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How to refresh graphics of a Window class in Java

I'm trying to draw over a vlcj (java binding of the VLC library) panel so that I can play a video and draw over it. And I have encounter some issues. Here is the full base code:
Code-listing 1: AppOverlay.java
package app;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.HeadlessException;
import java.awt.Window;
import java.awt.image.BufferedImage;
import java.io.IOException;
import javax.imageio.ImageIO;
import com.sun.jna.platform.WindowUtils;
#SuppressWarnings("serial")
public class AppOverlay extends Window implements Runnable {
private final boolean isRunning;
private final int fps;
private BufferedImage graphics;
private BufferedImage img;
private int x, y;
private boolean ltr;
public AppOverlay(Window owner) {
super(owner, WindowUtils.getAlphaCompatibleGraphicsConfiguration());
setBackground(new Color(0,0,0,0));
graphics = new BufferedImage(1280,800, BufferedImage.TYPE_INT_ARGB);
isRunning = true;
img = null;
ltr = true;
fps = 60;
x = 0;
y = 0;
}
#Override
public void run(){
while(isRunning){
try{
Thread.sleep(1000/fps);
} catch(InterruptedException e){
e.printStackTrace();
}
if(ltr) {
if(x < 1280) x++;
else ltr = false;
} else {
if(x < 0) ltr = true;
else x--;
}
repaint();
}
}
public void createAndShowGUI() {
setVisible(true);
Thread thread = new Thread(this);
thread.start();
String path = "Drive:\\path\\to\\image.png";
try {
img = ImageIO.read(new java.io.FileInputStream(path));
} catch (IOException e) {
e.printStackTrace();
}
}
#Override
public void paint(Graphics g) {
Graphics2D g2d = (Graphics2D)g;
Graphics2D gfx = graphics.createGraphics();
gfx.setColor(new Color(255,255,255,0));
gfx.clearRect(0, 0, 1280, 800);
if(img != null) gfx.drawImage(img, x, y, null);
gfx.dispose();
g2d.drawImage(graphics, 0, 0, null);
}
}
Code-listing 2: AppPlayer.java
package app;
import uk.co.caprica.vlcj.player.component.EmbeddedMediaPlayerComponent;
#SuppressWarnings("serial")
public class AppPlayer extends EmbeddedMediaPlayerComponent {
}
Code-listing 3: AppFrame.java
package app;
import java.awt.Dimension;
import javax.swing.JFrame;
#SuppressWarnings("serial")
public class AppFrame extends JFrame {
private AppPlayer appPlayer;
private AppOverlay overlay;
public AppFrame(){
super();
}
public void createAndShowGUI() {
appPlayer = new AppPlayer();
appPlayer.setPreferredSize(new Dimension(1280,800));
getContentPane().add(appPlayer);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setTitle("App");
setVisible(true);
pack();
overlay = new AppOverlay(this);
appPlayer.mediaPlayer().overlay().set(overlay);
appPlayer.mediaPlayer().overlay().enable(true);
overlay.createAndShowGUI();
}
}
Code-listing 4: Main.java
package main;
import javax.swing.SwingUtilities;
import app.AppFrame;
public class Main {
public static void main(String[] args) {
final AppFrame app = new AppFrame();
SwingUtilities.invokeLater( new Runnable() {
#Override
public void run() {
app.createAndShowGUI();
}
});
}
}
with that and the vlcj-4 library you should be able to test my code yourself. My issue is that the Overlay (AppOverlay class that extends the Window class) doesn't display or refresh the animation unless I deselect the window (I click on another window or on the desktop or the OS toolbar) so that the window (application) is inactive then select the window (the application) again. It will only load one frame and that's it. I have to deselect and reselect the window again for it to load another frame (this is only the case for the Overlay i.e. if I play a video in the AppPlayer class the video will be playing just fine.
What I want is to be able to draw some animated graphics on the overlay. I know that with the JPanel class there is the paintComponent() method but the Window class doesn't have that method (only the paint() and repaint() methods are available).
What should I do to fix this?
EDIT:
I tried adding a JPanel on which I draw instead of drawing directly on the AppOverlay
Code-listing 5: AppPanel.java
package app;
import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JPanel;
public class AppPanel extends JPanel implements Runnable {
private int x, y;
private boolean ltr;
public AppPanel() {
x = 0;
y = 0;
ltr = true;
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(new Color(0,0,0,0));
g.clearRect(0, 0, 1280, 800);
g.setColor(Color.RED);
g.fillRect(x, y, 100, 100);
}
#Override
public void run() {
while(true){
try{
Thread.sleep(1000/60);
} catch(InterruptedException e){
e.printStackTrace();
}
if(ltr) {
if(x < 1280) x++;
else ltr = false;
} else {
if(x < 0) ltr = true;
else x--;
}
repaint();
}
}
}
then adding it to the AppOverlay.
Code-listing 6: AppOverlay.java with partial modification
public class AppOverlay extends Window implements Runnable {
//previous field declaration above ...
AppPanel panel;
AppPlayer player = null;
public AppOverlay(Window owner) {
//previous constructor instructions above...
panel = new AppPanel();
add(panel);
}
public void createAndShowGUI(AppPlayer player) {
setVisible(true);
/*
Thread thread = new Thread(this);
thread.start();
String path = "Drive:\\path\\to\\image.png";
try {
img = ImageIO.read(new java.io.FileInputStream(path));
} catch (IOException e) {
e.printStackTrace();
}
*/
Thread panelThread = new Thread(panel);
panelThread.start();
}
}
Doing this will display the graphics of the JPanel and animate them as needed.
If you know a way to make the JPanel background transparent (so that we can see through it) while still letting it display its graphics. That would solve the issue for sure.

