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package bezier.geom;
import java.util.ArrayList;
import java.util.List;
import bezier.geom.transform.TDHIdentity;
import bezier.geom.transform.TDHTransform;
/**
* Represents a bezier curve.
*/
public class Bezier {
/**
* The control points of the curve.
*/
public final List<TDPoint> controls;
/**
* The display properties for the curve.
*/
public BezierProperties data;
/**
* Create a new bezier curve from a set of control points.
*
* @param points
* The control points to use.
*/
public Bezier(TDPoint... points) {
data = new BezierProperties();
controls = new ArrayList<>();
for (TDPoint punkt : points) {
controls.add(punkt);
}
}
/**
* Do a scaled evaluation of the curve.
*
* @param t
* The value to evaluate at.
* @return The point on the curve, scaled by the curves scaling factor.
*/
public TDPoint scaleEval(double t) {
return eval(t).multiply(data.scale);
}
/**
* Do a scaled evaluation of the curve.
*
* @param t
* The value to evaluate at.
*/
public TDPoint eval(double t) {
if (controls.isEmpty())
return new TDPoint(0, 0);
TDPoint punkt = evalIntern(t, controls.size() - 1, 0);
return punkt;
}
/*
* Recursive evaluation of bezier curve.
*/
private TDPoint evalIntern(double t, int j, int k) {
/*
* Base case.
*/
if (j <= 0) {
return controls.get(k);
}
/*
* Get the two component points.
*/
TDPoint l = evalIntern(t, j - 1, k);
TDPoint r = evalIntern(t, j - 1, k + 1);
/*
* Adjust them by parameter value
*/
l = l.multiply(1 - t);
r = r.multiply(t);
/*
* Give back their sum
*/
return TDPoint.add(l, r);
}
/**
* Split a curve into two curves at a specific point.
*
* @param t
* The point to split the curve at.
* @return The two curves, split at that point.
*/
public Bezier[] decompose(double t) {
Bezier[] curves = new Bezier[2];
{
/*
* Get the first curve.
*/
TDPoint[] points = new TDPoint[controls.size()];
for (int i = 0; i < points.length; i++) {
points[i] = evalIntern(t, i, 0);
}
curves[0] = new Bezier(points);
}
{
/*
* Get the second curve.
*/
TDPoint[] points = new TDPoint[controls.size()];
for (int i = 0; i < points.length; i++) {
points[i] = evalIntern(t, (points.length - 1) - i, i);
}
curves[1] = new Bezier(points);
}
return curves;
}
/**
* Get the bounding box for this curves control points.
*
* @return The bounding box for the control points.
*/
public TDPoint[] extrema() {
return extrema(new TDHIdentity());
}
/**
* Get the bounding box for a transformed version of this curves control points.
*
* @param transform
* The transform to apply to the control points.
* @return The bounding box for the transformed control points.
*/
public TDPoint[] extrema(TDHTransform transform) {
TDPoint[] box = new TDPoint[4];
double xMin = Double.MAX_VALUE, xMax = Double.MIN_VALUE;
double yMin = Double.MAX_VALUE, yMax = Double.MIN_VALUE;
for (TDPoint punkt1 : controls) {
/*
* Get transformed point
*/
TDPoint punkt = punkt1.multiply(data.scale);
punkt = transform.transform(punkt.toTDHPoint()).toTDPoint();
/*
* Set min/max x vals
*/
if (punkt.x < xMin) {
xMin = punkt.x;
}
if (punkt.x > xMax) {
xMax = punkt.x;
}
/*
* Set min/max y vals
*/
if (punkt.y < yMin) {
yMin = punkt.y;
}
if (punkt.y > yMax) {
yMax = punkt.y;
}
}
/*
* Create returned points.
*/
box[0] = new TDPoint(xMin, yMin);
box[1] = new TDPoint(xMax, yMin);
box[2] = new TDPoint(xMax, yMax);
box[3] = new TDPoint(xMin, yMax);
return box;
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((controls == null) ? 0 : controls.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
Bezier other = (Bezier) obj;
if (controls == null) {
if (other.controls != null)
return false;
} else if (!controls.equals(other.controls))
return false;
return true;
}
@Override
public String toString() {
return String.format("Bezier [controls=%s]", controls);
}
}
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