src/gpc.h

   1 /*
   2 ===========================================================================
   3
   4 Project:   Generic Polygon Clipper
   5
   6            A new algorithm for calculating the difference, intersection,
   7            exclusive-or or union of arbitrary polygon sets.
   8
   9 File:      gpc.h
  10 Author:    Alan Murta (email: gpc@cs.man.ac.uk)
  11 Version:   2.32
  12 Date:      17th December 2004
  13
  14 Copyright: (C) 1997-2004, Advanced Interfaces Group,
  15            University of Manchester.
  16
  17            This software is free for non-commercial use. It may be copied,
  18            modified, and redistributed provided that this copyright notice
  19            is preserved on all copies. The intellectual property rights of
  20            the algorithms used reside with the University of Manchester
  21            Advanced Interfaces Group.
  22
  23            You may not use this software, in whole or in part, in support
  24            of any commercial product without the express consent of the
  25            author.
  26
  27            There is no warranty or other guarantee of fitness of this
  28            software for any purpose. It is provided solely "as is".
  29
  30 ===========================================================================
  31 */
  32
  33 #ifndef __gpc_h
  34 #define __gpc_h
  35
  36 #include <stdio.h>
  37
  38
  39 /*
  40 ===========================================================================
  41                                Constants
  42 ===========================================================================
  43 */
  44
  45 /* Increase GPC_EPSILON to encourage merging of near coincident edges    */
  46
  47 #define GPC_EPSILON (DBL_EPSILON)
  48
  49 #define GPC_VERSION "2.32"
  50
  51
  52 /*
  53 ===========================================================================
  54                            Public Data Types
  55 ===========================================================================
  56 */
  57
  58 typedef enum                        /* Set operation type                */
  59 {
  60   GPC_DIFF,                         /* Difference                        */
  61   GPC_INT,                          /* Intersection                      */
  62   GPC_XOR,                          /* Exclusive or                      */
  63   GPC_UNION                         /* Union                             */
  64 } gpc_op;
  65
  66 typedef struct                      /* Polygon vertex structure          */
  67 {
  68   double              x;            /* Vertex x component                */
  69   double              y;            /* vertex y component                */
  70 } gpc_vertex;
  71
  72 typedef struct                      /* Vertex list structure             */
  73 {
  74   int                 num_vertices; /* Number of vertices in list        */
  75   gpc_vertex         *vertex;       /* Vertex array pointer              */
  76 } gpc_vertex_list;
  77
  78 typedef struct                      /* Polygon set structure             */
  79 {
  80   int                 num_contours; /* Number of contours in polygon     */
  81   int                *hole;         /* Hole / external contour flags     */
  82   gpc_vertex_list    *contour;      /* Contour array pointer             */
  83 } gpc_polygon;
  84
  85 typedef struct                      /* Tristrip set structure            */
  86 {
  87   int                 num_strips;   /* Number of tristrips               */
  88   gpc_vertex_list    *strip;        /* Tristrip array pointer            */
  89 } gpc_tristrip;
  90
  91
  92 /*
  93 ===========================================================================
  94                        Public Function Prototypes
  95 ===========================================================================
  96 */
  97
  98 void gpc_read_polygon        (FILE            *infile_ptr,
  99                               int              read_hole_flags,
 100                               gpc_polygon     *polygon);
 101
 102 void gpc_write_polygon       (FILE            *outfile_ptr,
 103                               int              write_hole_flags,
 104                               gpc_polygon     *polygon);
 105
 106 void gpc_add_contour         (gpc_polygon     *polygon,
 107                               gpc_vertex_list *contour,
 108                               int              hole);
 109
 110 void gpc_polygon_clip        (gpc_op           set_operation,
 111                               gpc_polygon     *subject_polygon,
 112                               gpc_polygon     *clip_polygon,
 113                               gpc_polygon     *result_polygon);
 114
 115 void gpc_tristrip_clip       (gpc_op           set_operation,
 116                               gpc_polygon     *subject_polygon,
 117                               gpc_polygon     *clip_polygon,
 118                               gpc_tristrip    *result_tristrip);
 119
 120 void gpc_polygon_to_tristrip (gpc_polygon     *polygon,
 121                               gpc_tristrip    *tristrip);
 122
 123 void gpc_free_polygon        (gpc_polygon     *polygon);
 124
 125 void gpc_free_tristrip       (gpc_tristrip    *tristrip);
 126
 127 #endif
 128
 129 /*
 130 ===========================================================================
 131                            End of file: gpc.h
 132 ===========================================================================
 133 */