My JFrame uses a BorderLayout and it has a JLabel nested in several panels with different layout managers. I've tried several methods, however, cannot get the true position of where it sits in the frame.
I made a test UI and it seems like when other components are added the getX and getY parameters do not update. Other methods like getLocation do not provide a correct result either. Is there any way to obtain the exact location without manually calculating every possible offset from each component.
I am tracking the stated positions of the label (content) using a similar sized panel called content2 in the glass pane which I want to sit underneath content perfectly.
public class test {
private Dimension pSize = new Dimension(100,100);
private JFrame frame = new JFrame();
public static void main(String[] args) {
new test();
}
public test() {
//setup frame basics
frame.setPreferredSize(new Dimension(500,500));
frame.setLayout(new BorderLayout());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// setup GUI
JMenuBar j = new JMenuBar();
JMenuItem a = new JMenuItem("lol");
j.add(a);
JPanel j2 = new JPanel();
//setup main panel
JPanel main = new JPanel();
main.setBackground(Color.DARK_GRAY);
//setup side panel
FlowLayout f1 = new FlowLayout(FlowLayout.LEADING);
f1.setHgap(10);
f1.setVgap(0);
JPanel side = new JPanel();
side.setLayout(new BorderLayout());
side.setBackground(Color.gray);
side.setPreferredSize(new Dimension(150,100));
//setup JLabel (the main focus)
JLabel content = new JLabel("a");
content.setOpaque(true);
content.setBackground(Color.blue);
content.setPreferredSize(pSize);
// Setup the internal panels of side
JPanel top = new JPanel();//The panel where CONTENT is, the main focus
JPanel bot = new JPanel();
top.setBackground(Color.WHITE);
bot.setBackground(Color.orange);
top.setLayout(f1);
top.add(content);
side.add(top, BorderLayout.NORTH);
side.add(bot, BorderLayout.CENTER);
frame.add(main, BorderLayout.CENTER);
frame.add(side, BorderLayout.WEST);
frame.add(j2, BorderLayout.NORTH);
frame.setJMenuBar(j);
frame.pack();
frame.setVisible(true);
//Setting up the glass panel
JPanel pane = new JPanel();
pane.setLayout(null);
pane.setOpaque(false);
JPanel content2 = new JPanel();
content2.setBackground(Color.red);
content.revalidate();
int x = content.getX();
int y = content.getY();
// y = (int) content.getLocation().getY(); //returns a completely wrong location
//y = (int) content.getLocationOnScreen(); //returns a completely wrong location
/*
Point p = new Point();
p.setLocation(x, y);
p = SwingUtilities.convertPoint(content2, x, y, frame);
//SwingUtilities.convertPoint(content, p, frame);
y = (int) p.getY();
*
* Tried multiple SwingUtility converions to no avail
*
*/
// y = y +j.getHeight() + j2.getHeight(); // Manually calculating the Y off set works successfully but is too tedious for large project
y = y + content.getHeight();
content2.setBounds(x,y,100,100);
pane.add(content2);
frame.setGlassPane(pane);
frame.getGlassPane().setVisible(true);
frame.pack();
}
}
//frame.getContentPane().add(content);
//frame.add(content);
frame.setPreferredSize(new Dimension(500,500));
content.setBorder(BorderFactory.createEmptyBorder());
side.setLayout(new BorderLayout());
JPanel top = new JPanel();
JPanel bot = new JPanel();
top.setBackground(Color.WHITE);
bot.setBackground(Color.orange);
side.add(top, BorderLayout.NORTH);
top.setLayout(f1);
top.add(content);
side.add(bot, BorderLayout.CENTER);
frame.add(main, BorderLayout.CENTER);
frame.add(j2, BorderLayout.NORTH);
frame.add(side, BorderLayout.WEST);
frame.pack();
frame.setVisible(true);
JPanel pane = new JPanel();
pane.setLayout(null);
pane.setOpaque(false);
JPanel content2 = new JPanel();
content2.setBackground(Color.red);
content.revalidate();
int x = content.getX();
int y = content.getY();
// y = y +j.getHeight() + j2.getHeight();
y = y + content.getHeight();
content2.setBounds(x,y,100,100);
pane.add(content2);
frame.setGlassPane(pane);
frame.getGlassPane().setVisible(true);
frame.pack();
}
}
Conceptually you could make use of SwingUtilities.convertPoint or SwingUtilities.convertRectangle to convert between container contexts, for example...
