Image not showing up in Swing?

Image not showing up in Swing? - java

I honestly don't know what I'm doing wrong. (Although I'm sure it's quite a bit.) I've been trying to adjust my code for hours to no avail.
I'm attempting to cut up pieces of a picture and display them. Later, I will randomize where they are located and try to place them in their correct positions. Now, however, I'm having issues having anything show up on my JPanel at all. At one point, my test code displayed the image. Now, however, the same test code doesn't work.
If you can see what I'm doing wrong/where the issue is, please let me know. Hopefully it's something simple and stupid.
import java.awt.*;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.geom.*;
import java.awt.image.BufferedImage;
import java.io.*;
import java.util.*;
import javax.imageio.*;
import javax.swing.*;
public class Lab10 {
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
MyFrame frame = new MyFrame();
MyPanel panel = new MyPanel();
frame.add(panel);
panel.setFocusable(true);
}
}
class MyFrame extends JFrame{
MyFrame(){
setDefaultCloseOperation(EXIT_ON_CLOSE);
setVisible(true);
setSize(800,800);
setResizable(false);
}
}
class MyPanel extends JPanel{
public static final int SIZE = 4;
private int oldx = -1;
private int oldy = -1;
private final String fileName = "houseTyrell.png";
public ImageArray imageArray = new ImageArray(fileName, SIZE);
MyPanel(){
addMouseListener(new MouseAdapter(){
public void mousePressed(MouseEvent e){
if(e.getButton()==1){
if(oldx == -1){
oldx = e.getX();
oldy = e.getY();
}else{
//imageArray.swapPoints(oldx, oldy, e.getX(), e.getY());
oldx = -1;
oldy = -1;
repaint();
}
}
}
});
}
public void paintComponent(Graphics g){
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
imageArray.draw(g2);
/*Image image2;
try {
image2 = ImageIO.read(new File("houseTyrell.png"));
System.out.println("I should print");
try{
g2.drawImage(image2, 0, 0, null);
} catch(Exception my){
System.out.println("Drawing issue");
}
} catch (IOException ex) {
System.out.println("Reading issue");
}*/
}
}
class ImageArray{
private Square[][] squares;
private String fileName;
private int size;
private int w;
private int h;
public ImageArray(String fileName, int size) {
this.size = size;
this.fileName= fileName;
squares = new Square[size][size];
try {
BufferedImage image = ImageIO.read(new File(fileName));
w = image.getWidth() / size;
h = image.getHeight() / size;
for (int row = 0; row < size; row++) {
for (int col = 0; col < size; col++) {
squares[row][col] = new Square(
image.getSubimage(row * w , col * h , w, h), row, col, w, h);
}
}
} catch (Exception e) {
System.out.println("Can't open file!");
}
shuffle();
}
//TODO
public void shuffle(){
for(int i = 0; i < size * size; i++){
}
}
//TODO
public void swapPoints(int oldx, int oldy, int newx, int newy){
}
public void draw(Graphics2D g2){
for(int i = 0; i < squares.length; i++){
for(int j = 0; j < squares[0].length; j++){
Square square = squares[i][j];
square.draw(g2);
}
}
}
}
class Square{
private BufferedImage image;
private int row;
private int col;
private int x,y;
private int w;
private int h;
Square(BufferedImage image, int row, int col, int w, int h){
this.image = image;
this.row = row;
this.col = col;
this.x = row * w;
this.y = col * h;
this.w = w;
this.h = h;
}
public void draw(Graphics2D g2){
try{
g2.drawImage(image, x, y, null);
} catch (Exception my){
System.out.println("Square issue");
}
}
public BufferedImage getImage(){
return image;
}
public int getRow(){
return row;
}
public int getCol(){
return col;
}
}

