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I am not able to draw after clear my jpanel

import javax.swing.*;
import java.awt.*;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JFrame;
import javax.swing.border.BevelBorder;
public class Cliente extends JPanel {
private JButton adelanteButton;
private JButton undoButton;
private JPanel panel1;
private JPanel panelDibujo;
private Rectangulo rectangulo = new Rectangulo();
Originator originator;
Caretaker caretaker;
public static void main(String[] args) {
JFrame.setDefaultLookAndFeelDecorated(true);
JFrame frame = new JFrame("Patron Memento");
Cliente cliente = new Cliente();
frame.setContentPane(cliente.panel1);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
for (Memento m : caretaker.history) {
System.out.println("forcitooooooo");
dibujar(m.getState(), Color.GREEN);
}
}
public Cliente() {
caretaker = new Caretaker();
originator = new Originator();
createUIComponents();
undoButton.addActionListener(e -> {
caretaker.anterior();
panelDibujo.repaint();
});
panelDibujo.setBackground(Color.WHITE);
panelDibujo.setBorder(BorderFactory.createBevelBorder(BevelBorder.RAISED));
panelDibujo.addMouseListener(new MouseAdapter() {
#Override
public void mousePressed(MouseEvent e) {
MousePressedEvent(e);
}
#Override
public void mouseReleased(MouseEvent e) {
MouseReleasedEvent(e);
}
});
}
private void createUIComponents() {
}
private void MousePressedEvent(MouseEvent e){
rectangulo.setX1(e.getX());
rectangulo.setY1(e.getY());
}
private void MouseReleasedEvent(MouseEvent e){
rectangulo.setX2(e.getX());
rectangulo.setY2(e.getY());
originator.setState(rectangulo);
dibujar(rectangulo, Color.orange);
caretaker.addMemento(originator.CreateMemento());
rectangulo = new Rectangulo();
}
public void dibujar(Rectangulo r, Color c) {
Graphics g = panelDibujo.getGraphics();
g.setColor(c);
g.drawRect(r.getX1(), r.getY1(), r.getX2() - r.getX1(), r.getY2() - r.getY1());
g.dispose();
}
}
Hello i am applying the memento pattern by using a jpanel and drawing some rectangles inside, right now my code is working fine about drawing with the mouse events, but the issue is when i try to undo. My logic so far is clear the jpanel and redo all the rectangles minus the last one.
But after clearing my jpanel is not drawing again :( can someone help me to fix it? thank you
Caretaker.java
import javax.swing.*;
import java.awt.*;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.Stack;
public class Caretaker {
LinkedList<Memento> history;
int indice;
public Caretaker(){
history = new LinkedList<>();
indice = 0;
}
void addMemento(Memento m){
if (history.size() == indice || history.isEmpty()){
indice++;
history.add(m);
}else {
indice = history.size()-1;
history.subList(indice +1, history.size()).clear();
}
}
Memento anterior(){
if (history.size() > 0){
indice--;
return history.removeLast();
}
JOptionPane.showMessageDialog(null, "No hay mas wey!");
return null;
}
Memento siguiente(){
if (indice < history.size()+1){
indice++;
return history.get(indice+1);
}
JOptionPane.showMessageDialog(null, "No hay mas wey!");
return null;
}
public void redibujar(JPanel f){
Graphics g = f.getGraphics();
for (Memento m: history) {
g.drawRect(m.getState().getX1(), m.getState().getY1(), m.getState().getX2() - m.getState().getX1(), m.getState().getY2() - m.getState().getY1());
g.dispose();
}
}
public void clear(){
history.clear();
indice = 0;
}
}
Memento.java
public class Memento {
Rectangulo state;
/*
Constructor, unica manera de mandar/crear/guardar los datos
*/
public Memento(Rectangulo state) {
this.state = state;
}
public Memento(){
state = new Rectangulo();
}
Rectangulo getState(){
return state;
}
}
Originator.java
public class Originator {
Rectangulo state;
public void setState(Rectangulo rectangulo){
this.state = rectangulo;
}
public Memento CreateMemento(){
return new Memento(state);
}
public void setMemento(Memento m) {
setState(m.getState());
}
}
Rectangulo.java
import java.awt.*;
public class Rectangulo {
private int x1;
private int x2;
private int y1;
private int y2;
Rectangulo(){
}
public Rectangulo(int x1, int x2, int y1, int y2) {
this.x1 = x1;
this.x2 = x2;
this.y1 = y1;
this.y2 = y2;
}
public int getX1() {
return x1;
}
public void setX1(int x1) {
this.x1 = x1;
}
public int getX2() {
return x2;
}
public void setX2(int x2) {
this.x2 = x2;
}
public int getY1() {
return y1;
}
public void setY1(int y1) {
this.y1 = y1;
}
public int getY2() {
return y2;
}
public void setY2(int y2) {
this.y2 = y2;
}
public void draw(Graphics g){
g.setColor(Color.orange);
g.drawRect(this.getX1(), this.getY1(), this.getX2() - this.getX1(), this.getY2() - this.getY1());
}
}

