How to use

BezierFigure

in

org.jhotdraw.draw

private boolean add(final BezierPath bezierPath, boolean isClosed) {
  bezierPath.setClosed(isClosed);
  BezierFigure figure = new BezierFigure(isClosed);
  figure.setBezierPath(bezierPath);
  return figures.add(figure);
}

@SuppressWarnings("unchecked")
protected BezierFigure createFigure() {
  BezierFigure f = (BezierFigure) prototype.clone();
  getEditor().applyDefaultAttributesTo(f);
  if (attributes != null) {
    for (Map.Entry<AttributeKey, Object> entry : attributes.entrySet()) {
      f.set(entry.getKey(), entry.getValue());
    }
  }
  return f;
}

@Override
protected void drawStroke(Graphics2D g) {
  for (final BezierFigure figure : figures) {
    g.draw(figure.getBezierPath());
  }
}

/**
 * Adds a control point.
 */
public void addNode(BezierPath.Node p) {
  addNode(getNodeCount(), p);
}

public void setClosed(boolean newValue) {
  set(PATH_CLOSED, newValue);
  setConnectable(newValue);
}

/**
 * Convenience method for setting the point coordinate of the end point.
 * If the BezierFigure has not at least two nodes, nodes are added
 * to the figure until the BezierFigure has at least two nodes.
 */
public void setEndPoint(Point2D.Double p) {
  // Add two nodes if we haven't at least two nodes
  for (int i = getNodeCount(); i < 2; i++) {
    addNode(0, new BezierPath.Node(p.x, p.y));
  }
  setPoint(getNodeCount() - 1, p);
}

@Override
public Collection<Handle> createSecondaryHandles() {
  BezierFigure f = getOwner();
  LinkedList<Handle> list = new LinkedList<Handle>();
  BezierPath.Node v = f.getNode(index);
  if ((v.mask & BezierPath.C1_MASK) != 0 &&
      (index != 0 || f.isClosed())) {
    list.add(new BezierControlPointHandle(f, index, 1, getTransformOwner()));
  }
  if ((v.mask & BezierPath.C2_MASK) != 0 &&
      (index < f.getNodeCount() - 1 ||
      f.isClosed())) {
    list.add(new BezierControlPointHandle(f, index, 2, getTransformOwner()));
  }
  if (index > 0 || f.isClosed()) {
    int i = (index == 0) ? f.getNodeCount() - 1 : index - 1;
    v = f.getNode(i);
    if ((v.mask & BezierPath.C2_MASK) != 0) {
      list.add(new BezierControlPointHandle(f, i, 2, getTransformOwner()));
    }
  }
  if (index < f.getNodeCount() - 1 || f.isClosed()) {
    int i = (index == f.getNodeCount() - 1) ? 0 : index + 1;
    v = f.getNode(i);
    if ((v.mask & BezierPath.C1_MASK) != 0) {
      list.add(new BezierControlPointHandle(f, i, 1, getTransformOwner()));
    }
  }
  return list;
}

@Override
public void keyPressed(KeyEvent evt) {
  final BezierFigure f = getOwner();
  BezierPath.Node oldNode = f.getNode(index);
      f.willChange();
      f.setPoint(index, controlPointIndex, new Point2D.Double(oldNode.x[controlPointIndex], oldNode.y[controlPointIndex] - 1d));
      f.changed();
      view.getDrawing().fireUndoableEditHappened(new BezierNodeEdit(f, index, oldNode, f.getNode(index)));
      evt.consume();
      break;
    case KeyEvent.VK_DOWN:
      f.willChange();
      f.setPoint(index, controlPointIndex, new Point2D.Double(oldNode.x[controlPointIndex], oldNode.y[controlPointIndex] + 1d));
      f.changed();
      view.getDrawing().fireUndoableEditHappened(new BezierNodeEdit(f, index, oldNode, f.getNode(index)));
      evt.consume();
      break;
    case KeyEvent.VK_LEFT:
      f.willChange();
      f.setPoint(index, controlPointIndex, new Point2D.Double(oldNode.x[controlPointIndex] - 1d, oldNode.y[controlPointIndex]));
      f.changed();
      view.getDrawing().fireUndoableEditHappened(new BezierNodeEdit(f, index, oldNode, f.getNode(index)));
      evt.consume();
      break;
    case KeyEvent.VK_RIGHT:
      f.willChange();
      f.setPoint(index, controlPointIndex, new Point2D.Double(oldNode.x[controlPointIndex] + 1d, oldNode.y[controlPointIndex]));
      f.changed();
      view.getDrawing().fireUndoableEditHappened(new BezierNodeEdit(f, index, oldNode, f.getNode(index)));