You are making the frame visible BEFORE you've finished establishing UI, try calling invalidate, validate and repaint on the frame AFTER you've added the panel...
public static void main(String[] args) {
MyFrame frame = new MyFrame();
MyPanel panel = new MyPanel();
frame.add(panel);
panel.setFocusable(true);
frame.invalidate();
frame.validate();
frame.repaint();
}
Frankly, your MyFrame class is doing very little (other then making your life more difficult), I'd consider getting rid of it, maybe replace it with a builder method which returns a frame which is not visible yet...
You should also be creating your UI from within the context of the Event Dispatching Thread, which can help solve other "weird" issues.
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
MyFrame frame = new MyFrame();
MyPanel panel = new MyPanel();
frame.add(panel);
panel.setFocusable(true);
frame.invalidate();
frame.validate();
frame.repaint();
}
});
}
See Initial Threads for more details

In the main method of Class Lab10, initialize the JPanel before the JFrame and it should work.
PS: Make sure the image referenced "houseTyrell.png" exists or use a fully qualified path temporarily for testing (i.e. c://test//houseTyrell.png).

Related

Extra dummy components painted during thread execution

In a Java applet, I'm trying to slow down the painting of an image made up of parts, so I wrote a test program to get the basic concept working. I'm using a thread to draw a number of boxes one at a time instead of a timer because I want to be able to click the go button to reset the drawing process at any time.
The problem is, after drawing a box, it moves down a bit and an extra of the label shows up at the top of the screen. When the mouse moves off the button at the bottom, a dummy button also shows up at the top of the screen. The dummy button doesn't respond to clicks (only the real one at the bottom does), it's just there.
I'm still pretty new at this, so any help would be greatly appreciated.
Here's the JApplet class:
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class TestDraw extends JApplet implements ActionListener
{
private DrawPanel panel;
private JLabel lbl1;
JButton go;
Thread t;
public void init()
{
lbl1 = new JLabel("hi");
go = new JButton("GO");
go.addActionListener(this);
panel = new DrawPanel();
getContentPane().setBackground(Color.yellow);
add(lbl1, BorderLayout.NORTH);
add(panel, BorderLayout.CENTER);
add(go, BorderLayout.SOUTH);
}
public void actionPerformed(ActionEvent ae){
// tried adding these. didnt help
//panel.validate();
//panel.repaint();
//validate();
panel.resetBoxes();
repaint();
}
public void start(){
t = new Thread(panel);
t.start();
}
}
Here's the DrawPanel Class:
import java.awt.*;
import java.security.SecureRandom;
import javax.swing.*;
public class DrawPanel extends JPanel implements Runnable
{
private SecureRandom randGen = new SecureRandom();
private Box[] boxes;
private int box2draw = 0;
public DrawPanel()
{
setBackground(Color.WHITE);
boxes = new Box[5];
for (int count = 0; count < boxes.length; count++){
int x = randGen.nextInt(300);
int y = randGen.nextInt(300);
int w = randGen.nextInt(300);
int h = randGen.nextInt(300);
Color color = new Color(randGen.nextInt(256), randGen.nextInt(256), randGen.nextInt(256));
boxes[count] = new Box(x,y,w,h,color);
}
}
public void paintComponent(Graphics g)
{
boxes[box2draw].draw(g);
box2draw++;
}
public void resetBoxes(){
boxes = new Box[5];
for (int count = 0; count < boxes.length; count++){
int x = randGen.nextInt(300);
int y = randGen.nextInt(300);
int w = randGen.nextInt(300);
int h = randGen.nextInt(300);
Color color = new Color(randGen.nextInt(256), randGen.nextInt(256), randGen.nextInt(256));
boxes[count] = new Box(x,y,w,h,color);
box2draw = 0;
}
}
public void run(){
while(true){
try{
Thread.sleep(750);
}
catch(InterruptedException e){
JOptionPane.showMessageDialog(null, "interrupted");
}
repaint();
}
}
}
And finally, the Box class:
import java.awt.Color;
import java.awt.Graphics;
public class Box
{
private int x;
private int y;
private int w;
private int h;
private Color color;
public Box(int x,int y,int w,int h,Color color)
{
// initialise instance variables
this.x = x;
this.y=y;
this.w=w;
this.h = h;
this.color=color;
}
public void draw(Graphics g)
{
g.setColor(color);
g.drawRect( x, y, w, h);
}
}
Thank you for your time!