Again, you're not drawing correctly. You are trying to render using a JPanel, cliente, that is never added to the GUI, and you're trying to use a Graphics object that is extracted from this unrendered component, making the Graphics object thus obtained short-lived and unstable.
Instead, do all drawing in the paintComponent method. You can use a BufferedImage and draw that in paintComponent if desired, especially if you want images with objects that show different colors, or you can use your List (here a LinkedList, but ArrayList will work) and draw in paintComponent. For instance, something simple like:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.event.*;
import java.util.ArrayList;
import java.util.List;
import javax.swing.*;
public class Cliente2 extends JPanel {
private static final int BI_WIDTH = 800;
private static final int BI_HEIGHT = 650;
private Rectangle drawingRect = null;
// private java.util.List<Rectangulo> rectangulos = new ArrayList<>();
List<Rectangulo2> rectangulos = new ArrayList<>();
private JButton clearBtn = new JButton("Clear");
public Cliente2() {
setBackground(Color.WHITE);
MyMouse myMouse = new MyMouse();
addMouseListener(myMouse);
addMouseMotionListener(myMouse);
clearBtn.addActionListener(e -> clear());
add(clearBtn);
}
private void clear() {
rectangulos.clear();
repaint();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(BI_WIDTH, BI_HEIGHT);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
if (drawingRect != null) {
g2.setColor(Color.LIGHT_GRAY);
g2.draw(drawingRect);
}
for (Rectangulo2 rectangulo : rectangulos) {
rectangulo.draw(g2);
}
}
private class MyMouse extends MouseAdapter {
private Point p0;
#Override
public void mousePressed(MouseEvent e) {
p0 = e.getPoint();
}
#Override
public void mouseDragged(MouseEvent e) {
drawingRect = createDrawingRect(e);
repaint();
}
private Rectangle createDrawingRect(MouseEvent e) {
Point p1 = e.getPoint();
int x = Math.min(p0.x, p1.x);
int y = Math.min(p0.y, p1.y);
int width = Math.abs(p0.x - p1.x);
int height = Math.abs(p0.y - p1.y);
return new Rectangle(x, y, width, height);
}
#Override
public void mouseReleased(MouseEvent e) {
// lets create some random colors:
float hue = (float) Math.random();
float brightness = (float) Math.random();
Color color = Color.getHSBColor(hue, 1f, brightness);
Rectangulo2 rectangulo = new Rectangulo2(color, p0, e.getPoint());
rectangulos.add(rectangulo);
drawingRect = null;
repaint();
}
}
public static void main(String[] args) {
JFrame.setDefaultLookAndFeelDecorated(true);
JFrame frame = new JFrame("Patron Memento");
// Cliente cliente = new Cliente();
// frame.setContentPane(cliente.panel1);
frame.add(new Cliente2());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
}
class Rectangulo2 {
private static final Stroke STROKE = new BasicStroke(3f);
private Color color;
private Point p0, p1;
public Rectangulo2() {
}
public Rectangulo2(Color color, Point p0, Point p1) {
super();
this.color = color;
this.p0 = p0;
this.p1 = p1;
}
public Color getColor() {
return color;
}
public Point getP0() {
return p0;
}
public Point getP1() {
return p1;
}
public void draw(Graphics g) {
Graphics2D g2 = (Graphics2D) g.create();
g2.setColor(color);
int x = Math.min(p0.x, p1.x);
int y = Math.min(p0.y, p1.y);
int width = Math.abs(p0.x - p1.x);
int height = Math.abs(p0.y - p1.y);
g2.fillRect(x, y, width, height);
g2.setStroke(STROKE);
g2.setColor(Color.BLACK);
g2.drawRect(x, y, width, height);
g2.dispose();
}
}

