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path_inter, path_distance, path_length, dist_ppath now do the right

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things with closed paths --- ie, include the closing line segment in
their calculations.  Per bug report from Curtis Barrett 9-Oct-01.
This commit is contained in:
Tom Lane 2001-10-13 17:40:24 +00:00
parent 58dc94abac
commit cf5dc330b9
1 changed files with 94 additions and 22 deletions
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116
src/backend/utils/adt/geo_ops.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/adt/geo_ops.c,v 1.58 2001/03/22 03:59:50 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/adt/geo_ops.c,v 1.59 2001/10/13 17:40:24 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -948,7 +948,7 @@ line_construct_pts(LINE *line, Point *pt1, Point *pt2)
}
else if (FPeq(pt1->y, pt2->y))
{ /* horizontal */
/* use "x = C" */
/* use "y = C" */
line->A = 0;
line->B = -1;
line->C = pt1->y;
@ -1376,6 +1376,9 @@ path_inter(PG_FUNCTION_ARGS)
LSEG seg1,
seg2;
if (p1->npts <= 0 || p2->npts <= 0)
PG_RETURN_BOOL(false);
b1.high.x = b1.low.x = p1->p[0].x;
b1.high.y = b1.low.y = p1->p[0].y;
for (i = 1; i < p1->npts; i++)
@ -1398,12 +1401,34 @@ path_inter(PG_FUNCTION_ARGS)
PG_RETURN_BOOL(false);
/* pairwise check lseg intersections */
for (i = 0; i < p1->npts - 1; i++)
for (i = 0; i < p1->npts; i++)
{
for (j = 0; j < p2->npts - 1; j++)
int iprev;
if (i > 0)
iprev = i-1;
else
{
statlseg_construct(&seg1, &p1->p[i], &p1->p[i + 1]);
statlseg_construct(&seg2, &p2->p[j], &p2->p[j + 1]);
if (!p1->closed)
continue;
iprev = p1->npts-1; /* include the closure segment */
}
for (j = 0; j < p2->npts; j++)
{
int jprev;
if (j > 0)
jprev = j-1;
else
{
if (!p2->closed)
continue;
jprev = p2->npts-1; /* include the closure segment */
}
statlseg_construct(&seg1, &p1->p[iprev], &p1->p[i]);
statlseg_construct(&seg2, &p2->p[jprev], &p2->p[j]);
if (lseg_intersect_internal(&seg1, &seg2))
PG_RETURN_BOOL(true);
}
@ -1422,20 +1447,42 @@ path_distance(PG_FUNCTION_ARGS)
{
PATH *p1 = PG_GETARG_PATH_P(0);
PATH *p2 = PG_GETARG_PATH_P(1);
bool have_min = false;
float8 min = 0.0; /* initialize to keep compiler quiet */
bool have_min = false;
float8 tmp;
int i,
j;
LSEG seg1,
seg2;
for (i = 0; i < p1->npts - 1; i++)
for (i = 0; i < p1->npts; i++)
{
for (j = 0; j < p2->npts - 1; j++)
int iprev;
if (i > 0)
iprev = i-1;
else
{
statlseg_construct(&seg1, &p1->p[i], &p1->p[i + 1]);
statlseg_construct(&seg2, &p2->p[j], &p2->p[j + 1]);
if (!p1->closed)
continue;
iprev = p1->npts-1; /* include the closure segment */
}
for (j = 0; j < p2->npts; j++)
{
int jprev;
if (j > 0)
jprev = j-1;
else
{
if (!p2->closed)
continue;
jprev = p2->npts-1; /* include the closure segment */
}
statlseg_construct(&seg1, &p1->p[iprev], &p1->p[i]);
statlseg_construct(&seg2, &p2->p[jprev], &p2->p[j]);
tmp = DatumGetFloat8(DirectFunctionCall2(lseg_distance,
LsegPGetDatum(&seg1),
@ -1463,12 +1510,24 @@ Datum
path_length(PG_FUNCTION_ARGS)
{
PATH *path = PG_GETARG_PATH_P(0);
float8 result;
float8 result = 0.0;
int i;
result = 0.0;
for (i = 0; i < (path->npts - 1); i++)
result += point_dt(&path->p[i], &path->p[i + 1]);
for (i = 0; i < path->npts; i++)
{
int iprev;
if (i > 0)
iprev = i-1;
else
{
if (!path->closed)
continue;
iprev = path->npts-1; /* include the closure segment */
}
result += point_dt(&path->p[iprev], &path->p[i]);
}
PG_RETURN_FLOAT8(result);
}
@ -2133,17 +2192,18 @@ dist_ppath(PG_FUNCTION_ARGS)
Point *pt = PG_GETARG_POINT_P(0);
PATH *path = PG_GETARG_PATH_P(1);
float8 result = 0.0; /* keep compiler quiet */
bool have_min = false;
float8 tmp;
int i;
LSEG lseg;
switch (path->npts)
{
/* no points in path? then result is undefined... */
case 0:
/* no points in path? then result is undefined... */
PG_RETURN_NULL();
/* one point in path? then get distance between two points... */
case 1:
/* one point in path? then get distance between two points... */
result = point_dt(pt, &path->p[0]);
break;
default:
@ -2154,12 +2214,26 @@ dist_ppath(PG_FUNCTION_ARGS)
* the distance from a point to a path is the smallest
* distance from the point to any of its constituent segments.
*/
for (i = 0; i < path->npts - 1; i++)
for (i = 0; i < path->npts; i++)
{
statlseg_construct(&lseg, &path->p[i], &path->p[i + 1]);
int iprev;
if (i > 0)
iprev = i-1;
else
{
if (!path->closed)
continue;
iprev = path->npts-1; /* include the closure segment */
}
statlseg_construct(&lseg, &path->p[iprev], &path->p[i]);
tmp = dist_ps_internal(pt, &lseg);
if (i == 0 || tmp < result)
if (!have_min || tmp < result)
{
result = tmp;
have_min = true;
}
}
break;
}
@ -2824,8 +2898,6 @@ on_pb(PG_FUNCTION_ARGS)
* but not cross.
* (we can do p-in-p in lg(n), but it takes preprocessing)
*/
#define NEXT(A) (((A)+1) % path->npts) /* cyclic "i+1" */
Datum
on_ppath(PG_FUNCTION_ARGS)
{