private Iterator sortedChildren(final NodeItem n) {
double base = 0;
// update base angle for node ordering
NodeItem p = (NodeItem) n.getParent();
if (p != null) {
base = normalize(Math.atan2(p.getY() - n.getY(), p.getX() - n.getX()));
}
int cc = n.getChildCount();
if (cc == 0) return null;
NodeItem c = (NodeItem) n.getFirstChild();
if (!c.isStartVisible()) {
// use natural ordering for previously invisible nodes
return n.children();
}
double angle[] = new double[cc];
final int idx[] = new int[cc];
for (int i = 0; i < cc; ++i, c = (NodeItem) c.getNextSibling()) {
idx[i] = i;
angle[i] = normalize(-base + Math.atan2(c.getY() - n.getY(), c.getX() - n.getX()));
}
ArrayLib.sort(angle, idx);
// return iterator over sorted children
return new Iterator() {
int cur = 0;
public Object next() {
return n.getChild(idx[cur++]);
}
public boolean hasNext() {
return cur < idx.length;
}
public void remove() {
throw new UnsupportedOperationException();
}
};
}
/**
* Compute the layout.
*
* @param n the root of the current subtree under consideration
* @param r the radius, current distance from the center
* @param theta1 the start (in radians) of this subtree's angular region
* @param theta2 the end (in radians) of this subtree's angular region
*/
protected void layout(NodeItem n, double r, double theta1, double theta2) {
double dtheta = (theta2 - theta1);
double dtheta2 = dtheta / 2.0;
double width = ((Params) n.get(PARAMS)).width;
double cfrac, nfrac = 0.0;
Iterator childIter = sortedChildren(n);
while (childIter != null && childIter.hasNext()) {
NodeItem c = (NodeItem) childIter.next();
Params cp = (Params) c.get(PARAMS);
cfrac = cp.width / width;
if (c.isExpanded() && c.getChildCount() > 0) {
layout(c, r + m_radiusInc, theta1 + nfrac * dtheta, theta1 + (nfrac + cfrac) * dtheta);
}
setPolarLocation(c, n, r, theta1 + nfrac * dtheta + cfrac * dtheta2);
cp.angle = cfrac * dtheta;
nfrac += cfrac;
}
}
/**
* Computes relative measures of the angular widths of each expanded subtree. Node diameters are
* taken into account to improve space allocation for variable-sized nodes.
*
* <p>This method also updates the base angle value for nodes to ensure proper ordering of nodes.
*/
private double calcAngularWidth(NodeItem n, int d) {
if (d > m_maxDepth) m_maxDepth = d;
double aw = 0;
Rectangle2D bounds = n.getBounds();
double w = bounds.getWidth(), h = bounds.getHeight();
double diameter = d == 0 ? 0 : Math.sqrt(w * w + h * h) / d;
if (n.isExpanded() && n.getChildCount() > 0) {
Iterator childIter = n.children();
while (childIter.hasNext()) {
NodeItem c = (NodeItem) childIter.next();
aw += calcAngularWidth(c, d + 1);
}
aw = Math.max(diameter, aw);
} else {
aw = diameter;
}
((Params) n.get(PARAMS)).width = aw;
return aw;
}