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geo_ops.c 92.74 KiB
/*-------------------------------------------------------------------------
*
* geo_ops.c
* 2D geometric operations
*
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/adt/geo_ops.c,v 1.51 2000/06/13 07:35:07 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include <math.h>
#include <limits.h>
#include <float.h>
#include <ctype.h>
#include "postgres.h"
#include "utils/geo_decls.h"
#ifndef PI
#define PI 3.1415926536
#endif
/*
* Internal routines
*/
static int point_inside(Point *p, int npts, Point *plist);
static int lseg_crossing(double x, double y, double px, double py);
static BOX *box_construct(double x1, double x2, double y1, double y2);
static BOX *box_copy(BOX *box);
static BOX *box_fill(BOX *result, double x1, double x2, double y1, double y2);
static double box_ht(BOX *box);
static double box_wd(BOX *box);
static double circle_ar(CIRCLE *circle);
static CIRCLE *circle_copy(CIRCLE *circle);
static LINE *line_construct_pm(Point *pt, double m);
static double lseg_dt(LSEG *l1, LSEG *l2);
static void make_bound_box(POLYGON *poly);
static PATH *path_copy(PATH *path);
static bool plist_same(int npts, Point *p1, Point *p2);
static Point *point_construct(double x, double y);
static Point *point_copy(Point *pt);
static int single_decode(char *str, float8 *x, char **ss);
static int single_encode(float8 x, char *str);
static int pair_decode(char *str, float8 *x, float8 *y, char **s);
static int pair_encode(float8 x, float8 y, char *str);
static int pair_count(char *s, char delim);
static int path_decode(int opentype, int npts, char *str, int *isopen, char **ss, Point *p);
static char *path_encode(bool closed, int npts, Point *pt);
static void statlseg_construct(LSEG *lseg, Point *pt1, Point *pt2);
static double box_ar(BOX *box);
static Point *interpt_sl(LSEG *lseg, LINE *line);
/*
* Delimiters for input and output strings.
* LDELIM, RDELIM, and DELIM are left, right, and separator delimiters, respectively.
* LDELIM_EP, RDELIM_EP are left and right delimiters for paths with endpoints.
*/
#define LDELIM '('
#define RDELIM ')'
#define DELIM ','
#define LDELIM_EP '['
#define RDELIM_EP ']'#define LDELIM_C '<'
#define RDELIM_C '>'
/* Maximum number of output digits printed */
#define P_MAXDIG DBL_DIG
#define P_MAXLEN (2*(P_MAXDIG+7)+1)
static int digits8 = P_MAXDIG;
/*
* Geometric data types are composed of points.
* This code tries to support a common format throughout the data types,
* to allow for more predictable usage and data type conversion.
* The fundamental unit is the point. Other units are line segments,
* open paths, boxes, closed paths, and polygons (which should be considered
* non-intersecting closed paths).
*
* Data representation is as follows:
* point: (x,y)
* line segment: [(x1,y1),(x2,y2)]
* box: (x1,y1),(x2,y2)
* open path: [(x1,y1),...,(xn,yn)]
* closed path: ((x1,y1),...,(xn,yn))
* polygon: ((x1,y1),...,(xn,yn))
*
* For boxes, the points are opposite corners with the first point at the top right.
* For closed paths and polygons, the points should be reordered to allow
* fast and correct equality comparisons.
*
* XXX perhaps points in complex shapes should be reordered internally
* to allow faster internal operations, but should keep track of input order
* and restore that order for text output - tgl 97/01/16
*/
static int
single_decode(char *str, float8 *x, char **s)
{
char *cp;
if (!PointerIsValid(str))
return FALSE;
while (isspace(*str))
str++;
*x = strtod(str, &cp);
#ifdef GEODEBUG
fprintf(stderr, "single_decode- (%x) try decoding %s to %g\n", (cp - str), str, *x);
#endif
if (cp <= str)
return FALSE;
while (isspace(*cp))
cp++;
if (s != NULL)
*s = cp;
return TRUE;
} /* single_decode() */
static int
single_encode(float8 x, char *str)
{
sprintf(str, "%.*g", digits8, x);
return TRUE;
} /* single_encode() */
static int
pair_decode(char *str, float8 *x, float8 *y, char **s)
{ int has_delim;
char *cp;
if (!PointerIsValid(str))
return FALSE;
while (isspace(*str))
str++;
if ((has_delim = (*str == LDELIM)))
str++;
while (isspace(*str))
str++;
*x = strtod(str, &cp);
if (cp <= str)
return FALSE;
while (isspace(*cp))
cp++;
if (*cp++ != DELIM)
return FALSE;
while (isspace(*cp))
cp++;
*y = strtod(cp, &str);
if (str <= cp)
return FALSE;
while (isspace(*str))
str++;
if (has_delim)
{
if (*str != RDELIM)
return FALSE;
str++;
while (isspace(*str))
str++;
}
if (s != NULL)
*s = str;
return TRUE;
}
static int
pair_encode(float8 x, float8 y, char *str)
{
sprintf(str, "%.*g,%.*g", digits8, x, digits8, y);
return TRUE;
}
static int
path_decode(int opentype, int npts, char *str, int *isopen, char **ss, Point *p)
{
int depth = 0;
char *s,
*cp;
int i;
s = str;
while (isspace(*s))
s++;
if ((*isopen = (*s == LDELIM_EP)))
{
/* no open delimiter allowed? */
if (!opentype)
return FALSE;
depth++;
s++;
while (isspace(*s))
s++;
} else if (*s == LDELIM)
{
cp = (s + 1);
while (isspace(*cp))
cp++;
if (*cp == LDELIM)
{
#ifdef NOT_USED
/* nested delimiters with only one point? */
if (npts <= 1)
return FALSE;
#endif
depth++;
s = cp;
}
else if (strrchr(s, LDELIM) == s)
{
depth++;
s = cp;
}
}
for (i = 0; i < npts; i++)
{
if (!pair_decode(s, &(p->x), &(p->y), &s))
return FALSE;
if (*s == DELIM)
s++;
p++;
}
while (depth > 0)
{
if ((*s == RDELIM)
|| ((*s == RDELIM_EP) && (*isopen) && (depth == 1)))
{
depth--;
s++;
while (isspace(*s))
s++;
}
else
return FALSE;
}
*ss = s;
return TRUE;
} /* path_decode() */
static char *
path_encode(bool closed, int npts, Point *pt)
{
char *result = palloc(npts * (P_MAXLEN + 3) + 2);
char *cp;
int i;
cp = result;
switch (closed)
{
case TRUE:
*cp++ = LDELIM;
break;
case FALSE:
*cp++ = LDELIM_EP;
break;
default:
break;
}
for (i = 0; i < npts; i++)
{
*cp++ = LDELIM;
if (!pair_encode(pt->x, pt->y, cp))
elog(ERROR, "Unable to format path");
cp += strlen(cp);
*cp++ = RDELIM;
*cp++ = DELIM;
pt++;
}
cp--;
switch (closed)
{
case TRUE:
*cp++ = RDELIM;
break;
case FALSE:
*cp++ = RDELIM_EP;
break;
default:
break;
}
*cp = '\0';
return result;
} /* path_encode() */
/*-------------------------------------------------------------
* pair_count - count the number of points
* allow the following notation:
* '((1,2),(3,4))'
* '(1,3,2,4)'
* require an odd number of delim characters in the string
*-------------------------------------------------------------*/
static int
pair_count(char *s, char delim)
{
int ndelim = 0;
while ((s = strchr(s, delim)) != NULL)
{
ndelim++;
s++;
}
return (ndelim % 2) ? ((ndelim + 1) / 2) : -1;
}
/***********************************************************************
**
** Routines for two-dimensional boxes.
**
***********************************************************************/
/*----------------------------------------------------------
* Formatting and conversion routines.
*---------------------------------------------------------*/
/* box_in - convert a string to internal form.
*
* External format: (two corners of box)
* "(f8, f8), (f8, f8)"
* also supports the older style "(f8, f8, f8, f8)"
*/
BOX *
box_in(char *str)
{
BOX *box = palloc(sizeof(BOX));
int isopen; char *s;
double x,
y;
if (!PointerIsValid(str))
elog(ERROR, " Bad (null) box external representation");
if ((!path_decode(FALSE, 2, str, &isopen, &s, &(box->high)))
|| (*s != '\0'))
elog(ERROR, "Bad box external representation '%s'", str);
/* reorder corners if necessary... */
if (box->high.x < box->low.x)
{
x = box->high.x;
box->high.x = box->low.x;
box->low.x = x;
}
if (box->high.y < box->low.y)
{
y = box->high.y;
box->high.y = box->low.y;
box->low.y = y;
}
return box;
} /* box_in() */
/* box_out - convert a box to external form.
*/
char *
box_out(BOX *box)
{
if (!PointerIsValid(box))
return NULL;
return path_encode(-1, 2, (Point *) &(box->high));
} /* box_out() */
/* box_construct - fill in a new box.
*/
static BOX *
box_construct(double x1, double x2, double y1, double y2)
{
BOX *result = palloc(sizeof(BOX));
return box_fill(result, x1, x2, y1, y2);
}
/* box_fill - fill in a static box
*/
static BOX *
box_fill(BOX *result, double x1, double x2, double y1, double y2)
{
if (x1 > x2)
{
result->high.x = x1;
result->low.x = x2;
}
else
{
result->high.x = x2;
result->low.x = x1;
}
if (y1 > y2)
{
result->high.y = y1;
result->low.y = y2; }
else
{
result->high.y = y2;
result->low.y = y1;
}
return result;
}
/* box_copy - copy a box
*/
static BOX *
box_copy(BOX *box)
{
BOX *result = palloc(sizeof(BOX));
memmove((char *) result, (char *) box, sizeof(BOX));
return result;
}
/*----------------------------------------------------------
* Relational operators for BOXes.
* <, >, <=, >=, and == are based on box area.
*---------------------------------------------------------*/
/* box_same - are two boxes identical?
*/
bool
box_same(BOX *box1, BOX *box2)
{
return ((FPeq(box1->high.x, box2->high.x) && FPeq(box1->low.x, box2->low.x)) &&
(FPeq(box1->high.y, box2->high.y) && FPeq(box1->low.y, box2->low.y)));
}
/* box_overlap - does box1 overlap box2?
*/
bool
box_overlap(BOX *box1, BOX *box2)
{
return (((FPge(box1->high.x, box2->high.x) && FPle(box1->low.x, box2->high.x)) ||
(FPge(box2->high.x, box1->high.x) && FPle(box2->low.x, box1->high.x))) &&
((FPge(box1->high.y, box2->high.y) && FPle(box1->low.y, box2->high.y)) ||
(FPge(box2->high.y, box1->high.y) && FPle(box2->low.y, box1->high.y))));
}
/* box_overleft - is the right edge of box1 to the left of
* the right edge of box2?
*
* This is "less than or equal" for the end of a time range,
* when time ranges are stored as rectangles.
*/
bool
box_overleft(BOX *box1, BOX *box2)
{
return FPle(box1->high.x, box2->high.x);
}
/* box_left - is box1 strictly left of box2?
*/
bool
box_left(BOX *box1, BOX *box2)
{
return FPlt(box1->high.x, box2->low.x);
}
/* box_right - is box1 strictly right of box2? */
bool
box_right(BOX *box1, BOX *box2)
{
return FPgt(box1->low.x, box2->high.x);
}
/* box_overright - is the left edge of box1 to the right of
* the left edge of box2?
*
* This is "greater than or equal" for time ranges, when time ranges
* are stored as rectangles.
*/
bool
box_overright(BOX *box1, BOX *box2)
{
return box1->low.x >= box2->low.x;
}
/* box_contained - is box1 contained by box2?
*/
bool
box_contained(BOX *box1, BOX *box2)
{
return ((FPle(box1->high.x, box2->high.x) && FPge(box1->low.x, box2->low.x)) &&
(FPle(box1->high.y, box2->high.y) && FPge(box1->low.y, box2->low.y)));
}
/* box_contain - does box1 contain box2?
*/
bool
box_contain(BOX *box1, BOX *box2)
{
return ((FPge(box1->high.x, box2->high.x) && FPle(box1->low.x, box2->low.x) &&
FPge(box1->high.y, box2->high.y) && FPle(box1->low.y, box2->low.y)));
}
/* box_positionop -
* is box1 entirely {above,below} box2?
*/
bool
box_below(BOX *box1, BOX *box2)
{
return FPle(box1->high.y, box2->low.y);
}
bool
box_above(BOX *box1, BOX *box2)
{
return FPge(box1->low.y, box2->high.y);
}
/* box_relop - is area(box1) relop area(box2), within
* our accuracy constraint?
*/
bool
box_lt(BOX *box1, BOX *box2)
{
return FPlt(box_ar(box1), box_ar(box2));
}
bool
box_gt(BOX *box1, BOX *box2)
{
return FPgt(box_ar(box1), box_ar(box2));
}
boolbox_eq(BOX *box1, BOX *box2)
{
return FPeq(box_ar(box1), box_ar(box2));
}
bool
box_le(BOX *box1, BOX *box2)
{
return FPle(box_ar(box1), box_ar(box2));
}
bool
box_ge(BOX *box1, BOX *box2)
{
return FPge(box_ar(box1), box_ar(box2));
}
/*----------------------------------------------------------
* "Arithmetic" operators on boxes.
* box_foo returns foo as an object (pointer) that
can be passed between languages.
