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triangle.h

/*****************************************************************************/
/*                                                                           */
/*  (triangle.h)                                                             */
/*                                                                           */
/*  Include file for programs that call Triangle.                            */
/*                                                                           */
/*  Accompanies Triangle Version 1.3                                         */
/*  July 19, 1996                                                            */
/*                                                                           */
/*  Copyright 1996                                                           */
/*  Jonathan Richard Shewchuk                                                */
/*  School of Computer Science                                               */
/*  Carnegie Mellon University                                               */
/*  5000 Forbes Avenue                                                       */
/*  Pittsburgh, Pennsylvania  15213-3891                                     */
/*  jrs@cs.cmu.edu                                                           */
/*                                                                           */
/*****************************************************************************/

/*****************************************************************************/
/*                                                                           */
/*  How to call Triangle from another program                                */
/*                                                                           */
/*                                                                           */
/*  If you haven't read Triangle's instructions (run "triangle -h" to read   */
/*  them), you won't understand what follows.                                */
/*                                                                           */
/*  Triangle must be compiled into an object file (triangle.o) with the      */
/*  TRILIBRARY symbol defined (preferably by using the -DTRILIBRARY compiler */
/*  switch).  The makefile included with Triangle will do this for you if    */
/*  you run "make trilibrary".  The resulting object file can be called via  */
/*  the procedure triangulate().                                             */
/*                                                                           */
/*  If the size of the object file is important to you, you may wish to      */
/*  generate a reduced version of triangle.o.  The REDUCED symbol gets rid   */
/*  of all features that are primarily of research interest.  Specifically,  */
/*  the -DREDUCED switch eliminates Triangle's -i, -F, -s, and -C switches.  */
/*  The CDT_ONLY symbol gets rid of all meshing algorithms above and beyond  */
/*  constrained Delaunay triangulation.  Specifically, the -DCDT_ONLY switch */
/*  eliminates Triangle's -r, -q, -a, -S, and -s switches.                   */
/*                                                                           */
/*  IMPORTANT:  These definitions (TRILIBRARY, REDUCED, CDT_ONLY) must be    */
/*  made in the makefile or in triangle.c itself.  Putting these definitions */
/*  in this file will not create the desired effect.                         */
/*                                                                           */
/*                                                                           */
/*  The calling convention for triangulate() follows.                        */
/*                                                                           */
/*      void triangulate(triswitches, in, out, vorout)                       */
/*      char *triswitches;                                                   */
/*      struct triangulateio *in;                                            */
/*      struct triangulateio *out;                                           */
/*      struct triangulateio *vorout;                                        */
/*                                                                           */
/*  `triswitches' is a string containing the command line switches you wish  */
/*  to invoke.  No initial dash is required.  Some suggestions:              */
/*                                                                           */
/*  - You'll probably find it convenient to use the `z' switch so that       */
/*    points (and other items) are numbered from zero.  This simplifies      */
/*    indexing, because the first item of any type always starts at index    */
/*    [0] of the corresponding array, whether that item's number is zero or  */
/*    one.                                                                   */
/*  - You'll probably want to use the `Q' (quiet) switch in your final code, */
/*    but you can take advantage of Triangle's printed output (including the */
/*    `V' switch) while debugging.                                           */
/*  - If you are not using the `q' or `a' switches, then the output points   */
/*    will be identical to the input points, except possibly for the         */
/*    boundary markers.  If you don't need the boundary markers, you should  */
/*    use the `N' (no nodes output) switch to save memory.  (If you do need  */
/*    boundary markers, but need to save memory, a good nasty trick is to    */
/*    set out->pointlist equal to in->pointlist before calling triangulate(),*/
/*    so that Triangle overwrites the input points with identical copies.)   */
/*  - The `I' (no iteration numbers) and `g' (.off file output) switches     */
/*    have no effect when Triangle is compiled with TRILIBRARY defined.      */
/*                                                                           */
/*  `in', `out', and `vorout' are descriptions of the input, the output,     */
/*  and the Voronoi output.  If the `v' (Voronoi output) switch is not used, */
/*  `vorout' may be NULL.  `in' and `out' may never be NULL.                 */
/*                                                                           */
/*  Certain fields of the input and output structures must be initialized,   */
/*  as described below.                                                      */
/*                                                                           */
/*****************************************************************************/