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridBagLayout;
import java.awt.Rectangle;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.border.EmptyBorder;
public class Main {
public static void main(String[] args) {
new Main();
}
public Main() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
GlassPane glassPane = new GlassPane();
JFrame frame = new JFrame();
frame.setGlassPane(glassPane);
frame.add(new MainPane(glassPane));
glassPane.setVisible(true);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public interface Tracker {
public void addTrackable(Trackable trackable);
public void removeTrackable(Trackable trackable);
}
public interface Trackable {
public JComponent[] getTrackedComponents();
}
public class MainPane extends JPanel {
private JLabel label = new JLabel("Catch me if you can");
public MainPane(Tracker tracker) {
setLayout(new GridBagLayout());
setBorder(new EmptyBorder(32, 32, 32, 32));
add(label);
tracker.addTrackable(new Trackable() {
#Override
public JComponent[] getTrackedComponents() {
return new JComponent[] { label };
}
});
}
}
public class GlassPane extends JPanel implements Tracker {
private List<Trackable> trackables = new ArrayList<>(8);
public GlassPane() {
setOpaque(false);
}
#Override
public void addTrackable(Trackable trackable) {
trackables.add(trackable);
revalidate();
repaint();
}
#Override
public void removeTrackable(Trackable trackable) {
trackables.remove(trackable);
revalidate();
repaint();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.setColor(Color.RED);
for (Trackable trackable : trackables) {
for (JComponent component : trackable.getTrackedComponents()) {
Rectangle relativeBounds = SwingUtilities.convertRectangle(component.getParent(), component.getBounds(), this);
g2d.draw(relativeBounds);
}
}
g2d.dispose();
}
}
}
Well, that's pretty boring, it's one component inside one container, let's trying something a little more complicated...
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import java.awt.Rectangle;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.border.CompoundBorder;
import javax.swing.border.EmptyBorder;
import javax.swing.border.LineBorder;
public class Main {
public static void main(String[] args) {
new Main();
}
public Main() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
GlassPane glassPane = new GlassPane();
JFrame frame = new JFrame();
frame.setLayout(new GridLayout(2, 2, 8, 8));
frame.add(new MainPane(glassPane));
frame.add(new MainPane(glassPane));
frame.add(new MainPane(glassPane));
frame.add(new MainPane(glassPane));
frame.setGlassPane(glassPane);
glassPane.setVisible(true);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public interface Tracker {
public void addTrackable(Trackable trackable);
public void removeTrackable(Trackable trackable);
}
public interface Trackable {
public JComponent[] getTrackedComponents();
}
public class MainPane extends JPanel {
private JLabel label = new JLabel("Catch me if you can");
public MainPane(Tracker tracker) {
setLayout(new GridBagLayout());
setBorder(new CompoundBorder(new LineBorder(Color.DARK_GRAY, 1, true), new EmptyBorder(32, 32, 32, 32)));
add(label);
tracker.addTrackable(new Trackable() {
#Override
public JComponent[] getTrackedComponents() {
return new JComponent[]{label};
}
});
}
}
public class GlassPane extends JPanel implements Tracker {
private List<Trackable> trackables = new ArrayList<>(8);
private List<Color> masterColors = new ArrayList<>(Arrays.asList(new Color[]{
Color.RED,
Color.GREEN,
Color.BLUE,
Color.CYAN,
Color.DARK_GRAY,
Color.GRAY,
Color.MAGENTA,
Color.ORANGE,
Color.PINK,
Color.YELLOW,}));
public GlassPane() {
setOpaque(false);
}
#Override
public void addTrackable(Trackable trackable) {
trackables.add(trackable);
revalidate();
repaint();
}
#Override
public void removeTrackable(Trackable trackable) {
trackables.remove(trackable);
revalidate();
repaint();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.setColor(Color.RED);
List<Color> colors = new ArrayList<>(masterColors);
for (Trackable trackable : trackables) {
for (JComponent component : trackable.getTrackedComponents()) {
if (colors.isEmpty()) {
colors = new ArrayList<>(masterColors);
}
g2d.setColor(colors.remove(0));
Rectangle relativeBounds = SwingUtilities.convertRectangle(component.getParent(), component.getBounds(), this);
g2d.draw(relativeBounds);
}
}
g2d.dispose();
}
}
}
Here is a new smipler example program, trying to keep as close to your code as possible, that uses the convertRectangle but I can't manage to run it correctly
int y = (int) (r.getY() + r.getHeight()); ... are you deliberately trying to offset the "overlay"? This seems weird to me.