* box_xx is an internal routine which returns the
* actual value (and cannot be handed back to
* LISP).
*---------------------------------------------------------*/
/* box_area - returns the area of the box.
*/
double *
box_area(BOX *box)
{
double *result = palloc(sizeof(double));
*result = box_wd(box) * box_ht(box);
return result;
}
/* box_width - returns the width of the box
* (horizontal magnitude).
*/
double *
box_width(BOX *box)
{
double *result = palloc(sizeof(double));
*result = box->high.x - box->low.x;
return result;
} /* box_width() */
/* box_height - returns the height of the box
* (vertical magnitude).
*/
double *
box_height(BOX *box)
{
double *result = palloc(sizeof(double));
*result = box->high.y - box->low.y;
return result;
}
/* box_distance - returns the distance between the
* center points of two boxes. */
double *
box_distance(BOX *box1, BOX *box2)
{
double *result = palloc(sizeof(double));
Point *a,
*b;
a = box_center(box1);
b = box_center(box2);
*result = HYPOT(a->x - b->x, a->y - b->y);
pfree(a);
pfree(b);
return result;
}
/* box_center - returns the center point of the box.
*/
Point *
box_center(BOX *box)
{
Point *result = palloc(sizeof(Point));
result->x = (box->high.x + box->low.x) / 2.0;
result->y = (box->high.y + box->low.y) / 2.0;
return result;
}
/* box_ar - returns the area of the box.
*/
static double
box_ar(BOX *box)
{
return box_wd(box) * box_ht(box);
}
/* box_wd - returns the width (length) of the box
* (horizontal magnitude).
*/
static double
box_wd(BOX *box)
{
return box->high.x - box->low.x;
}
/* box_ht - returns the height of the box
* (vertical magnitude).
*/
static double
box_ht(BOX *box)
{
return box->high.y - box->low.y;
}
/* box_dt - returns the distance between the
* center points of two boxes.
*/
#ifdef NOT_USED
static double
box_dt(BOX *box1, BOX *box2)
{
double result;
Point *a, *b;
a = box_center(box1);
b = box_center(box2);
result = HYPOT(a->x - b->x, a->y - b->y);
pfree(a);
pfree(b);
return result;
}
#endif
/*----------------------------------------------------------
* Funky operations.
*---------------------------------------------------------*/
/* box_intersect -
* returns the overlapping portion of two boxes,
* or NULL if they do not intersect.
*/
BOX *
box_intersect(BOX *box1, BOX *box2)
{
BOX *result;
if (!box_overlap(box1, box2))
return NULL;
result = palloc(sizeof(BOX));
result->high.x = Min(box1->high.x, box2->high.x);
result->low.x = Max(box1->low.x, box2->low.x);
result->high.y = Min(box1->high.y, box2->high.y);
result->low.y = Max(box1->low.y, box2->low.y);
return result;
}
/* box_diagonal -
* returns a line segment which happens to be the
* positive-slope diagonal of "box".
* provided, of course, we have LSEGs.
*/
LSEG *
box_diagonal(BOX *box)
{
Point p1,
p2;
p1.x = box->high.x;
p1.y = box->high.y;
p2.x = box->low.x;
p2.y = box->low.y;
return lseg_construct(&p1, &p2);
}
/***********************************************************************
**
** Routines for 2D lines.
** Lines are not intended to be used as ADTs per se,
** but their ops are useful tools for other ADT ops. Thus,
** there are few relops.
**
***********************************************************************/
LINE *
line_in(char *str)
{ LINE *line;
#ifdef ENABLE_LINE_TYPE
LSEG lseg;
int isopen;
char *s;
#endif
if (!PointerIsValid(str))
elog(ERROR, " Bad (null) line external representation");
#ifdef ENABLE_LINE_TYPE
if ((!path_decode(TRUE, 2, str, &isopen, &s, &(lseg.p[0])))
|| (*s != '\0'))
elog(ERROR, "Bad line external representation '%s'", str);
line = line_construct_pp(&(lseg.p[0]), &(lseg.p[1]));
#else
elog(ERROR, "line not yet implemented");
line = NULL;
#endif
return line;
} /* line_in() */
char *
line_out(LINE *line)
{
char *result;
#ifdef ENABLE_LINE_TYPE
LSEG lseg;
#endif
if (!PointerIsValid(line))
return NULL;
#ifdef ENABLE_LINE_TYPE
if (FPzero(line->B))
{ /* vertical */
/* use "x = C" */
result->A = -1;
result->B = 0;
result->C = pt1->x;
#ifdef GEODEBUG
printf("line_construct_pp- line is vertical\n");
#endif
#ifdef NOT_USED
result->m = DBL_MAX;
#endif
}
else if (FPzero(line->A))
{ /* horizontal */
/* use "x = C" */
result->A = 0;
result->B = -1;
result->C = pt1->y;
#ifdef GEODEBUG
printf("line_construct_pp- line is horizontal\n");
#endif
#ifdef NOT_USED
result->m = 0.0;
#endif
}
else {
}
if (line_horizontal(line))
{
}
else if (line_vertical(line))
{
}
else
{
}
return path_encode(TRUE, 2, (Point *) &(ls->p[0]));
#else
elog(ERROR, "line not yet implemented");
result = NULL;
#endif
return result;
} /* line_out() */
/*----------------------------------------------------------
* Conversion routines from one line formula to internal.
* Internal form: Ax+By+C=0
*---------------------------------------------------------*/
/* line_construct_pm()
* point-slope
*/
static LINE *
line_construct_pm(Point *pt, double m)
{
LINE *result = palloc(sizeof(LINE));
/* use "mx - y + yinter = 0" */
result->A = m;
result->B = -1.0;
if (m == DBL_MAX)
result->C = pt->y;
else
result->C = pt->y - m * pt->x;
#ifdef NOT_USED
result->m = m;
#endif
return result;
} /* line_construct_pm() */
/* line_construct_pp()
* two points
*/
LINE *
line_construct_pp(Point *pt1, Point *pt2)
{
LINE *result = palloc(sizeof(LINE));
if (FPeq(pt1->x, pt2->x))
{ /* vertical */
/* use "x = C" */
result->A = -1;
result->B = 0;
result->C = pt1->x;
#ifdef GEODEBUG
printf("line_construct_pp- line is vertical\n");
#endif
#ifdef NOT_USED result->m = DBL_MAX;
#endif
}
else if (FPeq(pt1->y, pt2->y))
{ /* horizontal */
/* use "x = C" */
result->A = 0;
result->B = -1;
result->C = pt1->y;
#ifdef GEODEBUG
printf("line_construct_pp- line is horizontal\n");
#endif
#ifdef NOT_USED
result->m = 0.0;
#endif
}
else
{
/* use "mx - y + yinter = 0" */
#ifdef NOT_USED
result->A = (pt1->y - pt2->y) / (pt1->x - pt2->x);
#endif
result->A = (pt2->y - pt1->y) / (pt2->x - pt1->x);
result->B = -1.0;
result->C = pt1->y - result->A * pt1->x;
#ifdef GEODEBUG
printf("line_construct_pp- line is neither vertical nor horizontal (diffs x=%.*g, y=%.*g\n",
digits8, (pt2->x - pt1->x), digits8, (pt2->y - pt1->y));
#endif
#ifdef NOT_USED
result->m = result->A;
#endif
}
return result;
} /* line_construct_pp() */
/*----------------------------------------------------------
* Relative position routines.
*---------------------------------------------------------*/
bool
line_intersect(LINE *l1, LINE *l2)
{
return !line_parallel(l1, l2);
}
bool
line_parallel(LINE *l1, LINE *l2)
{
#ifdef NOT_USED
return FPeq(l1->m, l2->m);
#endif
if (FPzero(l1->B))
return FPzero(l2->B);
return FPeq(l2->A, l1->A * (l2->B / l1->B));
} /* line_parallel() */
bool
line_perp(LINE *l1, LINE *l2)
{
#ifdef NOT_USED
if (l1->m)
return FPeq(l2->m / l1->m, -1.0);
else if (l2->m)
return FPeq(l1->m / l2->m, -1.0);
#endif if (FPzero(l1->A))
return FPzero(l2->B);
else if (FPzero(l1->B))
return FPzero(l2->A);
return FPeq(((l1->A * l2->B) / (l1->B * l2->A)), -1.0);
} /* line_perp() */
bool
line_vertical(LINE *line)
{
#ifdef NOT_USED
return FPeq(line->A, -1.0) && FPzero(line->B);
#endif
return FPzero(line->B);
} /* line_vertical() */
bool
line_horizontal(LINE *line)
{
#ifdef NOT_USED
return FPzero(line->m);
#endif
return FPzero(line->A);
} /* line_horizontal() */
bool
line_eq(LINE *l1, LINE *l2)
{
double k;
if (!FPzero(l2->A))
k = l1->A / l2->A;
else if (!FPzero(l2->B))
k = l1->B / l2->B;
else if (!FPzero(l2->C))
k = l1->C / l2->C;
else
k = 1.0;
return (FPeq(l1->A, k * l2->A) &&
FPeq(l1->B, k * l2->B) &&
FPeq(l1->C, k * l2->C));
}
/*----------------------------------------------------------
* Line arithmetic routines.
*---------------------------------------------------------*/
/* line_distance()
* Distance between two lines.
*/
double *
line_distance(LINE *l1, LINE *l2)
{
double *result = palloc(sizeof(double));
Point *tmp;
if (line_intersect(l1, l2))
{
*result = 0.0;
return result;
}
if (line_vertical(l1))
*result = fabs(l1->C - l2->C);
else
{
tmp = point_construct(0.0, l1->C);
result = dist_pl(tmp, l2); pfree(tmp);
}
return result;
}
/* line_interpt()
* Point where two lines l1, l2 intersect (if any)
*/
Point *
line_interpt(LINE *l1, LINE *l2)
{
Point *result;
double x,
y;
if (line_parallel(l1, l2))
return NULL;
#ifdef NOT_USED
if (line_vertical(l1))
result = point_construct(l2->m * l1->C + l2->C, l1->C);
else if (line_vertical(l2))
result = point_construct(l1->m * l2->C + l1->C, l2->C);
else
{
x = (l1->C - l2->C) / (l2->A - l1->A);
result = point_construct(x, l1->m * x + l1->C);
}
#endif
if (line_vertical(l1))
{
#ifdef NOT_USED
x = l1->C;
y = -((l2->A * x + l2->C) / l2->B);
#endif
x = l1->C;
y = (l2->A * x + l2->C);
}
else if (line_vertical(l2))
{
#ifdef NOT_USED
x = l2->C;
y = -((l1->A * x + l1->C) / l1->B);
#endif
x = l2->C;
y = (l1->A * x + l1->C);
}
else
{
#ifdef NOT_USED
x = (l2->B * l1->C - l1->B * l2->C) / (l2->A * l1->B - l1->A * l2->B);
y = -((l1->A * x + l1->C) / l1->B);
#endif
x = (l1->C - l2->C) / (l2->A - l1->A);
y = (l1->A * x + l1->C);
}
result = point_construct(x, y);
#ifdef GEODEBUG
printf("line_interpt- lines are A=%.*g, B=%.*g, C=%.*g, A=%.*g, B=%.*g, C=%.*g\n",
digits8, l1->A, digits8, l1->B, digits8, l1->C, digits8, l2->A, digits8, l2->B, digits8, l2->C);
printf("line_interpt- lines intersect at (%.*g,%.*g)\n", digits8, x, digits8, y);
#endif
return result;
} /* line_interpt() */
/*********************************************************************** **
** Routines for 2D paths (sequences of line segments, also
** called `polylines').
**
** This is not a general package for geometric paths,
** which of course include polygons; the emphasis here
** is on (for example) usefulness in wire layout.
**
***********************************************************************/
/*----------------------------------------------------------
* String to path / path to string conversion.
* External format:
* "((xcoord, ycoord),... )"
* "[(xcoord, ycoord),... ]"
* "(xcoord, ycoord),... "
* "[xcoord, ycoord,... ]"
* Also support older format:
* "(closed, npts, xcoord, ycoord,... )"
*---------------------------------------------------------*/
PATH *
path_in(char *str)
{
PATH *path;
int isopen;
char *s;
int npts;
int size;
int depth = 0;
if (!PointerIsValid(str))
elog(ERROR, "Bad (null) path external representation");
if ((npts = pair_count(str, ',')) <= 0)
elog(ERROR, "Bad path external representation '%s'", str);
s = str;
while (isspace(*s))
s++;
/* skip single leading paren */
if ((*s == LDELIM) && (strrchr(s, LDELIM) == s))
{
s++;
depth++;
}
size = offsetof(PATH, p[0]) +(sizeof(path->p[0]) * npts);
path = palloc(size);
path->size = size;
path->npts = npts;
if ((!path_decode(TRUE, npts, s, &isopen, &s, &(path->p[0])))
&& (!((depth == 0) && (*s == '\0'))) && !((depth >= 1) && (*s == RDELIM)))
elog(ERROR, "Bad path external representation '%s'", str);
path->closed = (!isopen);
return path;
} /* path_in() */
char *
path_out(PATH *path)
{
if (!PointerIsValid(path))
return NULL;
return path_encode(path->closed, path->npts, (Point *) &(path->p[0]));
} /* path_out() */
/*----------------------------------------------------------
* Relational operators.
* These are based on the path cardinality,
* as stupid as that sounds.
*
* Better relops and access methods coming soon.
