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Delta encoding for motion within features

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This commit is contained in:
Eric Fischer 2015-06-17 17:48:29 -07:00
parent 725ea71e57
commit 46626e4f08
3 changed files with 24 additions and 12 deletions
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13
geojson.c
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@ -100,7 +100,7 @@ void serialize_string(FILE *out, const char *s, long long *fpos, const char *fna
*fpos += len + 1;
}
void parse_geometry(int t, json_object *j, unsigned *bbox, long long *fpos, FILE *out, int op, const char *fname, json_pull *source) {
void parse_geometry(int t, json_object *j, unsigned *bbox, long long *fpos, FILE *out, int op, const char *fname, json_pull *source, long long *wx, long long *wy) {
if (j == NULL || j->type != JSON_ARRAY) {
fprintf(stderr, "%s:%d: expected array for type %d\n", fname, source->line, t);
return;
@ -119,7 +119,7 @@ void parse_geometry(int t, json_object *j, unsigned *bbox, long long *fpos, FILE
}
}
parse_geometry(within, j->array[i], bbox, fpos, out, op, fname, source);
parse_geometry(within, j->array[i], bbox, fpos, out, op, fname, source, wx, wy);
}
} else {
if (j->length >= 2 && j->array[0]->type == JSON_NUMBER && j->array[1]->type == JSON_NUMBER) {
@ -153,8 +153,10 @@ void parse_geometry(int t, json_object *j, unsigned *bbox, long long *fpos, FILE
}
serialize_byte(out, op, fpos, fname);
serialize_uint(out, x, fpos, fname);
serialize_uint(out, y, fpos, fname);
serialize_long_long(out, x - *wx, fpos, fname);
serialize_long_long(out, y - *wy, fpos, fname);
*wx = x;
*wy = y;
} else {
fprintf(stderr, "%s:%d: malformed point\n", fname, source->line);
}
@ -652,7 +654,8 @@ int read_json(int argc, char **argv, char *fname, const char *layername, int max
serialize_byte(geomfile, mb_geometry[t], &geompos, fname);
serialize_byte(geomfile, n, &geompos, fname);
serialize_long_long(geomfile, metastart, &geompos, fname);
parse_geometry(t, coordinates, bbox, &geompos, geomfile, VT_MOVETO, fname, jp);
long long wx = 0, wy = 0;
parse_geometry(t, coordinates, bbox, &geompos, geomfile, VT_MOVETO, fname, jp, &wx, &wy);
serialize_byte(geomfile, VT_END, &geompos, fname);
/*

16
geometry.cc
View File

@ -25,6 +25,8 @@ drawvec decode_geometry(char **meta, int z, unsigned tx, unsigned ty, int detail
bbox[2] = LONG_LONG_MIN;
bbox[3] = LONG_LONG_MIN;
long long wx = 0, wy = 0;
while (1) {
draw d;
@ -34,12 +36,16 @@ drawvec decode_geometry(char **meta, int z, unsigned tx, unsigned ty, int detail
}
if (d.op == VT_MOVETO || d.op == VT_LINETO) {
unsigned wx, wy;
deserialize_uint(meta, &wx);
deserialize_uint(meta, &wy);
long long dx, dy;
long long wwx = (unsigned) wx;
long long wwy = (unsigned) wy;
deserialize_long_long(meta, &dx);
deserialize_long_long(meta, &dy);
wx += dx;
wy += dy;
long long wwx = wx;
long long wwy = wy;
if (z != 0) {
wwx -= tx << (32 - z);

7
tile.cc
View File

@ -506,13 +506,16 @@ long long write_tile(char **geoms, char *metabase, char *stringpool, unsigned *f
serialize_byte(geomfile[j], t, &geompos[j], fname);
serialize_byte(geomfile[j], layer, &geompos[j], fname);
serialize_long_long(geomfile[j], metastart, &geompos[j], fname);
long long wx = 0, wy = 0;
for (unsigned u = 0; u < geom.size(); u++) {
serialize_byte(geomfile[j], geom[u].op, &geompos[j], fname);
if (geom[u].op != VT_CLOSEPATH) {
serialize_uint(geomfile[j], geom[u].x + sx, &geompos[j], fname);
serialize_uint(geomfile[j], geom[u].y + sy, &geompos[j], fname);
serialize_long_long(geomfile[j], geom[u].x + sx - wx, &geompos[j], fname);
serialize_long_long(geomfile[j], geom[u].y + sy - wy, &geompos[j], fname);
wx = geom[u].x + sx;
wy = geom[u].y + sy;
}
}