/**
* Calculates the average aspect ratio of the given list of nodes if the provided height may be
* used.
*/
private <T> double calcAvgAspect(List<ITreeMapNode<T>> l, double layoutHeight, double areaScale) {
if (l.isEmpty()) {
return 1e8;
}
double area = 0;
for (ITreeMapNode<T> node : l) {
area += node.getArea();
}
double layoutWidth = area * areaScale / layoutHeight;
double aspectSum = 0;
for (ITreeMapNode<T> node : l) {
double localHeight = node.getArea() * areaScale / layoutWidth;
double localAspect = Math.max(layoutWidth / localHeight, localHeight / layoutWidth);
aspectSum += localAspect;
}
return aspectSum / l.size();
}
/**
* Layout the given list of nodes in one column.
*
* @param l the list of nodes.
* @param layoutHeight the height of the column.
* @param layoutX the x start value.
* @param layoutY the y start value.
* @param areaScale the scale factor used to convert from node area to layout area.
* @return the layout width of the column.
*/
private <T> double layoutList(
List<ITreeMapNode<T>> l,
double layoutHeight,
double layoutX,
double layoutY,
double areaScale) {
double nodeArea = 0;
for (ITreeMapNode<T> node : l) {
nodeArea += node.getArea();
}
double layoutWidth = nodeArea * areaScale / layoutHeight;
for (ITreeMapNode<T> node : l) {
double nodeHeight = node.getArea() * areaScale / layoutWidth;
node.setLayoutRectangle(new Rectangle2D.Double(layoutX, layoutY, layoutWidth, nodeHeight));
layoutY += nodeHeight;
layoutChildren(node);
}
return layoutWidth;
}
/** Layouts the children of the given node (if it has any). */
private <T> void layoutChildren(ITreeMapNode<T> node) {
if (node.getChildren().isEmpty()) {
return;
}
Rectangle2D rect = node.getLayoutRectangle();
double scale = rect.getWidth() * rect.getHeight() / node.getArea();
double layoutX = rect.getMinX();
double lastX = 0;
List<ITreeMapNode<T>> l = new ArrayList<ITreeMapNode<T>>();
List<ITreeMapNode<T>> lastList = new ArrayList<ITreeMapNode<T>>();
for (ITreeMapNode<T> child : node.getChildren()) {
double oldAspect = calcAvgAspect(l, rect.getHeight(), scale);
l.add(child);
double newAspect = calcAvgAspect(l, rect.getHeight(), scale);
if (oldAspect < newAspect) {
l.remove(l.size() - 1);
lastX = layoutX;
lastList.clear();
lastList.addAll(l);
layoutX += layoutList(l, rect.getHeight(), layoutX, rect.getMinY(), scale);
l.clear();
l.add(child);
}
}
// last list might be too small, so potentially merge with previous one
lastList.addAll(l);
if (calcAvgAspect(lastList, rect.getHeight(), scale)
< calcAvgAspect(l, rect.getHeight(), scale)) {
layoutList(lastList, rect.getHeight(), lastX, rect.getMinY(), scale);
} else {
layoutList(l, rect.getHeight(), layoutX, rect.getMinY(), scale);
}
}
/** {@inheritDoc} */
@Override
public <T> void layout(ITreeMapNode<T> tree, Rectangle2D target) {
tree.setLayoutRectangle(target);
layoutChildren(tree);
}