Problems:
You've got code logic within a painting method -- something that you should never do -- including your incrementing an array index. You don't have full control of when or even if this method is called and so program logic does not belong there, just painting. If you need to increment your array index, do it elsewhere, perhaps within your thread's while (true) loop. Also take care not to have the index go beyond the size of the array.
You never call the super's paintComponent method within your override, and this will prevent the component from doing housekeeping painting, probably your main problem.
If you need to display multiple items, then consider either drawing to a BufferedImage and displaying that within paintComponent, or creating a collection of Shape objects and drawing all of them within paintComponent via a for-loop.
I prefer to use the Swing-safer Swing Timer. While it doesn't matter if only calling repaint() if you want to make any other Swing calls intermittently, it makes life much easier and coding safer.
For example
package foo1;
import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Stroke;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;
import javax.swing.AbstractAction;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
public class TestDraw2 {
#SuppressWarnings("serial")
private static void createAndShowGui() {
final DrawPanel2 drawPanel = new DrawPanel2();
JButton drawButton = new JButton(new AbstractAction("Draw!") {
#Override
public void actionPerformed(ActionEvent e) {
drawPanel.resetBoxes();
}
});
JPanel btnPanel = new JPanel();
btnPanel.add(drawButton);
JFrame frame = new JFrame("TestDraw2");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(drawPanel);
frame.getContentPane().add(btnPanel, BorderLayout.PAGE_END);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
#SuppressWarnings("serial")
class DrawPanel2 extends JPanel {
private static final int BOX_COUNT = 5;
private static final int TIMER_DELAY = 750;
private static final int PREF_W = 600;
private static final int PREF_H = PREF_W;
private Random randGen = new Random();
private Box[] boxes;
private int box2draw = 0;
public DrawPanel2() {
setBackground(Color.YELLOW);
boxes = new Box[BOX_COUNT];
for (int count = 0; count < boxes.length; count++) {
int x = randGen.nextInt(300);
int y = randGen.nextInt(300);
int w = randGen.nextInt(300);
int h = randGen.nextInt(300);
Color color = new Color(randGen.nextInt(256), randGen.nextInt(256),
randGen.nextInt(256));
boxes[count] = new Box(x, y, w, h, color);
}
}
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
for (int i = 0; i < box2draw; i++) {
boxes[i].draw(g);
}
}
public void resetBoxes() {
boxes = new Box[BOX_COUNT];
for (int count = 0; count < boxes.length; count++) {
int x = randGen.nextInt(300);
int y = randGen.nextInt(300);
int w = randGen.nextInt(300);
int h = randGen.nextInt(300);
Color color = new Color(randGen.nextInt(256), randGen.nextInt(256),
randGen.nextInt(256));
boxes[count] = new Box(x, y, w, h, color);
box2draw = 0;
}
repaint();
new Timer(TIMER_DELAY, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
box2draw++;
if (box2draw > BOX_COUNT) {
box2draw = BOX_COUNT;
((Timer) e.getSource()).stop();
}
repaint();
}
}).start();
}
}

