Trying to draw on a canvas with sliders

Trying to draw on a canvas with sliders - java

I am attempting to use jsliders to allow a user to pinpoint the origin of a circle to be drawn on a canvas. I am using a button to show and hide the circle. I am using paint on an inner jpanel so that paint will not write over components. However, the coordinates inside the jpanel are different than the coordinates for the entire frame. So, it is very difficult for me to get the coordinates of the jslider and then translate it to the jpanel to draw the circle. Is there an easy way to figure this out without a ton of guess and check? I am also using the custom layout miglayout. I have included the code for my GUI class as well as my custom JPanel I made so I could mess with the paint method.
public class CircleGUI extends JFrame implements ActionListener {
private MigLayout layout = new MigLayout();
private CustomPanel innerpanel;
private JSlider x,y;
private JColorChooser colorpick;
private JButton state;
private boolean bstate;
CircleGUI() {
initialize();
}
private void initialize() {
Border blackline = BorderFactory.createLineBorder(Color.black);
bstate = false;
x = new JSlider(JSlider.HORIZONTAL,650,325);
x.setPaintTicks(true);
x.setPaintLabels(true);
x.setPreferredSize(new Dimension(650,0));
y = new JSlider(JSlider.HORIZONTAL,650,325);
y.setPaintTicks(true);
y.setPaintLabels(true);
y.setInverted(true);
y.setOrientation(JSlider.VERTICAL);
y.setPreferredSize(new Dimension (0,600));
colorpick = new JColorChooser();
state = new JButton("Show");
state.addActionListener(e -> {
if(!bstate) {
int positionx = x.getValue() - 80;
int positiony = y.getValue();
Color c = colorpick.getColor();
innerpanel.setColor(c);
innerpanel.setX(positionx);
innerpanel.setY(positiony);
innerpanel.repaint();
state.setText("Hide");
bstate = true;
} else {
Color transparent = new Color(0,0,0,0);
innerpanel.setColor(transparent);
innerpanel.repaint();
state.setText("Show");
bstate = false;
}
});
JPanel outerpanel = new JPanel(layout);
innerpanel = new CustomPanel();
innerpanel.setPreferredSize(new Dimension(600,600));
innerpanel.setBorder(blackline);
outerpanel.add(x,"wrap");
outerpanel.add(y,"split 2");
outerpanel.add(innerpanel);
outerpanel.add(state,"wrap");
outerpanel.add(colorpick);
this.setSize(1000, 1000);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.add(outerpanel);
}
#Override
public void actionPerformed(ActionEvent e) {
}
}
public class CustomPanel extends JPanel implements ActionListener {
private Color c;
private int x;
private int y;
public CustomPanel() {
c = null;
}
#Override
public void actionPerformed (ActionEvent e) {
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setPaint(c);
g2.fill(new Ellipse2D.Double(x, y, 100, 100));
}
public void setColor(Color c) {
this.c = c;
}
public void setX(int x) {
this.x = x;
}
public void setY(int y) {
this.y = y;
}
}

Your problem is you are trying to make a one-to-one mapping between the value of the JSlider and the coordinate in your CustomPanel. You should use the JSlider value as a percentage, i.e. minimum value zero and maximum value 100. If you want the circle to appear in the middle of the CustomPanel so you place both JSliders in their mid-points, i.e. both at 50%. Then you calculate 50% of the corresponding dimension to get the coordinate. If the width of CustomPanel is 600, then 50% of 600 is 300 so positionx needs to be 300.
The only thing I changed in your code is the calculation of positionx and positiony.
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.Ellipse2D;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JColorChooser;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.border.Border;
import net.miginfocom.swing.MigLayout;
public class CircleGUI extends JFrame implements ActionListener {
private MigLayout layout = new MigLayout();
private CustomPanel innerpanel;
private JSlider x,y;
private JColorChooser colorpick;
private JButton state;
private boolean bstate;
CircleGUI() {
initialize();
}
private void initialize() {
Border blackline = BorderFactory.createLineBorder(Color.black);
bstate = false;
// x = new JSlider(JSlider.HORIZONTAL, 650, 325);
x = new JSlider(0, 100, 10);
x.setPaintTicks(true);
x.setPaintLabels(true);
x.setPreferredSize(new Dimension(650, 0));
// y = new JSlider(JSlider.HORIZONTAL, 650, 325);
y = new JSlider(0, 100, 10);
y.setPaintTicks(true);
y.setPaintLabels(true);
y.setInverted(true);
y.setOrientation(JSlider.VERTICAL);
y.setPreferredSize(new Dimension(0, 600));
colorpick = new JColorChooser();
state = new JButton("Show");
state.addActionListener(e -> {
if (!bstate) {
int positionx = Math.round(x.getValue() / 100.0f * innerpanel.getSize().width) - 50;
int positiony = Math.round(y.getValue() / 100.0f * innerpanel.getSize().height) - 50;
Color c = colorpick.getColor();
innerpanel.setColor(c);
innerpanel.setX(positionx);
innerpanel.setY(positiony);
innerpanel.repaint();
state.setText("Hide");
bstate = true;
}
else {
Color transparent = new Color(0, 0, 0, 0);
innerpanel.setColor(transparent);
innerpanel.repaint();
state.setText("Show");
bstate = false;
}
});
JPanel outerpanel = new JPanel(layout);
innerpanel = new CustomPanel();
innerpanel.setPreferredSize(new Dimension(600, 600));
innerpanel.setBorder(blackline);
outerpanel.add(x, "wrap");
outerpanel.add(y, "split 2");
outerpanel.add(innerpanel);
outerpanel.add(state, "wrap");
outerpanel.add(colorpick);
this.setSize(1000, 1000);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.add(outerpanel);
}
#Override
public void actionPerformed(ActionEvent e) {
}
public static void main(String[] args) {
EventQueue.invokeLater(() -> {
CircleGUI cg = new CircleGUI();
cg.setVisible(true);
});
}
}
class CustomPanel extends JPanel implements ActionListener {
private Color c;
private int x;
private int y;
public CustomPanel() {
c = null;
}
#Override
public void actionPerformed(ActionEvent e) {
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
g2.setPaint(c);
g2.fill(new Ellipse2D.Double(x, y, 100, 100));
}
public void setColor(Color c) {
this.c = c;
}
public void setX(int x) {
this.x = x;
}
public void setY(int y) {
this.y = y;
}
}

Related

How to make ball drawn with Java bounce off the edges of the panel?

