1/* 2=========================================================================== 3 4Project: Generic Polygon Clipper 5 6 A new algorithm for calculating the difference, intersection, 7 exclusive-or or union of arbitrary polygon sets. 8 9File: gpc.h 10Author: Alan Murta (email: gpc@cs.man.ac.uk) 11Version: 2.32 12Date: 17th December 2004 13 14Copyright: (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 58typedef 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 66typedef struct /* Polygon vertex structure */ 67{ 68 double x; /* Vertex x component */ 69 double y; /* vertex y component */ 70} gpc_vertex; 71 72typedef 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 78typedef 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 85typedef 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 98void gpc_read_polygon (FILE *infile_ptr, 99 int read_hole_flags, 100 gpc_polygon *polygon); 101 102void gpc_write_polygon (FILE *outfile_ptr, 103 int write_hole_flags, 104 gpc_polygon *polygon); 105 106void gpc_add_contour (gpc_polygon *polygon, 107 gpc_vertex_list *contour, 108 int hole); 109 110void gpc_polygon_clip (gpc_op set_operation, 111 gpc_polygon *subject_polygon, 112 gpc_polygon *clip_polygon, 113 gpc_polygon *result_polygon); 114 115void gpc_tristrip_clip (gpc_op set_operation, 116 gpc_polygon *subject_polygon, 117 gpc_polygon *clip_polygon, 118 gpc_tristrip *result_tristrip); 119 120void gpc_polygon_to_tristrip (gpc_polygon *polygon, 121 gpc_tristrip *tristrip); 122 123void gpc_free_polygon (gpc_polygon *polygon); 124 125void gpc_free_tristrip (gpc_tristrip *tristrip); 126 127#endif 128 129/* 130=========================================================================== 131 End of file: gpc.h 132=========================================================================== 133*/ 134