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triangle.h
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1 /*****************************************************************************/
2 /* */
3 /* (triangle.h) */
4 /* */
5 /* Include file for programs that call Triangle. */
6 /* */
7 /* Accompanies Triangle Versions 1.3 and 1.4 */
8 /* July 19, 1996 */
9 /* */
10 /* Copyright 1996 */
11 /* Jonathan Richard Shewchuk */
12 /* 2360 Woolsey #H */
13 /* Berkeley, California 94705-1927 */
14 /* jrs@cs.berkeley.edu */
15 /* */
16 /*****************************************************************************/
17 
18 /*****************************************************************************/
19 /* */
20 /* How to call Triangle from another program */
21 /* */
22 /* */
23 /* If you haven't read Triangle's instructions (run "triangle -h" to read */
24 /* them), you won't understand what follows. */
25 /* */
26 /* Triangle must be compiled into an object file (triangle.o) with the */
27 /* TRILIBRARY symbol defined (preferably by using the -DTRILIBRARY compiler */
28 /* switch). The makefile included with Triangle will do this for you if */
29 /* you run "make trilibrary". The resulting object file can be called via */
30 /* the procedure triangulate(). */
31 /* */
32 /* If the size of the object file is important to you, you may wish to */
33 /* generate a reduced version of triangle.o. The REDUCED symbol gets rid */
34 /* of all features that are primarily of research interest. Specifically, */
35 /* the -DREDUCED switch eliminates Triangle's -i, -F, -s, and -C switches. */
36 /* The CDT_ONLY symbol gets rid of all meshing algorithms above and beyond */
37 /* constrained Delaunay triangulation. Specifically, the -DCDT_ONLY switch */
38 /* eliminates Triangle's -r, -q, -a, -S, and -s switches. */
39 /* */
40 /* IMPORTANT: These definitions (TRILIBRARY, REDUCED, CDT_ONLY) must be */
41 /* made in the makefile or in triangle.c itself. Putting these definitions */
42 /* in this file will not create the desired effect. */
43 /* */
44 /* */
45 /* The calling convention for triangulate() follows. */
46 /* */
47 /* void triangulate(triswitches, in, out, vorout) */
48 /* char *triswitches; */
49 /* struct triangulateio *in; */
50 /* struct triangulateio *out; */
51 /* struct triangulateio *vorout; */
52 /* */
53 /* `triswitches' is a string containing the command line switches you wish */
54 /* to invoke. No initial dash is required. Some suggestions: */
55 /* */
56 /* - You'll probably find it convenient to use the `z' switch so that */
57 /* points (and other items) are numbered from zero. This simplifies */
58 /* indexing, because the first item of any type always starts at index */
59 /* [0] of the corresponding array, whether that item's number is zero or */
60 /* one. */
61 /* - You'll probably want to use the `Q' (quiet) switch in your final code, */
62 /* but you can take advantage of Triangle's printed output (including the */
63 /* `V' switch) while debugging. */
64 /* - If you are not using the `q' or `a' switches, then the output points */
65 /* will be identical to the input points, except possibly for the */
66 /* boundary markers. If you don't need the boundary markers, you should */
67 /* use the `N' (no nodes output) switch to save memory. (If you do need */
68 /* boundary markers, but need to save memory, a good nasty trick is to */
69 /* set out->pointlist equal to in->pointlist before calling triangulate(),*/
70 /* so that Triangle overwrites the input points with identical copies.) */
71 /* - The `I' (no iteration numbers) and `g' (.off file output) switches */
72 /* have no effect when Triangle is compiled with TRILIBRARY defined. */
73 /* */
74 /* `in', `out', and `vorout' are descriptions of the input, the output, */
75 /* and the Voronoi output. If the `v' (Voronoi output) switch is not used, */
76 /* `vorout' may be NULL. `in' and `out' may never be NULL. */
77 /* */
78 /* Certain fields of the input and output structures must be initialized, */
79 /* as described below. */
80 /* */
81 /*****************************************************************************/
82 
83 /*****************************************************************************/
84 /* */
85 /* The `triangulateio' structure. */
86 /* */
87 /* Used to pass data into and out of the triangulate() procedure. */
88 /* */
89 /* */
90 /* Arrays are used to store points, triangles, markers, and so forth. In */
91 /* all cases, the first item in any array is stored starting at index [0]. */
92 /* However, that item is item number `1' unless the `z' switch is used, in */
93 /* which case it is item number `0'. Hence, you may find it easier to */
94 /* index points (and triangles in the neighbor list) if you use the `z' */
95 /* switch. Unless, of course, you're calling Triangle from a Fortran */
96 /* program. */
97 /* */
98 /* Description of fields (except the `numberof' fields, which are obvious): */
99 /* */
100 /* `pointlist': An array of point coordinates. The first point's x */