I have java code that draws a red ball inside a class that extends the JPanel class, I have a timer that is enabled by a button that updates the position of the ball with timer ctor variable elapse. I am trying to get the difference of the height of the panel and the YPOSITION where the circle is drawn if its less than 0 the the bounce ball needs to keep moving down else it should move up, my ball hits the wall and keeps hitting it. Help me debug the code that is causing that to happen.
RightPanel class
import javax.swing.*;
import java.awt.*;
public class RightPanel extends JPanel {
//define the position where the circle will be drawn
private int positionX=150;
private int positionY=150;
private int radius=100;//as the shape is a circle
//override the paint method to draw the bounce ball on the second panel
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d= (Graphics2D) g;
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setColor(Color.RED);
g2d.fillOval(positionX,positionY,radius,radius);
}
//let's us update the position of the ball from another class
public int getPositionY(){
public void setPositionX(int positionX) {
this.positionX = positionX;
}
public void setPositionY(int positionY){
this.positionY=positionY;
}
public int getPositionX(){
return this.positionX;
}
return this.positionY;
}
}
The logic in the timer class below is the one I need help with
GameInterface class
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
public class GameInterface extends JFrame {
//declare a Timer object to start the movement
Graphics ctx;
RightPanel rightpanel;
private int height;
//declare a timer to start moving the ball
Timer mytimer= new Timer(50, new AbstractAction() {
#Override
public void actionPerformed(ActionEvent e) {
//check this and keep moving the ball down
if(rightpanel.getPositionY()- rightpanel.getHeight()<0){
rightpanel.setPositionY(rightpanel.getPositionY()+5);
rightpanel.paint(rightpanel.getGraphics());
}else{
//move the ball up
rightpanel.setPositionY(rightpanel.getPositionY()-5);
rightpanel.paint(rightpanel.getGraphics());
}
}
});
public GameInterface(){
setSize(new Dimension(800, 600));
height=this.getHeight();
setResizable(false);
setTitle("Bounce Game");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBackground(Color.black);
//define a new JSplitPane and use it to add two JPanels
JPanel leftpanel= new JPanel();
//add buttons to the left panel programatically
JButton up= new JButton("Move up");
//set the event listeners for the buttons
up.addActionListener(new AbstractAction() {
#Override
public void actionPerformed(ActionEvent e) {
//start he timer
mytimer.start();
}
});
JButton down = new JButton("Move down");
down.addActionListener(new AbstractAction() {
#Override
public void actionPerformed(ActionEvent e) {
//move my ball down
rightpanel.setPositionX(rightpanel.getPositionX());
rightpanel.setPositionY(rightpanel.getPositionY()+5);
rightpanel.paint(rightpanel.getGraphics());
}
});
leftpanel.add(up);
leftpanel.add(down);
rightpanel= new RightPanel();
JSplitPane splitpane= new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,leftpanel,rightpanel);
this.add(splitpane);
setVisible(true);
ctx=this.getGraphics();
}
}

The basic idea is, when you "drop" the ball, you need to determine the direction of movement that the ball should move in. When the timer ticks, it will apply that direction of movement until it either reaches the bottom, at which time the delta is reversed, or it reaches the top.
The important part here is, all the state the timer needs should be determined before the timer is started and not calculated within the timer itself, as the state it needs is no longer relevant.
For example...
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridBagLayout;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.Shape;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.Ellipse2D;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
public class Main {
public static void main(String[] args) {
new Main();
}
public Main() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
Ball ball = new Ball(20);
JFrame frame = new JFrame();
frame.add(new MainPane(ball));
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class Ball {
private Point location;
private Dimension size;
private Shape shape;
public Ball(int radius) {
location = new Point(0, 0);
size = new Dimension(radius * 2, radius * 2);
shape = new Ellipse2D.Double(0, 0, radius * 2, radius * 2);
}
public Rectangle getBounds() {
return new Rectangle(location, size);
}
public void setLocation(Point p) {
location = new Point(p);
}
public void paint(Graphics2D g2d) {
g2d = (Graphics2D) g2d.create();
g2d.setColor(Color.RED);
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2d.translate(location.x, location.y);
g2d.fill(shape);
g2d.dispose();
}
}
public class SurfacePane extends JPanel {
private Ball ball;
private Timer timer;
private int yDelta;
public SurfacePane(Ball ball) {
this.ball = ball;
this.ball.setLocation(new Point(200 - (ball.getBounds().width / 2), 0));
}
#Override
public Dimension getPreferredSize() {
return new Dimension(400, 400);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
ball.paint(g2d);
g2d.dispose();
}
public void moveBallDown() {
Rectangle bounds = ball.getBounds();
Dimension size = ball.size;
Point location = bounds.getLocation();
location.y += size.height;
if (location.y + size.height > getHeight()) {
location.y = getHeight() - size.height;
}
ball.setLocation(location);
repaint();
}
public void dropBall() {
if (timer != null) {
return;
}
Rectangle bounds = ball.getBounds();
Dimension size = ball.size;
Point location = bounds.getLocation();
if (location.y + size.height > getHeight()) {
yDelta = -1;
} else {
yDelta = 1;
}
timer = new Timer(5, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
Rectangle bounds = ball.getBounds();
Dimension size = ball.size;
Point location = bounds.getLocation();
location.y += yDelta;
if (location.y < 0) {
location.y = 0;
yDelta = 0;
timer.stop();
timer = null;
} else if (location.y + size.height > getHeight()) {
location.y = getHeight() - size.height;
yDelta *= -1;
}
ball.setLocation(location);
repaint();
}
});
timer.start();
}
}
public class MainPane extends JPanel {
private Ball ball;
private SurfacePane surfacePane;
public MainPane(Ball ball) {
setLayout(new BorderLayout());
this.ball = ball;
surfacePane = new SurfacePane(ball);
add(surfacePane);
JPanel actionPane = new JPanel(new GridBagLayout());
JButton up = new JButton("Up");
JButton down = new JButton("Down");
actionPane.add(up);
actionPane.add(down);
add(actionPane, BorderLayout.SOUTH);
up.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
surfacePane.dropBall();
}
});
down.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
surfacePane.moveBallDown();
}
});
}
}
}