Swing draws only after resizing

Program should draw the line twice longer after clicking the button, but it only does that after clicking AND THEN resizing the window. I don't know what is happening, i thought this is gonna be easy.
Could you tell me how can I fix it?
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.Line2D;
import java.awt.geom.Point2D;
import java.util.Random;
import java.util.Stack;
class MyButtonPanel extends JPanel {
public static final int HEIGHT = 800;
public static final int WIDTH = 800;
private JButton greenButton;
private JPanel buttonPanel;
Stack<Point> points;
int X = 25;
int Y = 25;
public MyButtonPanel() {
greenButton = new GreenButton();
points = new Stack<Point>();
buttonPanel = this;
setLayout(new FlowLayout());
setPreferredSize(new Dimension(WIDTH, HEIGHT));
add(greenButton);
}
class GreenButton extends JButton implements ActionListener
{
GreenButton() {
super("LongerLine");
addActionListener(this);
}
#Override
public void actionPerformed(ActionEvent e) {
//points.push(new Point(0,0));
X = 2 * X;
Y = 2 * Y;
validate();
}
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
//g2d.setColor(Color.WHITE);
//g2d.fillRect(0, 0, WIDTH, HEIGHT);
g2d.setColor(Color.BLACK);
//drawLines(g2d);
Line2D lin = new Line2D.Double(0,0, X, Y);
g2d.draw(lin);
}
private void drawLines(Graphics2D g2d) {
//Line2D lin = new Line2D.Float(100, 100, 250, 260);
//g2d.draw(lin);
double x1, y1, x2, y2;
/*
for(Point point: points) {
x1 = (double) point.getX();
y1 = (double) point.getY();
Line2D line = new Line2D.Double(x1,y1,200,200);
g2d.draw(line);
}
*/
}
}
public class MyActionFrame extends JFrame {
public MyActionFrame() {
super("Test akcji");
JPanel buttonPanel = new MyButtonPanel();
add(buttonPanel);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
pack();
setVisible(true);
//setResizable(false);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
new MyActionFrame();
}
});
}
}

This validate();, or better revalidate(); is called when a container's layout needs to be re-done, often when components are added or removed, and is not what you're doing or desiring. Instead you want to call repaint() which suggests that the component be painted.

How to pass Graphics objects between classes and methods to draw lines

I am making a gui program with the mouseListener and mouseMotionListener. I have the following Line class
public class Line {
private int x1, x2, y1, y2;
private Color color;
public Line(int x1, int x2, int y1, int y2, Color color)
{
this.x1 = x1;
this.x2 = x2;
this.y1 = y1;
this.y2 = y2;
this.color = color;
}
public void draw(Graphics page)
{
page.drawLine(x1, y1, x2, y2);
page.setColor(color);
}
}
here is my mouseReleased where i get the final points of the desired line.
public void mouseReleased (MouseEvent event)
{ // ending points
moving = false;
Point p2 = event.getPoint();
x2 = p2.x;
y2 = p2.y;
line = new Line(x1,x2,y1,y2,currentColor);
lineList.add(line);
canvas.paintComponent(??????????);
Here is the canvas method that should draw all of these lines in the array list "lineList". to the canvas
private class CanvasPanel extends JPanel
{
//this method draws all shapes specified by a user
public void paintComponent(Graphics page)
{
super.paintComponent(page);
setBackground(Color.WHITE);
for(int i = 0; i <lineList.size()-1;i++)
{
line.draw(page);
}
However I do not know how to pass the graphics object to the canvas class in order to actually draw my lines on the JPanel. Assuming i have all other info correct(initial line points, JPanel set correctly, and buttons set up) how do i pass these to actually make it draw the lines to the canvas. Thank you!

