/** @see prefuse.action.Action#run(double) */
public void run(double frac) {
Graph g = (Graph) m_vis.getGroup(m_group);
initSchema(g.getNodes());
m_origin = getLayoutAnchor();
NodeItem n = getLayoutRoot();
Params np = (Params) n.get(PARAMS);
// calc relative widths and maximum tree depth
// performs one pass over the tree
m_maxDepth = 0;
calcAngularWidth(n, 0);
if (m_autoScale) setScale(getLayoutBounds());
if (!m_setTheta) calcAngularBounds(n);
// perform the layout
if (m_maxDepth > 0) layout(n, m_radiusInc, m_theta1, m_theta2);
// update properties of the root node
setX(n, null, m_origin.getX());
setY(n, null, m_origin.getY());
np.angle = m_theta2 - m_theta1;
}
/**
* 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;
}
}
/**
* Calculates the angular bounds of the layout, attempting to preserve the angular orientation of
* the display across transitions.
*/
private void calcAngularBounds(NodeItem r) {
if (m_prevRoot == null || !m_prevRoot.isValid() || r == m_prevRoot) {
m_prevRoot = r;
return;
}
// try to find previous parent of root
NodeItem p = m_prevRoot;
while (true) {
NodeItem pp = (NodeItem) p.getParent();
if (pp == r) {
break;
} else if (pp == null) {
m_prevRoot = r;
return;
}
p = pp;
}
// compute offset due to children's angular width
double dt = 0;
Iterator iter = sortedChildren(r);
while (iter.hasNext()) {
Node n = (Node) iter.next();
if (n == p) break;
dt += ((Params) n.get(PARAMS)).width;
}
double rw = ((Params) r.get(PARAMS)).width;
double pw = ((Params) p.get(PARAMS)).width;
dt = -MathLib.TWO_PI * (dt + pw / 2) / rw;
// set angular bounds
m_theta1 = dt + Math.atan2(p.getY() - r.getY(), p.getX() - r.getX());
m_theta2 = m_theta1 + MathLib.TWO_PI;
m_prevRoot = r;
}
/**
* 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;
}