Need help to adjust a Zoom system in Graphics2D - Java

This is my 1st question here. I'm trying to build a White Page adjustable by zoom. It's inside a JScrollPane, so the size of the JScrollPane's ScrollBars are adjustable in the Dimension of that JPanel.
I want to adjust the size of those ScrollBars as the Size of the page (variables width and height in the code) + 2 borderSize, so the full size is equal the Page + margin of a borderSize around it. It works if zoom = 1.0.
If zoom < 1.0, the scroll bar is smaller than the Page and cut a piece of it. If zoom > 1 the Dimension size is way bigger than the page, leaving a huger border on its right and down corners, bigger than the borderSize.
How do I do this?
PS: I'm started learning java by myself, in the Quarantine last year, never had a teacher, just the internet, so any critics or suggestions, please, tell me.
Here's the JPanel's code:
package test;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.event.AdjustmentEvent;
import java.awt.event.AdjustmentListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseWheelEvent;
import java.awt.event.MouseWheelListener;
import java.awt.event.WindowEvent;
import java.awt.event.WindowStateListener;
import java.awt.geom.AffineTransform;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SpringLayout;
import javax.swing.JSlider;
import javax.swing.JScrollPane;
import javax.swing.JLabel;
public class Main2 {
private MyPanel mp = new MyPanel();
private JFrame frame;
private JSlider zoomSlider = new JSlider();
private JLabel zoomLabel = new JLabel("Zoom: XXX");
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Main2 window = new Main2();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public Main2() {
initialize();
}
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 619, 403);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
SpringLayout springLayout = new SpringLayout();
frame.getContentPane().setLayout(springLayout);
springLayout.putConstraint(SpringLayout.SOUTH, zoomSlider, 40, SpringLayout.NORTH, frame.getContentPane());
springLayout.putConstraint(SpringLayout.EAST, zoomSlider, -115, SpringLayout.EAST, frame.getContentPane());
zoomSlider.setValue(100);
zoomSlider.setSnapToTicks(true);
zoomSlider.setPaintTicks(true);
zoomSlider.setMaximum(200);
zoomSlider.setMinorTickSpacing(5);
zoomSlider.setMinimum(5);
springLayout.putConstraint(SpringLayout.NORTH, zoomSlider, 0, SpringLayout.NORTH, frame.getContentPane());
springLayout.putConstraint(SpringLayout.WEST, zoomSlider, 0, SpringLayout.WEST, frame.getContentPane());
frame.getContentPane().add(zoomSlider);
JScrollPane scrollPane = new JScrollPane(mp);
springLayout.putConstraint(SpringLayout.NORTH, scrollPane, 10, SpringLayout.SOUTH, zoomSlider);
springLayout.putConstraint(SpringLayout.WEST, scrollPane, 10, SpringLayout.WEST, frame.getContentPane());
springLayout.putConstraint(SpringLayout.SOUTH, scrollPane, -10, SpringLayout.SOUTH, frame.getContentPane());
springLayout.putConstraint(SpringLayout.EAST, scrollPane, -10, SpringLayout.EAST, frame.getContentPane());
frame.getContentPane().add(scrollPane);
springLayout.putConstraint(SpringLayout.NORTH, zoomLabel, 10, SpringLayout.NORTH, frame.getContentPane());
springLayout.putConstraint(SpringLayout.WEST, zoomLabel, 6, SpringLayout.EAST, zoomSlider);
frame.getContentPane().add(zoomLabel);
frame.addWindowStateListener(new WindowStateListener() {
#Override
public void windowStateChanged(WindowEvent arg0) {
// TODO Auto-generated method stub
mp.draw();
}
});
zoomSlider.addMouseListener(new MouseListener() {
#Override
public void mouseClicked(MouseEvent arg0) {
// TODO Auto-generated method stub
int temp = (zoomSlider.getValue())-zoomSlider.getValue()%5;
setZoom(temp);
mp.draw();
}
#Override
public void mouseEntered(MouseEvent arg0) {
// TODO Auto-generated method stub
}
#Override
public void mouseExited(MouseEvent arg0) {
// TODO Auto-generated method stub
}
#Override
public void mousePressed(MouseEvent arg0) {
// TODO Auto-generated method stub
}
#Override
public void mouseReleased(MouseEvent arg0) {
int temp = (zoomSlider.getValue())-zoomSlider.getValue()%5;
setZoom(temp);
mp.draw();
}
});
mp.addMouseWheelListener(new MouseWheelListener() {
#Override
public void mouseWheelMoved(MouseWheelEvent e) {
if (e.getPreciseWheelRotation() < 0) {
setZoom(zoomSlider.getValue()- 5);
} else {
setZoom(zoomSlider.getValue()+ 5);
}
// zoom += e.getPreciseWheelRotation();
if (mp.getZoom()*100 < 10) {
setZoom(10);
}
mp.draw();
}
});
AdjustmentListener adj = new AdjustmentListener() {
#Override
public void adjustmentValueChanged(AdjustmentEvent e) {
setZoom(zoomSlider.getValue());
mp.draw();
}
};
scrollPane.getVerticalScrollBar().addAdjustmentListener(adj);
scrollPane.getHorizontalScrollBar().addAdjustmentListener(adj);
}
public void setZoom(int n) {
mp.setZoom(n);
zoomSlider.setValue(n);
zoomLabel.setText("Zoom: "+mp.getZoom()+"x");
}
}
class MyPanel extends JPanel{
private static final long serialVersionUID = -716735372803790424L;
int borderSize=28;
int zoom=100;
int height = 3565;
int width = 2537;
int widthz, heightz;
public MyPanel() {
setBackground(Color.DARK_GRAY);
}
#Override
public Dimension getPreferredSize() {
int a, b;
String temp;
Float x, y;
x=(getZoom()*width); //Size of the page adjusted by zoom
y=(getZoom()*height);
temp = x.toString();
String temp1[] = temp.split("\\."); // converted to string to convert it to int
a = Integer.valueOf(temp1[0])+2*borderSize; //that value + 2 BorderSize
temp = y.toString();
String temp2[] = temp.split("\\.");
b = Integer.valueOf(temp2[0])+2*borderSize;
return new Dimension (a,b);
}
#Override
public void paintComponent (Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d = putZoom(g2d);
g2d.setColor(Color.WHITE);
g2d.fillRect(this.getX(),this.getY(), width, height);
g2d.setColor(Color.BLACK);
g2d.drawRect(this.getX()+borderSize,this.getY()+borderSize,width-2*borderSize,height-2*borderSize);
g2d.dispose();
}
public Graphics2D putZoom(Graphics2D g) {
AffineTransform at = new AffineTransform();
at.translate(borderSize,borderSize); // put the page a borderSize from the upper-left corner
at.scale(getZoom(),getZoom()); //adjust the page as zoom
Graphics2D g2d = g;
g2d.setTransform(at);
return g2d;
}
public void draw() { //this method is to update the draw from the main
repaint();
}
public Float getZoom() {
return Float.valueOf(zoom)/100;
}
public void setZoom(int zom) { //this method is to update Zoom from the main
zoom=zom;
String zoomheight []= (String.valueOf(getZoom()*height)).split("\\.");
heightz = Integer.valueOf(zoomheight[0]);
String zoomwidth []= (String.valueOf(getZoom()*width)).split("\\.");
widthz = Integer.valueOf(zoomwidth[0]);
}
public int getZoomInt() {
return this.zoom;
}
}
Zoom(values from 0.1 to 2.0).
How can i improve this? Also, i have no idea how to update the JScrollPane's scrollbars together with the zoom.Thanks for the help.
UPDATE: i've created a minimal reproducible exemple.

