/*
   ===========================================================================

Project:   Generic Polygon Clipper

A new algorithm for calculating the difference, intersection,
exclusive-or or union of arbitrary polygon sets.

File:      gpc.h
Author:    Alan Murta (email: gpc@cs.man.ac.uk)
Version:   2.31
Date:      4th June 1999

Copyright: (C) 1997-1999, Advanced Interfaces Group,
University of Manchester.

This software is free for non-commercial use. It may be copied,
modified, and redistributed provided that this copyright notice
is preserved on all copies. The intellectual property rights of
the algorithms used reside with the University of Manchester
Advanced Interfaces Group.

You may not use this software, in whole or in part, in support
of any commercial product without the express consent of the
author.

There is no warranty or other guarantee of fitness of this
software for any purpose. It is provided solely "as is".

===========================================================================
 */

#ifndef __gpc_h
#define __gpc_h

#include <stdio.h>


/*
   ===========================================================================
   Constants
   ===========================================================================
 */

/* Increase GPC_EPSILON to encourage merging of near coincident edges    */

/*#define GPC_EPSILON (DBL_EPSILON)*/
#define GPC_EPSILON (1e-3)

#define GPC_VERSION "2.31"


/*
   ===========================================================================
   Public Data Types
   ===========================================================================
 */

typedef enum                        /* Set operation type                */
{
        GPC_DIFF,                         /* Difference                  */
        GPC_INT,                          /* Intersection                */
        GPC_XOR,                          /* Exclusive or                */
        GPC_UNION                         /* Union                       */
} gpc_op;

typedef struct                      /* Polygon vertex structure          */
{
        double              x;            /* Vertex x component          */
        double              y;            /* vertex y component          */
} gpc_vertex;

typedef struct                      /* Vertex list structure             */
{
        int                 num_vertices; /* Number of vertices in list  */
        gpc_vertex         *vertex;       /* Vertex array pointer        */
} gpc_vertex_list;

typedef struct                      /* Polygon set structure             */
{
        int                 num_contours; /* Number of contours in polygon  */
        int                *hole;         /* Hole / external contour flags  */
        gpc_vertex_list    *contour;      /* Contour array pointer          */
} gpc_polygon;

typedef struct                      /* Tristrip set structure            */
{
        int                 num_strips;   /* Number of tristrips               */
        gpc_vertex_list    *strip;        /* Tristrip array pointer            */
} gpc_tristrip;


/*
   ===========================================================================
   Public Function Prototypes
   ===========================================================================
 */

void gpc_init_polygon       (gpc_polygon     * polygon);


void gpc_copy_vertex        (gpc_vertex       * source,
                gpc_vertex       * dest);

void gpc_copy_vertex_list   (gpc_vertex_list  * source,
                gpc_vertex_list  * dest);

void gpc_copy_polygon       (gpc_polygon      * source,
                gpc_polygon      * dest);

void gpc_create_rectangle   (double x,double y,double width,double height,gpc_polygon *p);

void gpc_pie_polygon        (double             x_center,
                double             y_center,
                double             radius,
                double             theta_min,
                double             theta_max,
                int                num_edges, 
                gpc_polygon      * p);


void gpc_create_polygon     (double * points,int size, gpc_polygon *p);


void gpc_read_polygon        (FILE            *infile_ptr, 
                int              read_hole_flags,
                gpc_polygon     *polygon);

void gpc_write_polygon       (FILE            *outfile_ptr,
                int              write_hole_flags,
                gpc_polygon     *polygon);

void gpc_write_tristrip(FILE *fp, gpc_polygon *p);

void gpc_add_contour         (gpc_polygon     *polygon,
                gpc_vertex_list *contour,
                int              hole);

int gpc_test_intersection    (gpc_polygon     *p1,
                gpc_polygon     *p2);


unsigned int gpc_get_clip_number();
void gpc_polygon_clip        (gpc_op           set_operation,
                gpc_polygon     *subject_polygon,
                gpc_polygon     *clip_polygon,
                gpc_polygon     *result_polygon);

void gpc_tristrip_clip       (gpc_op           set_operation,
                gpc_polygon     *subject_polygon,
                gpc_polygon     *clip_polygon,
                gpc_tristrip    *result_tristrip);

void gpc_polygon_to_tristrip (gpc_polygon     *polygon,
                gpc_tristrip    *tristrip);



double gpc_poly_area         (gpc_polygon     *polygon);

double gpc_tristrip_area     (gpc_tristrip    *tristrip);


void gpc_free_polygon        (gpc_polygon     *polygon);

void gpc_free_tristrip       (gpc_tristrip    *tristrip);

void gpc_transform_polygon(gpc_polygon *source,
                double theta,double x, double y,gpc_polygon *dest);


void gpc_find_bounding_circle_radius(gpc_polygon *p,gpc_vertex *center,double *r);

void gpc_get_center(gpc_polygon *p,gpc_vertex *v);

void gpc_filter_polygon(gpc_polygon * poly);

gpc_vertex_list *  gpc_extract_vertex_list(gpc_polygon *p,
                int cont,int first, int last);

void gpc_cut_polygon(gpc_polygon *poly,gpc_polygon *result);

#endif

/*
   ===========================================================================
   End of file: gpc.h
   ===========================================================================
 */