*---------------------------------------------------------*/
bool
path_n_lt(PATH *p1, PATH *p2)
{
return (p1->npts < p2->npts);
}
bool
path_n_gt(PATH *p1, PATH *p2)
{
return (p1->npts > p2->npts);
}
bool
path_n_eq(PATH *p1, PATH *p2)
{
return (p1->npts == p2->npts);
}
bool
path_n_le(PATH *p1, PATH *p2)
{
return (p1->npts <= p2->npts);
}
bool
path_n_ge(PATH *p1, PATH *p2)
{
return (p1->npts >= p2->npts);
}
/*----------------------------------------------------------
* Conversion operators.
*---------------------------------------------------------*/
bool
path_isclosed(PATH *path)
{
if (!PointerIsValid(path))
return FALSE;
return path->closed;
} /* path_isclosed() */
bool
path_isopen(PATH *path)
{
if (!PointerIsValid(path))
return FALSE;
return !path->closed;
} /* path_isopen() */
int4
path_npoints(PATH *path)
{ if (!PointerIsValid(path))
return 0;
return path->npts;
} /* path_npoints() */
PATH *
path_close(PATH *path)
{
PATH *result;
if (!PointerIsValid(path))
return NULL;
result = path_copy(path);
result->closed = TRUE;
return result;
} /* path_close() */
PATH *
path_open(PATH *path)
{
PATH *result;
if (!PointerIsValid(path))
return NULL;
result = path_copy(path);
result->closed = FALSE;
return result;
} /* path_open() */
static PATH *
path_copy(PATH *path)
{
PATH *result;
int size;
size = offsetof(PATH, p[0]) +(sizeof(path->p[0]) * path->npts);
result = palloc(size);
memmove((char *) result, (char *) path, size);
return result;
} /* path_copy() */
/* path_inter -
* Does p1 intersect p2 at any point?
* Use bounding boxes for a quick (O(n)) check, then do a
* O(n^2) iterative edge check.
*/
bool
path_inter(PATH *p1, PATH *p2)
{
BOX b1,
b2;
int i,
j;
LSEG seg1,
seg2;
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++)
{
b1.high.x = Max(p1->p[i].x, b1.high.x); b1.high.y = Max(p1->p[i].y, b1.high.y);
b1.low.x = Min(p1->p[i].x, b1.low.x);
b1.low.y = Min(p1->p[i].y, b1.low.y);
}
b2.high.x = b2.low.x = p2->p[0].x;
b2.high.y = b2.low.y = p2->p[0].y;
for (i = 1; i < p2->npts; i++)
{
b2.high.x = Max(p2->p[i].x, b2.high.x);
b2.high.y = Max(p2->p[i].y, b2.high.y);
b2.low.x = Min(p2->p[i].x, b2.low.x);
b2.low.y = Min(p2->p[i].y, b2.low.y);
}
if (!box_overlap(&b1, &b2))
return FALSE;
/* pairwise check lseg intersections */
for (i = 0; i < p1->npts - 1; i++)
{
for (j = 0; j < p2->npts - 1; j++)
{
statlseg_construct(&seg1, &p1->p[i], &p1->p[i + 1]);
statlseg_construct(&seg2, &p2->p[j], &p2->p[j + 1]);
if (lseg_intersect(&seg1, &seg2))
return TRUE;
}
}
/* if we dropped through, no two segs intersected */
return FALSE;
} /* path_inter() */
/* path_distance()
* This essentially does a cartesian product of the lsegs in the
* two paths, and finds the min distance between any two lsegs
*/
double *
path_distance(PATH *p1, PATH *p2)
{
double *min = NULL,
*tmp;
int i,
j;
LSEG seg1,
seg2;
/*
statlseg_construct(&seg1, &p1->p[0], &p1->p[1]);
statlseg_construct(&seg2, &p2->p[0], &p2->p[1]);
min = lseg_distance(&seg1, &seg2);
*/
for (i = 0; i < p1->npts - 1; i++)
for (j = 0; j < p2->npts - 1; j++)
{
statlseg_construct(&seg1, &p1->p[i], &p1->p[i + 1]);
statlseg_construct(&seg2, &p2->p[j], &p2->p[j + 1]);
tmp = lseg_distance(&seg1, &seg2);
if ((min == NULL) || (*min < *tmp))
{
if (min != NULL)
pfree(min);
min = tmp;
}
else
pfree(tmp);
}
return min;} /* path_distance() */
/*----------------------------------------------------------
* "Arithmetic" operations.
*---------------------------------------------------------*/
double *
path_length(PATH *path)
{
double *result;
int i;
result = palloc(sizeof(double));
*result = 0;
for (i = 0; i < (path->npts - 1); i++)
*result += point_dt(&path->p[i], &path->p[i + 1]);
return result;
} /* path_length() */
#ifdef NOT_USED
double
path_ln(PATH *path)
{
double result;
int i;
result = 0;
for (i = 0; i < (path->npts - 1); i++)
result += point_dt(&path->p[i], &path->p[i + 1]);
return result;
} /* path_ln() */
#endif
/***********************************************************************
**
** Routines for 2D points.
**
***********************************************************************/
/*----------------------------------------------------------
* String to point, point to string conversion.
* External format:
* "(x,y)"
* "x,y"
*---------------------------------------------------------*/
Point *
point_in(char *str)
{
Point *point;
double x,
y;
char *s;
if (!PointerIsValid(str))
elog(ERROR, "Bad (null) point external representation");
if (!pair_decode(str, &x, &y, &s) || (strlen(s) > 0))
elog(ERROR, "Bad point external representation '%s'", str);
point = palloc(sizeof(Point));
point->x = x; point->y = y;
return point;
} /* point_in() */
char *
point_out(Point *pt)
{
if (!PointerIsValid(pt))
return NULL;
return path_encode(-1, 1, pt);
} /* point_out() */
static Point *
point_construct(double x, double y)
{
Point *result = palloc(sizeof(Point));
result->x = x;
result->y = y;
return result;
}
static Point *
point_copy(Point *pt)
{
Point *result;
if (!PointerIsValid(pt))
return NULL;
result = palloc(sizeof(Point));
result->x = pt->x;
result->y = pt->y;
return result;
}
/*----------------------------------------------------------
* Relational operators for Points.
* Since we do have a sense of coordinates being
* "equal" to a given accuracy (point_vert, point_horiz),
* the other ops must preserve that sense. This means
* that results may, strictly speaking, be a lie (unless
* EPSILON = 0.0).
*---------------------------------------------------------*/
bool
point_left(Point *pt1, Point *pt2)
{
return FPlt(pt1->x, pt2->x);
}
bool
point_right(Point *pt1, Point *pt2)
{
return FPgt(pt1->x, pt2->x);
}
bool
point_above(Point *pt1, Point *pt2)
{
return FPgt(pt1->y, pt2->y);
}
boolpoint_below(Point *pt1, Point *pt2)
{
return FPlt(pt1->y, pt2->y);
}
bool
point_vert(Point *pt1, Point *pt2)
{
return FPeq(pt1->x, pt2->x);
}
bool
point_horiz(Point *pt1, Point *pt2)
{
return FPeq(pt1->y, pt2->y);
}
bool
point_eq(Point *pt1, Point *pt2)
{
return point_horiz(pt1, pt2) && point_vert(pt1, pt2);
}
bool
point_ne(Point *pt1, Point *pt2)
{
return !point_eq(pt1, pt2);
}
/*----------------------------------------------------------
* "Arithmetic" operators on points.
*---------------------------------------------------------*/
int32
pointdist(Point *p1, Point *p2)
{
int32 result;
result = point_dt(p1, p2);
return result;
}
double *
point_distance(Point *pt1, Point *pt2)
{
double *result = palloc(sizeof(double));
*result = HYPOT(pt1->x - pt2->x, pt1->y - pt2->y);
return result;
}
double
point_dt(Point *pt1, Point *pt2)
{
#ifdef GEODEBUG
printf("point_dt- segment (%f,%f),(%f,%f) length is %f\n",
pt1->x, pt1->y, pt2->x, pt2->y, HYPOT(pt1->x - pt2->x, pt1->y - pt2->y));
#endif
return HYPOT(pt1->x - pt2->x, pt1->y - pt2->y);
}
double *
point_slope(Point *pt1, Point *pt2)
{
double *result = palloc(sizeof(double));
if (point_vert(pt1, pt2))
*result = (double) DBL_MAX;
else *result = (pt1->y - pt2->y) / (pt1->x - pt1->x);
return result;
}
double
point_sl(Point *pt1, Point *pt2)
{
return (point_vert(pt1, pt2)
? (double) DBL_MAX
: (pt1->y - pt2->y) / (pt1->x - pt2->x));
}
/***********************************************************************
**
** Routines for 2D line segments.
**
***********************************************************************/
/*----------------------------------------------------------
* String to lseg, lseg to string conversion.
* External forms: "[(x1, y1), (x2, y2)]"
* "(x1, y1), (x2, y2)"
* "x1, y1, x2, y2"
* closed form ok "((x1, y1), (x2, y2))"
* (old form) "(x1, y1, x2, y2)"
*---------------------------------------------------------*/
LSEG *
lseg_in(char *str)
{
LSEG *lseg;
int isopen;
char *s;
if (!PointerIsValid(str))
elog(ERROR, " Bad (null) lseg external representation");
lseg = palloc(sizeof(LSEG));
if ((!path_decode(TRUE, 2, str, &isopen, &s, &(lseg->p[0])))
|| (*s != '\0'))
elog(ERROR, "Bad lseg external representation '%s'", str);
#ifdef NOT_USED
lseg->m = point_sl(&lseg->p[0], &lseg->p[1]);
#endif
return lseg;
} /* lseg_in() */
char *
lseg_out(LSEG *ls)
{
if (!PointerIsValid(ls))
return NULL;
return path_encode(FALSE, 2, (Point *) &(ls->p[0]));
} /* lseg_out() */
/* lseg_construct -
* form a LSEG from two Points.
*/
LSEG *
lseg_construct(Point *pt1, Point *pt2)
{ LSEG *result = palloc(sizeof(LSEG));
result->p[0].x = pt1->x;
result->p[0].y = pt1->y;
result->p[1].x = pt2->x;
result->p[1].y = pt2->y;
#ifdef NOT_USED
result->m = point_sl(pt1, pt2);
#endif
return result;
}
/* like lseg_construct, but assume space already allocated */
static void
statlseg_construct(LSEG *lseg, Point *pt1, Point *pt2)
{
lseg->p[0].x = pt1->x;
lseg->p[0].y = pt1->y;
lseg->p[1].x = pt2->x;
lseg->p[1].y = pt2->y;
#ifdef NOT_USED
lseg->m = point_sl(pt1, pt2);
#endif
}
double *
lseg_length(LSEG *lseg)
{
double *result;
if (!PointerIsValid(lseg))
return NULL;
result = point_distance(&lseg->p[0], &lseg->p[1]);
return result;
} /* lseg_length() */
/*----------------------------------------------------------
* Relative position routines.
*---------------------------------------------------------*/
/*
** find intersection of the two lines, and see if it falls on
** both segments.
*/
bool
lseg_intersect(LSEG *l1, LSEG *l2)
{
LINE *ln;
Point *interpt;
bool retval;
ln = line_construct_pp(&l2->p[0], &l2->p[1]);
interpt = interpt_sl(l1, ln);
if (interpt != NULL && on_ps(interpt, l2)) /* interpt on l1 and l2 */
retval = TRUE;
else
retval = FALSE;
if (interpt != NULL)
pfree(interpt);
pfree(ln);
return retval;
}
boollseg_parallel(LSEG *l1, LSEG *l2)
{
#ifdef NOT_USED
return FPeq(l1->m, l2->m);
#endif
return (FPeq(point_sl(&(l1->p[0]), &(l1->p[1])),
point_sl(&(l2->p[0]), &(l2->p[1]))));
} /* lseg_parallel() */
/* lseg_perp()
* Determine if two line segments are perpendicular.
*
* This code did not get the correct answer for
* '((0,0),(0,1))'::lseg ?-| '((0,0),(1,0))'::lseg
* So, modified it to check explicitly for slope of vertical line
* returned by point_sl() and the results seem better.