I played around a bit with your example and came up with something working, but I wouldn't call it a nice solution.
The main issue seems to be that there is no way to tell the overlay to refresh (or I just have not found it). Just repainting the overlay does not update it on screen, so the workaround I used is to hide and show it again.
For the timeing of the update interval I used a javax.swing.Timer.
(In a real version you probably want to start and stop the timer via the MediaPlayerEventListener).
As a side effect the repaint method is called and the x coordinate is adjusted to move the image around the screen.
In the simplified example below (use your main to run it), I moved a red rectangle with the x coordinate instead of some unknown image.
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.HeadlessException;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.Timer;
import com.sun.jna.platform.WindowUtils;
import uk.co.caprica.vlcj.player.component.EmbeddedMediaPlayerComponent;
import uk.co.caprica.vlcj.player.embedded.OverlayApi;
public class AppFrame extends JFrame {
private static final long serialVersionUID = -1569823648323129877L;
public class Overlay extends Window {
private static final long serialVersionUID = 8337750467830040964L;
private int x, y;
private boolean ltr = true;
public Overlay(Window owner) throws HeadlessException {
super(owner, WindowUtils.getAlphaCompatibleGraphicsConfiguration());
setBackground(new Color(0,0,0,0));
}
#Override
public void paint(Graphics g) {
super.paint(g);
if (ltr) {
if (x < 1180)
x += 1;
else
ltr = false;
} else {
if (x < 0)
ltr = true;
else
x -= 1;
}
g.setColor(Color.RED);
g.fillRect(x, y, 100, 100);
String s = Integer.toString(x);
g.setColor(Color.WHITE);
g.drawChars(s.toCharArray(), 0, s.length(), x+10, y+50);
}
}
private EmbeddedMediaPlayerComponent appPlayer;
public void createAndShowGUI() {
appPlayer = new EmbeddedMediaPlayerComponent();
appPlayer.setPreferredSize(new Dimension(1280, 800));
getContentPane().add(appPlayer);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setTitle("App");
setVisible(true);
pack();
Overlay overlay = new Overlay(this);
OverlayApi api = appPlayer.mediaPlayer().overlay();
api.set(overlay);
api.enable(true);
//appPlayer.mediaPlayer().media().play(" ... ");
Timer timer = new Timer(0, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
api.enable(false);
api.enable(true);
}
});
timer.setRepeats(true);
timer.setDelay(200);
timer.start();
}
}
If that is an option for you, it might be far easier to use an animated gif instead. At least that is working on its own (no need for the Timer).
Update:
As you figured out using a JPanel seems to work better.
Just use setOpaque(false) to make it transparent.
Here an adjusted example.
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.HeadlessException;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;
import uk.co.caprica.vlcj.player.component.EmbeddedMediaPlayerComponent;
import uk.co.caprica.vlcj.player.embedded.OverlayApi;
public class AppFrame2 extends JFrame {
private static final long serialVersionUID = -1569823648323129877L;
public class OverlayPanel extends JPanel {
private static final long serialVersionUID = 8070414617530302145L;
private int x, y;
private boolean ltr = true;
public OverlayPanel() {
this.setOpaque(false);
}
#Override
public void paint(Graphics g) {
super.paint(g);
if (ltr) {
if (x < 1180)
x += 1;
else
ltr = false;
} else {
if (x < 0)
ltr = true;
else
x -= 1;
}
g.setColor(Color.RED);
g.fillRect(x, y, 100, 100);
String s = Integer.toString(x);
g.setColor(Color.WHITE);
g.drawChars(s.toCharArray(), 0, s.length(), x+10, y+50);
}
}
public class Overlay extends Window {
private static final long serialVersionUID = 8337750467830040964L;
OverlayPanel panel;
public Overlay(Window owner) throws HeadlessException {
super(owner);
setBackground(new Color(0,0,0,0));
panel = new OverlayPanel();
this.add(panel);
}
}
private EmbeddedMediaPlayerComponent appPlayer;
public void createAndShowGUI() {
appPlayer = new EmbeddedMediaPlayerComponent();
appPlayer.setPreferredSize(new Dimension(1280, 800));
getContentPane().add(appPlayer);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setTitle("App");
setVisible(true);
pack();
Overlay overlay = new Overlay(this);
OverlayApi api = appPlayer.mediaPlayer().overlay();
api.set(overlay);
api.enable(true);
//appPlayer.mediaPlayer().media().play(" ... ");
Timer timer = new Timer(0, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
overlay.panel.repaint();
}
});
timer.setRepeats(true);
timer.setDelay(17);
timer.start();
}
}