Introduction
I started working on this before you updated your question. I used a zoom percentage rather than a zoom factor.
I created the following GUI and set the initial state to 30 percent.
I made the inner JPanel a checkerboard so you can more easily see the zoom. I modified your initial values so the inner JPanel would represent an 8 1/2 x 11 piece of paper at 50 pixels per inch.
Here's the same GUI at 100 percent.
Here's the same GUI at 10 percent.
Explanation
I created a JFrame and a control JPanel to hold the JSlider. I used a GridLayout to create the control JPanel.
I created an inner JPanel to hold the drawing and a display JPanel that holds the JScrollPane. I made the display JPanel proportionate to the size of the inner JPanel so I wouldn't have any stretching issues.
Getting the GUI to revalidate / repaint turned out to be the biggest challenge. I wound up having to invalidate the JScrollPane, both JScrollBars, and the display JPanel. I also had to reset the JScrollBars to zero each time I changed the zoom percentage.
Code
Here's the complete runnable code. I made all of the classes inner classes so I could post this as one code block.
import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollBar;
import javax.swing.JScrollPane;
import javax.swing.JSlider;
import javax.swing.SwingUtilities;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class ZoomJPanelGUI implements Runnable {
public static void main(String[] args) {
SwingUtilities.invokeLater(new ZoomJPanelGUI());
}
private int zoomPercentage = 30;
private DisplayPanel displayPanel;
private JFrame frame;
#Override
public void run() {
frame = new JFrame("Zoom JPanel");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(createControlPanel(), BorderLayout.BEFORE_FIRST_LINE);
this.displayPanel = new DisplayPanel(zoomPercentage);
frame.add(displayPanel.getPanel(), BorderLayout.AFTER_LAST_LINE);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
private JPanel createControlPanel() {
JPanel panel = new JPanel(new GridLayout(0, 1));
panel.setBorder(BorderFactory.createEmptyBorder(5, 15, 5, 15));
JLabel label = new JLabel("Zoom Percentage");
label.setFont(panel.getFont().deriveFont(Font.BOLD, 24f));
panel.add(label);
JSlider slider = new JSlider(
JSlider.HORIZONTAL, 10, 100, zoomPercentage);
slider.setFont(panel.getFont().deriveFont(16f));
slider.setMajorTickSpacing(30);
slider.setMinorTickSpacing(5);
slider.setPaintTicks(true);
slider.setPaintLabels(true);
slider.addChangeListener(new ChangeListener() {
#Override
public void stateChanged(ChangeEvent event) {
JSlider slider = (JSlider) event.getSource();
if (!slider.getValueIsAdjusting()) {
zoomPercentage = (int) slider.getValue();
displayPanel.setZoomPercentage(zoomPercentage);
displayPanel.repaint();
frame.pack();
}
}
});
panel.add(slider);
return panel;
}
public class DisplayPanel {
private InnerPanel innerPanel;
private final JPanel panel;
private JScrollPane scrollPane;
private int zoomPercentage;
public DisplayPanel(int zoomPercentage) {
this.zoomPercentage = zoomPercentage;
this.panel = createDisplayPanel();
}
private JPanel createDisplayPanel() {
JPanel panel = new JPanel(new BorderLayout());
panel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
this.innerPanel = new InnerPanel(zoomPercentage);
scrollPane = new JScrollPane(innerPanel);
scrollPane.setPreferredSize(new Dimension(475, 600));
panel.add(scrollPane, BorderLayout.CENTER);
return panel;
}
public void setZoomPercentage(int zoomPercentage) {
this.zoomPercentage = zoomPercentage;
innerPanel.setZoomPercentage(zoomPercentage);
}
public JPanel getPanel() {
return panel;
}
public void repaint() {
innerPanel.repaint();
scrollPane.invalidate();
JScrollBar hScrollBar = scrollPane.getHorizontalScrollBar();
JScrollBar vScrollBar = scrollPane.getVerticalScrollBar();
hScrollBar.setValue(0);
vScrollBar.setValue(0);
hScrollBar.invalidate();
vScrollBar.invalidate();
panel.invalidate();
}
}
public class InnerPanel extends JPanel {
private static final long serialVersionUID = 1L;
private int maximumBorderSize = 25;
private int maximumCellSize = 50;
private int maximumHeight = 5500;
private int maximumWidth = 4250;
private int zoomPercentage;
public InnerPanel(int zoomPercentage) {
this.zoomPercentage = zoomPercentage;
}
public void setZoomPercentage(int zoomPercentage) {
this.zoomPercentage = zoomPercentage;
}
#Override
public Dimension getPreferredSize() {
int width = maximumWidth * zoomPercentage / 100;
int height = maximumHeight * zoomPercentage / 100;
return new Dimension(width, height);
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
int borderSize = maximumBorderSize * zoomPercentage / 100;
paintBackground(g2d);
paintBorder(g2d, borderSize);
paintCheckerboard(g2d, borderSize);
}
private void paintBackground(Graphics2D g2d) {
g2d.setColor(Color.WHITE);
g2d.fillRect(0, 0, getWidth(), getHeight());
}
private void paintBorder(Graphics2D g2d, int borderSize) {
g2d.setColor(Color.BLACK);
g2d.setStroke(new BasicStroke(3f));
g2d.drawRect(borderSize, borderSize, getWidth() - 2 * borderSize,
getHeight() - 2 * borderSize);
}
private void paintCheckerboard(Graphics2D g2d, int borderSize) {
int cellSize = maximumCellSize * zoomPercentage / 100;
int width = maximumWidth - maximumBorderSize * 2 - 2;
int height = maximumHeight - maximumBorderSize * 2 - 2;
int cellWidth = width / maximumCellSize;
int cellHeight = height / maximumCellSize;
boolean isBlue = true;
int x = borderSize;
int y = borderSize;
int heightRemainder = height - cellHeight * cellSize;
for (int i = 0; i < cellHeight; i++) {
int widthRemainder = width - cellWidth * cellSize;
for (int j = 0; j < cellWidth; j++) {
if (isBlue) {
g2d.setColor(Color.BLUE);
} else {
g2d.setColor(Color.YELLOW);
}
isBlue = !isBlue;
g2d.fillRect(x, y, cellSize, cellSize);
x += cellSize;
if (widthRemainder > 0) {
x++;
widthRemainder--;
}
}
// isBlue = !isBlue;
x = borderSize;
y += cellSize;
if (heightRemainder > 0) {
y++;
heightRemainder--;
}
}
}
}
}