No, you don't want to pass a Graphics object anywhere, and in fact you don't paint from within the MouseListener or MouseMotionListener. Instead you change fields from within those classes, call repaint() and then use the field results in your paintComponent method.
In fact in your code, if CanvasPanel has access to the lineList, all you need to do is call repaint() on it after adding a new line into the lineList collection. That's it.
Also, don't set background within paintComponent but rather within the constructor. Also you need to swap your method calls in the Line's draw method. You need to set the color before drawing the line.
e.g.,
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.ArrayList;
import java.util.List;
import javax.swing.*;
#SuppressWarnings("serial")
public class Drawing extends JPanel {
public static final Color BG = Color.WHITE;
public static final Color LINE_COLOR = Color.RED;
public static final Color CURRENT_LINE_COLOR = Color.LIGHT_GRAY;
public static final int PREF_W = 800;
public static final int PREF_H = PREF_W;
private List<Line> lineList = new ArrayList<>();
private Line currentLine = null;
private CanvasPanel canvasPanel = new CanvasPanel();
public Drawing() {
MyMouse myMouse = new MyMouse();
canvasPanel.addMouseListener(myMouse);
canvasPanel.addMouseMotionListener(myMouse);
setLayout(new BorderLayout());
add(canvasPanel);
}
private class CanvasPanel extends JPanel {
public CanvasPanel() {
setBackground(BG);
}
public void paintComponent(Graphics page) {
super.paintComponent(page);
// setBackground(Color.WHITE); // !! no, not here
for (Line line : lineList) {
line.draw(page);
}
if (currentLine != null) {
currentLine.draw(page);
}
}
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
}
private class MyMouse extends MouseAdapter {
private int x1;
private int y1;
#Override
public void mousePressed(MouseEvent e) {
if (e.getButton() != MouseEvent.BUTTON1) {
return;
}
x1 = e.getX();
y1 = e.getY();
currentLine = null;
canvasPanel.repaint();
}
#Override
public void mouseReleased(MouseEvent e) {
if (e.getButton() != MouseEvent.BUTTON1) {
return;
}
Line line = createLine(e, LINE_COLOR);
lineList.add(line);
currentLine = null;
canvasPanel.repaint();
}
#Override
public void mouseDragged(MouseEvent e) {
currentLine = createLine(e, CURRENT_LINE_COLOR);
repaint();
}
private Line createLine(MouseEvent e, Color currentColor) {
int x2 = e.getX();
int y2 = e.getY();
return new Line(x1, x2, y1, y2, currentColor);
}
}
private static void createAndShowGui() {
JFrame frame = new JFrame("Drawing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new Drawing());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
class Line {
private int x1, x2, y1, y2;
private Color color;
public Line(int x1, int x2, int y1, int y2, Color color) {
this.x1 = x1;
this.x2 = x2;
this.y1 = y1;
this.y2 = y2;
this.color = color;
}
public void draw(Graphics page) {
// swap these calls!
page.setColor(color); //!! This first!
page.drawLine(x1, y1, x2, y2); // **Then** this
// !! page.setColor(color);
}
}

Mouse listener not working with JPanel

The paintcomponent works fine, the image shows up, no problems on that end or with the JFrame. I want to implement zooming and panning but not getting any luck as the added mouse listener isn't responding.
import java.awt.Graphics;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseAdapter;
import javax.swing.JPanel;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
public class map extends JPanel {
public int moz = 100;
public void map()
{
addMouseListener(
new MouseAdapter()
{
#Override
public void mouseClicked(MouseEvent e)
{
moz = moz +100;
repaint();
}
}
);
}
public void paintComponent(Graphics g){
.....
g.drawLine( 0, moz, 100, 0 );
}
}

