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vicapow/geos-voronoi-in-js.c

Last active May 4, 2021 23:47
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example of compiling geos to JS because why not
Raw
geos-voronoi-in-js.c
/*
To compile:
first, get a version of geos and put it in `geos` relative path. then...
cd geos
emconfigure ./configure
emmake make
cd ..
emcc \
-s EXPORTED_FUNCTIONS='["_get_voronoi"]' \
-s ASSERTIONS=2 \
-s DEMANGLE_SUPPORT=1 \
src/example.c \
-lgeos_c \
-Lgeos/capi/.libs/ \
-Igeos/capi/ \
-Igeos/include \
-lgeos \
-Lgeos/src/.libs/
*/
#include <geos_c.h>
#include <stdio.h>
#include <stdlib.h>
#include <emscripten.h>
char* get_voronoi() {
initGEOS( (GEOSMessageHandler) printf, (GEOSMessageHandler) printf);
// 2 points with dimension, 2.
int size = 100;
GEOSCoordSequence *inputSequence = GEOSCoordSeq_create(size, 2);
if (inputSequence == NULL) {
printf("unable to initialize coordinate. Exiting...\n");
exit(1);
}
for (int i = 0; i < size; i++) {
GEOSCoordSeq_setX(inputSequence, i, emscripten_random() * 10);
GEOSCoordSeq_setY(inputSequence, i, emscripten_random() * 10);
}
GEOSGeometry *geometry = GEOSGeom_createLineString(inputSequence);
if (geometry == NULL) {
printf("geometry is null\n");
exit(1);
}
GEOSGeometry *envelope = NULL;
double tolerance = 0.0;
int onlyEdges = 0;
GEOSGeometry* voronoi = GEOSVoronoiDiagram(
geometry,
envelope,
tolerance,
onlyEdges
);
if (voronoi == NULL) {
printf("unable to compute voronoi\n");
}
GEOSWKTWriter* wktWriter = GEOSWKTWriter_create();
char *wkt = GEOSWKTWriter_write(wktWriter, voronoi);
GEOSWKTWriter_destroy(wktWriter);
wktWriter = NULL;
finishGEOS();
return wkt;
}
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