You have already done the bulk of the work. Simply repaint the frame every time you draw over it by calling app.repaint();

You can use the following methods from JComponent: ( http://download.oracle.com/javase/6/docs/api/javax/swing/JComponent.html )
void repaint(long tm, int x, int y, int width, int height)
//**Adds the specified region to the dirty region list if the component is showing.*//
void repaint(Rectangle r)
/**Adds the specified region to the dirty region list if the component is showing.*//
You can call those before redraw()

java simple bouncing ball flickers

This is just a simple red ball going up and down and i see it flickering. I already saw few subjects about that but did not find any answer that helped me.
Thank you :)
The Window class with the go method that makes the ball goes up and down.
The panel that also contains the ball positions and that just repaints.
Window.java
import java.awt.Dimension;
import javax.swing.JFrame;
public class Window extends JFrame
{
public static void main(String[] args)
{
new Window();
}
public Panel pan = new Panel();
public Window()
{
this.setSize(600, 600);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setLocationRelativeTo(null);
this.setContentPane(pan);
this.setVisible(true);
go();
}
private void go()
{
int vecY = 1;
while (true)
{
if (pan.y <= 100)
{
vecY = 1;
}
else if (pan.y >= 400)
{
vecY = -1;
}
pan.y += vecY;
pan.repaint();
try
{
Thread.sleep(10);
}
catch (InterruptedException e)
{
e.printStackTrace();
}
}
}
}
Panel.java
import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JPanel;
public class Panel extends JPanel
{
public int x = 300;
public int y = 300;
public void paintComponent(Graphics g)
{
g.setColor(Color.white);
g.fillRect(0, 0, this.getWidth(), this.getHeight());
g.setColor(Color.red);
g.fillOval(x, y, 50, 50);
}
}