Your class doesn't have a real constructor but rather has a "pseudo" constructor since it has a return type -- yes void counts. So get rid of the void return type by changing:
// this is not a constructor
public void map()
to:
// this is a real constructor
public map()
Also as a side recommendation, change your variable and class names to conform with Java naming conventions: class names all start with an upper-case letter and method/variable names with a lower-case letter.
So in your case you'd name your class Map, and in playing with the code could have something like:
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.Stroke;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.swing.*;
public class Map extends JPanel {
private static final int PREF_W = 800;
private static final int PREF_H = 650;
private static final Color DRAW_RECT_COLOR = new Color(200, 200, 255);
public static final Stroke IMAGE_STROKE = new BasicStroke(3f);
public static final Color IMAGE_COLOR = Color.RED;
private BufferedImage image = new BufferedImage(PREF_W, PREF_H, BufferedImage.TYPE_INT_ARGB);
private Rectangle drawRectangle = null;
private List<Color> colors = new ArrayList<>();
private Random random = new Random();
public Map() {
MyMouse myMouse = new MyMouse();
addMouseListener(myMouse);
addMouseMotionListener(myMouse);
for (int r = 0; r < 4; r++) {
int r1 = (r * 255) / 3;
for (int g = 0; g < 4; g++) {
int g1 = (g * 255) / 3;
for (int b = 0; b < 4; b++) {
int b1 = (b * 255) / 3;
colors.add(new Color(r1, g1, b1));
}
}
}
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(image, 0, 0, this);
Graphics2D g2 = (Graphics2D) g;
if (drawRectangle != null) {
g.setColor(DRAW_RECT_COLOR);
g2.draw(drawRectangle);
}
}
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
private class MyMouse extends MouseAdapter {
Point p1 = null;
#Override
public void mousePressed(MouseEvent e) {
p1 = e.getPoint();
}
#Override
public void mouseDragged(MouseEvent e) {
if (p1 == null) {
return;
}
Point p2 = e.getPoint();
drawRectangle = createDrawRect(p2);
repaint();
}
#Override
public void mouseReleased(MouseEvent e) {
Rectangle rectangle = createDrawRect(e.getPoint());
Graphics2D g2 = image.createGraphics();
g2.setStroke(IMAGE_STROKE);
Color c = colors.get(random.nextInt(colors.size()));
g2.setColor(c);
g2.draw(rectangle);
g2.dispose();
p1 = null;
drawRectangle = null;
repaint();
}
private Rectangle createDrawRect(Point p2) {
int x = Math.min(p1.x, p2.x);
int y = Math.min(p1.y, p2.y);
int w = Math.abs(p1.x - p2.x);
int h = Math.abs(p1.y - p2.y);
return new Rectangle(x, y, w, h);
}
}
private static void createAndShowGui() {
Map mainPanel = new Map();
JFrame frame = new JFrame("Map");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}

GUI button placement

I am trying to design a GUI with triangle shaped buttons. I have create the triangle button class correctly in so far as creating a JButton with my class constructor results in a triangle button on the page, but I fall short when it comes to placement of the button.
Could any direct me or have an example for creating a hexagonal shape from triangle buttons?
Here is my TriangleButton class for reference:
import java.awt.Polygon;
import java.awt.Shape;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.JPanel;
import java.awt.Dimension;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
class TriangleButton extends JButton {
final static double side_len = 52; //Change for variable triangle size
final static double y_offset = (Math.sqrt(3) * side_len / 2);
private Shape triangle;
public TriangleButton(int spot){
triangle = createTriangle(spot);
}
public void paintBorder( Graphics g ) {
((Graphics2D)g).draw(triangle);
}
public void paintComponent( Graphics g ) {
((Graphics2D)g).fill(triangle);
}
public Dimension getPreferredSize() {
return new Dimension((int)side_len, (int)y_offset);
}
public boolean contains(int x, int y) {
return triangle.contains(x, y);
}
private Shape createTriangle(int spot) {
Polygon p = new Polygon();
p.addPoint( 0 , 0 );
p.addPoint( (int)side_len , 0 );
p.addPoint( (int)side_len/2, (int)(y_offset) );
return p;
}
}
The look I had in mind would be something like..
With space between the buttons.. basically just up-pointing and down-pointing triangles lined up.
But anything to put me in the right direction would be appreciated!