Another issue is, how does the GlassPane know when the child has changed position/size
So, I modified your code, getting rid of the "modification" to the x/y position (so I'm 100% sure that the conversion between context spaces is correct) and added a ComponentListener to monitor changes to the "target" component
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Rectangle;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import java.awt.*;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
public class Main {
private Dimension pSize = new Dimension(100, 100);
private JFrame frame = new JFrame();
private JLabel content = new JLabel("Grief");
private JPanel content2 = new JPanel();
private SidePane sidePane = new SidePane();
private GlassPane glass = new GlassPane();
private Menu menu = new Menu();
public static void main(String[] args) {
new Main();
}
public Main() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
content.setBackground(Color.green);
content.setPreferredSize(pSize);
content.setOpaque(true);
//setup frame basics
frame.setPreferredSize(new Dimension(500, 500));
frame.setLayout(new BorderLayout());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.setGlassPane(glass);
frame.add(new MainPane());
// glass.setNewLocation();
// glass.revalidate();
frame.getGlassPane().setVisible(true);
// glass.setNewLocation();
frame.pack();
frame.setVisible(true);
}
});
}
public class MainPane extends JPanel {
public MainPane() {
//this.setBackground(Color.orange);
this.setLayout(new BorderLayout());
this.add(sidePane, BorderLayout.WEST);
this.add(menu, BorderLayout.NORTH);
}
}
public class SidePane extends JPanel {
public SidePane() {
FlowLayout f1 = new FlowLayout(FlowLayout.LEADING);
this.setLayout(f1);
this.setBackground(Color.blue);
this.add(content);
}
}
public class Menu extends JPanel {
public Menu() {
this.setBackground(Color.orange);
}
}
public class GlassPane extends JPanel {
private Rectangle target;
public GlassPane() {
this.setOpaque(false);
setLayout(null);
content2.setBackground(Color.BLACK);
content2.setPreferredSize(pSize);
content2.setOpaque(true);
add(content2);
content.addComponentListener(new ComponentAdapter() {
#Override
public void componentResized(ComponentEvent e) {
updateOverlay();
}
#Override
public void componentMoved(ComponentEvent e) {
updateOverlay();
}
});
}
protected void updateOverlay() {
// Rectangle t = new Rectangle();
// t.setBounds((int) content.getLocation().getX(), (int) content.getLocation().getY(), content.getWidth(), content.getHeight());
// Rectangle r = SwingUtilities.convertRectangle(content.getParent(), content.getBounds(), this);
// Rectangle r = SwingUtilities.convertRectangle(content.getParent(), content.getBounds(), this);
target = SwingUtilities.convertRectangle(content.getParent(), content.getBounds(), this);
content2.setBounds(target);
// r = SwingUtilities.convertRectangle(content.getParent(), t, this);
// int x = (int) r.getBounds().getX();
// x = (int) r.getX();
// int y = (int) (r.getY() + r.getHeight());
//
// content2.setBounds(x, y, 100, 100);
// this.add(content2);
}
#Override
public void paint(Graphics g) {
super.paint(g);
Graphics2D g2d = (Graphics2D) g.create();
if (target != null) {
g2d.setColor(Color.RED);
g2d.draw(target);
}
g2d.dispose();
}
}
}
If you have the coordinate within the component, transfer it to screen coordinates using your component's convertPointToScreen(). Afterwards you can transfer back to see where in the window it sits by using the frame's convertPointFromScreen().
Or eliminate one of the two steps by directly using convertPoint().
Fixed the positioning issue using #MadProgrammer 's method of SwingUtilities.convertRectangle and called a new method at the end of the constructor which positioned the tracker panel.
Created a separate class for the glass pane
private class GlassPane extends JPanel {
public GlassPane() {
this.setLayout(null);
}
public void setNewLocation() {
Rectangle r = SwingUtilities.convertRectangle(top, content.getBounds(), this);
JPanel content2 = new JPanel();
int x = (int) r.getBounds().getX();
x = (int) r.getX();
int y = (int) (r.getY() + r.getHeight() + 1);
content2.setBounds(x, y, 100,100);
this.add(content2);
}
}
And added a call to the new method setNewLocation() at the end of the constructor
public test() {
**...**
frame.pack();
frame.setVisible(true);
glass.setNewLocation();
}
Was trying to do an ActionListener JButton, but the size of the button does not change to what I want to, it follows the size of the frame. I am very new and read many tutorials on that, seems right, but it doesn't work.