There are a number of possible issues. The primary issue is likely to be a thread race condition between your while-loop and the paintComponent method.
Your while-loop is capable of change the state of the y position before the paintComponent has a chance to paint it's state. Painting is done at the leisure of the paint sub system, so calling repaint simply makes a request to the RepaintManager which decides what and when an actual paint cycle might take place, this means that you could be dropping frames.
For most animations in Swing, a Swing Timer is more the capable. It's safe to update the UI from within, as the ActionListener is called within the context of the EDT but won't block the EDT
For example:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
public class Window extends JFrame {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new Window();
}
});
}
public Panel pan = new Panel();
public Window() {
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setContentPane(pan);
pack();
this.setLocationRelativeTo(null);
this.setVisible(true);
go();
}
private void go() {
Timer timer = new Timer(10, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
pan.updateAnmationState();
}
});
timer.start();
}
public class Panel extends JPanel {
private int x = 300;
private int y = 300;
private int vecY = 1;
public void updateAnmationState() {
if (y <= 100) {
vecY = 1;
} else if (y >= 400) {
vecY = -1;
}
y += vecY;
repaint();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(400, 400);
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.white);
g.fillRect(0, 0, this.getWidth(), this.getHeight());
g.setColor(Color.red);
g.fillOval(x, y, 50, 50);
}
}
}
This example worked fine for me on MiniMac

Java graphics cannot relocate rectangle

I am trying to relocate a rectangle but for I cannot figure out why it stays in the same location.
It creates a red rectangle but does not change color or move to a new location.
Here is my code:
package grap_prj.dom.shenkar;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.util.concurrent.TimeUnit;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class graphic_main extends JPanel{
static Rectangle rec = new Rectangle ();
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
rec.setSize(10, 10);
rec.setLocation(10, 10);
g2d.setColor(Color.RED);
g2d.drawRect((int)rec.getX(),(int)rec.getY(), 10, 10);
g2d.fillRect((int)rec.getX(),(int)rec.getY(), 10, 10);
}
public static void update_ui (Graphics g)
{
System.out.println("in update");
rec.setLocation(50, 50);
Graphics2D g2d = (Graphics2D) g;
g2d.drawRect((int)rec.getX(),(int)rec.getY(), 10, 10);
g2d.fillRect((int)rec.getX(),(int)rec.getY(), 10, 10);
}
public static void main(String[] args) {
JFrame frame = new JFrame("Simple Graphics");
frame.add(new graphic_main());
frame.setSize(300, 300);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
try {
TimeUnit.SECONDS.sleep(10);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
graphic_main.update_ui(frame.getGraphics());
frame.revalidate();
}
}
Update:
I have made a few changes in the code, but still the same situation. I change the location but a new rectangle is added instead of moving the existing one.

You are continuosly setting location at 10,10 so the rectangle will always be drawn at 10,10.
After setting location 50,50 you aren't drawing anything. Next step you will set 10,10 again.

Whenever you override paintComponent(), you need to call super.paintComponent().
You are also calling repaint() from repaint(). You need to decide on some action that will cause it to repaint.

You should never call update() or repaint() inside of a paintComponent(...) method. Ever. This risks recursion or ineffective uncontrolled animation.
Don't change the state of your object inside of a paint or paintComponent method. You don't have full control over when or even if these methods get called.
Don't forget to call the super's method inside your paintComponent override to allow the JPanel to do its housekeeping graphics including erasing old dirty pixels.
Even though you change the Graphics context's Color to blue, it will change right back to red anytime the paintComponent is called. So your color change is futile code. Solution: make the Color a variable that can be set.
If you want to do Swing animation, use a Swing Timer.
For an example of Swing animation, have a look at my example here.
For another example, have a look at this:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
#SuppressWarnings("serial")
public class SimpleAnimation extends JPanel {
private static final int PREF_W = 800;
private static final int PREF_H = 650;
private static final Color[] COLORS = { Color.red, Color.orange,
Color.yellow, Color.green, Color.blue, Color.magenta };
private static final int RECT_WIDTH = 40;
private static final int TIMER_DELAY = 10;
private int x = 0;
private int y = 0;
private int colorIndex = 0;
private Color color = COLORS[colorIndex];
public SimpleAnimation() {
new Timer(TIMER_DELAY, new TimerListener()).start();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(PREF_W, PREF_H);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(color);
g.fillRect(x, y, RECT_WIDTH, RECT_WIDTH);
}
private class TimerListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
x++;
y++;
if (x + RECT_WIDTH > getWidth()) {
x = 0;
}
if (y + RECT_WIDTH > getHeight()) {
y = 0;
}
if (x % 40 == 0) {
colorIndex++;
colorIndex %= COLORS.length;
color = COLORS[colorIndex];
}
repaint();
}
}
private static void createAndShowGui() {
JFrame frame = new JFrame("SimpleAnimation");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new SimpleAnimation());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}

Your changing the location before the frame gets the chance to render it. So its creating it at 10, 10 and then when its rendered changes it to 50 50 then to 10, 10.