I've finally did it. Started by not using transformation for scaling it, but making a new draw with the size zoomed, adapting all sizes in the method setSizes(), and adjusting the Dimension by those sizes.
(Just changed this class)
class MyPanel extends JPanel{
private static final long serialVersionUID = -716735372803790424L;
int borderSize=28;
int zoom=100;
int height = 3565;
int width = 2537;
int widthz, heightz;
int maxHeight, maxWidth; //max size of draw
int maxAreaHeight, maxAreaWidth; //max size of area
public MyPanel() {
setBackground(Color.DARK_GRAY);
}
#Override
public Dimension getPreferredSize() {
setSizes();
return new Dimension (maxAreaWidth,maxAreaHeight);
}
#Override
public void paintComponent (Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d= createBase(g2d);
}
public void draw() { //this method is to update the draw from the main
repaint();
}
public Float getZoom() {return Float.valueOf(zoom)/100;}
public void setZoom(int zom) {zoom=zom;}
public int getZoomInt() {return this.zoom;}
public void setSizes () {
widthz= width*getZoomInt()/100;
heightz=height*getZoomInt()/100;
maxHeight = heightz+2*borderSize;
maxWidth = widthz +2*borderSize;
maxAreaHeight = this.getY()+maxHeight;
maxAreaWidth = this.getX()+maxWidth;
if (this.getSize() != new Dimension(maxAreaWidth, maxAreaHeight)) {
this.setSize(maxAreaWidth, maxAreaHeight);
}
}
public Graphics2D createBase(Graphics2D g2d) {
Graphics2D g = g2d;
setSizes();
g.setColor(Color.WHITE);
g.fillRect(this.getX()+borderSize,this.getY()+borderSize, widthz, heightz);
g.setColor(Color.BLACK);
g.drawRect(this.getX()+borderSize+borderSize*zoom/100,this.getY()+borderSize+borderSize*zoom/100,widthz-2*borderSize*zoom/100,heightz-2*borderSize*zoom/100);
return g;
}
}
Thanks for all the help.

Add a JComponent via Child to Parent

I want to accomplish something very similar to the image a Rectangle whit a Selector Line.
Basically, I have a Rectangle and I want to have a selector line all around it.
For that, I wanted to create an additional JComponent.
At the moment I can only draw the Rectangle. How could I get the parentPanel JPanel inside the Rectangle class, so that I could add the selector?
public class TestPanel extends JFrame {
public class Rectangle extends JComponent {
public Rectangle(){
setBounds(x1, y1, x2, y2);
JPanel Selector = new JPanel();
//Adds Selector to parentPanel within Rectangle
//setBounds(x1-1, y1-1, x2+1, y2+1)
//!Problem parent is initially null! cant even a use property
//Life hacks?
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawRect(0, 0, getWidth(), getHeight());
}
}
public TestPanel() {
Rectangle Rectangle = new Rectangle();
JPanel parentFrame = new JPanel();
parentFrame.add(Rectangle);
setSize(200, 200);
setVisible(true);
}
public static void main(String[] args) {
new TestPanel();
}
}
If I try to add the selector inside the rectangle, it will get out of the drawing area. If I resize the drawing area, it won't be scalable for later development.
If possible I would avoid dual binding like:
public TestPanel() {
Rectangle Rectangle = new Rectangle();
JPanel parentPanel = new JPanel();
parentPanel.add(Rectangle);
Rectangle.addParent(parentPanel)
...
}