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class TimeTester extends JPanel implements ActionListener {
private int x = 10;
private static TimeTester test = new TimeTester();
private static JFrame frame = new JFrame();
private static JButton button = new JButton("Next Frame");
public static void main(String[] args) {
button.setLocation(100, 100);
button.setVisible(true);
button.addActionListener(test);
button.setMaximumSize(new Dimension(50, 60));
frame.add(button);
frame.setSize(500, 500);
frame.setVisible(true);
frame.setLayout(null);
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
frame.setResizable(false);
frame.setLocationRelativeTo(null);
frame.add(test);
System.out.println(test.calcTime());
}
#Override
public void actionPerformed(ActionEvent e) {
}
private synchronized long calcTime(){
double a;
long start = System.nanoTime();
long end = System.nanoTime();
return (end - start);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.black);
g.drawLine(x, x, 100 + x, 100 + x);
}
}
There is constructor of class extending JFrame:
import java.awt.*;
import javax.swing.*;
public class ChessFrame extends JFrame {
public ChessFrame () {
setSize(520, 520);
setResizable(false);
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLayout(new GridLayout(1, 1));
// Add components
getContentPane().add(new Board());
pack();
setVisible(true);
}
}
And class extending JPanel:
import javax.swing.*;
public class Board extends JPanel {
public Board() {
setSize(new Dimension(520, 520));
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.fillRect(0, 0, 520, 520);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(520, 520);
}
}
As a result rectangle smaller then 520x520.
Size of black rectangle is about 496x510. There is more:
getWidth() and getHegiht() written inside the Board class, returns 0 and 0 (so size of this JPanel into JFrame is 0x0)
If I remove pack(), size of frame becomes 496x510 (black rectangle size)
It's actually copypaste of official java tutorial: https://docs.oracle.com/javase/tutorial/uiswing/painting/step2.html.
Do I do something wrong or it's something related with java? If it's second, why does this happen?
Any help would be appreciated.
This example only tries to establish the panel size once the frame (and panel) are visible on-screen. It returns the exact size (300 pixels) set in the code.
import java.awt.*;
import javax.swing.*;
public class ChessBoard extends JPanel {
int size = 300;
JLabel sizeLabel = new JLabel();
ChessBoard() {
setBackground(Color.CYAN);
setLayout(new GridBagLayout());
add(sizeLabel);
}
public void showSize() {
sizeLabel.setText(String.format("%1sx%1s", getWidth(), getHeight()));
}
#Override
public Dimension getPreferredSize() {
return new Dimension(size,size);
}
public static void main(String[] args) {
Runnable r = () -> {
ChessBoard cb = new ChessBoard();
JFrame f = new JFrame(cb.getClass().getSimpleName());
f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
f.setLocationByPlatform(true);
f.setContentPane(cb);
f.pack();
f.setMinimumSize(f.getSize());
f.setVisible(true);
// delay showing size until app. is on-screen
Runnable r1 = cb::showSize;
SwingUtilities.invokeLater(r1);
};
SwingUtilities.invokeLater(r);
}
}
I am currently working on a little game but I just encountered a problem:
I have three classes, the first one is the JFrame:
public class Game
{
public static void main(String[] args)
{
new Game().gui();
}
public void gui()
{
DrawPanel panel = new DrawPanel();
JFrame frame = new JFrame("Test");
//frame.add(panel);
frame.add(new MainMenu());
frame.setSize(800, 700);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setResizable(false);
}
}
Now I have two other classes, one is the mainMenu, currently consisting of just one JButton.