* - thomas 1998-01-31
*/
bool
lseg_perp(LSEG *l1, LSEG *l2)
{
double m1,
m2;
m1 = point_sl(&(l1->p[0]), &(l1->p[1]));
m2 = point_sl(&(l2->p[0]), &(l2->p[1]));
#ifdef GEODEBUG
printf("lseg_perp- slopes are %g and %g\n", m1, m2);
#endif
if (FPzero(m1))
return FPeq(m2, DBL_MAX);
else if (FPzero(m2))
return FPeq(m1, DBL_MAX);
return FPeq(m1 / m2, -1.0);
} /* lseg_perp() */
bool
lseg_vertical(LSEG *lseg)
{
return FPeq(lseg->p[0].x, lseg->p[1].x);
}
bool
lseg_horizontal(LSEG *lseg)
{
return FPeq(lseg->p[0].y, lseg->p[1].y);
}
bool
lseg_eq(LSEG *l1, LSEG *l2)
{
return (FPeq(l1->p[0].x, l2->p[0].x) &&
FPeq(l1->p[1].y, l2->p[1].y) &&
FPeq(l1->p[0].x, l2->p[0].x) &&
FPeq(l1->p[1].y, l2->p[1].y));
} /* lseg_eq() */
bool
lseg_ne(LSEG *l1, LSEG *l2)
{
return (!FPeq(l1->p[0].x, l2->p[0].x) ||
!FPeq(l1->p[1].y, l2->p[1].y) ||
!FPeq(l1->p[0].x, l2->p[0].x) ||
!FPeq(l1->p[1].y, l2->p[1].y));
} /* lseg_ne() */
boollseg_lt(LSEG *l1, LSEG *l2)
{
return FPlt(point_dt(&l1->p[0], &l1->p[1]), point_dt(&l2->p[0], &l2->p[1]));
} /* lseg_lt() */
bool
lseg_le(LSEG *l1, LSEG *l2)
{
return FPle(point_dt(&l1->p[0], &l1->p[1]), point_dt(&l2->p[0], &l2->p[1]));
} /* lseg_le() */
bool
lseg_gt(LSEG *l1, LSEG *l2)
{
return FPgt(point_dt(&l1->p[0], &l1->p[1]), point_dt(&l2->p[0], &l2->p[1]));
} /* lseg_gt() */
bool
lseg_ge(LSEG *l1, LSEG *l2)
{
return FPge(point_dt(&l1->p[0], &l1->p[1]), point_dt(&l2->p[0], &l2->p[1]));
} /* lseg_ge() */
/*----------------------------------------------------------
* Line arithmetic routines.
*---------------------------------------------------------*/
/* lseg_distance -
* If two segments don't intersect, then the closest
* point will be from one of the endpoints to the other
* segment.
*/
double *
lseg_distance(LSEG *l1, LSEG *l2)
{
double *result = palloc(sizeof(double));
*result = lseg_dt(l1, l2);
return result;
}
/* lseg_dt()
* Distance between two line segments.
* Must check both sets of endpoints to ensure minimum distance is found.
* - thomas 1998-02-01
*/
static double
lseg_dt(LSEG *l1, LSEG *l2)
{
double *d,
result;
if (lseg_intersect(l1, l2))
return 0.0;
d = dist_ps(&l1->p[0], l2);
result = *d;
pfree(d);
d = dist_ps(&l1->p[1], l2);
result = Min(result, *d);
pfree(d);
d = dist_ps(&l2->p[0], l1);
result = Min(result, *d);
pfree(d);
d = dist_ps(&l2->p[1], l1);
result = Min(result, *d);
pfree(d);
return result;
} /* lseg_dt() */
Point *
lseg_center(LSEG *lseg)
{
Point *result;
if (!PointerIsValid(lseg))
return NULL;
result = palloc(sizeof(Point));
result->x = (lseg->p[0].x - lseg->p[1].x) / 2;
result->y = (lseg->p[0].y - lseg->p[1].y) / 2;
return result;
} /* lseg_center() */
/* lseg_interpt -
* Find the intersection point of two segments (if any).
* Find the intersection of the appropriate lines; if the
* point is not on a given segment, there is no valid segment
* intersection point at all.
* If there is an intersection, then check explicitly for matching
* endpoints since there may be rounding effects with annoying
* lsb residue. - tgl 1997-07-09
*/
Point *
lseg_interpt(LSEG *l1, LSEG *l2)
{
Point *result;
LINE *tmp1,
*tmp2;
if (!PointerIsValid(l1) || !PointerIsValid(l2))
return NULL;
tmp1 = line_construct_pp(&l1->p[0], &l1->p[1]);
tmp2 = line_construct_pp(&l2->p[0], &l2->p[1]);
result = line_interpt(tmp1, tmp2);
if (PointerIsValid(result))
{
if (on_ps(result, l1))
{
if ((FPeq(l1->p[0].x, l2->p[0].x) && FPeq(l1->p[0].y, l2->p[0].y))
|| (FPeq(l1->p[0].x, l2->p[1].x) && FPeq(l1->p[0].y, l2->p[1].y)))
{
result->x = l1->p[0].x;
result->y = l1->p[0].y;
}
else if ((FPeq(l1->p[1].x, l2->p[0].x) && FPeq(l1->p[1].y, l2->p[0].y))
|| (FPeq(l1->p[1].x, l2->p[1].x) && FPeq(l1->p[1].y, l2->p[1].y)))
{
result->x = l1->p[1].x;
result->y = l1->p[1].y;
}
}
else
{
pfree(result);
result = NULL;
}
}
pfree(tmp1);
pfree(tmp2);
return result;
} /* lseg_interpt() */
/***********************************************************************
**
** Routines for position comparisons of differently-typed
** 2D objects.
**
***********************************************************************/
#define ABOVE 1
#define BELOW 0
#define UNDEF -1
/*---------------------------------------------------------------------
* dist_
* Minimum distance from one object to another.
*-------------------------------------------------------------------*/
double *
dist_pl(Point *pt, LINE *line)
{
double *result = palloc(sizeof(double));
*result = (line->A * pt->x + line->B * pt->y + line->C) /
HYPOT(line->A, line->B);
return result;
}
double *
dist_ps(Point *pt, LSEG *lseg)
{
double m; /* slope of perp. */
LINE *ln;
double *result,
*tmpdist;
Point *ip;
/*
* Construct a line perpendicular to the input segment
* and through the input point
*/
if (lseg->p[1].x == lseg->p[0].x)
m = 0;
else if (lseg->p[1].y == lseg->p[0].y)
{ /* slope is infinite */
m = (double) DBL_MAX;
}
else
{
#ifdef NOT_USED
m = (-1) * (lseg->p[1].y - lseg->p[0].y) /
(lseg->p[1].x - lseg->p[0].x);
#endif
m = ((lseg->p[0].y - lseg->p[1].y) / (lseg->p[1].x - lseg->p[0].x));
}
ln = line_construct_pm(pt, m);
#ifdef GEODEBUG
printf("dist_ps- line is A=%g B=%g C=%g from (point) slope (%f,%f) %g\n",
ln->A, ln->B, ln->C, pt->x, pt->y, m);
#endif
/*
* Calculate distance to the line segment
* or to the endpoints of the segment.
*/
/* intersection is on the line segment? */
if ((ip = interpt_sl(lseg, ln)) != NULL)
{
result = point_distance(pt, ip);
#ifdef GEODEBUG
printf("dist_ps- distance is %f to intersection point is (%f,%f)\n",
*result, ip->x, ip->y);
#endif
/* otherwise, intersection is not on line segment */
}
else
{
result = point_distance(pt, &lseg->p[0]);
tmpdist = point_distance(pt, &lseg->p[1]);
if (*tmpdist < *result)
*result = *tmpdist;
pfree(tmpdist);
}
if (ip != NULL)
pfree(ip);
pfree(ln);
return result;
}
/*
** Distance from a point to a path
*/
double *
dist_ppath(Point *pt, PATH *path)
{
double *result;
double *tmp;
int i;
LSEG lseg;
switch (path->npts)
{
/* no points in path? then result is undefined... */
case 0:
result = NULL;
break;
/* one point in path? then get distance between two points... */
case 1:
result = point_distance(pt, &path->p[0]);
break;
default:
/* make sure the path makes sense... */
Assert(path->npts > 1);
/*
* the distance from a point to a path is the smallest
* distance from the point to any of its constituent segments.
*/
result = palloc(sizeof(double));
for (i = 0; i < path->npts - 1; i++)
{
statlseg_construct(&lseg, &path->p[i], &path->p[i + 1]);
tmp = dist_ps(pt, &lseg);
if (i == 0 || *tmp < *result)
*result = *tmp;
pfree(tmp);
}
break;
}
return result;
}
double *
dist_pb(Point *pt, BOX *box)
{
Point *tmp;
double *result;
tmp = close_pb(pt, box);
result = point_distance(tmp, pt);
pfree(tmp);
return result;
}
double *
dist_sl(LSEG *lseg, LINE *line)
{
double *result,
*d2;
if (inter_sl(lseg, line))
{
result = palloc(sizeof(double));
*result = 0.0;
}
else
{
result = dist_pl(&lseg->p[0], line);
d2 = dist_pl(&lseg->p[1], line);
if (*d2 > *result)
{
pfree(result);
result = d2;
}
else
pfree(d2);
}
return result;
}
double *
dist_sb(LSEG *lseg, BOX *box)
{
Point *tmp;
double *result;
tmp = close_sb(lseg, box);
if (tmp == NULL)
{
result = palloc(sizeof(double));
*result = 0.0;
}
else
{
result = dist_pb(tmp, box);
pfree(tmp);
}
return result;
}
double *
dist_lb(LINE *line, BOX *box)
{
Point *tmp;
double *result;
tmp = close_lb(line, box);
if (tmp == NULL)
{
result = palloc(sizeof(double));
*result = 0.0;
}
else
{
result = dist_pb(tmp, box);
pfree(tmp);
}
return result;
}
double *
dist_cpoly(CIRCLE *circle, POLYGON *poly)
{
double *result;
int i;
double *d;
LSEG seg;
if (!PointerIsValid(circle) || !PointerIsValid(poly))
elog(ERROR, "Invalid (null) input for distance");
if (point_inside(&(circle->center), poly->npts, poly->p))
{
#ifdef GEODEBUG
printf("dist_cpoly- center inside of polygon\n");
#endif
result = palloc(sizeof(double));
*result = 0;
return result;
}
/* initialize distance with segment between first and last points */
seg.p[0].x = poly->p[0].x;
seg.p[0].y = poly->p[0].y;
seg.p[1].x = poly->p[poly->npts - 1].x;
seg.p[1].y = poly->p[poly->npts - 1].y;
result = dist_ps(&(circle->center), &seg);
#ifdef GEODEBUG
printf("dist_cpoly- segment 0/n distance is %f\n", *result);
#endif
/* check distances for other segments */
for (i = 0; (i < poly->npts - 1); i++)
{
seg.p[0].x = poly->p[i].x;
seg.p[0].y = poly->p[i].y;
seg.p[1].x = poly->p[i + 1].x;
seg.p[1].y = poly->p[i + 1].y;
d = dist_ps(&(circle->center), &seg);
#ifdef GEODEBUG
printf("dist_cpoly- segment %d distance is %f\n", (i + 1), *d);
#endif
if (*d < *result)
*result = *d;
pfree(d);
}
*result -= circle->radius;
if (*result < 0)
*result = 0;
return result;} /* dist_cpoly() */
/*---------------------------------------------------------------------
* interpt_
* Intersection point of objects.
* We choose to ignore the "point" of intersection between
* lines and boxes, since there are typically two.
*-------------------------------------------------------------------*/
static Point *
interpt_sl(LSEG *lseg, LINE *line)
{
LINE *tmp;
Point *p;
tmp = line_construct_pp(&lseg->p[0], &lseg->p[1]);
p = line_interpt(tmp, line);
#ifdef GEODEBUG
printf("interpt_sl- segment is (%.*g %.*g) (%.*g %.*g)\n",
digits8, lseg->p[0].x, digits8, lseg->p[0].y, digits8, lseg->p[1].x, digits8, lseg->p[1].y);
printf("interpt_sl- segment becomes line A=%.*g B=%.*g C=%.*g\n",
digits8, tmp->A, digits8, tmp->B, digits8, tmp->C);
#endif
if (PointerIsValid(p))
{
#ifdef GEODEBUG
printf("interpt_sl- intersection point is (%.*g %.*g)\n", digits8, p->x, digits8, p->y);
#endif
if (on_ps(p, lseg))
{
#ifdef GEODEBUG
printf("interpt_sl- intersection point is on segment\n");
#endif
}
else
{
pfree(p);
p = NULL;
}
}
pfree(tmp);
return p;
}
/*---------------------------------------------------------------------
* close_
* Point of closest proximity between objects.
*-------------------------------------------------------------------*/
/* close_pl -
* The intersection point of a perpendicular of the line
* through the point.
*/
Point *
close_pl(Point *pt, LINE *line)
{
Point *result;
LINE *tmp;
double invm;
result = palloc(sizeof(Point));
#ifdef NOT_USED
if (FPeq(line->A, -1.0) && FPzero(line->B))
{ /* vertical */
}
#endif if (line_vertical(line))
{
result->x = line->C;
result->y = pt->y;
return result;
#ifdef NOT_USED
}
else if (FPzero(line->m))
{ /* horizontal */
#endif
}
else if (line_horizontal(line))
{
result->x = pt->x;
result->y = line->C;
return result;
}
/* drop a perpendicular and find the intersection point */
#ifdef NOT_USED
invm = -1.0 / line->m;
#endif
/* invert and flip the sign on the slope to get a perpendicular */
invm = line->B / line->A;
tmp = line_construct_pm(pt, invm);
result = line_interpt(tmp, line);
return result;
} /* close_pl() */
/* close_ps()
* Closest point on line segment to specified point.
* Take the closest endpoint if the point is left, right,
* above, or below the segment, otherwise find the intersection
* point of the segment and its perpendicular through the point.
*
* Some tricky code here, relying on boolean expressions
* evaluating to only zero or one to use as an array index.