Adding ViewPort to JPanel

I would like to achieve the following for my swing project,
I was able to get this by extending a JPanel and and using JLayer.
I event tried using AlphaComposite but it didn't work.
Edit1: I think JTable or JViewport might help me to get what I want but I don't know how to use them.
Edit2: Updated the SSCCE, thank you trashgod for the suggestion.
I have made use of the Scalr library because after using getScaledInstance method of Image class, if i tried to use the getSubImage method of BufferedImage,the following exception is thrown:
java.lang.ClassCastException: sun.awt.image.ToolkitImage cannot be
cast to java.awt.image.BufferedImage
since the Image generated by getScaledInstance method is a instance of ToolkitImage so, it cannot be cast into a BufferedImage.
If you don't want to use the Scalr library,you can use the code suggested in this post to scale the BufferedImage and than use getSubImage method.
SCSE.java
import java.io.IOException;
import java.net.URL;
import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.image.BufferedImage;
import java.beans.PropertyChangeEvent;
import java.util.Random;
import javax.swing.*;
import javax.swing.plaf.LayerUI;
import org.imgscalr.Scalr;
public class SCSE {
private JFrame mainFrame;
private JPanel mainPanel;
private GridView gridView;
private JButton imgBtn, shuffleBtn;
private int gridX = -1, gridY = -1, gridWidth = -1, gridHeight = -1;
private boolean isGridEmpty = false;
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
SCSE sc = new SCSE();
sc.createGUI();
});
}
private void createGUI() {
mainFrame = new JFrame();
mainFrame.setSize(500, 500);
mainFrame.setResizable(false);
mainFrame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
mainPanel = new JPanel(new BorderLayout());
gridView = new GridView();
imgBtn = new JButton("Get-Image");
shuffleBtn = new JButton("Shuffle-ViewPort");
imgBtn.addActionListener((ActionEvent evt) -> {
try {
gridView.setImage(ImageIO.read(new URL("http://www.keenthemes.com/preview/metronic/theme/assets/global/plugins/jcrop/demos/demo_files/image1.jpg")));
} catch (IOException ex) {
System.out.println(ex);
}
});
shuffleBtn.addActionListener((ActionEvent evt) -> {
gridView.startShuffle();
});
mainPanel.add(gridView.getComponent(), BorderLayout.CENTER);
mainPanel.add(imgBtn, BorderLayout.NORTH);
mainPanel.add(shuffleBtn, BorderLayout.SOUTH);
mainFrame.add(mainPanel);
mainFrame.setLocationRelativeTo(null);
mainFrame.setVisible(true);
}
class GridView {
private Random shuffleRandom;
private RegisterUI layerUi = null;
private JLayer<JPanel> gridLayer = null;
private ImagePanel mainPanel = null;
private int gridNos = 21; //number of grids
int digit[];
private int viewportDimensions = 4; //no of rows and columns in viewport
private JLabel gridLabel[][] = new JLabel[gridNos][gridNos];
private int gridX = -1, gridY = -1, gridWidth = -1, gridHeight = -1;
private boolean isGridInitialized = false;
public GridView() {
initPersuasive();
initPanel();
initGrids();
}
private void initPanel() {
mainPanel = new ImagePanel();
mainPanel.setLayout(new GridLayout(gridNos, gridNos, 0, 0)); //creates layout to place labels in grid form
layerUi = new RegisterUI();
gridLayer = new JLayer<>(mainPanel, layerUi);
}
private void initGrids() {
