Java Utililty Methods Geometry Algorithm

List of utility methods to do Geometry Algorithm

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Description

The list of methods to do Geometry Algorithm are organized into topic(s).

Method

intdot(Point a, Point b, Point c)

Help function:

This function calculates the dot product of vector ab and bc. 

return (b.x - a.x) * (c.x - b.x) + (b.y - a.y) * (c.y - b.y);
doubledotNorm(final Point2D a, final Point2D b)
Calculates the normalized dot product of two vectors. 
return dot(a, b) / (vecLength(a) * vecLength(b));
voiddrag(Robot robot, Point startPoint, Point endPoint, int button)
Drags from one point to another with the specified mouse button pressed. 
if (!(button == InputEvent.BUTTON1_MASK || button == InputEvent.BUTTON2_MASK
        || button == InputEvent.BUTTON3_MASK)) {
    throw new IllegalArgumentException("invalid mouse button");
robot.mouseMove(startPoint.x, startPoint.y);
robot.mousePress(button);
try {
    mouseMove(robot, startPoint, endPoint);
...
intdx(Point a, Point b)
dx 
return Math.abs(a.x - b.x);
HashSetedge(Collection points)
Calculate the edge of the specified linked area. 
HashSet<Point> edge = new HashSet<Point>();
int x = 0;
int y = 0;
for (Point p : points) {
    if (p.x > x)
        x = p.x;
    if (p.y > y)
        y = p.y;
...
voidextendLine(Point2D p0, Point2D p1, double toLength)
extend Line 
final double oldLength = p0.distance(p1);
final double lengthFraction = oldLength != 0.0 ? toLength / oldLength : 0.0;
p1.setLocation(p0.getX() + (p1.getX() - p0.getX()) * lengthFraction,
        p0.getY() + (p1.getY() - p0.getY()) * lengthFraction);
doublefindArea(Point2D p1, Point2D p2, Point2D p3)
Given three points each represents the vertex of a triangle, return the area of this triangle. 
if (!preprocess(p1, p2, p3)) {
    return 0.0;
} else {
    double p4x;
    double p4y;
    double m13 = findSlope(p1.getX(), p1.getY(), p3.getX(), p3.getY());
    double m24 = 0;
    if (Double.isNaN(m13)) {
...
DimensionfindDimension(Point2D[] pts)
Returns the dimensions of the smallest rectangle that could contain the supplied points. 
double minx = Double.POSITIVE_INFINITY;
double maxx = Double.NEGATIVE_INFINITY;
double miny = Double.POSITIVE_INFINITY;
double maxy = Double.NEGATIVE_INFINITY;
for (Point2D pt : pts) {
    minx = Math.min(minx, pt.getX());
    maxx = Math.max(maxx, pt.getX());
    miny = Math.min(miny, pt.getY());
...
Point2DfindDistancedPoint(double t, Point2D sp, Point2D c1, Point2D c2, Point2D ep)
method used to find any point in given distance in cubic bezier curve 
double d = 1 - t;
double dCube = d * d * d;
double dSqr = d * d;
double tCube = t * t * t;
double tSqr = t * t;
double xCoord = (dCube * sp.getX()) + (3 * t * dSqr * c1.getX()) + (3 * tSqr * d * c2.getX())
        + (tCube * ep.getX());
double yCoord = (dCube * sp.getY()) + (3 * t * dSqr * c1.getY()) + (3 * tSqr * d * c2.getY())
...
Point2DfindIntersect(Point2D p1, Point2D p2, Point2D p3, Point2D p4)
find Intersect 
double xD1, yD1, xD2, yD2, xD3, yD3;
double ua, div;
xD1 = p2.getX() - p1.getX();
xD2 = p4.getX() - p3.getX();
yD1 = p2.getY() - p1.getY();
yD2 = p4.getY() - p3.getY();
xD3 = p1.getX() - p3.getX();
yD3 = p1.getY() - p3.getY();
...