/*****************************************************************************/
/*                                                                           */
/*  The `triangulateio' structure.                                           */
/*                                                                           */
/*  Used to pass data into and out of the triangulate() procedure.           */
/*                                                                           */
/*                                                                           */
/*  Arrays are used to store points, triangles, markers, and so forth.  In   */
/*  all cases, the first item in any array is stored starting at index [0].  */
/*  However, that item is item number `1' unless the `z' switch is used, in  */
/*  which case it is item number `0'.  Hence, you may find it easier to      */
/*  index points (and triangles in the neighbor list) if you use the `z'     */
/*  switch.  Unless, of course, you're calling Triangle from a Fortran       */
/*  program.                                                                 */
/*                                                                           */
/*  Description of fields (except the `numberof' fields, which are obvious): */
/*                                                                           */
/*  `pointlist':  An array of point coordinates.  The first point's x        */
/*    coordinate is at index [0] and its y coordinate at index [1], followed */
/*    by the coordinates of the remaining points.  Each point occupies two   */
/*    REALs.                                                                 */
/*  `pointattributelist':  An array of point attributes.  Each point's       */
/*    attributes occupy `numberofpointattributes' REALs.                     */
/*  `pointmarkerlist':  An array of point markers; one int per point.        */
/*                                                                           */
/*  `trianglelist':  An array of triangle corners.  The first triangle's     */
/*    first corner is at index [0], followed by its other two corners in     */
/*    counterclockwise order, followed by any other nodes if the triangle    */
/*    represents a nonlinear element.  Each triangle occupies                */
/*    `numberofcorners' ints.                                                */
/*  `triangleattributelist':  An array of triangle attributes.  Each         */
/*    triangle's attributes occupy `numberoftriangleattributes' REALs.       */
/*  `trianglearealist':  An array of triangle area constraints; one REAL per */
/*    triangle.  Input only.                                                 */
/*  `neighborlist':  An array of triangle neighbors; three ints per          */
/*    triangle.  Output only.                                                */
/*                                                                           */
/*  `segmentlist':  An array of segment endpoints.  The first segment's      */
/*    endpoints are at indices [0] and [1], followed by the remaining        */
/*    segments.  Two ints per segment.                                       */
/*  `segmentmarkerlist':  An array of segment markers; one int per segment.  */
/*                                                                           */
/*  `holelist':  An array of holes.  The first hole's x and y coordinates    */
/*    are at indices [0] and [1], followed by the remaining holes.  Two      */
/*    REALs per hole.  Input only, although the pointer is copied to the     */
/*    output structure for your convenience.                                 */
/*                                                                           */
/*  `regionlist':  An array of regional attributes and area constraints.     */
/*    The first constraint's x and y coordinates are at indices [0] and [1], */
/*    followed by the regional attribute and index [2], followed by the      */
/*    maximum area at index [3], followed by the remaining area constraints. */
/*    Four REALs per area constraint.  Note that each regional attribute is  */
/*    used only if you select the `A' switch, and each area constraint is    */
/*    used only if you select the `a' switch (with no number following), but */
/*    omitting one of these switches does not change the memory layout.      */
/*    Input only, although the pointer is copied to the output structure for */
/*    your convenience.                                                      */
/*                                                                           */
/*  `edgelist':  An array of edge endpoints.  The first edge's endpoints are */
/*    at indices [0] and [1], followed by the remaining edges.  Two ints per */
/*    edge.  Output only.                                                    */
/*  `edgemarkerlist':  An array of edge markers; one int per edge.  Output   */
/*    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.                                      */
/*                                                                           */
/*  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. */
/*                                                                           */
/*****************************************************************************/

# define REAL double

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 *);
#else /* not ANSI_DECLARATORS */
void triangulate();
#endif /* not ANSI_DECLARATORS */

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