diegoripley/tippecanoe
1
0
Fork 0
mirror of https://github.com/felt/tippecanoe.git synced 2026-10-02 08:25:40 +02:00
Code Issues Packages Projects Releases Wiki Activity

Only accept longitude corrections that give rings the right winding

Browse Source
This commit is contained in:
Erica Fischer
2023-12-11 13:38:54 -08:00
parent f53d9f77d2
commit 02e9e4e952
1 changed files with 35 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files
serial.cpp
+35 -12
View File
@@ -313,11 +313,12 @@ serial_feature deserialize_feature(std::string &geoms, unsigned z, unsigned tx,
return sf;
}
static long long scale_geometry(struct serialization_state *sst, long long *bbox, drawvec &geom) {
static long long scale_geometry(struct serialization_state *sst, long long *bbox, drawvec &geom, int t) {
double scale = 1.0 / (1 << geometry_scale);
if (additional[A_DETECT_WRAPAROUND]) {
drawvec out;
bool outer = true; // first ring is expected to be outer
for (size_t i = 0; i < geom.size(); i++) {
if (geom[i].op == VT_MOVETO) {
@@ -333,6 +334,7 @@ static long long scale_geometry(struct serialization_state *sst, long long *bbox
bool balanced = true;
drawvec ring;
bool changed = false;
for (size_t k = i; k < j; k++) {
draw op = geom[k];
op.x += offset;
@@ -349,6 +351,7 @@ static long long scale_geometry(struct serialization_state *sst, long long *bbox
offset -= 1LL << 32;
op.x -= 1LL << 32;
changed = true;
} else if (prev_x - op.x > (1LL << 31) && prev_x - op.x != (1LL << 32)) {
if (offset > 0) {
// already shifted right, but seems to need another shift right
@@ -358,22 +361,40 @@ static long long scale_geometry(struct serialization_state *sst, long long *bbox
offset += 1LL << 32;
op.x += 1LL << 32;
changed = true;
}
ring.push_back(op);
prev_x = op.x;
}
// If this is a polygon, in which the first and last
// points of each ring are supposed to be identical,
// make sure the antimeridian wraparound detection
// preserves that expectation. If it doesn't, it means
// we have detected something wrongly.
if (geom[j - 1] == geom[i]) {
if (offset != 0) {
// first and last points are supposed to be the same
// but there is an unresolved antimeridian shift
balanced = false;
if (changed && balanced) {
// If this is a polygon, in which the first and last
// points of each ring are supposed to be identical,
// make sure the antimeridian wraparound detection
// preserves that expectation. If it doesn't, it means
// we have detected something wrongly.
if (geom[j - 1] == geom[i]) {
if (offset != 0) {
// first and last points are supposed to be the same
// but there is an unresolved antimeridian shift
balanced = false;
}
}
if (t == VT_POLYGON) {
// don't accept longitude corrections that would give
// a ring a winding counter to what the geojson structure
// says the winding should be
double area_after = get_area(ring, 0, ring.size());
if ((outer && area_after < 0) ||
(!outer && area_after > 0)) {
// wraparound detection gave a ring a winding different from
// what its position in the GeoJSON structure indicates that
// it should have.
balanced = false;
}
}
}
@@ -391,8 +412,10 @@ static long long scale_geometry(struct serialization_state *sst, long long *bbox
}
i = j - 1;
outer = false;
} else if (geom[i].op == VT_CLOSEPATH) {
out.push_back(geom[i]);
outer = true;
}
}
@@ -520,7 +543,7 @@ int serialize_feature(struct serialization_state *sst, serial_feature &sf) {
// try to remind myself that the geometry in this function is in SCALED COORDINATES
drawvec scaled_geometry = sf.geometry;
sf.geometry.clear();
scale_geometry(sst, sf.bbox, scaled_geometry);
scale_geometry(sst, sf.bbox, scaled_geometry, sf.t);
// This has to happen after scaling so that the wraparound detection has happened first.
// Otherwise the inner/outer calculation will be confused by bad geometries.