Pausing a program

I'm working with JFrame, and I have a while loop. Inside that while loop I change the background of the frame to black then white, and have it do it again. However, I need it to pause for a second or two in between changing so you can actually see it. Thread.sleep(), and Timer don't seem to work. Can anyone help?

If you want to use a timer from swing this is the proper way to do it:
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.Timer;
public class Animation extends JFrame implements ActionListener {
private Timer t;
private Color myColor;
private int howManyTimesIwantThis;
private int count = 0;
public Animation() {
t = new Timer(1000, this); // actionPerformed will be called every 1 sec
t.start();
this.howManyTimesIwantThis = 10;
this.setVisible(true);
this.setSize(500, 500);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setLocationRelativeTo(null);
myColor = Color.blue;
}
public void actionPerformed(ActionEvent e) {
if (count < howManyTimesIwantThis) {
count++;
if (myColor.equals(Color.blue)) {
myColor = Color.red;
} else {
myColor = Color.blue;
}
repaint(); //calls the paint method
}
}
public void paint(Graphics g) {
super.paint(g);
g.setColor(myColor);
g.fillRect(0, 0, this.getWidth(), this.getHeight());
g.dispose();
}
}
And if you want to use Thread.sleep(), you can do something like this:
import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JFrame;
public class Animation extends JFrame{
private Color myColor;
private int howManyTimesIwantThis;
private int count = 0;
public Animation() {
this.howManyTimesIwantThis = 10;
this.setVisible(true);
this.setSize(500, 500);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setLocationRelativeTo(null);
myColor = Color.blue;
}
public void paint(Graphics g) {
super.paint(g);
while (count < howManyTimesIwantThis) {
count++;
if (myColor.equals(Color.blue)) {
myColor = Color.red;
} else {
myColor = Color.blue;
}
g.setColor(myColor);
g.fillRect(0, 0, this.getWidth(), this.getHeight());
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
g.dispose();
}
}
If you have any questions about the code please feel free to ask.

Draw multiple moving graphics

I have already made this program able to draw an instance of a small ball bouncing around a screen using these two classes
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.JPanel;
import javax.swing.Timer;
public class move extends JPanel implements ActionListener
{
Timer t = new Timer(7, this);
int x = 10, y = 10, velX = 7, velY = 7;
public void paintComponent(Graphics g, Graphics h)
{
super.paintComponent(h);
super.paintComponent(g);
System.out.println(g);
Graphics2D g2 = (Graphics2D) g;
Ellipse2D circle = new Ellipse2D.Double(x, y, 40, 40);
g2.fill(circle);
t.start();
}
public void actionPerformed(ActionEvent e) {
if(x<0 || x > getWidth())
{
velX = -velX;
}
if(y < 0 || y > getHeight())
{
velY = -velY;
}
x += velX;
y += velY;
repaint();
}
}
This class just simply draws the ball and provides the logic for the timer and such
import java.awt.Color;
import javax.swing.JFrame;
public class Gui {
public static void main(String[] args)
{
move s = new move();
JFrame f = new JFrame("move");
f.add(s);
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setSize(1000, 1000);
f.setTitle("Moving Circle");
f.setBackground(Color.GREEN);
}
}
This next class just puts it all in a JFrame, very simple stuff I know but I'm just trying to draw multiple instances within the same JFrame. I'm just trying to experiment with my knowledge of code, some sample of code to implement would be great.
How to draw multiple moving graphics?

This code could have a class Ball class that knows its position & size and how to draw itself to a Graphics.
As each ball is created, they are added to a list. At time of paint, iterate the list and paint each Ball.