diegoripley/tippecanoe
1
0
Fork 0
mirror of https://github.com/felt/tippecanoe.git synced 2026-10-02 16:35:40 +02:00
Code Issues Packages Projects Releases Wiki Activity

Do some intersecting

Browse Source
This commit is contained in:
Erica Fischer
2023-11-09 11:09:40 -08:00
parent 3f98aa96b2
commit 22c308f623
1 changed files with 50 additions and 11 deletions
Download Patch File Download Diff File Expand all files Collapse all files
polygon.cpp
+50 -11
View File
@@ -36,17 +36,15 @@ std::pair<double, double> get_line_intersection(double p0_x, double p0_y, double
t = (d23_x * (p0_y - p2_y) - d23_y * (p0_x - p2_x)) / det;
s = (-d01_y * (p0_x - p2_x) + d01_x * (p0_y - p2_y)) / det;
if (s >= 0 && s <= 1 && t >= 0 && t <= 1) {
return std::make_pair(t, s);
return std::make_pair(t, s);
#if 0
printf("%f,%f to %f,%f and %f,%f to %f,%f: %f and %f\n",
p0_x, p0_y, p1_x, p1_y, p2_x, p2_y, p3_x, p3_y, t, s);
printf("%f,%f or %f,%f\n",
p0_x + t * d01_x, p0_y + t * d01_y,
p2_x + s * d23_x, p2_y + s * d23_y);
printf("%f,%f to %f,%f and %f,%f to %f,%f: %f and %f\n",
p0_x, p0_y, p1_x, p1_y, p2_x, p2_y, p3_x, p3_y, t, s);
printf("%f,%f or %f,%f\n",
p0_x + t * d01_x, p0_y + t * d01_y,
p2_x + s * d23_x, p2_y + s * d23_y);
#endif
}
}
return std::make_pair(-1, -1);
@@ -59,10 +57,51 @@ bool intersect(std::vector<segment> &segs, size_t s1, size_t s2) {
std::round(segs[s2].second.x), std::round(segs[s2].second.y));
bool changed = false;
if (intersections.first >= 0) {
// XXX introduce a new node
} else {
if (intersections.first >= 0 && intersections.first <= 1 && intersections.second >= 0 && intersections.second <= 1) {
double x = std::round(segs[s1].first.x + intersections.first * (segs[s1].second.x - segs[s1].first.x));
double y = std::round(segs[s1].first.y + intersections.first * (segs[s1].second.y - segs[s1].first.y));
// try intersecting the original segments without rounding,
// since that intersection should be more true to the original
// intent of the data.
auto intersections2 = get_line_intersection((segs[s1].first.x), (segs[s1].first.y),
(segs[s1].second.x), (segs[s1].second.y),
(segs[s2].first.x), (segs[s2].first.y),
(segs[s2].second.x), (segs[s2].second.y));
if (intersections2.first >= 0 && intersections2.first <= 1 && intersections2.second >= 0 && intersections2.second <= 1) {
double x2 = std::round(segs[s1].first.x + intersections2.first * (segs[s1].second.x - segs[s1].first.x));
double y2 = std::round(segs[s1].first.y + intersections2.first * (segs[s1].second.y - segs[s1].first.y));
if (x != x2 || y != y2) {
// printf("would intersect at %f,%f; from rounded chose %f,%f\n", x2, y2, x, y);
x = x2;
y = y2;
}
}
if ((x == std::round(segs[s1].first.x) && y == std::round(segs[s1].first.y)) ||
(x == std::round(segs[s1].second.x) && y == std::round(segs[s1].second.y))) {
// at an endpoint in s1, so it doesn't need to be changed
} else {
segs.push_back(std::make_pair(point(x, y), segs[s1].second));
segs[s1] = std::make_pair(segs[s1].first, point(x, y));
changed = true;
}
if ((x == std::round(segs[s2].first.x) && y == std::round(segs[s2].first.y)) ||
(x == std::round(segs[s2].second.x) && y == std::round(segs[s2].second.y))) {
// at an endpoint in s2, so it doesn't need to be changed
} else {
segs.push_back(std::make_pair(point(x, y), segs[s2].second));
segs[s2] = std::make_pair(segs[s2].first, point(x, y));
changed = true;
}
} else if (intersections.first == -1 && intersections.second == -1) {
// XXX handle collinear
} else {
// could intersect, but does not
}
return changed;