for (int i = 0; i < gridNos; i++) {
for (int j = 0; j < gridNos; j++) {
gridLabel[i][j] = new JLabel();
gridLabel[i][j].setOpaque(false);
gridLabel[i][j].setName("" + (i + 1)); // Since for loop index is 0 to 80, we add 1 to the name to make it 1 to 81
mainPanel.add(gridLabel[i][j]); //add it to mainPanel
}
}
}
private void initPersuasive() {
shuffleRandom = new Random();
digit = new int[2];
}
private void random() {
digit[0] = shuffleRandom.nextInt(gridNos - viewportDimensions);
digit[1] = shuffleRandom.nextInt(gridNos - viewportDimensions);
}
public void startShuffle() {
random();
int x = gridLabel[digit[0]][digit[1]].getX();
int y = gridLabel[digit[0]][digit[1]].getY();
layerUi.placeViewport(x, y);
}
public void stopShuffle() {
layerUi.removeViewPort();
}
public void setupGridView() {
gridX = gridLabel[0][0].getX();
gridY = gridLabel[0][0].getY();
gridWidth = gridLabel[0][0].getWidth();
gridHeight = gridLabel[0][0].getHeight();
mainPanel.setValues(gridX, gridY);
layerUi.setViewSize(gridWidth * viewportDimensions, gridHeight * viewportDimensions);
}
public void setImage(BufferedImage img) {
if (!isGridInitialized) {
setupGridView();
isGridInitialized = true;
}
BufferedImage sendImg = Scalr.resize(img, Scalr.Mode.FIT_EXACT, gridWidth * gridNos, gridHeight * gridNos, Scalr.OP_ANTIALIAS);
layerUi.setupViewport(img);
mainPanel.paintImage(img);
}
public JLayer<JPanel> getComponent() {
return gridLayer;
}
}
class RegisterUI extends LayerUI<JPanel> {
private int viewX, viewY, viewWidth, viewHeight;
private boolean shuffleIsRunning = false;
private BufferedImage viewportImage = null;
private void drawPCCP(Graphics g, int w, int h) {
Graphics2D g2 = ((Graphics2D) g);
Color c = new Color(1.0f, 1.0f, 1.0f, 0.7f);
g2.setPaint(c);
g2.fillRect(0, 0, w, h);
BufferedImage highlightGrid = Scalr.pad(Scalr.crop(viewportImage, viewX, viewY, viewWidth, viewHeight), 2, Color.BLACK, Scalr.OP_ANTIALIAS);
g2.drawImage(highlightGrid, viewX, viewY, null);
g2.dispose();
}
public void paint(Graphics g, JComponent c) {
super.paint(g, c);
int w = c.getWidth();
int h = c.getHeight();
if (shuffleIsRunning) {
drawPCCP(g, w, h);
}
}
public void setupViewport(BufferedImage bi) {
viewportImage = bi;
}
public void setViewSize(int w, int h) {
viewWidth = w;
viewHeight = h;
}
public void placeViewport(int x, int y) {
viewX = x;
viewY = y;
if (!shuffleIsRunning) {
shuffleIsRunning = true;
}
firePropertyChange("shuffleui", 0, 1);
}
public void removeViewPort() {
if (!shuffleIsRunning) {
return;
}
viewX = 0;
viewY = 0;
viewWidth = 0;
viewHeight = 0;
shuffleIsRunning = false;
firePropertyChange("shuffleui", 0, 1);
}
#Override
public void applyPropertyChange(PropertyChangeEvent evt, JLayer<? extends JPanel> l) {
if ("disableui".equals(evt.getPropertyName()) || "shuffleui".equals(evt.getPropertyName())) {
l.repaint();
}
}
}
class ImagePanel extends JPanel {
private BufferedImage displayImage = null;
private int x, y;
public void setValues(int x, int y) {
this.x = x;
this.y = y;
}
public void paintImage(BufferedImage bi) {
System.out.print(bi);
displayImage = bi;
repaint(); // repaint calls paintComponent method internally
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(displayImage, x, y, this); // To Paint the image on the panel
}
}
}

