(angle, a1, a2, a3, p1->m, p2->m, p3->m); ptarray_append_point(pa, &pt, LW_FALSE); ++points_added; angle_shift = 0; } if ( reverse ) {{ int i; ptarray_append_point(to, p3, LW_FALSE); for ( i=pa->npoints; i>0; i-- ) { getPoint4d_p(pa, i-1, &pt); ptarray_append_point(to, &pt, LW_FALSE); } ptarray_free(pa); }} return points_added; }