triangle.h

一个用于三角剖分的类.实用性非常好。对于需要从多边形

/*    only.                                                                  */
/*  `normlist':  An array of normal vectors, used for infinite rays in       */
/*    Voronoi diagrams.  The first normal vector's x and y magnitudes are    */
/*    at indices [0] and [1], followed by the remaining vectors.  For each   */
/*    finite edge in a Voronoi diagram, the normal vector written is the     */
/*    zero vector.  Two REALs per edge.  Output only.                        */
/*                                                                           */
/*                                                                           */
/*  Any input fields that Triangle will examine must be initialized.         */
/*  Furthermore, for each output array that Triangle will write to, you      */
/*  must either provide space by setting the appropriate pointer to point    */
/*  to the space you want the data written to, or you must initialize the    */
/*  pointer to NULL, which tells Triangle to allocate space for the results. */
/*  The latter option is preferable, because Triangle always knows exactly   */
/*  how much space to allocate.  The former option is provided mainly for    */
/*  people who need to call Triangle from Fortran code, though it also makes */
/*  possible some nasty space-saving tricks, like writing the output to the  */
/*  same arrays as the input.                                                */
/*                                                                           */
/*  Triangle will not free() any input or output arrays, including those it  */
/*  allocates itself; that's up to you.  You should free arrays allocated by */
/*  Triangle by calling the trifree() procedure defined below.  (By default, */
/*  trifree() just calls the standard free() library procedure, but          */
/*  applications that call triangulate() may replace trimalloc() and         */
/*  trifree() in triangle.c to use specialized memory allocators.)           */
/*                                                                           */
/*  Here's a guide to help you decide which fields you must initialize       */
/*  before you call triangulate().                                           */
/*                                                                           */
/*  `in':                                                                    */
/*                                                                           */
/*    - `pointlist' must always point to a list of points; `numberofpoints'  */
/*      and `numberofpointattributes' must be properly set.                  */
/*      `pointmarkerlist' must either be set to NULL (in which case all      */
/*      markers default to zero), or must point to a list of markers.  If    */
/*      `numberofpointattributes' is not zero, `pointattributelist' must     */
/*      point to a list of point attributes.                                 */
/*    - If the `r' switch is used, `trianglelist' must point to a list of    */
/*      triangles, and `numberoftriangles', `numberofcorners', and           */
/*      `numberoftriangleattributes' must be properly set.  If               */
/*      `numberoftriangleattributes' is not zero, `triangleattributelist'    */
/*      must point to a list of triangle attributes.  If the `a' switch is   */
/*      used (with no number following), `trianglearealist' must point to a  */
/*      list of triangle area constraints.  `neighborlist' may be ignored.   */
/*    - If the `p' switch is used, `segmentlist' must point to a list of     */
/*      segments, `numberofsegments' must be properly set, and               */
/*      `segmentmarkerlist' must either be set to NULL (in which case all    */
/*      markers default to zero), or must point to a list of markers.        */
/*    - If the `p' switch is used without the `r' switch, then               */
/*      `numberofholes' and `numberofregions' must be properly set.  If      */
/*      `numberofholes' is not zero, `holelist' must point to a list of      */
/*      holes.  If `numberofregions' is not zero, `regionlist' must point to */
/*      a list of region constraints.                                        */
/*    - If the `p' switch is used, `holelist', `numberofholes',              */
/*      `regionlist', and `numberofregions' is copied to `out'.  (You can    */
/*      nonetheless get away with not initializing them if the `r' switch is */
/*      used.)                                                               */
/*    - `edgelist', `edgemarkerlist', `normlist', and `numberofedges' may be */
/*      ignored.                                                             */
/*                                                                           */
/*  `out':                                                                   */
/*                                                                           */
/*    - `pointlist' must be initialized (NULL or pointing to memory) unless  */
/*      the `N' switch is used.  `pointmarkerlist' must be initialized       */
/*      unless the `N' or `B' switch is used.  If `N' is not used and        */
/*      `in->numberofpointattributes' is not zero, `pointattributelist' must */
/*      be initialized.                                                      */
/*    - `trianglelist' must be initialized unless the `E' switch is used.    */
/*      `neighborlist' must be initialized if the `n' switch is used.  If    */
/*      the `E' switch is not used and (`in->numberofelementattributes' is   */
/*      not zero or the `A' switch is used), `elementattributelist' must be  */
/*      initialized.  `trianglearealist' may be ignored.                     */
/*    - `segmentlist' must be initialized if the `p' or `c' switch is used,  */
/*      and the `P' switch is not used.  `segmentmarkerlist' must also be    */
/*      initialized under these circumstances unless the `B' switch is used. */
/*    - `edgelist' must be initialized if the `e' switch is used.            */
/*      `edgemarkerlist' must be initialized if the `e' switch is used and   */
/*      the `B' switch is not.                                               */
/*    - `holelist', `regionlist', `normlist', and all scalars may be ignored.*/
/*                                                                           */
/*  `vorout' (only needed if `v' switch is used):                            */
/*                                                                           */
/*    - `pointlist' must be initialized.  If `in->numberofpointattributes'   */
/*      is not zero, `pointattributelist' must be initialized.               */
/*      `pointmarkerlist' may be ignored.                                    */
/*    - `edgelist' and `normlist' must both be initialized.                  */
/*      `edgemarkerlist' may be ignored.                                     */
/*    - Everything else may be ignored.                                      */
/*                                                                           */
/*  After a call to triangulate(), the valid fields of `out' and `vorout'    */
/*  will depend, in an obvious way, on the choice of switches used.  Note    */
/*  that when the `p' switch is used, the pointers `holelist' and            */
/*  `regionlist' are copied from `in' to `out', but no new space is          */
/*  allocated; be careful that you don't free() the same array twice.  On    */
/*  the other hand, Triangle will never copy the `pointlist' pointer (or any */
/*  others); new space is allocated for `out->pointlist', or if the `N'      */
/*  switch is used, `out->pointlist' remains uninitialized.                  */
/*                                                                           */
/*  All of the meaningful `numberof' fields will be properly set; for        */
/*  instance, `numberofedges' will represent the number of edges in the      */
/*  triangulation whether or not the edges were written.  If segments are    */
/*  not used, `numberofsegments' will indicate the number of boundary edges. */
/*                                                                           */
/*****************************************************************************/