* bug fixes by gthaker@atl.lmco.com; May 1, 1998
*/
Point *
close_ps(Point *pt, LSEG *lseg)
{
Point *result;
LINE *tmp;
double invm;
int xh,
yh;
#ifdef GEODEBUG
printf("close_sp:pt->x %f pt->y %f\nlseg(0).x %f lseg(0).y %f lseg(1).x %f lseg(1).y %f\n",
pt->x, pt->y, lseg->p[0].x, lseg->p[0].y, lseg->p[1].x, lseg->p[1].y);
#endif
result = NULL;
xh = lseg->p[0].x < lseg->p[1].x;
yh = lseg->p[0].y < lseg->p[1].y;
/* !xh (or !yh) is the index of lower x( or y) end point of lseg */
/* vertical segment? */
if (lseg_vertical(lseg))
{
#ifdef GEODEBUG
printf("close_ps- segment is vertical\n");
#endif
/* first check if point is below or above the entire lseg. */
if (pt->y < lseg->p[!yh].y)
result = point_copy(&lseg->p[!yh]); /* below the lseg */
else if (pt->y > lseg->p[yh].y)
result = point_copy(&lseg->p[yh]); /* above the lseg */ if (result != NULL)
return result;
/* point lines along (to left or right) of the vertical lseg. */
result = palloc(sizeof(*result));
result->x = lseg->p[0].x;
result->y = pt->y;
return result;
}
else if (lseg_horizontal(lseg))
{
#ifdef GEODEBUG
printf("close_ps- segment is horizontal\n");
#endif
/* first check if point is left or right of the entire lseg. */
if (pt->x < lseg->p[!xh].x)
result = point_copy(&lseg->p[!xh]); /* left of the lseg */
else if (pt->x > lseg->p[xh].x)
result = point_copy(&lseg->p[xh]); /* right of the lseg */
if (result != NULL)
return result;
/* point lines along (at top or below) the horiz. lseg. */
result = palloc(sizeof(*result));
result->x = pt->x;
result->y = lseg->p[0].y;
return result;
}
/*
* vert. and horiz. cases are down, now check if the closest point is
* one of the end points or someplace on the lseg.
*/
/* TODO: Ask if "tmp" should be freed to prevent memory leak */
invm = -1.0 / point_sl(&(lseg->p[0]), &(lseg->p[1]));
tmp = line_construct_pm(&lseg->p[!yh], invm); /* lower edge of the
* "band" */
if (pt->y < (tmp->A * pt->x + tmp->C))
{ /* we are below the lower edge */
result = point_copy(&lseg->p[!yh]); /* below the lseg, take
* lower end pt */
/* fprintf(stderr,"below: tmp A %f B %f C %f m %f\n",tmp->A,tmp->B,tmp->C, tmp->m); */
return result;
}
tmp = line_construct_pm(&lseg->p[yh], invm); /* upper edge of the
* "band" */
if (pt->y > (tmp->A * pt->x + tmp->C))
{ /* we are below the lower edge */
result = point_copy(&lseg->p[yh]); /* above the lseg, take
* higher end pt */
/* fprintf(stderr,"above: tmp A %f B %f C %f m %f\n",tmp->A,tmp->B,tmp->C, tmp->m); */
return result;
}
/*
* at this point the "normal" from point will hit lseg. The closet
* point will be somewhere on the lseg
*/
tmp = line_construct_pm(pt, invm);
/* fprintf(stderr,"tmp A %f B %f C %f m %f\n",tmp->A,tmp->B,tmp->C, tmp->m); */
result = interpt_sl(lseg, tmp);
/* fprintf(stderr,"result.x %f result.y %f\n", result->x, result->y); */
return result;
} /* close_ps() */
/* close_lseg() * Closest point to l1 on l2.
*/
Point *
close_lseg(LSEG *l1, LSEG *l2)
{
Point *result = NULL;
Point point;
double dist;
double *d;
d = dist_ps(&l1->p[0], l2);
dist = *d;
memcpy(&point, &l1->p[0], sizeof(point));
pfree(d);
if (*(d = dist_ps(&l1->p[1], l2)) < dist)
{
dist = *d;
memcpy(&point, &l1->p[1], sizeof(point));
}
pfree(d);
if (*(d = dist_ps(&l2->p[0], l1)) < dist)
{
result = close_ps(&l2->p[0], l1);
memcpy(&point, result, sizeof(point));
pfree(result);
result = close_ps(&point, l2);
}
pfree(d);
if (*(d = dist_ps(&l2->p[1], l1)) < dist)
{
if (result != NULL)
pfree(result);
result = close_ps(&l2->p[1], l1);
memcpy(&point, result, sizeof(point));
pfree(result);
result = close_ps(&point, l2);
}
pfree(d);
if (result == NULL)
{
result = palloc(sizeof(*result));
memcpy(result, &point, sizeof(*result));
}
return result;
} /* close_lseg() */
/* close_pb()
* Closest point on or in box to specified point.
*/
Point *
close_pb(Point *pt, BOX *box)
{
LSEG lseg,
seg;
Point point;
double dist,
*d;
if (on_pb(pt, box))
return pt;
/* pairwise check lseg distances */
point.x = box->low.x;
point.y = box->high.y; statlseg_construct(&lseg, &box->low, &point);
dist = *(d = dist_ps(pt, &lseg));
pfree(d);
statlseg_construct(&seg, &box->high, &point);
if (*(d = dist_ps(pt, &seg)) < dist)
{
dist = *d;
memcpy(&lseg, &seg, sizeof(lseg));
}
pfree(d);
point.x = box->high.x;
point.y = box->low.y;
statlseg_construct(&seg, &box->low, &point);
if (*(d = dist_ps(pt, &seg)) < dist)
{
dist = *d;
memcpy(&lseg, &seg, sizeof(lseg));
}
pfree(d);
statlseg_construct(&seg, &box->high, &point);
if (*(d = dist_ps(pt, &seg)) < dist)
{
dist = *d;
memcpy(&lseg, &seg, sizeof(lseg));
}
pfree(d);
return close_ps(pt, &lseg);
} /* close_pb() */
/* close_sl()
* Closest point on line to line segment.
*
* XXX THIS CODE IS WRONG
* The code is actually calculating the point on the line segment
* which is backwards from the routine naming convention.
* Copied code to new routine close_ls() but haven't fixed this one yet.
* - thomas 1998-01-31
*/
Point *
close_sl(LSEG *lseg, LINE *line)
{
Point *result;
double *d1,
*d2;
result = interpt_sl(lseg, line);
if (result)
return result;
d1 = dist_pl(&lseg->p[0], line);
d2 = dist_pl(&lseg->p[1], line);
if (d1 < d2)
result = point_copy(&lseg->p[0]);
else
result = point_copy(&lseg->p[1]);
pfree(d1);
pfree(d2);
return result;
}
/* close_ls()
* Closest point on line segment to line.
*/
Point *
close_ls(LINE *line, LSEG *lseg){
Point *result;
double *d1,
*d2;
result = interpt_sl(lseg, line);
if (result)
return result;
d1 = dist_pl(&lseg->p[0], line);
d2 = dist_pl(&lseg->p[1], line);
if (d1 < d2)
result = point_copy(&lseg->p[0]);
else
result = point_copy(&lseg->p[1]);
pfree(d1);
pfree(d2);
return result;
} /* close_ls() */
/* close_sb()
* Closest point on or in box to line segment.
*/
Point *
close_sb(LSEG *lseg, BOX *box)
{
Point *result;
Point *pt;
Point point;
LSEG bseg,
seg;
double dist,
d;
/* segment intersects box? then just return closest point to center */
if (inter_sb(lseg, box))
{
pt = box_center(box);
result = close_ps(pt, lseg);
pfree(pt);
return result;
}
/* pairwise check lseg distances */
point.x = box->low.x;
point.y = box->high.y;
statlseg_construct(&bseg, &box->low, &point);
dist = lseg_dt(lseg, &bseg);
statlseg_construct(&seg, &box->high, &point);
if ((d = lseg_dt(lseg, &seg)) < dist)
{
dist = d;
memcpy(&bseg, &seg, sizeof(bseg));
}
point.x = box->high.x;
point.y = box->low.y;
statlseg_construct(&seg, &box->low, &point);
if ((d = lseg_dt(lseg, &seg)) < dist)
{
dist = d;
memcpy(&bseg, &seg, sizeof(bseg));
}
statlseg_construct(&seg, &box->high, &point);
if ((d = lseg_dt(lseg, &seg)) < dist)
{ dist = d;
memcpy(&bseg, &seg, sizeof(bseg));
}
/* OK, we now have the closest line segment on the box boundary */
return close_lseg(lseg, &bseg);
} /* close_sb() */
Point *
close_lb(LINE *line, BOX *box)
{
/* think about this one for a while */
elog(ERROR, "close_lb not implemented");
return NULL;
}
/*---------------------------------------------------------------------
* on_
* Whether one object lies completely within another.
*-------------------------------------------------------------------*/
/* on_pl -
* Does the point satisfy the equation?
*/
bool
on_pl(Point *pt, LINE *line)
{
if (!PointerIsValid(pt) || !PointerIsValid(line))
return FALSE;
return FPzero(line->A * pt->x + line->B * pt->y + line->C);
}
/* on_ps -
* Determine colinearity by detecting a triangle inequality.
* This algorithm seems to behave nicely even with lsb residues - tgl 1997-07-09
*/
bool
on_ps(Point *pt, LSEG *lseg)
{
if (!PointerIsValid(pt) || !PointerIsValid(lseg))
return FALSE;
return (FPeq(point_dt(pt, &lseg->p[0]) + point_dt(pt, &lseg->p[1]),
point_dt(&lseg->p[0], &lseg->p[1])));
}
bool
on_pb(Point *pt, BOX *box)
{
if (!PointerIsValid(pt) || !PointerIsValid(box))
return FALSE;
return (pt->x <= box->high.x && pt->x >= box->low.x &&
pt->y <= box->high.y && pt->y >= box->low.y);
}
/* on_ppath -
* Whether a point lies within (on) a polyline.
* If open, we have to (groan) check each segment.
* (uses same algorithm as for point intersecting segment - tgl 1997-07-09)
* If closed, we use the old O(n) ray method for point-in-polygon.
* The ray is horizontal, from pt out to the right.
* Each segment that crosses the ray counts as an
* intersection; note that an endpoint or edge may touch
* 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" */
bool
on_ppath(Point *pt, PATH *path)
{
int i,
n;
double a,
b;
if (!PointerIsValid(pt) || !PointerIsValid(path))
return FALSE;
/*-- OPEN --*/
if (!path->closed)
{
n = path->npts - 1;
a = point_dt(pt, &path->p[0]);
for (i = 0; i < n; i++)
{
b = point_dt(pt, &path->p[i + 1]);
if (FPeq(a + b,
point_dt(&path->p[i], &path->p[i + 1])))
return TRUE;
a = b;
}
return FALSE;
}
/*-- CLOSED --*/
return point_inside(pt, path->npts, path->p);
} /* on_ppath() */
bool
on_sl(LSEG *lseg, LINE *line)
{
if (!PointerIsValid(lseg) || !PointerIsValid(line))
return FALSE;
return on_pl(&lseg->p[0], line) && on_pl(&lseg->p[1], line);
} /* on_sl() */
bool
on_sb(LSEG *lseg, BOX *box)
{
if (!PointerIsValid(lseg) || !PointerIsValid(box))
return FALSE;
return on_pb(&lseg->p[0], box) && on_pb(&lseg->p[1], box);
} /* on_sb() */
/*---------------------------------------------------------------------
* inter_
* Whether one object intersects another.
*-------------------------------------------------------------------*/
bool
inter_sl(LSEG *lseg, LINE *line)
{
Point *tmp;
if (!PointerIsValid(lseg) || !PointerIsValid(line))
return FALSE;
tmp = interpt_sl(lseg, line);
if (tmp)
{
pfree(tmp);
return TRUE; }
return FALSE;
}
/* inter_sb()
* Do line segment and box intersect?
*
* Segment completely inside box counts as intersection.
* If you want only segments crossing box boundaries,
* try converting box to path first.
*
* Optimize for non-intersection by checking for box intersection first.
* - thomas 1998-01-30
*/
bool
inter_sb(LSEG *lseg, BOX *box)
{
BOX lbox;
LSEG bseg;
Point point;
if (!PointerIsValid(lseg) || !PointerIsValid(box))
return FALSE;
lbox.low.x = Min(lseg->p[0].x, lseg->p[1].x);
lbox.low.y = Min(lseg->p[0].y, lseg->p[1].y);
lbox.high.x = Max(lseg->p[0].x, lseg->p[1].x);
lbox.high.y = Max(lseg->p[0].y, lseg->p[1].y);
/* nothing close to overlap? then not going to intersect */
if (!box_overlap(&lbox, box))
return FALSE;
/* an endpoint of segment is inside box? then clearly intersects */
if (on_pb(&lseg->p[0], box) || on_pb(&lseg->p[1], box))
return TRUE;
/* pairwise check lseg intersections */
point.x = box->low.x;
point.y = box->high.y;
statlseg_construct(&bseg, &box->low, &point);
if (lseg_intersect(&bseg, lseg))
return TRUE;
statlseg_construct(&bseg, &box->high, &point);
if (lseg_intersect(&bseg, lseg))
return TRUE;
point.x = box->high.x;
point.y = box->low.y;
statlseg_construct(&bseg, &box->low, &point);
if (lseg_intersect(&bseg, lseg))
return TRUE;
statlseg_construct(&bseg, &box->high, &point);
if (lseg_intersect(&bseg, lseg))
return TRUE;
/* if we dropped through, no two segs intersected */
return FALSE;
} /* inter_sb() */
/* inter_lb()
* Do line and box intersect?