@Override
public void updateFigure(final OverlayView view, final BezierFigure figure) {
  super.updateFigure(view, figure);
  assert view.getData() instanceof GeneralPathOverlay;
  final GeneralPathOverlay gpo = (GeneralPathOverlay) view.getData();
  final GeneralPathRegionOfInterest gpr = gpo.getRegionOfInterest();
  final PathIterator pi = gpr.getGeneralPath().getPathIterator(null);
  final int nCount = figure.getNodeCount();
  int i = 0;
  final double[] pos = new double[6];
  while (!pi.isDone()) {
    pi.currentSegment(pos);
    final Node n = new Node(pos[0], pos[1]);
    if (i < nCount) figure.getNode(i).setTo(n);
    else figure.addNode(n);
    pi.next();
    i++;
  }
  while (i < figure.getNodeCount())
    figure.removeNode(i);
}

if (createdFigure.getNodeCount() > nodeCountBeforeDrag + 1) {
  createdFigure.willChange();
  BezierPath figurePath = createdFigure.getBezierPath();
  BezierPath digitizedPath = new BezierPath();
  for (int i = nodeCountBeforeDrag - 1, n = figurePath.size(); i < n; i++) {
  createdFigure.setBezierPath(figurePath);
  createdFigure.changed();
  nodeCountBeforeDrag = createdFigure.getNodeCount();
  if (createdFigure.getNodeCount() > 1) {
    Rectangle r = new Rectangle(anchor.x, anchor.y, 0, 0);
    r.add(evt.getX(), evt.getY());

protected void addPointToFigure(Point2D.Double newPoint) {
  int pointCount = createdFigure.getNodeCount();
  createdFigure.willChange();
  if (pointCount < 2) {
    createdFigure.addNode(new BezierPath.Node(newPoint));
  } else {
    Point2D.Double endPoint = createdFigure.getEndPoint();
    Point2D.Double secondLastPoint = (pointCount <= 1) ? endPoint : createdFigure.getPoint(pointCount - 2, 0);
    if (newPoint.equals(endPoint)) {
      // nothing to do
    } else if (pointCount > 1 && Geom.lineContainsPoint(newPoint.x, newPoint.y, secondLastPoint.x, secondLastPoint.y, endPoint.x, endPoint.y, 0.9f / getView().getScaleFactor())) {
      createdFigure.setPoint(pointCount - 1, 0, newPoint);
    } else {
      createdFigure.addNode(new BezierPath.Node(newPoint));
    }
  }
  createdFigure.changed();
}

final BezierFigure f = getOwner();
   BezierPath.Node oldValue = (BezierPath.Node) oldNode.clone();;
   BezierPath.Node newValue = f.getNode(index);
  f.willChange();
  if (index > 0 && index < f.getNodeCount() || f.isClosed()) {
    newValue.mask = (newValue.mask + 3) % 4;
  } else if (index == 0) {
    newValue.mask = ((newValue.mask & BezierPath.C1_MASK) == 0) ? BezierPath.C1_MASK : 0;
  f.setNode(index, newValue);
  f.changed();
  fireHandleRequestSecondaryHandles();

@Nullable
protected BezierPath.Node getBezierNode() {
  return getBezierFigure().getNodeCount() > index ? getBezierFigure().getNode(index) : null;
}

final BezierFigure figure = getBezierFigure();
BezierPath.Node oldValue = (BezierPath.Node) oldNode.clone();
BezierPath.Node newValue = figure.getNode(index);
if ((modifiersEx & (InputEvent.META_DOWN_MASK | InputEvent.CTRL_DOWN_MASK | InputEvent.ALT_DOWN_MASK | InputEvent.SHIFT_DOWN_MASK)) != 0) {
  figure.willChange();
  newValue.keepColinear = !newValue.keepColinear;
  if (newValue.keepColinear) {
    Point2D.Double p = figure.getPoint(index, controlPointIndex);
    double a = Math.PI + Math.atan2(p.y - newValue.y[0], p.x - newValue.x[0]);
    int c2 = (controlPointIndex == 1) ? 2 : 1;
    newValue.y[c2] = p2.y;
  figure.setNode(index, newValue);
  figure.changed();

public boolean handleMouseClick(Point2D.Double p, MouseEvent evt, DrawingView view) {
  if (evt.getClickCount() == 2 && view.getHandleDetailLevel() % 2 == 0) {
    willChange();
    final int index = splitSegment(p, 5f / view.getScaleFactor());
    if (index != -1) {
      final BezierPath.Node newNode = getNode(index);
      fireUndoableEditHappened(new AbstractUndoableEdit() {
      changed();
      evt.consume();
      return true;

@Override
public void redo() throws CannotRedoException {
  super.redo();
  willChange();
  addNode(index, newNode);
  changed();
}

/**
 * Sets an attribute of the figure.
 * AttributeKey name and semantics are defined by the class implementing
 * the figure interface.
 */
@Override
public <T> void set(AttributeKey<T> key, T newValue) {
  super.set(key, newValue);
  for (final BezierFigure figure : figures) {
    figure.set(key, newValue);
  }
}

@Override
public boolean add(final BezierFigure figure) {
  figure.restoreAttributesTo(SwingGeneralPathFigure.this.getAttributesRestoreData());
  figure.addFigureListener(new FigureListener() {
    @Override
    public void areaInvalidated(FigureEvent e) {

@Override
public Collection<Handle> createHandles(final int detailLevel) {
  final LinkedList<Handle> handles = new LinkedList<>();
  for (final BezierFigure figure : figures) {
    handles.addAll(figure.createHandles(detailLevel));
  }
  return handles;
}

@Override
public Object getTransformRestoreData() {
  final List<BezierFigure> result = new ArrayList<>();
  for (final BezierFigure figure : figures) {
    result.add(figure.clone());
  }
  return result;
}