package com.vividsolutions.jtstest.function;
import java.util.ArrayList;
import java.util.List;
import com.vividsolutions.jts.geom.Coordinate;
import com.vividsolutions.jts.geom.Envelope;
import com.vividsolutions.jts.geom.Geometry;
import com.vividsolutions.jts.geom.GeometryFactory;
import com.vividsolutions.jts.shape.random.RandomPointsBuilder;
import com.vividsolutions.jts.shape.random.RandomPointsInGridBuilder;
public class CreateRandomShapeFunctions {
public static Geometry randomPointsInGrid(Geometry g, int nPts) {
RandomPointsInGridBuilder shapeBuilder = new RandomPointsInGridBuilder(FunctionsUtil.getFactoryOrDefault(g));
shapeBuilder.setExtent(FunctionsUtil.getEnvelopeOrDefault(g));
shapeBuilder.setNumPoints(nPts);
return shapeBuilder.getGeometry();
}
public static Geometry randomPointsInGridCircles(Geometry g, int nPts) {
RandomPointsInGridBuilder shapeBuilder = new RandomPointsInGridBuilder(FunctionsUtil.getFactoryOrDefault(g));
shapeBuilder.setExtent(FunctionsUtil.getEnvelopeOrDefault(g));
shapeBuilder.setNumPoints(nPts);
shapeBuilder.setConstrainedToCircle(true);
return shapeBuilder.getGeometry();
}
public static Geometry randomPointsInGridWithGutter(Geometry g, int nPts, double gutterFraction) {
RandomPointsInGridBuilder shapeBuilder = new RandomPointsInGridBuilder(FunctionsUtil.getFactoryOrDefault(g));
shapeBuilder.setExtent(FunctionsUtil.getEnvelopeOrDefault(g));
shapeBuilder.setNumPoints(nPts);
shapeBuilder.setGutterFraction(gutterFraction);
return shapeBuilder.getGeometry();
}
public static Geometry randomPoints(Geometry g, int nPts) {
RandomPointsBuilder shapeBuilder = new RandomPointsBuilder(FunctionsUtil.getFactoryOrDefault(g));
shapeBuilder.setExtent(FunctionsUtil.getEnvelopeOrDefault(g));
shapeBuilder.setNumPoints(nPts);
return shapeBuilder.getGeometry();
}
public static Geometry randomPointsInPolygon(Geometry g, int nPts) {
RandomPointsBuilder shapeBuilder = new RandomPointsBuilder(FunctionsUtil.getFactoryOrDefault(g));
shapeBuilder.setExtent(g);
shapeBuilder.setNumPoints(nPts);
return shapeBuilder.getGeometry();
}
public static Geometry randomPointsInTriangle(Geometry g, int nPts) {
GeometryFactory geomFact = FunctionsUtil.getFactoryOrDefault(g);
Coordinate[] gpts = g.getCoordinates();
Coordinate tri0 = gpts[0];
Coordinate tri1 = gpts[1];
Coordinate tri2 = gpts[2];
List pts = new ArrayList();
for (int i = 0; i < nPts; i++) {
pts.add(geomFact.createPoint(randomPointInTriangle(tri0, tri1, tri2)));
}
return geomFact.buildGeometry(pts);
}
private static Coordinate randomPointInTriangle(Coordinate p0, Coordinate p1, Coordinate p2)
{
double s = Math.random();
double t = Math.random();
if (s + t > 1) {
s = 1.0 - s;
t = 1.0 - t;
}
double a = 1 - (s + t);
double b = s;
double c = t;
double rpx = a * p0.x + b * p1.x + c * p2.x;
double rpy = a * p0.y + b * p1.y + c * p2.y;
return new Coordinate(rpx, rpy);
}
public static Geometry randomRadialPoints(Geometry g, int nPts) {
Envelope env = FunctionsUtil.getEnvelopeOrDefault(g);
GeometryFactory geomFact = FunctionsUtil.getFactoryOrDefault(g);
double xLen = env.getWidth();
double yLen = env.getHeight();
double rMax = Math.min(xLen, yLen) / 2.0;
double centreX = env.getMinX() + xLen/2;
double centreY = env.getMinY() + yLen/2;
List pts = new ArrayList();
for (int i = 0; i < nPts; i++) {
double rand = Math.random();
// use rans^2 to accentuate radial distribution
