geometry.h

/*	geometry.h
	Header file for geometric data types

	by: Steven Skiena
*/

/*
Copyright 2003 by Steven S. Skiena; all rights reserved. 

Permission is granted for use in non-commerical applications
provided this copyright notice remains intact and unchanged.

This program appears in my book:

"Programming Challenges: The Programming Contest Training Manual"
by Steven Skiena and Miguel Revilla, Springer-Verlag, New York 2003.

See our website www.programming-challenges.com for additional information.

This book can be ordered from Amazon.com at

http://www.amazon.com/exec/obidos/ASIN/0387001638/thealgorithmrepo/

*/

#include "bool.h"

#define	PI      3.1415926   /* ratio of circumference to diameter */
#define EPSILON 0.000001    /* a quantity small enough to be zero */

typedef struct {
    double a;       /* x-coefficient */
    double b;       /* y-coefficient */
    double c;       /* constant term */
} line;

#define DIMENSION  2  /* dimension of points */
#define X          0  /* x-coordinate index */
#define	Y          1  /* y-coordinate index */

typedef double point[DIMENSION];

#define MAXPOLY    200 /* maximum number of points in a polygon */

typedef struct {
    int n;              /* number of points in polygon */
    point p[MAXPOLY];   /* array of points in polygon */
} polygon;

typedef struct {
    point p1, p2;       /* endpoints of line segment */
} segment;

typedef point triangle[3];  /* triangle datatype */

typedef struct {
    int n;              /* number of triangles in triangulation */
    int t[MAXPOLY][3];  /* indicies of vertices in triangulation */
} triangulation;

typedef struct {
    point c;        /* center of circle */
    double r;       /* radius of circle */
} circle;

/*	Comparison macros  */

#define	max(A, B)		((A) > (B) ? (A) : (B))
#define min(A, B)		((A) < (B) ? (A) : (B))

void points_to_line(point p1, point p2, line *l);
void point_and_slope_to_line(point p, double m, line *l);
bool parallelQ(line l1, line l2);
bool same_lineQ(line l1, line l2);
void intersection_point(line l1, line l2, point p);
void closest_point(point p_in, line l, point p_c);
double distance(point a, point b);
void copy_point(point a, point b);
void swap_point(point a, point b);
void points_to_segment(point a, point b, segment *s);
void segment_to_points(segment s, point p1, point p2);
bool point_in_box(point p, point b1, point b2);
bool segments_intersect(segment s1, segment s2);
double signed_triangle_area(point a, point b, point c);
double triangle_area(point a, point b, point c);
bool ccw(point a, point b, point c);
bool cw(point a, point b, point c);
bool collinear(point a, point b, point c);
void print_points(point p[], int n);
void print_polygon(polygon *p);
void print_point(point p);
void print_line(line l);
void print_segment(segment s);