I decided to make the menu its own class because later, I want to call the menu by pressing escape, but the problem is that (for testing reasons) I want to draw an rectangle when "start" is pressed. I tried different approaches but nothing happens.
public class MainMenu extends JPanel implements ActionListener
{
GamePanel panel = new GamePanel();
public MainMenu()
{
setLayout(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
JButton b1 = new JButton("Start");
c.fill = GridBagConstraints.HORIZONTAL;
c.ipadx = 200;
b1.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent e) {
setVisible(false);
}
});
add(b1, c);
}
}
public class DrawPanel extends JPanel
{
public void paint(Graphics g)
{
g.drawRect (10, 10, 200, 200);
}
}
There are several errors I found in your code:
You're not adding your DrawPanel to anything because this line
frame.add(panel);
is commented, so, that leads us to the next problem:
You're overriding paint() method instead of paintComponent() and also don't forget to call
super.paintComponent();
at the very beginning of the method. Without it, you're preventing your code to keep painting the rest of the components. See Custom painting in Swing
That still doesn't makes anything appear because you haven't declared a location for your DrawPanel and thus it's taking JFrame's default Layout Manager which is BorderLayout and it's default location when not specified is CENTER, and as you're adding new MainMenu() to it on the same position it replaces the DrawPanel panel, since only one component can exist on the same position.
Instead try and place the DrawPanel to the CENTER and the MainMenu to the SOUTH. It now should look like this:
Don't forget to place your program on the Event Dispatch Thread (EDT) by writing your main method as follows:
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
//Your constructor here
}
});
}
You're implementing ActionListener on MainMenu but not implementing it's methods, remove it or implement the actionPerformed method and move the code inside the b1 action listener to it. However I highly recommend you to take at Should your class implement ActionListener or use an object of an anonymous ActionListener class too
You're playing with MainMenu's JPanel visibility, instead you should try using a CardLayout or consider using JDialogs.
For example I would make a JDialog and place the JButton there, so it will open the JFrame with the Rectangle drawn in it.
Now, the code that made the above output and follows all recommendations (but #6) is:
import java.awt.BorderLayout;
import java.awt.Graphics;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class Game {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new Game().gui();
}
});
}
public void gui() {
DrawPanel panel = new DrawPanel();
JFrame frame = new JFrame("Test");
frame.add(panel, BorderLayout.CENTER);
frame.add(new MainMenu(), BorderLayout.SOUTH);
frame.setSize(400, 300);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setResizable(false);
}
}
class MainMenu extends JPanel {
// GamePanel panel = new GamePanel();
public MainMenu() {
setLayout(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
JButton b1 = new JButton("Start");
c.fill = GridBagConstraints.HORIZONTAL;
c.ipadx = 200;
b1.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
setVisible(false);
}
});
add(b1, c);
}
}
class DrawPanel extends JPanel {
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawRect(10, 10, 200, 200);
}
}
As suggested in the comments by #MadProgrammer, you can also override the getPreferredSize() method of your DrawPanel and then call frame.pack():
Your DrawPanel class should now look like this:
class DrawPanel extends JPanel {
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawRect(10, 10, 200, 200);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(400, 300);
}
}
My problem is I want to draw a huge Panel but its not possible to see this panel in a small size frame so i supposed to use ScrollPane and I used it..
But by scrolling clashes occurs so i cant see any panel there .i just want to fix it
Please anyone see my code and run it and help to solve the problem
import java.awt.*;
import javax.swing.*;
public class Swing{
JFrame frame;
Panel panel;
public static void main(String [] args){
Swing a = new Swing();
a.go();
}
public void go(){
frame = new JFrame();
panel = new Panel();
panel.setPreferredSize(new Dimension(5000, 5000));
JScrollPane scroll = new JScrollPane(panel);
frame.add(scroll);
frame.pack();
frame.setVisible(true);
}
class Panel extends JPanel{
public void paintComponent(Graphics g){
Graphics2D a = (Graphics2D)g;
a.setColor(Color.RED);
a.drawLine(50, 50, 5000, 5000);
}
}
}
Thanks in advance!
Always make sure to call super.paintComponent(g); to redraw the rest of the component. Otherwise these types of painting artifacts are seen.
import java.awt.*;
import javax.swing.*;
public class Swing{
JFrame frame;
Panel panel;
public static void main(String [] args){
Swing a = new Swing();
a.go();
}
public void go(){
frame = new JFrame();
panel = new Panel();
panel.setPreferredSize(new Dimension(5000, 5000));
JScrollPane scroll = new JScrollPane(panel);
frame.add(scroll);
frame.pack();
frame.setVisible(true);
}
class Panel extends JPanel{
public void paintComponent(Graphics g){
super.paintComponent(g); // VERY IMPORTANT!
Graphics2D a = (Graphics2D)g;
a.setColor(Color.RED);
a.drawLine(50, 50, 5000, 5000);
}
}
}