101 /* coordinate is at index [0] and its y coordinate at index [1], followed */
102 /* by the coordinates of the remaining points. Each point occupies two */
103 /* REALs. */
104 /* `pointattributelist': An array of point attributes. Each point's */
105 /* attributes occupy `numberofpointattributes' REALs. */
106 /* `pointmarkerlist': An array of point markers; one int per point. */
107 /* */
108 /* `trianglelist': An array of triangle corners. The first triangle's */
109 /* first corner is at index [0], followed by its other two corners in */
110 /* counterclockwise order, followed by any other nodes if the triangle */
111 /* represents a nonlinear element. Each triangle occupies */
112 /* `numberofcorners' ints. */
113 /* `triangleattributelist': An array of triangle attributes. Each */
114 /* triangle's attributes occupy `numberoftriangleattributes' REALs. */
115 /* `trianglearealist': An array of triangle area constraints; one REAL per */
116 /* triangle. Input only. */
117 /* `neighborlist': An array of triangle neighbors; three ints per */
118 /* triangle. Output only. */
119 /* */
120 /* `segmentlist': An array of segment endpoints. The first segment's */
121 /* endpoints are at indices [0] and [1], followed by the remaining */
122 /* segments. Two ints per segment. */
123 /* `segmentmarkerlist': An array of segment markers; one int per segment. */
124 /* */
125 /* `holelist': An array of holes. The first hole's x and y coordinates */
126 /* are at indices [0] and [1], followed by the remaining holes. Two */
127 /* REALs per hole. Input only, although the pointer is copied to the */
128 /* output structure for your convenience. */
129 /* */
130 /* `regionlist': An array of regional attributes and area constraints. */
131 /* The first constraint's x and y coordinates are at indices [0] and [1], */
132 /* followed by the regional attribute and index [2], followed by the */
133 /* maximum area at index [3], followed by the remaining area constraints. */
134 /* Four REALs per area constraint. Note that each regional attribute is */
135 /* used only if you select the `A' switch, and each area constraint is */
136 /* used only if you select the `a' switch (with no number following), but */
137 /* omitting one of these switches does not change the memory layout. */
138 /* Input only, although the pointer is copied to the output structure for */
139 /* your convenience. */
140 /* */
141 /* `edgelist': An array of edge endpoints. The first edge's endpoints are */
142 /* at indices [0] and [1], followed by the remaining edges. Two ints per */
143 /* edge. Output only. */
144 /* `edgemarkerlist': An array of edge markers; one int per edge. Output */
145 /* only. */
146 /* `normlist': An array of normal vectors, used for infinite rays in */
147 /* Voronoi diagrams. The first normal vector's x and y magnitudes are */
148 /* at indices [0] and [1], followed by the remaining vectors. For each */
149 /* finite edge in a Voronoi diagram, the normal vector written is the */
150 /* zero vector. Two REALs per edge. Output only. */
151 /* */
152 /* */
153 /* Any input fields that Triangle will examine must be initialized. */
154 /* Furthermore, for each output array that Triangle will write to, you */
155 /* must either provide space by setting the appropriate pointer to point */
156 /* to the space you want the data written to, or you must initialize the */
157 /* pointer to NULL, which tells Triangle to allocate space for the results. */
158 /* The latter option is preferable, because Triangle always knows exactly */
159 /* how much space to allocate. The former option is provided mainly for */
160 /* people who need to call Triangle from Fortran code, though it also makes */
161 /* possible some nasty space-saving tricks, like writing the output to the */
162 /* same arrays as the input. */
163 /* */
164 /* Triangle will not free() any input or output arrays, including those it */
165 /* allocates itself; that's up to you. */
166 /* */
167 /* Here's a guide to help you decide which fields you must initialize */
168 /* before you call triangulate(). */
169 /* */
170 /* `in': */
171 /* */
172 /* - `pointlist' must always point to a list of points; `numberofpoints' */
173 /* and `numberofpointattributes' must be properly set. */
174 /* `pointmarkerlist' must either be set to NULL (in which case all */
175 /* markers default to zero), or must point to a list of markers. If */
176 /* `numberofpointattributes' is not zero, `pointattributelist' must */
177 /* point to a list of point attributes. */
178 /* - If the `r' switch is used, `trianglelist' must point to a list of */
179 /* triangles, and `numberoftriangles', `numberofcorners', and */
180 /* `numberoftriangleattributes' must be properly set. If */
181 /* `numberoftriangleattributes' is not zero, `triangleattributelist' */
182 /* must point to a list of triangle attributes. If the `a' switch is */
183 /* used (with no number following), `trianglearealist' must point to a */
184 /* list of triangle area constraints. `neighborlist' may be ignored. */
