Changeset 18990 in josm

Timestamp:

2024-02-20T18:14:31+01:00 (3 months ago)

Author:

taylor.smock

Message:

Fix #23472: Decrease cost of Geometry#polygonIntersectionResult (specifically for geometry.mapcss)

When profiling the validator with an overpass download of Mesa County, Colorado,
~50% of the total CPU time are taken up by Geometry#polygonIntersectionResult.

Specifically (inside the function), the improvements for this patch are as follows:

• CPU cycles: -95.7%
• Memory allocations: -97.9%

When taken as a whole, the total time taken by the validator was reduced by ~75%.

File:

• trunk/src/org/openstreetmap/josm/tools/Geometry.java (modified) (2 diffs)

trunk/src/org/openstreetmap/josm/tools/Geometry.java

@@ -694 +694 @@
      */
     public static Pair<PolygonIntersection, Area> polygonIntersectionResult(Area a1, Area a2, double eps) {
+        // Simple intersect check (if their bounds don't intersect, don't bother going further; there will be no intersection)
+        // This avoids the more expensive Area#intersect call some of the time (decreases CPU and memory allocation by ~95%)
+        // in Mesa County, CO geometry validator test runs.
+        final Rectangle2D a12d = a1.getBounds2D();
+        final Rectangle2D a22d = a2.getBounds2D();
+        if (!a12d.intersects(a22d) || !a1.intersects(a22d) || !a2.intersects(a12d)) {
+            return new Pair<>(PolygonIntersection.OUTSIDE, new Area());
+        }
         Area inter = new Area(a1);
         inter.intersect(a2);
@@ -699 +707 @@
         if (inter.isEmpty() || !checkIntersection(inter, eps)) {
             return new Pair<>(PolygonIntersection.OUTSIDE, inter);
-        } else if (a2.getBounds2D().contains(a1.getBounds2D()) && inter.equals(a1)) {
+        } else if (a22d.contains(a12d) && inter.equals(a1)) {
             return new Pair<>(PolygonIntersection.FIRST_INSIDE_SECOND, inter);
-        } else if (a1.getBounds2D().contains(a2.getBounds2D()) && inter.equals(a2)) {
+        } else if (a12d.contains(a22d) && inter.equals(a2)) {
             return new Pair<>(PolygonIntersection.SECOND_INSIDE_FIRST, inter);
         } else {