As an alternative, due to the complexities of generating a suitable layout to allow components to overlap, you could simply create a single button which housed all the triangles and which provided centralised control, for example
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridBagLayout;
import java.awt.Polygon;
import java.awt.Shape;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.geom.Path2D;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import javax.swing.AbstractButton;
import javax.swing.DefaultButtonModel;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
public TestPane() {
setLayout(new GridBagLayout());
HexagonButton btn = new HexagonButton();
btn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
System.out.println(Arrays.toString(btn.getSelectedObjects()));
System.out.println(e.getActionCommand());
}
});
add(btn);
}
}
public class HexagonButton extends AbstractButton {
public static final String TOP_RIGHT_QUAD = "Top.right";
public static final String TOP_QUAD = "Top";
public static final String TOP_LEFT_QUAD = "Top.left";
public static final String BOTTOM_LEFT_QUAD = "Bottom.left";
public static final String BOTTOM_QUAD = "Bottom";
public static final String BOTTOM_RIGHT_QUAD = "Bottom.right";
private Shape top;
private Shape topRight;
private Shape topLeft;
private Shape bottomLeft;
private Shape bottomRight;
private Shape bottom;
private Map<String, Shape> paths;
private String selectedQuad;
public HexagonButton() {
setModel(new DefaultButtonModel());
createPaths();
addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
String previousQuad = selectedQuad;
selectedQuad = null;
for (String quad : paths.keySet()) {
Shape shape = paths.get(quad);
if (shape.contains(e.getPoint())) {
getModel().setPressed(true);
getModel().setArmed(true);
selectedQuad = quad;
if (!selectedQuad.equals(previousQuad)) {
fireActionPerformed(new ActionEvent(HexagonButton.this, ActionEvent.ACTION_PERFORMED, selectedQuad));
}
break;
}
}
repaint();
}
#Override
public void mouseReleased(MouseEvent e) {
getModel().setArmed(false);
getModel().setPressed(false);
}
});
}
#Override
public Object[] getSelectedObjects() {
return new Object[]{selectedQuad};
}
#Override
public void invalidate() {
super.invalidate();
createPaths();
}
protected void createPaths() {
topRight = create(0d, -60d);
top = create(-60d, -120d);
topLeft = create(-120d, -180d);
bottomLeft = create(-180d, -240d);
bottom = create(-240d, -300d);
bottomRight = create(-300d, -360d);
paths = new HashMap<>(6);
paths.put(TOP_RIGHT_QUAD, topRight);
paths.put(TOP_QUAD, top);
paths.put(TOP_LEFT_QUAD, topLeft);
paths.put(BOTTOM_LEFT_QUAD, bottomLeft);
paths.put(BOTTOM_QUAD, bottom);
paths.put(BOTTOM_RIGHT_QUAD, bottomRight);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(104, 104);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g); //To change body of generated methods, choose Tools | Templates.
Graphics2D g2d = (Graphics2D) g.create();
if (selectedQuad != null) {
Shape path = paths.get(selectedQuad);
g2d.setColor(UIManager.getColor("List.selectionBackground"));
g2d.fill(path);
}
g2d.setColor(getForeground());
g2d.draw(topRight);
g2d.draw(top);
g2d.draw(topLeft);
g2d.draw(bottomLeft);
g2d.draw(bottom);
g2d.draw(bottomRight);
g2d.dispose();
}
public Shape create(double startAngle, double endAngle) {
double width = getWidth();
double height = getHeight();
double radius = Math.min(width, height) / 2;
double xOffset = width - radius;
double yOffset = height - radius;
double startX = xOffset + radius * (Math.cos(Math.toRadians(startAngle)));
double startY = yOffset + radius * (Math.sin(Math.toRadians(startAngle)));
double endX = xOffset + radius * (Math.cos(Math.toRadians(endAngle)));
double endY = yOffset + radius * (Math.sin(Math.toRadians(endAngle)));
Path2D path = new Path2D.Double();
path.moveTo(xOffset, yOffset);
path.lineTo(startX, startY);
path.lineTo(endX, endY);
path.closePath();
return path;
}
}
public static class TriangleButton extends JButton {
final static double side_len = 52; //Change for variable triangle size
final static double y_offset = (Math.sqrt(3) * side_len / 2);
private Shape triangle;
public TriangleButton(int spot) {
triangle = createTriangle(spot);
}
#Override
public void paintBorder(Graphics g) {
super.paintBorder(g);
((Graphics2D) g).draw(triangle);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
((Graphics2D) g).fill(triangle);
}
#Override
public Dimension getPreferredSize() {
return new Dimension((int) side_len, (int) y_offset);
}
#Override
public boolean contains(int x, int y) {
return triangle.contains(x, y);
}
private Shape createTriangle(int spot) {
Polygon p = new Polygon();
p.addPoint(0, 0);
p.addPoint((int) side_len, 0);
p.addPoint((int) side_len / 2, (int) (y_offset));
return p;
}
}
}

