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behrangsabehrangsa
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Merge pull request #1 from behrangsa/demo
Added demo
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11 files changed

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‎.github/workflows/gradle-publish.yml‎

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‎.github/workflows/gradle.yml‎

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# This workflow uses actions that are not certified by GitHub.
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# They are provided by a third-party and are governed by
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# separate terms of service, privacy policy, and support
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# documentation.
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# This workflow will build a Java project with Gradle and cache/restore any dependencies to improve the workflow execution time
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# For more information see: https://docs.github.com/en/actions/automating-builds-and-tests/building-and-testing-java-with-gradle
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name: Java CI with Gradle
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name: CI
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on:
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push:
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branches: [ "master" ]
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pull_request:
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branches: [ "master" ]
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build:
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runs-on: ubuntu-latest
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steps:
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- uses: actions/checkout@v3
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- name: Set up JDK 17
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uses: actions/setup-java@v3
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with:
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java-version: '17'
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distribution: 'temurin'
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- name: Build with Gradle
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uses: gradle/gradle-build-action@bd5760595778326ba7f1441bcf7e88b49de61a25 # v2.6.0
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with:
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arguments: build
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- uses: actions/checkout@v3
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- name: Set up JDK 17
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uses: actions/setup-java@v3
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with:
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java-version: '17'
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distribution: 'temurin'
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- name: Build with Gradle
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uses: gradle/gradle-build-action@bd5760595778326ba7f1441bcf7e88b49de61a25 # v2.6.0
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with:
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arguments: build

‎build.gradle‎

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}
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group = 'org.behrang.algorithm'
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version = '1.0.0'
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version = '1.0-SNAPSHOT'
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description = 'John Q Walker Node Positioning Algorithm'
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java {

‎src/main/java/org/behrang/algorithm/tree/DimensionCalculator.java‎

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package org.behrang.algorithm.tree;
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import java.awt.*;
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import java.awt.geom.Dimension2D;
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import java.util.concurrent.atomic.AtomicReference;
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public class DimensionCalculator {
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public static <T> Dimension2D calculateTreeDimension(Node<T> root) {
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final AtomicReference<Double> minX = new AtomicReference<>(Double.MAX_VALUE);
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final AtomicReference<Double> minY = new AtomicReference<>(Double.MAX_VALUE);
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final AtomicReference<Double> maxX = new AtomicReference<>(Double.MIN_VALUE);
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final AtomicReference<Double> maxY = new AtomicReference<>(Double.MIN_VALUE);
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TreeTraversal.preorder(root, n -> {
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if (n.getX() < minX.get()) {
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minX.set(n.getX());
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}
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if (n.getY() < minY.get()) {
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minY.set(n.getY());
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}
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double x2 = n.getX() + n.getWidth();
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if (x2 > maxX.get()) {
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maxX.set(x2);
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}
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double y2 = n.getY() + n.getHeight();
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if (y2 > maxY.get()) {
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maxY.set(y2);
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}
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});
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double width = (maxX.get() - minX.get());
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double height = (maxY.get() - minY.get());
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Dimension dim = new Dimension();
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dim.setSize(width, height);
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return dim;
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}
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public static <T> Dimension2D calculateMaxNodeDimension(Node<T> root) {
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final AtomicReference<Double> width = new AtomicReference<>(Double.MIN_VALUE);
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final AtomicReference<Double> height = new AtomicReference<>(Double.MIN_VALUE);
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TreeTraversal.preorder(root, n -> {
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if (width.get() < n.getWidth()) {
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width.set(n.getWidth());
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}
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if (height.get() < n.getHeight()) {
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height.set(n.getHeight());
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}
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});
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Dimension dim = new Dimension();
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dim.setSize(width.get(), height.get());
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return dim;
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}
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}

‎src/main/java/org/behrang/algorithm/tree/TreeTraversal.java‎

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package org.behrang.algorithm.tree;
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import org.behrang.algorithm.tree.Node;
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import java.util.function.Consumer;
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public class TreeTraversal {
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public static <T> void preorder(Node<T> root, Consumer<Node<T>> consumer) {
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consumer.accept(root);
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root.getChildren().forEach(ch -> {
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preorder(ch, consumer);
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});
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}
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}

‎src/main/java/org/behrang/algorithm/tree/WalkerAlgorithm.java‎

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public class WalkerAlgorithm<T> {
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private static final long MAX_DEPTH = Long.MAX_VALUE;
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/**
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* During the operation of the algorithm, we walk the tree two times.
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* <p>
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* Whenever we visit a new node {@code N} at a level {@code L}, we store it in this map.
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* <p>
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* Then whenever we need to look up a node's neighboring node to the left, we can consult this map.
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* <p>
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* For example, consider the following tree:
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* <pre>
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* A
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* ┌───┼───┐
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* B C D
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* │ │
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* E F
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* </pre>
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* <p>
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* As you can see, node {@code A} is at level 0, nodes {@code B}, {@code C}, {@code D} are at level 1, and nodes
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* {@code E} and {@code F} are at level 2.
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* <p>
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* When we arrive at node {@code F}, we can consult to look up its left neighbor {@code E} using this table:
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* <pre>{@code
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* // leftNeighbor will resolve to node "E"
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* var leftNeighbor = previousNodeAtLevel.get(2);
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* }</pre>
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* <p>
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* Similarly, when we arrive at node {@code C}:
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* <pre>{@code
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* // leftNeighbor will resolve to node "B"
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* var leftNeighbor = previousNodeAtLevel.get(1);
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* }</pre>
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*/
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private final Map<Integer, Node<T>> previousNodeAtLevel;
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private final double siblingSeparation;