*/
bool
inter_lb(LINE *line, BOX *box)
{
LSEG bseg;
Point p1, p2;
if (!PointerIsValid(line) || !PointerIsValid(box))
return FALSE;
/* pairwise check lseg intersections */
p1.x = box->low.x;
p1.y = box->low.y;
p2.x = box->low.x;
p2.y = box->high.y;
statlseg_construct(&bseg, &p1, &p2);
if (inter_sl(&bseg, line))
return TRUE;
p1.x = box->high.x;
p1.y = box->high.y;
statlseg_construct(&bseg, &p1, &p2);
if (inter_sl(&bseg, line))
return TRUE;
p2.x = box->high.x;
p2.y = box->low.y;
statlseg_construct(&bseg, &p1, &p2);
if (inter_sl(&bseg, line))
return TRUE;
p1.x = box->low.x;
p1.y = box->low.y;
statlseg_construct(&bseg, &p1, &p2);
if (inter_sl(&bseg, line))
return TRUE;
/* if we dropped through, no intersection */
return FALSE;
}
/*------------------------------------------------------------------
* The following routines define a data type and operator class for
* POLYGONS .... Part of which (the polygon's bounding box) is built on
* top of the BOX data type.
*
* make_bound_box - create the bounding box for the input polygon
*------------------------------------------------------------------*/
/*---------------------------------------------------------------------
* Make the smallest bounding box for the given polygon.
*---------------------------------------------------------------------*/
static void
make_bound_box(POLYGON *poly)
{
int i;
double x1,
y1,
x2,
y2;
if (poly->npts > 0)
{
x2 = x1 = poly->p[0].x;
y2 = y1 = poly->p[0].y;
for (i = 1; i < poly->npts; i++)
{
if (poly->p[i].x < x1)
x1 = poly->p[i].x;
if (poly->p[i].x > x2)
x2 = poly->p[i].x;
if (poly->p[i].y < y1)
y1 = poly->p[i].y;
if (poly->p[i].y > y2)
y2 = poly->p[i].y;
}
box_fill(&(poly->boundbox), x1, x2, y1, y2); }
else
elog(ERROR, "Unable to create bounding box for empty polygon");
}
/*------------------------------------------------------------------
* poly_in - read in the polygon from a string specification
*
* External format:
* "((x0,y0),...,(xn,yn))"
* "x0,y0,...,xn,yn"
* also supports the older style "(x1,...,xn,y1,...yn)"
*------------------------------------------------------------------*/
POLYGON *
poly_in(char *str)
{
POLYGON *poly;
int npts;
int size;
int isopen;
char *s;
if (!PointerIsValid(str))
elog(ERROR, " Bad (null) polygon external representation");
if ((npts = pair_count(str, ',')) <= 0)
elog(ERROR, "Bad polygon external representation '%s'", str);
size = offsetof(POLYGON, p[0]) +(sizeof(poly->p[0]) * npts);
poly = palloc(size);
MemSet((char *) poly, 0, size); /* zero any holes */
poly->size = size;
poly->npts = npts;
if ((!path_decode(FALSE, npts, str, &isopen, &s, &(poly->p[0])))
|| (*s != '\0'))
elog(ERROR, "Bad polygon external representation '%s'", str);
make_bound_box(poly);
return poly;
} /* poly_in() */
/*---------------------------------------------------------------
* poly_out - convert internal POLYGON representation to the
* character string format "((f8,f8),...,(f8,f8))"
* also support old format "(f8,f8,...,f8,f8)"
*---------------------------------------------------------------*/
char *
poly_out(POLYGON *poly)
{
if (!PointerIsValid(poly))
return NULL;
return path_encode(TRUE, poly->npts, &(poly->p[0]));
} /* poly_out() */
/*-------------------------------------------------------
* Is polygon A strictly left of polygon B? i.e. is
* the right most point of A left of the left most point
* of B?
*-------------------------------------------------------*/
bool
poly_left(POLYGON *polya, POLYGON *polyb)
{
return polya->boundbox.high.x < polyb->boundbox.low.x;
}
/*-------------------------------------------------------
* Is polygon A overlapping or left of polygon B? i.e. is
* the left most point of A left of the right most point
* of B?
*-------------------------------------------------------*/
bool
poly_overleft(POLYGON *polya, POLYGON *polyb)
{
return polya->boundbox.low.x <= polyb->boundbox.high.x;
}
/*-------------------------------------------------------
* Is polygon A strictly right of polygon B? i.e. is
* the left most point of A right of the right most point
* of B?
*-------------------------------------------------------*/
bool
poly_right(POLYGON *polya, POLYGON *polyb)
{
return polya->boundbox.low.x > polyb->boundbox.high.x;
}
/*-------------------------------------------------------
* Is polygon A overlapping or right of polygon B? i.e. is
* the right most point of A right of the left most point
* of B?
*-------------------------------------------------------*/
bool
poly_overright(POLYGON *polya, POLYGON *polyb)
{
return polya->boundbox.high.x > polyb->boundbox.low.x;
}
/*-------------------------------------------------------
* Is polygon A the same as polygon B? i.e. are all the
* points the same?
* Check all points for matches in both forward and reverse
* direction since polygons are non-directional and are
* closed shapes.
*-------------------------------------------------------*/
bool
poly_same(POLYGON *polya, POLYGON *polyb)
{
if (!PointerIsValid(polya) || !PointerIsValid(polyb))
return FALSE;
if (polya->npts != polyb->npts)
return FALSE;
return plist_same(polya->npts, polya->p, polyb->p);
#ifdef NOT_USED
for (i = 0; i < polya->npts; i++)
{
if ((polya->p[i].x != polyb->p[i].x)
|| (polya->p[i].y != polyb->p[i].y))
return FALSE;
}
return TRUE;
#endif
} /* poly_same() */
/*-----------------------------------------------------------------
* Determine if polygon A overlaps polygon B by determining if
* their bounding boxes overlap.
*-----------------------------------------------------------------*/
bool
poly_overlap(POLYGON *polya, POLYGON *polyb)
{
return box_overlap(&(polya->boundbox), &(polyb->boundbox));}
/*-----------------------------------------------------------------
* Determine if polygon A contains polygon B by determining if A's
* bounding box contains B's bounding box.
*-----------------------------------------------------------------*/
#ifdef NOT_USED
bool
poly_contain(POLYGON *polya, POLYGON *polyb)
{
return box_contain(&(polya->boundbox), &(polyb->boundbox));
}
#endif
bool
poly_contain(POLYGON *polya, POLYGON *polyb)
{
int i;
if (!PointerIsValid(polya) || !PointerIsValid(polyb))
return FALSE;
if (box_contain(&(polya->boundbox), &(polyb->boundbox)))
{
for (i = 0; i < polyb->npts; i++)
{
if (point_inside(&(polyb->p[i]), polya->npts, &(polya->p[0])) == 0)
{
#if GEODEBUG
printf("poly_contain- point (%f,%f) not in polygon\n", polyb->p[i].x, polyb->p[i].y);
#endif
return FALSE;
}
}
for (i = 0; i < polya->npts; i++)
{
if (point_inside(&(polya->p[i]), polyb->npts, &(polyb->p[0])) == 1)
{
#if GEODEBUG
printf("poly_contain- point (%f,%f) in polygon\n", polya->p[i].x, polya->p[i].y);
#endif
return FALSE;
}
}
return TRUE;
}
#if GEODEBUG
printf("poly_contain- bound box ((%f,%f),(%f,%f)) not inside ((%f,%f),(%f,%f))\n",
polyb->boundbox.low.x, polyb->boundbox.low.y, polyb->boundbox.high.x, polyb->boundbox.high.y,
polya->boundbox.low.x, polya->boundbox.low.y, polya->boundbox.high.x, polya->boundbox.high.y);
#endif
return FALSE;
} /* poly_contain() */
/*-----------------------------------------------------------------
* Determine if polygon A is contained by polygon B by determining
* if A's bounding box is contained by B's bounding box.
*-----------------------------------------------------------------*/
#ifdef NOT_USED
bool
poly_contained(POLYGON *polya, POLYGON *polyb)
{
return box_contained(&(polya->boundbox), &(polyb->boundbox));
}
#endif
bool
poly_contained(POLYGON *polya, POLYGON *polyb)
{
return poly_contain(polyb, polya);
} /* poly_contained() */
/* poly_contain_pt()
* Test to see if the point is inside the polygon.
* Code adapted from integer-based routines in
* Wn: A Server for the HTTP
* File: wn/image.c
* Version 1.15.1
* Copyright (C) 1995 <by John Franks>
* (code offered for use by J. Franks in Linux Journal letter.)
*/
bool
poly_contain_pt(POLYGON *poly, Point *p)
{
if (!PointerIsValid(poly) || !PointerIsValid(p))
return FALSE;
return point_inside(p, poly->npts, &(poly->p[0])) != 0;
} /* poly_contain_pt() */
bool
pt_contained_poly(Point *p, POLYGON *poly)
{
if (!PointerIsValid(p) || !PointerIsValid(poly))
return FALSE;
return poly_contain_pt(poly, p);
} /* pt_contained_poly() */
double *
poly_distance(POLYGON *polya, POLYGON *polyb)
{
double *result;
if (!PointerIsValid(polya) || !PointerIsValid(polyb))
return NULL;
result = palloc(sizeof(double));
*result = 0;
return result;
} /* poly_distance() */
/***********************************************************************
**
** Routines for 2D points.
**
***********************************************************************/
Point *
point(float8 *x, float8 *y)
{
if (!(PointerIsValid(x) && PointerIsValid(y)))
return NULL;
return point_construct(*x, *y);
} /* point() */
Point *
point_add(Point *p1, Point *p2){
Point *result;
if (!(PointerIsValid(p1) && PointerIsValid(p2)))
return NULL;
result = palloc(sizeof(Point));
result->x = (p1->x + p2->x);
result->y = (p1->y + p2->y);
return result;
} /* point_add() */
Point *
point_sub(Point *p1, Point *p2)
{
Point *result;
if (!(PointerIsValid(p1) && PointerIsValid(p2)))
return NULL;
result = palloc(sizeof(Point));
result->x = (p1->x - p2->x);
result->y = (p1->y - p2->y);
return result;
} /* point_sub() */
Point *
point_mul(Point *p1, Point *p2)
{
Point *result;
if (!(PointerIsValid(p1) && PointerIsValid(p2)))
return NULL;
result = palloc(sizeof(Point));
result->x = (p1->x * p2->x) - (p1->y * p2->y);
result->y = (p1->x * p2->y) + (p1->y * p2->x);
return result;
} /* point_mul() */
Point *
point_div(Point *p1, Point *p2)
{
Point *result;
double div;
if (!(PointerIsValid(p1) && PointerIsValid(p2)))
return NULL;
result = palloc(sizeof(Point));
div = (p2->x * p2->x) + (p2->y * p2->y);
if (div == 0.0)
elog(ERROR, "point_div: divide by 0.0 error");
result->x = ((p1->x * p2->x) + (p1->y * p2->y)) / div;
result->y = ((p2->x * p1->y) - (p2->y * p1->x)) / div;
return result;
} /* point_div() */
/*********************************************************************** **
** Routines for 2D boxes.
**
***********************************************************************/
BOX *
box(Point *p1, Point *p2)
{
BOX *result;
if (!(PointerIsValid(p1) && PointerIsValid(p2)))
return NULL;
result = box_construct(p1->x, p2->x, p1->y, p2->y);
return result;
} /* box() */
BOX *
box_add(BOX *box, Point *p)
{
BOX *result;
if (!(PointerIsValid(box) && PointerIsValid(p)))
return NULL;
result = box_construct((box->high.x + p->x), (box->low.x + p->x),
(box->high.y + p->y), (box->low.y + p->y));
return result;
} /* box_add() */
BOX *
box_sub(BOX *box, Point *p)
{
BOX *result;
if (!(PointerIsValid(box) && PointerIsValid(p)))
return NULL;
result = box_construct((box->high.x - p->x), (box->low.x - p->x),
(box->high.y - p->y), (box->low.y - p->y));
return result;
} /* box_sub() */
BOX *
box_mul(BOX *box, Point *p)
{
BOX *result;
Point *high,
*low;
if (!(PointerIsValid(box) && PointerIsValid(p)))
return NULL;
high = point_mul(&box->high, p);
low = point_mul(&box->low, p);
result = box_construct(high->x, low->x, high->y, low->y);
pfree(high);
pfree(low);
return result;
} /* box_mul() */
BOX *
box_div(BOX *box, Point *p)
{
BOX *result; Point *high,
*low;
if (!(PointerIsValid(box) && PointerIsValid(p)))
return NULL;
high = point_div(&box->high, p);
low = point_div(&box->low, p);
result = box_construct(high->x, low->x, high->y, low->y);
pfree(high);
pfree(low);
return result;
} /* box_div() */
/***********************************************************************
**
** Routines for 2D paths.
**
***********************************************************************/
/* path_add()
* Concatenate two paths (only if they are both open).
*/
PATH *
path_add(PATH *p1, PATH *p2)
{
PATH *result;
int size;
int i;
if (!(PointerIsValid(p1) && PointerIsValid(p2))
|| p1->closed || p2->closed)
return NULL;
size = offsetof(PATH, p[0]) +(sizeof(p1->p[0]) * (p1->npts + p2->npts));
result = palloc(size);
result->size = size;
result->npts = (p1->npts + p2->npts);
result->closed = p1->closed;
for (i = 0; i < p1->npts; i++)
{
result->p[i].x = p1->p[i].x;
result->p[i].y = p1->p[i].y;
}
for (i = 0; i < p2->npts; i++)
{
result->p[i + p1->npts].x = p2->p[i].x;
result->p[i + p1->npts].y = p2->p[i].y;
}
return result;
} /* path_add() */
/* path_add_pt()
* Translation operator.
