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Treat tiny polygon holes as dust again, but accumulated separately now

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Erica Fischer
2023-08-25 12:22:55 -07:00
parent 39ad95ed73
commit f294e2af8a
4 changed files with 29 additions and 9 deletions
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geometry.cpp
+25 -5
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@@ -186,7 +186,7 @@ void check_polygon(drawvec &geom) {
}
}
drawvec reduce_tiny_poly(drawvec &geom, int z, int detail, bool *reduced, double *accum_area, serial_feature *this_feature, serial_feature *tiny_feature) {
drawvec reduce_tiny_poly(drawvec &geom, int z, int detail, bool *reduced, double *accum_area, double *accum_hole, serial_feature *this_feature, serial_feature *tiny_feature) {
drawvec out;
const double pixel = (1LL << (32 - detail - z)) * (double) tiny_polygon_size;
bool includes_real = false;
@@ -222,7 +222,7 @@ drawvec reduce_tiny_poly(drawvec &geom, int z, int detail, bool *reduced, double
// OR it is an inner ring and we haven't output an outer ring for it to be
// cut out of, so we are just subtracting its area from the tiny polygon
// rather than trying to deal with it geometrically
if ((area > 0 && area <= pixel * pixel) || (area < 0 && !included_last_outer)) {
if ((area > 0 && area <= pixel * pixel) || (area < 0 && -area <= pixel * pixel && !included_last_outer)) {
// printf("area is only %f vs %lld so using square\n", area, pixel * pixel);
*accum_area += area;
@@ -243,10 +243,30 @@ drawvec reduce_tiny_poly(drawvec &geom, int z, int detail, bool *reduced, double
included_last_outer = false;
}
}
// this is a tiny hole, and we have a real outer ring that we can cut it out of,
// so accumulate some hole, and if we have enough to be worth cutting, cut it out.
//
// these hole areas are accumulated separately rather than just decrementing
// the accumulated area, because otherwise it is possible to accumulate enough
// negative area to lose entire outer rings in the process of getting back up to 0.
else if (area < 0 && -area <= pixel * pixel && included_last_outer) {
*accum_hole -= area;
if (*accum_hole > pixel * pixel) {
// XXX use centroid;
out.push_back(draw(VT_MOVETO, geom[i].x - pixel / 2, geom[i].y - pixel / 2));
out.push_back(draw(VT_LINETO, geom[i].x - pixel / 2 + pixel, geom[i].y - pixel / 2));
out.push_back(draw(VT_LINETO, geom[i].x - pixel / 2 + pixel, geom[i].y - pixel / 2 + pixel));
out.push_back(draw(VT_LINETO, geom[i].x - pixel / 2, geom[i].y - pixel / 2 + pixel));
out.push_back(draw(VT_LINETO, geom[i].x - pixel / 2, geom[i].y - pixel / 2));
includes_dust = true;
*accum_hole -= pixel * pixel;
}
}
// i.e., this ring is large enough that it gets to represent itself
// or it is a tiny hole out of a real polygon, which we are still treating
// as a real geometry because otherwise we can accumulate enough tiny holes
// that we will drop the next several outer rings getting back up to 0.
else {
// printf("area is %f so keeping instead of %lld\n", area, pixel * pixel);