Again, I'm not 100% clear on what you're trying to achieve. If what you wish to create is a user-created dashed line, one that can change with mouse press/drag/release, then you don't need to create a new component but rather use a MouseAdapter as a MouseListener and MouseMotionListener, all to help you create the Rectangle, and then simply draw the Rectangle with a dashed line using an appropriate Stroke, as per this answer.
For example, something like would create a dashed line that is user-selectable:
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 javax.swing.*;
public class SelectorPanel extends JPanel {
private static final int PREF_W = 800;
private static final int PREF_H = 650;
private static final Stroke DASHED_STROKE = new BasicStroke(2, BasicStroke.CAP_BUTT,
BasicStroke.JOIN_BEVEL, 0, new float[] { 5 }, 0);
private static final Color DASHED_COLOR = Color.LIGHT_GRAY;
private Rectangle rectangle = null;
public SelectorPanel() {
MyMouse myMouse = new MyMouse();
addMouseListener(myMouse);
addMouseMotionListener(myMouse);
}
private class MyMouse extends MouseAdapter {
private Point p1 = null;
#Override
public void mousePressed(MouseEvent e) {
p1 = e.getPoint();
rectangle = null;
}
#Override
public void mouseDragged(MouseEvent e) {
if (p1 != null) {
createRectangle(e);
}
}
#Override
public void mouseReleased(MouseEvent e) {
if (p1 != null) {
createRectangle(e);
p1 = null;
}
}
private void createRectangle(MouseEvent e) {
Point p2 = e.getPoint();
int x = Math.min(p1.x, p2.x);
int y = Math.min(p1.y, p2.y);
int width = Math.abs(p1.x - p2.x);
int height = Math.abs(p1.y - p2.y);
rectangle = new Rectangle(x, y, width, height);
repaint();
}
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (rectangle != null) {
Graphics2D g2 = (Graphics2D) g.create();
g2.setColor(DASHED_COLOR);
g2.setStroke(DASHED_STROKE);
g2.draw(rectangle);
g2.dispose();
}
}
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
private static void createAndShowGui() {
SelectorPanel mainPanel = new SelectorPanel();
JFrame frame = new JFrame("SelectorPanel");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
}

Draw Randomly-Sized Shape from User JList Selection of Shapes in Java GUI

I have to produce a randomly-sized shape (from 50 to 300 pixels) in a java GUI. There is a JList of 3 shapes (rectangle, square, circle) that the user can choose from, and when they choose one, a randomly-sized rectangle, square, or circle should appear in the GUI.
I guess I'm just having trouble figuring out where and how to implement the list selection listeners.
Here is my code so far:
import javax.swing.*;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics;
public class ShapeSelectionWindow extends JPanel implements ListSelectionListener{
public void paintComponent(Graphics g) {
int x, y, width, height;
super.paintComponent(g);
width = (int)Math.floor(Math.random()*250) + 50;
height = (int)Math.floor(Math.random()*250) + 50;
x = (int)Math.floor((615 - width) / 2);
y = (int)Math.floor((661 - height) / 2);
g.fillRect(x, y, width, height);
}
public static void main(String[] args) {
ShapeSelectionWindow ssw = new ShapeSelectionWindow();
JFrame jf = new JFrame();
JPanel shapeListPanel = new JPanel();
shapeListPanel.setBackground(Color.WHITE);
DefaultListModel<String> dlm = new DefaultListModel<String>();
dlm.addElement("Rectangle");
dlm.addElement("Square");
dlm.addElement("Circle");
JList<String> shapeList = new JList<String>(dlm);
shapeList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
shapeListPanel.add(shapeList);
jf.getContentPane().setLayout(new BorderLayout());
jf.getContentPane().add(ssw, BorderLayout.CENTER);
jf.getContentPane().add(shapeListPanel, BorderLayout.EAST);
jf.setTitle("Simple Drawing GUI");
jf.setSize(700, 700);
jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jf.setVisible(true);
}
#Override
public void valueChanged(ListSelectionEvent e) {
// TODO Auto-generated method stub
}
}
The current paintComponent method is for painting a rectangle. Like I said, I'm not sure how to implement the list selection listeners for this project in order to produce different shapes based on the user's selection.

Your current approach is placing too many eggs in a single basket. Why would ShapeSelectionWindow be responsible for managing the JList? It's sole responsibility is to draw a random shape.
Instead, you should break your design down.
I would start by defining a simple "shape" entity...
public enum Shape {
RECTANGLE("Rectangle"), SQUARE("Square"), CIRCLE("Circle");
private String name;
private Shape(String name) {
this.name = name;
}
public String getName() {
return name;
}
#Override
public String toString() {
return getName();
}
}
This just provides a limit set of options which can be used.
I would then update the "shape pane" to support these options...
public class ShapePane extends JPanel {
private Shape shape;
public void setShape(Shape shape) {
this.shape = shape;
repaint();
}
public Shape getShape() {
return shape;
}
#Override
public Dimension getPreferredSize() {
return new Dimension(800, 800);
}
public void paintComponent(Graphics g) {
int x, y, width, height;
super.paintComponent(g);
Shape shape = getShape();
if (shape == null) {
return;
}
width = (int) Math.floor(Math.random() * 250) + 50;
height = (int) Math.floor(Math.random() * 250) + 50;
x = (int) Math.floor((615 - width) / 2);
y = (int) Math.floor((661 - height) / 2);
switch (shape) {
case RECTANGLE:
g.fillRect(x, y, width, height);
break;
case SQUARE:
break;
case CIRCLE:
break;
}
}
}
The ShapePane doesn't care "how" the Shape is specified, it only cares when it changes and wants to paint it
I would then use another component to act as the primary controller between the JList and the ShapePane...
public class MainPane extends JPanel {
private JList<Shape> list;
private ShapePane shapePane;
public MainPane() {
setLayout(new BorderLayout());
DefaultListModel<Shape> model = new DefaultListModel<>();
model.addElement(Shape.SQUARE);
model.addElement(Shape.RECTANGLE);
model.addElement(Shape.CIRCLE);
shapePane = new ShapePane();
list = new JList<Shape>(model);
list.addListSelectionListener(new ListSelectionListener() {
#Override
public void valueChanged(ListSelectionEvent e) {
Shape shape = list.getSelectedValue();
shapePane.setShape(shape);
}
});
add(list, BorderLayout.WEST);
add(shapePane, BorderLayout.CENTER);
}
}
Runnable Example...
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import javax.swing.DefaultListModel;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
frame.add(new MainPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public enum Shape {
RECTANGLE("Rectangle"), SQUARE("Square"), CIRCLE("Circle");
private String name;
private Shape(String name) {
this.name = name;
}
public String getName() {
return name;
}
#Override
public String toString() {
return getName();
}
}
public class MainPane extends JPanel {
private JList<Shape> list;
private ShapePane shapePane;
public MainPane() {
setLayout(new BorderLayout());
DefaultListModel<Shape> model = new DefaultListModel<>();
model.addElement(Shape.SQUARE);
model.addElement(Shape.RECTANGLE);
model.addElement(Shape.CIRCLE);
shapePane = new ShapePane();
list = new JList<Shape>(model);
list.addListSelectionListener(new ListSelectionListener() {
#Override
public void valueChanged(ListSelectionEvent e) {
Shape shape = list.getSelectedValue();
shapePane.setShape(shape);
}
});
add(list, BorderLayout.WEST);
add(shapePane, BorderLayout.CENTER);
}
}
public class ShapePane extends JPanel {
private Shape shape;
public void setShape(Shape shape) {
this.shape = shape;
repaint();
}
public Shape getShape() {
return shape;
}
#Override
public Dimension getPreferredSize() {
return new Dimension(800, 800);
}
public void paintComponent(Graphics g) {
int x, y, width, height;
super.paintComponent(g);
Shape shape = getShape();
if (shape == null) {
return;
}
width = (int) Math.floor(Math.random() * 250) + 50;
height = (int) Math.floor(Math.random() * 250) + 50;
x = (int) Math.floor((615 - width) / 2);
y = (int) Math.floor((661 - height) / 2);
switch (shape) {
case RECTANGLE:
g.fillRect(x, y, width, height);
break;
case SQUARE:
break;
case CIRCLE:
break;
}
}
}
}