‎src/main/java/org/behrang/algorithm/tree/demo/DemoFrame.java‎

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package org.behrang.algorithm.tree.demo;
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import javax.swing.*;
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import java.awt.*;
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public class DemoFrame extends JFrame {
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private JPanel mainPanel;
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public DemoFrame() {
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mainPanel = new TreePanel<>(SampleTree.newUniformInstance(64, 64));
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add(mainPanel, BorderLayout.CENTER);
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}
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public static void main(String[] args) {
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DemoFrame demoFrame = new DemoFrame();
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demoFrame.setTitle("Walker Algorithm Demo");
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demoFrame.setSize(1024, 768);
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demoFrame.setResizable(false);
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demoFrame.setLocationByPlatform(true);
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demoFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
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demoFrame.setVisible(true);
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}
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}

‎src/main/java/org/behrang/algorithm/tree/demo/SampleTree.java‎

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package org.behrang.algorithm.tree.demo;
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import org.behrang.algorithm.tree.Node;
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public final class SampleTree {
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private SampleTree() {
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}
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public static Node<String> newUniformInstance() {
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return newUniformInstance(2, 2);
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}
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public static Node<String> newUniformInstance(double nodeWidth, double nodeHeight) {
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Node<String> a, b, c, d, e, f, g, h, i, j, k, l, m, n, o;
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o = node("O", nodeWidth, nodeHeight);
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e = node("E", nodeWidth, nodeHeight);
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f = node("F", nodeWidth, nodeHeight);
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n = node("N", nodeWidth, nodeHeight);
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link(o, e, f, n);
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a = node("A", nodeWidth, nodeHeight);
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d = node("D", nodeWidth, nodeHeight);
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link(e, a, d);
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b = node("B", nodeWidth, nodeHeight);
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c = node("C", nodeWidth, nodeHeight);
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link(d, b, c);
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g = node("G", nodeWidth, nodeHeight);
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m = node("M", nodeWidth, nodeHeight);
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link(n, g, m);
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h = node("H", nodeWidth, nodeHeight);
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i = node("I", nodeWidth, nodeHeight);
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j = node("J", nodeWidth, nodeHeight);
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k = node("K", nodeWidth, nodeHeight);
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l = node("L", nodeWidth, nodeHeight);
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link(m, h, i, j, k, l);
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return o;
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}
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static Node<String> node(String value, double nodeWidth, double nodeHeight) {
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Node<String> node = new Node<>(value);
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node.setWidth(nodeWidth);
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node.setHeight(nodeHeight);
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return node;
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}
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@SafeVarargs
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static void link(Node<String> parent, Node<String>... children) {
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for (var child : children) {
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parent.getChildren().add(child);
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child.setParent(parent);
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}
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}
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}

‎src/main/java/org/behrang/algorithm/tree/demo/TreePanel.java‎

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package org.behrang.algorithm.tree.demo;
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import org.behrang.algorithm.tree.Node;
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import org.behrang.algorithm.tree.TreeTraversal;
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import org.behrang.algorithm.tree.WalkerAlgorithm;
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import javax.swing.*;
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import javax.swing.border.EmptyBorder;
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import java.awt.*;
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import java.awt.geom.Line2D;
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import java.awt.geom.Rectangle2D;
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import static org.behrang.algorithm.tree.DimensionCalculator.calculateMaxNodeDimension;
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public class TreePanel<T> extends JPanel {
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private Node<T> root;
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public TreePanel(Node<T> root) {
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setLayout(null);
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setRoot(root);
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}
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public void setRoot(Node<T> root) {
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this.root = root;
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repaint();
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}
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@Override
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protected void paintComponent(Graphics g) {
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super.paintComponent(g);
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if (root == null) {
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return;
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}
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var dim = calculateMaxNodeDimension(root);
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var walker = new WalkerAlgorithm<T>(
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dim.getWidth(),
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dim.getWidth(),
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20,
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20,
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dim.getHeight() * 2
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);
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walker.position(root);
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var g2 = (Graphics2D) g;
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TreeTraversal.preorder(root, n -> {
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drawNode(g2, n);
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});
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}
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void drawNode(Graphics2D g, Node<T> node) {
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double labelMarginX = 12.0;
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double labelMarginY = 1.0;
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g.setColor(Color.BLACK);
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Rectangle2D rect = new Rectangle2D.Double(
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node.getX(),
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node.getY(),
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node.getWidth(),
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node.getHeight()
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);
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g.draw(rect);
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String label = node.getValue().toString();
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g.setColor(Color.DARK_GRAY);
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Font font = new Font(Font.SERIF, Font.ITALIC, 24);
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g.setFont(font);
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FontMetrics fontMetrics = g.getFontMetrics(font);
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Rectangle2D labelBounds = fontMetrics.getStringBounds(label, g);
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g.drawString(label,
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(float) (node.getX() + labelMarginX),
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(float) (node.getY() + labelMarginY + labelBounds.getHeight())
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);
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if (node.hasParent()) {
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Node<T> parent = node.getParent();
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double x0 = parent.getX() + parent.getWidth() / 2;
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double y0 = parent.getY() + parent.getHeight();
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double x1 = node.getX() + node.getWidth() / 2;
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double y1 = node.getY();
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Line2D line2D = new Line2D.Double(x0, y0, x1, y1);
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g.draw(line2D);
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}
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}
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}

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