struct triangulateio {
  REAL *pointlist;                                               /* In / out */
  REAL *pointattributelist;                                      /* In / out */
  int *pointmarkerlist;                                          /* In / out */
  int numberofpoints;                                            /* In / out */
  int numberofpointattributes;                                   /* In / out */

  int *trianglelist;                                             /* In / out */
  REAL *triangleattributelist;                                   /* In / out */
  REAL *trianglearealist;                                         /* In only */
  int *neighborlist;                                             /* Out only */
  int numberoftriangles;                                         /* In / out */
  int numberofcorners;                                           /* In / out */
  int numberoftriangleattributes;                                /* In / out */

  int *segmentlist;                                              /* In / out */
  int *segmentmarkerlist;                                        /* In / out */
  int numberofsegments;                                          /* In / out */

  REAL *holelist;                        /* In / pointer to array copied out */
  int numberofholes;                                      /* In / copied out */

  REAL *regionlist;                      /* In / pointer to array copied out */
  int numberofregions;                                    /* In / copied out */

  int *edgelist;                                                 /* Out only */
  int *edgemarkerlist;            /* Not used with Voronoi diagram; out only */
  REAL *normlist;                /* Used only with Voronoi diagram; out only */
  int numberofedges;                                             /* Out only */
};

#ifdef ANSI_DECLARATORS
void triangulate(char *, struct triangulateio *, struct triangulateio *,
                 struct triangulateio *);
void trifree(VOID *memptr);
#else /* not ANSI_DECLARATORS */
void triangulate();
void trifree();
#endif /* not ANSI_DECLARATORS */