double r = rMax * rand * rand;
// produces even distribution
//double r = rMax * Math.sqrt(rand);
double ang = 2 * Math.PI * Math.random();
double x = centreX + r * Math.cos(ang);
double y = centreY + r * Math.sin(ang);
pts.add(geomFact.createPoint(new Coordinate(x, y)));
}
return geomFact.buildGeometry(pts);
}
public static Geometry randomSegments(Geometry g, int nPts) {
Envelope env = FunctionsUtil.getEnvelopeOrDefault(g);
GeometryFactory geomFact = FunctionsUtil.getFactoryOrDefault(g);
double xLen = env.getWidth();
double yLen = env.getHeight();
List lines = new ArrayList();
for (int i = 0; i < nPts; i++) {
double x0 = env.getMinX() + xLen * Math.random();
double y0 = env.getMinY() + yLen * Math.random();
double x1 = env.getMinX() + xLen * Math.random();
double y1 = env.getMinY() + yLen * Math.random();
lines.add(geomFact.createLineString(new Coordinate[] {
new Coordinate(x0, y0), new Coordinate(x1, y1) }));
}
return geomFact.buildGeometry(lines);
}
public static Geometry randomSegmentsInGrid(Geometry g, int nPts) {
Envelope env = FunctionsUtil.getEnvelopeOrDefault(g);
GeometryFactory geomFact = FunctionsUtil.getFactoryOrDefault(g);
int nCell = (int) Math.sqrt(nPts) + 1;
double xLen = env.getWidth() / nCell;
double yLen = env.getHeight() / nCell;
List lines = new ArrayList();
for (int i = 0; i < nCell; i++) {
for (int j = 0; j < nCell; j++) {
double x0 = env.getMinX() + i * xLen + xLen * Math.random();
double y0 = env.getMinY() + j * yLen + yLen * Math.random();
double x1 = env.getMinX() + i * xLen + xLen * Math.random();
double y1 = env.getMinY() + j * yLen + yLen * Math.random();
lines.add(geomFact.createLineString(new Coordinate[] {
new Coordinate(x0, y0), new Coordinate(x1, y1) }));
}
}
return geomFact.buildGeometry(lines);
}
public static Geometry randomLineString(Geometry g, int nPts) {
Envelope env = FunctionsUtil.getEnvelopeOrDefault(g);
GeometryFactory geomFact = FunctionsUtil.getFactoryOrDefault(g);
double width = env.getWidth();
double hgt = env.getHeight();
Coordinate[] pts = new Coordinate[nPts];
for (int i = 0; i < nPts; i++) {
double xLen = width * Math.random();
double yLen = hgt * Math.random();
pts[i] = randomPtInRectangleAround(env.centre(), xLen, yLen);
}
return geomFact.createLineString(pts);
}
public static Geometry randomRectilinearWalk(Geometry g, int nPts) {
Envelope env = FunctionsUtil.getEnvelopeOrDefault(g);
GeometryFactory geomFact = FunctionsUtil.getFactoryOrDefault(g);
double xLen = env.getWidth();
double yLen = env.getHeight();
Coordinate[] pts = new Coordinate[nPts];
boolean xory = true;
for (int i = 0; i < nPts; i++) {
Coordinate pt = null;
if (i == 0) {
pt = randomPtInRectangleAround(env.centre(), xLen, yLen);
}
else {
double dist = xLen * (Math.random() - 0.5);
double x = pts[i-1].x;
double y = pts[i-1].y;
if (xory) {
x += dist;
}
else {
y += dist;
}
// switch orientation
xory = ! xory;
pt = new Coordinate(x, y);
}
pts[i] = pt;
}
return geomFact.createLineString(pts);
}
private static int randomQuadrant(int exclude)
{
while (true) {
int quad = (int) (Math.random() * 4);
if (quad > 3) quad = 3;
if (quad != exclude) return quad;
}
}
private static Coordinate randomPtInRectangleAround(Coordinate centre, double width, double height)
{
double x0 = centre.x + width * (Math.random() - 0.5);
double y0 = centre.y + height * (Math.random() - 0.5);
return new Coordinate(x0, y0);
}
}