Painting on a class extending JFrame in Java

i'm kind of new with Java graphics, i'm trying to create a simple crossroad GUI interface with 4 traffic lights on it, when using the following classes that I have created - I get a window with a large grey rectangle on it (I assume that since I didn't allocate a traffic lights in the center it has been filled with the default grey background), how do I control the size of the center of the JFrame?
This is what i'm looking to acheive:
This is what i'm getting:
This is the JFrame class.
import java.awt.*;
import javax.swing.*;
public class CrossroadInterface extends JFrame /*implements IAppInterface*/ {
private static final int WIDTH_OF_WINDOW = 400;
private static final int HEIGHT_OF_WINDOW = 400;
//Panels
TrafficLight tLightW, tLightC, tLightE, tLightS, tLightN;
//Other
public CrossroadInterface() {
super("My Crossroad");
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setSize(WIDTH_OF_WINDOW, HEIGHT_OF_WINDOW);
this.setVisible(true);
createInterface();
}
public void createInterface () {
tLightW = new TrafficLight();
tLightE = new TrafficLight();
tLightS = new TrafficLight();
tLightN = new TrafficLight();
this.add(tLightW, BorderLayout.WEST);
this.add(tLightN, BorderLayout.NORTH);
this.add(tLightE, BorderLayout.EAST);
this.add(tLightS, BorderLayout.SOUTH);
}
}
This is the Jpanel class.
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.GridLayout;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class TrafficLight extends JPanel {
private final Color offRed = new Color(128, 0, 0);
private final Color offGreen = new Color(0, 96, 0);
private static final int CAR_DIAMETER = 50;
private static final int PERSON_HEIGHT = 100;
private static final int PERSON_WIDTH = 50;
private int status;
public TrafficLight() {
super();
this.setSize(CAR_DIAMETER, 120);
this.setBackground(Color.BLACK);
status = 0;
this.setVisible(true);
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(offRed);
g.fillOval(this.getX(), this.getY(), CAR_DIAMETER, CAR_DIAMETER);
g.setColor(offGreen);
g.fillOval(this.getX(), this.getY()+CAR_DIAMETER, CAR_DIAMETER, CAR_DIAMETER);
g.setColor(offRed);
g.fillRect(this.getX(), this.getY()+CAR_DIAMETER+PERSON_HEIGHT, PERSON_WIDTH, PERSON_HEIGHT);
g.setColor(offGreen);
g.fillRect(this.getX(), this.getY()+CAR_DIAMETER+2*PERSON_HEIGHT, PERSON_WIDTH, PERSON_HEIGHT);
//drawIlluminatedLights(g);
System.out.println(this.getX()+" "+this.getY());
}
}
EDIT:
Following Hovercraft Full Of Eels' advise, here are my new classes:
import java.awt.*;
import javax.swing.*;
public class CrossroadInterface extends JFrame /*implements IAppInterface*/ {
private static final int WIDTH_OF_WINDOW = 900;
private static final int HEIGHT_OF_WINDOW = 900;
//Panels
TrafficLight tLightW, tLightC, tLightE, tLightS, tLightN;
//Other
public CrossroadInterface() {
super("My Crossroad");
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setSize(WIDTH_OF_WINDOW, HEIGHT_OF_WINDOW);
setLayout(new GridLayout(3,3));
createInterface();
}
public void createInterface () {
tLightW = new TrafficLight();
tLightE = new TrafficLight();
tLightS = new TrafficLight();
tLightN = new TrafficLight();
this.add(new JPanel());
this.add(tLightW);
this.add(new JPanel());
this.add(tLightN);
this.add(new JPanel());
this.add(tLightE);
this.add(new JPanel());
this.add(tLightS);
this.setVisible(true);
}
}
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import javax.swing.JPanel;
public class TrafficLight extends JPanel {
private final Color offRed = new Color(128, 0, 0);
private final Color offGreen = new Color(0, 96, 0);
private static final int CAR_DIAMETER = 50;
private static final int PERSON_HEIGHT = 50;
private static final int PERSON_WIDTH = 50;
private int status;
public TrafficLight() {
super();
status = 0;
this.setPreferredSize(new Dimension(CAR_DIAMETER,2*CAR_DIAMETER+2*PERSON_HEIGHT));
this.setVisible(true);
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(offRed);
g.fillOval(100, 50, CAR_DIAMETER, CAR_DIAMETER);
g.setColor(offGreen);
g.fillOval(100, 50+CAR_DIAMETER, CAR_DIAMETER, CAR_DIAMETER);
g.setColor(offRed);
g.fillRect(100, 50+CAR_DIAMETER+PERSON_HEIGHT, PERSON_WIDTH, PERSON_HEIGHT);
g.setColor(offGreen);
g.fillRect(100, 50+CAR_DIAMETER+2*PERSON_HEIGHT, PERSON_WIDTH, PERSON_HEIGHT);
//drawIlluminatedLights(g);
}
}