Using your class I made some changes and came up with the following:
import java.awt.*;
import java.awt.Shape;
import java.awt.Graphics;
import java.awt.Graphics2D;
import javax.swing.*;
import java.awt.Dimension;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
public class TriangleButton2 extends JButton {
final static double side_len = 52; //Change for variable triangle size
final static double y_offset = (Math.sqrt(3) * side_len / 2);
private Shape triangle;
public TriangleButton2(int degrees){
triangle = createTriangle(degrees);
setRolloverEnabled( false );
setContentAreaFilled( false );
setBorderPainted( false );
}
public void paintBorder( Graphics g ) {
((Graphics2D)g).draw(triangle);
}
public void paintComponent( Graphics g ) {
super.paintComponent(g);
((Graphics2D)g).fill(triangle);
}
public Dimension getPreferredSize() {
return new Dimension((int)side_len, (int)y_offset);
}
public boolean contains(int x, int y) {
return triangle.contains(x, y);
}
private Shape createTriangle(int degrees) {
Polygon p = new Polygon();
p.addPoint( 0 , 0 );
p.addPoint( (int)side_len , 0 );
p.addPoint( (int)side_len/2, (int)(y_offset) );
return ShapeUtils.rotate(p, degrees);
// return p;
}
private static void createAndShowGUI()
{
JPanel panelNorth = new JPanel( new FlowLayout(FlowLayout.CENTER, -22, 2) );
panelNorth.add( new TriangleButton2(180) );
panelNorth.add( new TriangleButton2(0) );
panelNorth.add( new TriangleButton2(180) );
JPanel panelSouth = new JPanel( new FlowLayout(FlowLayout.CENTER, -22, 1) );
panelSouth.add( new TriangleButton2(0) );
panelSouth.add( new TriangleButton2(180) );
panelSouth.add( new TriangleButton2(0) );
JFrame frame = new JFrame("SSCCE");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(panelNorth, BorderLayout.NORTH);
frame.add(panelSouth, BorderLayout.SOUTH);
frame.setLocationByPlatform( true );
frame.pack();
frame.setVisible( true );
}
public static void main(String[] args)
{
EventQueue.invokeLater(new Runnable()
{
public void run()
{
createAndShowGUI();
}
});
}
}
The above code uses the ShapeUtils class found in Playing With Shapes.
Not sure of the exact functionality you want from the button. Your current implantation doesn't have any visual effects when you click on the button or mouse over the button.
In this case you might want to consider just creating an Icon to represent your triangle. you can use the ShapeIcon class found in Playing With Shapes to create your triangle icons. Then you can use the ShapeComponent class also found in Playing With Shapes to create an actual component that you add to the panel.
The FlowLayout shows how you can overlap the buttons to get your desired layout effect.

Check out this page for some relatable information:
Creating custom JButton from images containing transparent pixels
It just might be easier creating JButtons from triangle images.