// Tree drawing (Processing)
// Jacob Bandes-Storch, April 2010

class Node {
    ArrayList children = new ArrayList();
    int x = 0, y = 0;
    int numberLeft(int leftNum) {
        x = leftNum;
        for (Node n : children) {
            leftNum = n.numberLeft(leftNum+1);
        }
        return leftNum;
    }
    int numberRight(int rightNum) {
        ArrayList rev = reversed(children);
        y = rightNum;
        for (Node n : rev) {
            rightNum = n.numberRight(rightNum+1);
        }
        return rightNum;
    }
    void populate(int maxChildren, int maxDepth) {
        if (maxDepth <= 0) return;
        int i;
        int r = random(maxChildren);
        for (i = 0; i < r; i++) {
            Node n = new Node();
            n.populate(maxChildren, maxDepth - 1);
            children.add(n);
        }
    }
}

ArrayList reversed(ArrayList l) {
    ArrayList l2 = new ArrayList();
    for (int i = l.size()-1; i >= 0; i--) {
        l2.add(l.get(i));
    }
    return l2;
}

Node tree = null;

void retree() {
    tree = new Node();
    tree.populate(4, 3);
    tree.numberLeft(0);
    tree.numberRight(0);
    redraw();
}

void setup() {
    size(351, 351);
    smooth();
    noLoop();
    retree();
}
void mousePressed() {
    retree();
}
void mouseMoved() {
    redraw();
}
void draw() {
    background(#cccccc);
    pushStyle();
    fill(#99c7cc);
    noStroke();
    rect(0, 0, 10*ceil(mouseX/10.0), 10*ceil(mouseY/10.0));
    stroke(#999999);
    for (int i = 0; i < width; i += 10) {
        line(0, i, width, i);
        line(i, 0, i, height);
    }
    popStyle();
    Queue q = new ArrayList();
    Node n = tree;
    while (n != null) {
        if (!n.children.isEmpty()) {
            for (Node c : n.children) {
                q.add(c);
                line(n.x*10+5, n.y*10+5,
                     c.x*10+5, c.y*10+5);
            }
        }
        rect(n.x*10+2, n.y*10+2, 6, 6);
        n = q.size() > 0 ? q.remove(0) : null;
    }
}