Instead of using AlphaComposite directly, as shown here, try RescaleOp to alter the image's color/alpha bands, as shown in this example. This will allow you to mute the tone of the entire image as desired. Copy a portion of the original image using getSubimage() to restore the highlight.

Show video stream from multiple cameras in jpanel grids in java opencv

My current code for grid to show video stream is as follow
//Function for displaying grid window//
public void createMap(int maxX, int maxY) {
gameGrid = new JPanel(new GridLayout(maxX, maxY, 1, 1));
gameGrid.setBackground(Color.GREEN);
for (int i = 0; i < maxX; i++) {
for (int j = 0; j < maxY; j++) {
JPanel panel = new JPanel();
panel.setPreferredSize(PREF_SIZE);
String name = String.format("[%d, %d]", i, j);
panel.setName(name);
panel.setBackground(Color.black);
gameGrid.add(panel);
}
}
}
I call this function as createMap(2,2) so it create grid for 2x2(4 window).
I want to show video stream in each of these grid.
I receiving the video stream through 4 cctv cameras attached with DVR.
I used following code for Showing video streams using opencv
package cctvmonitorsystem;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.awt.image.DataBufferByte;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JButton;
// DB connectivity classes
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
import java.sql.SQLException;
import java.sql.ResultSet;
import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.highgui.Highgui;
import org.opencv.highgui.VideoCapture;
import org.opencv.imgproc.Imgproc;
import java.util.Arrays;
public class Video {
public static void main(String args[]) throws SQLException {
int maxCamNo = 4;
//create connection
DbConnect dbcon = new DbConnect();
Connection con = dbcon.openCon();
Statement stmt = con.createStatement();
String getDevice="select * from device order by d_id limit 1";
ResultSet res=stmt.executeQuery(getDevice);
// DECLARE VARIABLES FOR DEVICE ADDRESS & PORT
String devAddress = null;
int httpPort=0;
while (res.next())
{
devAddress=res.getString("d_address");
httpPort=res.getInt("d_http_port");
}
dbcon.closeCon(con); // Connection closed
VideoCapture vcam[] = new VideoCapture[maxCamNo];
System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
for (int i = 0; i < vcam.length; i++) {
try {
vcam[i] = new VideoCapture();
vcam[i].open("http://"+devAddress+":"+httpPort+"/cgi-bin/view.cgi?chn=" + i + "&u=admin&p=");
//vcam[i]=new VideoCapture(i);
} catch (Exception e) {
e.printStackTrace();
}
if (!vcam[i].isOpened()) {
System.out.println("Camera " + i + " error");
}
}
AccessVideo av = new AccessVideo(vcam);
//Initialize swing components
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(av);
//frame.setSize(1024,768);
frame.setMaximumSize(null);
frame.setExtendedState(java.awt.Frame.MAXIMIZED_BOTH);
frame.setVisible(true);
while (vcam[0].isOpened()) {
av.repaint();
}
}
}
class AccessVideo extends JPanel {
VideoCapture[] camera = new VideoCapture[6];
AccessVideo(VideoCapture[] camView) {
camera = camView;
}
public BufferedImage Mat2BufferedImage(Mat m) {
System.out.println("Channels - "+m.channels());
int type = BufferedImage.TYPE_BYTE_GRAY;
if (m.channels() > 1) {
type = BufferedImage.TYPE_3BYTE_BGR;
}
int bufferSize = m.channels() * m.cols() * m.rows();
byte[] b = new byte[bufferSize];
m.get(0, 0, b); // get all the pixels
BufferedImage img = new BufferedImage(m.cols(), m.rows(), type);
final byte[] targetPixels = ((DataBufferByte) img.getRaster().getDataBuffer()).getData();
System.arraycopy(b, 0, targetPixels, 0, b.length);
return img;
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
Mat[] mat = new Mat[camera.length];
int width=400;
int height=300;
int xpos = 0;
int ypos = 0;
int y = 1;
for (int i = 0; i < camera.length; i++) {
mat[i] = new Mat();
camera[i].read(mat[i]);
BufferedImage image = Mat2BufferedImage(mat[i]);
g.drawImage(image, xpos, ypos, width, height, null);
xpos = xpos + width;
if (y == 3) {
xpos = 0;
ypos = ypos + height;
y = 0;
}
y++;
}
}
}
Here the video streams will show according to x & y co-ordinates.
But I want to show these video streams in grids which i mention above.
Can anyone help me to resolve this issue.