Your problem is not that the center of the JFrame is too large, but rather it's because the size of your surrounding JPanels are too small. Understand that most Swing layout managers respect a components preferred size, and use this to set the size of the component. Your other problems include
using getX() and getY() to place your drawings. These values give the location of the JPanel within its container, but that won't help you place your drawing since when you draw within the JPanel the drawing's location is placed relative to the location of the pixel within the JPanel not its container, so using these methods will mess you up.
Calling the JFrame's setVisible(true) before adding all components. This risks not displaying all components.
Making your TrafficLight class extend JPanel. You're far better off using a single JPanel to do all the drawing and have your TrafficLight class not extend from any Swing component but rather be a logical class. Give it a public void draw(Graphics2D g2) method that you can call within the drawing JPanel's paintComponent method.
For example:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.Shape;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.Ellipse2D;
import java.util.ArrayList;
import java.util.EnumMap;
import java.util.List;
import java.util.Map;
import java.util.Random;
import javax.swing.*;
#SuppressWarnings("serial")
public class CrossRoads2 extends JPanel {
private static final int PREF_W = 400;
private static final int PREF_H = PREF_W;
private static final int TIMER_DELAY = 100;
List<TrafficLight2> lights = new ArrayList<>();
public CrossRoads2() {
// create a timer to randomly change traffic light state
// and start it
new Timer(TIMER_DELAY, new TimerListener()).start();
// create 4 TrafficLight2 objects and place them at 4
// compass locations, and add to lights ArrayList
int x = (PREF_W - TrafficLight2.getWidth()) / 2;
int y = 0;
lights.add(new TrafficLight2(x, y));
x = 0;
y = (PREF_H - TrafficLight2.getHeight()) / 2;
lights.add(new TrafficLight2(x, y));
x = (PREF_W - TrafficLight2.getWidth());
lights.add(new TrafficLight2(x, y));
x = (PREF_W - TrafficLight2.getWidth()) / 2;
y = (PREF_H - TrafficLight2.getHeight());
lights.add(new TrafficLight2(x, y));
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
// cast g into a Graphics2 object
Graphics2D g2 = (Graphics2D) g;
// for smooth rendering
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
// iterate through the ArrayList, calling the draw method on each light
for (TrafficLight2 light : lights) {
light.draw(g2);
}
}
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
// give our JPanel a decent size
return new Dimension(PREF_W, PREF_H);
}
// ActionListener that randomly changes the LightState of each traffic light
private class TimerListener implements ActionListener {
private Random random = new Random();
#Override
public void actionPerformed(ActionEvent e) {
for (TrafficLight2 light : lights) {
// random number 0 to 2
int randomIndex = random.nextInt(LightState.values().length);
// get one of the LightStates using the index above
LightState lightState = LightState.values()[randomIndex];
// set our light to this state
light.setLightState(lightState);
}
repaint();
}
}
private static void createAndShowGui() {
CrossRoads2 mainPanel = new CrossRoads2();
JFrame frame = new JFrame("Cross Roads");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> createAndShowGui());
}
}
class TrafficLight2 {
private static final int ELLIPSE_W = 40;
private static final int GAP = 4;
private int x;
private int y;
private LightState lightState = LightState.RED; // what color is bright
// map to hold our 3 ellipses, each one corresponding to a LightState
private Map<LightState, Shape> lightMap = new EnumMap<>(LightState.class);
public TrafficLight2(int x, int y) {
// create 3 ellipses, one each for RED, YELLOW, GREEN
// place each one below the previous
// associate each one with one of our RED, YELLOW, or GREEN LightStates
// putting the Ellipse into the map with the light state as key
this.x = x;
this.y = y;
int tempX = x + GAP;
int tempY = y + GAP;
lightMap.put(LightState.RED, new Ellipse2D.Double(tempX, tempY, ELLIPSE_W, ELLIPSE_W));
tempY += ELLIPSE_W + GAP;
lightMap.put(LightState.YELLOW, new Ellipse2D.Double(tempX, tempY, ELLIPSE_W, ELLIPSE_W));
tempY += ELLIPSE_W + GAP;
lightMap.put(LightState.GREEN, new Ellipse2D.Double(tempX, tempY, ELLIPSE_W, ELLIPSE_W));
}
// called by JPanel's paintComponent
public void draw(Graphics2D g2) {
// iterate through the 3 LightStates
for (LightState ltSt : LightState.values()) {
// if the ltSt in the for loop is this traffic light's LightState
// then the display color should be bright
Color c = ltSt == lightState ? ltSt.getColor() :
// other wise the display color should be very dark
ltSt.getColor().darker().darker().darker();
g2.setColor(c);
g2.fill(lightMap.get(ltSt)); // fill the oval with color
g2.setColor(Color.BLACK);
g2.draw(lightMap.get(ltSt)); // draw a black border
}
}
public int getX() {
return x;
}
public int getY() {
return y;
}
public LightState getLightState() {
return lightState;
}
public void setLightState(LightState lightState) {
this.lightState = lightState;
}
// static method for the width of our traffic lights
public static int getWidth() {
return 2 * GAP + ELLIPSE_W;
}
// static method for the height of our traffic lights
public static int getHeight() {
return 4 * GAP + 3 * ELLIPSE_W;
}
}
// enum that encapsulates the 3 possible states of the traffic light
enum LightState {
RED("Red", Color.RED), YELLOW("Yellow", Color.YELLOW), GREEN("Green", Color.GREEN);
private LightState(String text, Color color) {
this.text = text;
this.color = color;
}
private String text;
private Color color;
public String getText() {
return text;
}
public Color getColor() {
return color;
}
}

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