*/
PATH *
path_add_pt(PATH *path, Point *point)
{
PATH *result;
int i;
if ((!PointerIsValid(path)) || (!PointerIsValid(point)))
return NULL;
result = path_copy(path);
for (i = 0; i < path->npts; i++)
{
result->p[i].x += point->x;
result->p[i].y += point->y;
}
return result;
} /* path_add_pt() */
PATH *
path_sub_pt(PATH *path, Point *point)
{
PATH *result;
int i;
if ((!PointerIsValid(path)) || (!PointerIsValid(point)))
return NULL;
result = path_copy(path);
for (i = 0; i < path->npts; i++)
{
result->p[i].x -= point->x;
result->p[i].y -= point->y;
}
return result;
} /* path_sub_pt() */
/* path_mul_pt()
* Rotation and scaling operators.
*/
PATH *
path_mul_pt(PATH *path, Point *point)
{
PATH *result;
Point *p;
int i;
if ((!PointerIsValid(path)) || (!PointerIsValid(point)))
return NULL;
result = path_copy(path);
for (i = 0; i < path->npts; i++)
{
p = point_mul(&path->p[i], point);
result->p[i].x = p->x;
result->p[i].y = p->y;
pfree(p);
}
return result;
} /* path_mul_pt() */
PATH *
path_div_pt(PATH *path, Point *point)
{
PATH *result;
Point *p;
int i;
if ((!PointerIsValid(path)) || (!PointerIsValid(point)))
return NULL;
result = path_copy(path);
for (i = 0; i < path->npts; i++)
{
p = point_div(&path->p[i], point);
result->p[i].x = p->x;
result->p[i].y = p->y;
pfree(p);
}
return result;
} /* path_div_pt() */
Point *
path_center(PATH *path)
{
Point *result;
if (!PointerIsValid(path))
return NULL;
elog(ERROR, "path_center not implemented");
result = palloc(sizeof(Point));
result = NULL;
return result;
} /* path_center() */
POLYGON *
path_poly(PATH *path)
{
POLYGON *poly;
int size;
int i;
if (!PointerIsValid(path))
return NULL;
if (!path->closed)
elog(ERROR, "Open path cannot be converted to polygon");
size = offsetof(POLYGON, p[0]) +(sizeof(poly->p[0]) * path->npts);
poly = palloc(size);
poly->size = size;
poly->npts = path->npts;
for (i = 0; i < path->npts; i++)
{
poly->p[i].x = path->p[i].x;
poly->p[i].y = path->p[i].y;
}
make_bound_box(poly);
return poly;
} /* path_polygon() */
/* upgradepath()
* Convert path read from old-style string into correct representation.
*
* Old-style: '(closed,#pts,x1,y1,...)' where closed is a boolean flag
* New-style: '((x1,y1),...)' for closed path
* '[(x1,y1),...]' for open path
*/
PATH *
upgradepath(PATH *path)
{
PATH *result; int size,
npts;
int i;
if (!PointerIsValid(path) || (path->npts < 2))
return NULL;
if (!isoldpath(path))
elog(ERROR, "upgradepath: path already upgraded?");
npts = (path->npts - 1);
size = offsetof(PATH, p[0]) +(sizeof(path->p[0]) * npts);
result = palloc(size);
MemSet((char *) result, 0, size);
result->size = size;
result->npts = npts;
result->closed = (path->p[0].x != 0);
for (i = 0; i < result->npts; i++)
{
result->p[i].x = path->p[i + 1].x;
result->p[i].y = path->p[i + 1].y;
}
return result;
} /* upgradepath() */
bool
isoldpath(PATH *path)
{
if (!PointerIsValid(path) || (path->npts < 2))
return FALSE;
return path->npts == (path->p[0].y + 1);
} /* isoldpath() */
/***********************************************************************
**
** Routines for 2D polygons.
**
***********************************************************************/
int4
poly_npoints(POLYGON *poly)
{
if (!PointerIsValid(poly))
return FALSE;
return poly->npts;
} /* poly_npoints() */
Point *
poly_center(POLYGON *poly)
{
Point *result;
CIRCLE *circle;
if (!PointerIsValid(poly))
return NULL;
if (PointerIsValid(circle = poly_circle(poly)))
{
result = circle_center(circle);
pfree(circle);
}
else result = NULL;
return result;
} /* poly_center() */
BOX *
poly_box(POLYGON *poly)
{
BOX *box;
if (!PointerIsValid(poly) || (poly->npts < 1))
return NULL;
box = box_copy(&poly->boundbox);
return box;
} /* poly_box() */
/* box_poly()
* Convert a box to a polygon.
*/
POLYGON *
box_poly(BOX *box)
{
POLYGON *poly;
int size;
if (!PointerIsValid(box))
return NULL;
/* map four corners of the box to a polygon */
size = offsetof(POLYGON, p[0]) +(sizeof(poly->p[0]) * 4);
poly = palloc(size);
poly->size = size;
poly->npts = 4;
poly->p[0].x = box->low.x;
poly->p[0].y = box->low.y;
poly->p[1].x = box->low.x;
poly->p[1].y = box->high.y;
poly->p[2].x = box->high.x;
poly->p[2].y = box->high.y;
poly->p[3].x = box->high.x;
poly->p[3].y = box->low.y;
box_fill(&poly->boundbox, box->high.x, box->low.x, box->high.y, box->low.y);
return poly;
} /* box_poly() */
PATH *
poly_path(POLYGON *poly)
{
PATH *path;
int size;
int i;
if (!PointerIsValid(poly) || (poly->npts < 0))
return NULL;
size = offsetof(PATH, p[0]) +(sizeof(path->p[0]) * poly->npts);
path = palloc(size);
path->size = size;
path->npts = poly->npts;
path->closed = TRUE;
for (i = 0; i < poly->npts; i++)
{
path->p[i].x = poly->p[i].x;
path->p[i].y = poly->p[i].y;
}
return path;
} /* poly_path() */
/* upgradepoly()
* Convert polygon read as pre-v6.1 string to new interpretation.
* Old-style: '(x1,x2,...,y1,y2,...)'
* New-style: '(x1,y1,x2,y2,...)'
*/
POLYGON *
upgradepoly(POLYGON *poly)
{
POLYGON *result;
int size;
int n2,
i,
ii;
if (!PointerIsValid(poly) || (poly->npts < 1))
return NULL;
size = offsetof(POLYGON, p[0]) +(sizeof(poly->p[0]) * poly->npts);
result = palloc(size);
MemSet((char *) result, 0, size);
result->size = size;
result->npts = poly->npts;
n2 = poly->npts / 2;
for (i = 0; i < n2; i++)
{
result->p[2 * i].x = poly->p[i].x; /* even indices */
result->p[2 * i + 1].x = poly->p[i].y; /* odd indices */
}
if ((ii = ((poly->npts % 2) ? 1 : 0)))
{
result->p[poly->npts - 1].x = poly->p[n2].x;
result->p[0].y = poly->p[n2].y;
}
for (i = 0; i < n2; i++)
{
result->p[2 * i + ii].y = poly->p[i + n2 + ii].x; /* even (+offset)
* indices */
result->p[2 * i + ii + 1].y = poly->p[i + n2 + ii].y; /* odd (+offset) indices */
}
return result;
} /* upgradepoly() */
/* revertpoly()
* Reverse effect of upgradepoly().
*/
POLYGON *
revertpoly(POLYGON *poly)
{
POLYGON *result;
int size;
int n2,
i,
ii;
if (!PointerIsValid(poly) || (poly->npts < 1))
return NULL;
size = offsetof(POLYGON, p[0]) +(sizeof(poly->p[0]) * poly->npts);
result = palloc(size);
MemSet((char *) result, 0, size);
result->size = size;
result->npts = poly->npts;
n2 = poly->npts / 2;
for (i = 0; i < n2; i++)
{
result->p[i].x = poly->p[2 * i].x; /* even indices */
result->p[i].y = poly->p[2 * i + 1].x; /* odd indices */
}
if ((ii = ((poly->npts % 2) ? 1 : 0)))
{
result->p[n2].x = poly->p[poly->npts - 1].x;
result->p[n2].y = poly->p[0].y;
}
for (i = 0; i < n2; i++)
{
result->p[i + n2 + ii].x = poly->p[2 * i + ii].y; /* even (+offset)
* indices */
result->p[i + n2 + ii].y = poly->p[2 * i + ii + 1].y; /* odd (+offset) indices */
}
return result;
} /* revertpoly() */
/***********************************************************************
**
** Routines for circles.
**
***********************************************************************/
/*----------------------------------------------------------
* Formatting and conversion routines.
*---------------------------------------------------------*/
/* circle_in - convert a string to internal form.
*
* External format: (center and radius of circle)
* "((f8,f8)<f8>)"
* also supports quick entry style "(f8,f8,f8)"
*/
CIRCLE *
circle_in(char *str)
{
CIRCLE *circle;
char *s,
*cp;
int depth = 0;
if (!PointerIsValid(str))
elog(ERROR, " Bad (null) circle external representation");
circle = palloc(sizeof(CIRCLE));
s = str;
while (isspace(*s))
s++;
if ((*s == LDELIM_C) || (*s == LDELIM)) {
depth++;
cp = (s + 1);
while (isspace(*cp))
cp++;
if (*cp == LDELIM)
s = cp;
}
if (!pair_decode(s, &circle->center.x, &circle->center.y, &s))
elog(ERROR, "Bad circle external representation '%s'", str);
if (*s == DELIM)
s++;
while (isspace(*s))
s++;
if ((!single_decode(s, &circle->radius, &s)) || (circle->radius < 0))
elog(ERROR, "Bad circle external representation '%s'", str);
while (depth > 0)
{
if ((*s == RDELIM)
|| ((*s == RDELIM_C) && (depth == 1)))
{
depth--;
s++;
while (isspace(*s))
s++;
}
else
elog(ERROR, "Bad circle external representation '%s'", str);
}
if (*s != '\0')
elog(ERROR, "Bad circle external representation '%s'", str);
return circle;
} /* circle_in() */
/* circle_out - convert a circle to external form.
*/
char *
circle_out(CIRCLE *circle)
{
char *result;
char *cp;
if (!PointerIsValid(circle))
return NULL;
result = palloc(3 * (P_MAXLEN + 1) + 3);
cp = result;
*cp++ = LDELIM_C;
*cp++ = LDELIM;
if (!pair_encode(circle->center.x, circle->center.y, cp))
elog(ERROR, "Unable to format circle");
cp += strlen(cp);
*cp++ = RDELIM;
*cp++ = DELIM;
if (!single_encode(circle->radius, cp))
elog(ERROR, "Unable to format circle");
cp += strlen(cp);
*cp++ = RDELIM_C;
*cp = '\0';
return result;} /* circle_out() */
/*----------------------------------------------------------
* Relational operators for CIRCLEs.
* <, >, <=, >=, and == are based on circle area.
*---------------------------------------------------------*/
/* circles identical?
*/
bool
circle_same(CIRCLE *circle1, CIRCLE *circle2)
{
return (FPeq(circle1->radius, circle2->radius)
&& FPeq(circle1->center.x, circle2->center.x)
&& FPeq(circle1->center.y, circle2->center.y));
} /* circle_same() */
/* circle_overlap - does circle1 overlap circle2?
*/
bool
circle_overlap(CIRCLE *circle1, CIRCLE *circle2)
{
return FPle(point_dt(&circle1->center, &circle2->center), (circle1->radius + circle2->radius));
}
/* circle_overleft - is the right edge of circle1 to the left of
* the right edge of circle2?
*/
bool
circle_overleft(CIRCLE *circle1, CIRCLE *circle2)
{
return FPle((circle1->center.x + circle1->radius), (circle2->center.x + circle2->radius));
}
/* circle_left - is circle1 strictly left of circle2?
*/
bool
circle_left(CIRCLE *circle1, CIRCLE *circle2)
{
return FPle((circle1->center.x + circle1->radius), (circle2->center.x - circle2->radius));
}
/* circle_right - is circle1 strictly right of circle2?
*/
bool
circle_right(CIRCLE *circle1, CIRCLE *circle2)
{
return FPge((circle1->center.x - circle1->radius), (circle2->center.x + circle2->radius));
}
/* circle_overright - is the left edge of circle1 to the right of
* the left edge of circle2?
*/
bool
circle_overright(CIRCLE *circle1, CIRCLE *circle2)
{
return FPge((circle1->center.x - circle1->radius), (circle2->center.x - circle2->radius));
}
/* circle_contained - is circle1 contained by circle2?
*/
bool
circle_contained(CIRCLE *circle1, CIRCLE *circle2)
{
return FPle((point_dt(&circle1->center, &circle2->center) + circle1->radius), circle2->radius);
}
/* circle_contain - does circle1 contain circle2?
*/bool
circle_contain(CIRCLE *circle1, CIRCLE *circle2)
{
return FPle((point_dt(&circle1->center, &circle2->center) + circle2->radius), circle1->radius);
}
/* circle_positionop -
* is circle1 entirely {above,below} circle2?
