diff options
Diffstat (limited to 'CSMath/src/bezier/Bezier.java')
| -rw-r--r-- | CSMath/src/bezier/Bezier.java | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/CSMath/src/bezier/Bezier.java b/CSMath/src/bezier/Bezier.java new file mode 100644 index 0000000..fcc191c --- /dev/null +++ b/CSMath/src/bezier/Bezier.java @@ -0,0 +1,219 @@ +package bezier;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import bezier.transforms.TDHIdentity;
+import bezier.transforms.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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