185 /* - If the `p' switch is used, `segmentlist' must point to a list of */
186 /* segments, `numberofsegments' must be properly set, and */
187 /* `segmentmarkerlist' must either be set to NULL (in which case all */
188 /* markers default to zero), or must point to a list of markers. */
189 /* - If the `p' switch is used without the `r' switch, then */
190 /* `numberofholes' and `numberofregions' must be properly set. If */
191 /* `numberofholes' is not zero, `holelist' must point to a list of */
192 /* holes. If `numberofregions' is not zero, `regionlist' must point to */
193 /* a list of region constraints. */
194 /* - If the `p' switch is used, `holelist', `numberofholes', */
195 /* `regionlist', and `numberofregions' is copied to `out'. (You can */
196 /* nonetheless get away with not initializing them if the `r' switch is */
197 /* used.) */
198 /* - `edgelist', `edgemarkerlist', `normlist', and `numberofedges' may be */
199 /* ignored. */
200 /* */
201 /* `out': */
202 /* */
203 /* - `pointlist' must be initialized (NULL or pointing to memory) unless */
204 /* the `N' switch is used. `pointmarkerlist' must be initialized */
205 /* unless the `N' or `B' switch is used. If `N' is not used and */
206 /* `in->numberofpointattributes' is not zero, `pointattributelist' must */
207 /* be initialized. */
208 /* - `trianglelist' must be initialized unless the `E' switch is used. */
209 /* `neighborlist' must be initialized if the `n' switch is used. If */
210 /* the `E' switch is not used and (`in->numberofelementattributes' is */
211 /* not zero or the `A' switch is used), `elementattributelist' must be */
212 /* initialized. `trianglearealist' may be ignored. */
213 /* - `segmentlist' must be initialized if the `p' or `c' switch is used, */
214 /* and the `P' switch is not used. `segmentmarkerlist' must also be */
215 /* initialized under these circumstances unless the `B' switch is used. */
216 /* - `edgelist' must be initialized if the `e' switch is used. */
217 /* `edgemarkerlist' must be initialized if the `e' switch is used and */
218 /* the `B' switch is not. */
219 /* - `holelist', `regionlist', `normlist', and all scalars may be ignored.*/
220 /* */
221 /* `vorout' (only needed if `v' switch is used): */
222 /* */
223 /* - `pointlist' must be initialized. If `in->numberofpointattributes' */
224 /* is not zero, `pointattributelist' must be initialized. */
225 /* `pointmarkerlist' may be ignored. */
226 /* - `edgelist' and `normlist' must both be initialized. */
227 /* `edgemarkerlist' may be ignored. */
228 /* - Everything else may be ignored. */
229 /* */
230 /* After a call to triangulate(), the valid fields of `out' and `vorout' */
231 /* will depend, in an obvious way, on the choice of switches used. Note */
232 /* that when the `p' switch is used, the pointers `holelist' and */
233 /* `regionlist' are copied from `in' to `out', but no new space is */
234 /* allocated; be careful that you don't free() the same array twice. On */
235 /* the other hand, Triangle will never copy the `pointlist' pointer (or any */
236 /* others); new space is allocated for `out->pointlist', or if the `N' */
237 /* switch is used, `out->pointlist' remains uninitialized. */
238 /* */
239 /* All of the meaningful `numberof' fields will be properly set; for */
240 /* instance, `numberofedges' will represent the number of edges in the */
241 /* triangulation whether or not the edges were written. If segments are */
242 /* not used, `numberofsegments' will indicate the number of boundary edges. */
243 /* */
244 /*****************************************************************************/
245 
246 struct triangulateio {
247  REAL *pointlist; /* In / out */
248  REAL *pointattributelist; /* In / out */
249  int *pointmarkerlist; /* In / out */
250  int numberofpoints; /* In / out */
251  int numberofpointattributes; /* In / out */
252 
253  int *trianglelist; /* In / out */
254  REAL *triangleattributelist; /* In / out */
255  REAL *trianglearealist; /* In only */
256  int *neighborlist; /* Out only */
257  int numberoftriangles; /* In / out */
258  int numberofcorners; /* In / out */
259  int numberoftriangleattributes; /* In / out */
260 
261  int *segmentlist; /* In / out */
262  int *segmentmarkerlist; /* In / out */
263  int numberofsegments; /* In / out */
264 
265  REAL *holelist; /* In / pointer to array copied out */
266  int numberofholes; /* In / copied out */
267 
268  REAL *regionlist; /* In / pointer to array copied out */
269  int numberofregions; /* In / copied out */
270 
271  int *edgelist; /* Out only */
272  int *edgemarkerlist; /* Not used with Voronoi diagram; out only */
273  REAL *normlist; /* Used only with Voronoi diagram; out only */
274  int numberofedges; /* Out only */
275 };
276 
277 #ifdef ANSI_DECLARATORS
278 void triangulate(char *, struct triangulateio *, struct triangulateio *,
279  struct triangulateio *);
280 #else /* not ANSI_DECLARATORS */
281 void triangulate();
282 #endif /* not ANSI_DECLARATORS */
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