*/
bool
circle_below(CIRCLE *circle1, CIRCLE *circle2)
{
return FPle((circle1->center.y + circle1->radius), (circle2->center.y - circle2->radius));
}
bool
circle_above(CIRCLE *circle1, CIRCLE *circle2)
{
return FPge((circle1->center.y - circle1->radius), (circle2->center.y + circle2->radius));
}
/* circle_relop - is area(circle1) relop area(circle2), within
* our accuracy constraint?
*/
bool
circle_eq(CIRCLE *circle1, CIRCLE *circle2)
{
return FPeq(circle_ar(circle1), circle_ar(circle2));
} /* circle_eq() */
bool
circle_ne(CIRCLE *circle1, CIRCLE *circle2)
{
return !circle_eq(circle1, circle2);
} /* circle_ne() */
bool
circle_lt(CIRCLE *circle1, CIRCLE *circle2)
{
return FPlt(circle_ar(circle1), circle_ar(circle2));
} /* circle_lt() */
bool
circle_gt(CIRCLE *circle1, CIRCLE *circle2)
{
return FPgt(circle_ar(circle1), circle_ar(circle2));
} /* circle_gt() */
bool
circle_le(CIRCLE *circle1, CIRCLE *circle2)
{
return FPle(circle_ar(circle1), circle_ar(circle2));
} /* circle_le() */
bool
circle_ge(CIRCLE *circle1, CIRCLE *circle2)
{
return FPge(circle_ar(circle1), circle_ar(circle2));
} /* circle_ge() */
/*----------------------------------------------------------
* "Arithmetic" operators on circles.
* circle_foo returns foo as an object (pointer) that
can be passed between languages.
* circle_xx is an internal routine which returns the
* actual value.
*---------------------------------------------------------*/
static CIRCLE *
circle_copy(CIRCLE *circle)
{
CIRCLE *result;
if (!PointerIsValid(circle))
return NULL;
result = palloc(sizeof(CIRCLE));
memmove((char *) result, (char *) circle, sizeof(CIRCLE));
return result;
} /* circle_copy() */
/* circle_add_pt()
* Translation operator.
*/
CIRCLE *
circle_add_pt(CIRCLE *circle, Point *point)
{
CIRCLE *result;
if (!PointerIsValid(circle) || !PointerIsValid(point))
return NULL;
result = circle_copy(circle);
result->center.x += point->x;
result->center.y += point->y;
return result;
} /* circle_add_pt() */
CIRCLE *
circle_sub_pt(CIRCLE *circle, Point *point)
{
CIRCLE *result;
if (!PointerIsValid(circle) || !PointerIsValid(point))
return NULL;
result = circle_copy(circle);
result->center.x -= point->x;
result->center.y -= point->y;
return result;
} /* circle_sub_pt() */
/* circle_mul_pt()
* Rotation and scaling operators.
*/
CIRCLE *
circle_mul_pt(CIRCLE *circle, Point *point)
{
CIRCLE *result;
Point *p;
if (!PointerIsValid(circle) || !PointerIsValid(point))
return NULL;
result = circle_copy(circle);
p = point_mul(&circle->center, point);
result->center.x = p->x;
result->center.y = p->y;
pfree(p); result->radius *= HYPOT(point->x, point->y);
return result;
} /* circle_mul_pt() */
CIRCLE *
circle_div_pt(CIRCLE *circle, Point *point)
{
CIRCLE *result;
Point *p;
if (!PointerIsValid(circle) || !PointerIsValid(point))
return NULL;
result = circle_copy(circle);
p = point_div(&circle->center, point);
result->center.x = p->x;
result->center.y = p->y;
pfree(p);
result->radius /= HYPOT(point->x, point->y);
return result;
} /* circle_div_pt() */
/* circle_area - returns the area of the circle.
*/
double *
circle_area(CIRCLE *circle)
{
double *result;
result = palloc(sizeof(double));
*result = circle_ar(circle);
return result;
}
/* circle_diameter - returns the diameter of the circle.
*/
double *
circle_diameter(CIRCLE *circle)
{
double *result;
result = palloc(sizeof(double));
*result = (2 * circle->radius);
return result;
}
/* circle_radius - returns the radius of the circle.
*/
double *
circle_radius(CIRCLE *circle)
{
double *result;
result = palloc(sizeof(double));
*result = circle->radius;
return result;
}
/* circle_distance - returns the distance between
* two circles. */
double *
circle_distance(CIRCLE *circle1, CIRCLE *circle2)
{
double *result;
result = palloc(sizeof(double));
*result = (point_dt(&circle1->center, &circle2->center)
- (circle1->radius + circle2->radius));
if (*result < 0)
*result = 0;
return result;
} /* circle_distance() */
bool
circle_contain_pt(CIRCLE *circle, Point *point)
{
bool within;
double *d;
if (!PointerIsValid(circle) || !PointerIsValid(point))
return FALSE;
d = point_distance(&(circle->center), point);
within = (*d <= circle->radius);
pfree(d);
return within;
} /* circle_contain_pt() */
bool
pt_contained_circle(Point *point, CIRCLE *circle)
{
return circle_contain_pt(circle, point);
} /* circle_contain_pt() */
/* dist_pc - returns the distance between
* a point and a circle.
*/
double *
dist_pc(Point *point, CIRCLE *circle)
{
double *result;
result = palloc(sizeof(double));
*result = (point_dt(point, &circle->center) - circle->radius);
if (*result < 0)
*result = 0;
return result;
} /* dist_pc() */
/* circle_center - returns the center point of the circle.
*/
Point *
circle_center(CIRCLE *circle)
{
Point *result;
result = palloc(sizeof(Point));
result->x = circle->center.x;
result->y = circle->center.y;
return result;}
/* circle_ar - returns the area of the circle.
*/
static double
circle_ar(CIRCLE *circle)
{
return PI * (circle->radius * circle->radius);
}
/* circle_dt - returns the distance between the
* center points of two circlees.
*/
#ifdef NOT_USED
double
circle_dt(CIRCLE *circle1, CIRCLE *circle2)
{
double result;
result = point_dt(&circle1->center, &circle2->center);
return result;
}
#endif
/*----------------------------------------------------------
* Conversion operators.
*---------------------------------------------------------*/
CIRCLE *
circle(Point *center, float8 *radius)
{
CIRCLE *result;
if (!(PointerIsValid(center) && PointerIsValid(radius)))
return NULL;
result = palloc(sizeof(CIRCLE));
result->center.x = center->x;
result->center.y = center->y;
result->radius = *radius;
return result;
}
BOX *
circle_box(CIRCLE *circle)
{
BOX *box;
double delta;
if (!PointerIsValid(circle))
return NULL;
box = palloc(sizeof(BOX));
delta = circle->radius / sqrt(2.0e0);
box->high.x = circle->center.x + delta;
box->low.x = circle->center.x - delta;
box->high.y = circle->center.y + delta;
box->low.y = circle->center.y - delta;
return box;
} /* circle_box() */
/* box_circle()
* Convert a box to a circle.
*/
CIRCLE *
box_circle(BOX *box)
{
CIRCLE *circle;
if (!PointerIsValid(box))
return NULL;
circle = palloc(sizeof(CIRCLE));
circle->center.x = (box->high.x + box->low.x) / 2;
circle->center.y = (box->high.y + box->low.y) / 2;
circle->radius = point_dt(&circle->center, &box->high);
return circle;
} /* box_circle() */
Datum
circle_poly(PG_FUNCTION_ARGS)
{
int32 npts = PG_GETARG_INT32(0);
CIRCLE *circle = PG_GETARG_CIRCLE_P(1);
POLYGON *poly;
int size;
int i;
double angle;
if (FPzero(circle->radius) || (npts < 2))
elog(ERROR, "Unable to convert circle to polygon");
size = offsetof(POLYGON, p[0]) +(sizeof(poly->p[0]) * npts);
poly = (POLYGON *) palloc(size);
MemSet((char *) poly, 0, size); /* zero any holes */
poly->size = size;
poly->npts = npts;
for (i = 0; i < npts; i++)
{
angle = i * (2 * PI / npts);
poly->p[i].x = circle->center.x - (circle->radius * cos(angle));
poly->p[i].y = circle->center.y + (circle->radius * sin(angle));
}
make_bound_box(poly);
PG_RETURN_POLYGON_P(poly);
}
/* poly_circle - convert polygon to circle
*
* XXX This algorithm should use weighted means of line segments
* rather than straight average values of points - tgl 97/01/21.
*/
CIRCLE *
poly_circle(POLYGON *poly)
{
CIRCLE *circle;
int i;
if (!PointerIsValid(poly))
return NULL;
if (poly->npts < 2) elog(ERROR, "Unable to convert polygon to circle");
circle = palloc(sizeof(CIRCLE));
circle->center.x = 0;
circle->center.y = 0;
circle->radius = 0;
for (i = 0; i < poly->npts; i++)
{
circle->center.x += poly->p[i].x;
circle->center.y += poly->p[i].y;
}
circle->center.x /= poly->npts;
circle->center.y /= poly->npts;
for (i = 0; i < poly->npts; i++)
circle->radius += point_dt(&poly->p[i], &circle->center);
circle->radius /= poly->npts;
if (FPzero(circle->radius))
elog(ERROR, "Unable to convert polygon to circle");
return circle;
} /* poly_circle() */
/***********************************************************************
**
** Private routines for multiple types.
**
***********************************************************************/
#define HIT_IT INT_MAX
static int
point_inside(Point *p, int npts, Point *plist)
{
double x0,
y0;
double px,
py;
int i;
double x,
y;
int cross,
crossnum;
/*
* We calculate crossnum, which is twice the crossing number of a
* ray from the origin parallel to the positive X axis.
* A coordinate change is made to move the test point to the origin.
* Then the function lseg_crossing() is called to calculate the crossnum of
* one segment of the translated polygon with the ray which is the
* positive X-axis.
*/
crossnum = 0;
i = 0;
if (npts <= 0)
return 0;
x0 = plist[0].x - p->x;
y0 = plist[0].y - p->y;
px = x0;
py = y0;
for (i = 1; i < npts; i++)
{ x = plist[i].x - p->x;
y = plist[i].y - p->y;
if ((cross = lseg_crossing(x, y, px, py)) == HIT_IT)
return 2;
crossnum += cross;
px = x;
py = y;
}
if ((cross = lseg_crossing(x0, y0, px, py)) == HIT_IT)
return 2;
crossnum += cross;
if (crossnum != 0)
return 1;
return 0;
} /* point_inside() */
/* lseg_crossing()
* The function lseg_crossing() returns +2, or -2 if the segment from (x,y)
* to previous (x,y) crosses the positive X-axis positively or negatively.
* It returns +1 or -1 if one endpoint is on this ray, or 0 if both are.
* It returns 0 if the ray and the segment don't intersect.
* It returns HIT_IT if the segment contains (0,0)
*/
static int
lseg_crossing(double x, double y, double px, double py)
{
double z;
int sgn;
/* If (px,py) = (0,0) and not first call we have already sent HIT_IT */
if (FPzero(y))
{
if (FPzero(x))
{
return HIT_IT;
}
else if (FPgt(x, 0))
{
if (FPzero(py))
return FPgt(px, 0) ? 0 : HIT_IT;
return FPlt(py, 0) ? 1 : -1;
}
else
{ /* x < 0 */
if (FPzero(py))
return FPlt(px, 0) ? 0 : HIT_IT;
return 0;
}
}
/* Now we know y != 0; set sgn to sign of y */
sgn = (FPgt(y, 0) ? 1 : -1);
if (FPzero(py))
return FPlt(px, 0) ? 0 : sgn;
if (FPgt((sgn * py), 0))
{ /* y and py have same sign */
return 0;
}
else
{ /* y and py have opposite signs */
if (FPge(x, 0) && FPgt(px, 0)) return 2 * sgn;
if (FPlt(x, 0) && FPle(px, 0))
return 0;
z = (x - px) * y - (y - py) * x;
if (FPzero(z))
return HIT_IT;
return FPgt((sgn * z), 0) ? 0 : 2 * sgn;
}
} /* lseg_crossing() */
static bool
plist_same(int npts, Point *p1, Point *p2)
{
int i,
ii,
j;
/* find match for first point */
for (i = 0; i < npts; i++)
{
if ((FPeq(p2[i].x, p1[0].x))
&& (FPeq(p2[i].y, p1[0].y)))
{
/* match found? then look forward through remaining points */
for (ii = 1, j = i + 1; ii < npts; ii++, j++)
{
if (j >= npts)
j = 0;
if ((!FPeq(p2[j].x, p1[ii].x))
|| (!FPeq(p2[j].y, p1[ii].y)))
{
#ifdef GEODEBUG
printf("plist_same- %d failed forward match with %d\n", j, ii);
#endif
break;
}
}
#ifdef GEODEBUG
printf("plist_same- ii = %d/%d after forward match\n", ii, npts);
#endif
if (ii == npts)
return TRUE;
/* match not found forwards? then look backwards */
for (ii = 1, j = i - 1; ii < npts; ii++, j--)
{
if (j < 0)
j = (npts - 1);
if ((!FPeq(p2[j].x, p1[ii].x))
|| (!FPeq(p2[j].y, p1[ii].y)))
{
#ifdef GEODEBUG
printf("plist_same- %d failed reverse match with %d\n", j, ii);
#endif
break;
}
}
#ifdef GEODEBUG
printf("plist_same- ii = %d/%d after reverse match\n", ii, npts);
#endif
if (ii == npts)
return TRUE;
}
}
return FALSE;
} /* plist_same() */