Mercurial > dive4elements > river
view artifacts/src/main/java/org/dive4elements/river/artifacts/math/Utils.java @ 7471:fff862f4ef76
Experimental caching of datacage recommendations. The respective hook is called a lot and running the datacage over and over again when loading data can be expensive. So the generated recommendations are cached for some time.
Hopefully this improves the overall speed of loading data from the datacage.
author | Sascha L. Teichmann <teichmann@intevation.de> |
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date | Wed, 30 Oct 2013 15:26:21 +0100 |
parents | af13ceeba52a |
children |
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/* Copyright (C) 2011, 2012, 2013 by Bundesanstalt für Gewässerkunde * Software engineering by Intevation GmbH * * This file is Free Software under the GNU AGPL (>=v3) * and comes with ABSOLUTELY NO WARRANTY! Check out the * documentation coming with Dive4Elements River for details. */ package org.dive4elements.river.artifacts.math; public final class Utils { public static final double EPSILON = 1e-3; private Utils() { } public static final boolean epsilonEquals(double a, double b) { return epsilonEquals(a, b, EPSILON); } public static final boolean epsilonEquals(double a, double b, double eps) { return Math.abs(a - b) < eps; } public static int relativeCCW( double x1, double y1, double x2, double y2, double px, double py ) { if ((epsilonEquals(x1, x2) && epsilonEquals(y1, y2)) || ((epsilonEquals(x1, px) && epsilonEquals(y1, py)))) { return 0; // Coincident points. } // Translate to the origin. x2 -= x1; y2 -= y1; px -= x1; py -= y1; double slope2 = y2 / x2; double slopep = py / px; if (epsilonEquals(slope2, slopep) || (epsilonEquals(x2, 0.0) && epsilonEquals(px, 0.0))) { return y2 > EPSILON // Colinear. ? (py < -EPSILON ? -1 : py > y2 ? 1 : 0) : (py > -EPSILON ? -1 : py < y2 ? 1 : 0); } if (x2 >= EPSILON && slope2 >= EPSILON) { return px >= EPSILON // Quadrant 1. ? (slope2 > slopep ? 1 : -1) : (slope2 < slopep ? 1 : -1); } if (y2 > EPSILON) { return px < -EPSILON // Quadrant 2. ? (slope2 > slopep ? 1 : -1) : (slope2 < slopep ? 1 : -1); } if (slope2 >= EPSILON) { return px >= EPSILON // Quadrant 3. ? (slope2 < slopep ? 1 : -1) : (slope2 > slopep ? 1 : -1); } return px < -EPSILON // Quadrant 4. ? (slope2 < slopep ? 1 : -1) : (slope2 > slopep ? 1 : -1); } }