I did something similar here is my code, but this is hardcoded to only 6 cameras.
This is the main function where I called the addComponentsToPane.
public static void main(String[] args) {
CamtestMonitor f = new CamtestMonitor("Monitor");
f.addWindowListener(new WindowAdapter() {
#Override
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
//Set up the content pane.
f.addComponentsToPane(f.getContentPane());
//Display the window.
f.pack();
f.setVisible(true);
}
This is the addComponentsToPane function where we add 6 different ServerUI's. Each one extends the JLabel class and implements DataListener.
public void addComponentsToPane(final Container pane) {
final JPanel jp = new JPanel();
jp.setLayout(gl);
//Set up components preferred size
jp.add(new ServerUI(8880));
jp.add(new ServerUI(8891));
jp.add(new ServerUI(8892));
jp.add(new ServerUI(8893));
jp.add(new ServerUI(8894));
jp.add(new ServerUI(8895));
jp.setPreferredSize(new Dimension(1600, 900));
//Set up the horizontal gap value
gl.setHgap(gapSize);
//Set up the vertical gap value
gl.setVgap(gapSize);
//Set up the layout of the buttons
gl.layoutContainer(jp);
pane.add(jp, BorderLayout.NORTH);
pane.add(new JSeparator(), BorderLayout.SOUTH);
}
There you have the Constructor of the ServerUI:
public ServerUI(int port) {
SocketServer server = new SocketServer(port);
server.setOnDataListener(this);
server.start();
}
Finally, here we have the overrrided function that refresh the image on each JLabel.
#Override
public void paint(Graphics g) {
synchronized (queue) {
if (queue.size() > 0) {
lastFrame = queue.poll();
}
}
if (lastFrame != null) {
g.drawImage(lastFrame, 0, 0, null);
}
}

You can have one thread for each camera, and also you extend JPanel class and override the paintComponent() method, like example below
public class MyJPanel extends JPanel {
private BufferedImage image;
public MyJPanel() {
super();
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
if (image != null) {
g2.drawImage(image, 0, 0, this.getWidth(), this.getHeight(), this);
}
}
public void refresh(BufferedImage image) {
this.image = image;
this.repaint();
}
}
public class CameraHandler implements Runnable {
VideoCapture vCapture;
MyJPanel mPanel;
public CameraHandler(VideoCapture vCapture, MyJPanel mPanel) {
this.vCapture = vCapture;
this.mPanel = mPanel;
}
public void run() {
while(vCapture.canReadFrame...) {
then convert the Mat to BufferedImage;
then call this:
mPanel.refresh(convertedImage);
}
}
}
public class MainClass {
public static void main(String[] args) {
VideoCapture vcam[] = new VideoCapture[maxCamNo];
System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
for (int i = 0; i < vcam.length; i++) {
try {
vcam[i] = new VideoCapture();
vcam[i].open("http://"+devAddress+":"+httpPort+"/cgi-bin/view.cgi?chn=" + i + "&u=admin&p=");
//vcam[i]=new VideoCapture(i);
if(vcam[i].isOpen) {
new Thread(new CameraHandler(vcam[i], and you MyJPanel reference)).start();
}
} catch (Exception e) {
e.printStackTrace();
}
if (!vcam[i].isOpened()) {
System.out.println("Camera " + i + " error");
}
}
}
}
The code above is just an example to show the way, if you use this then need to arrange the code as your need. Hope this code help you!

dynamically update JPanel background does't work

After reading image from JFilechooser, I am trying to read pixel of an image one by one and display it to JPanel after some delay in sequential manner. can't update the background of JPanel.
public class ImageMain extends JFrame implements ActionListener {
/**
*
*/
private static final long serialVersionUID = 2916361361443483318L;
private JFileChooser fc = null;
private JMenuItem item1, item2;
private BufferedImage image = null;
private JPanel panel = null;
private int width = 0;
private int height = 0;
private BorderLayout card;
private Container contentPane;
//private int loopcount = 0;
//private int counter = 0;
public ImageMain() {
JFrame frame = new JFrame("Image Extraction Tool");
frame.setExtendedState(Frame.MAXIMIZED_BOTH);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
contentPane = frame.getContentPane();
panel = new JPanel();
card = new BorderLayout();
panel.setLayout(card);
panel.setBackground(Color.white);
JMenuBar menuBar = new JMenuBar();
JMenu menu = new JMenu("Menu");
menuBar.add(menu);
item1 = new JMenuItem("Browse an image");
item2 = new JMenuItem("Exit");
item1.addActionListener(this);
item2.addActionListener(this);
menu.add(item1);
menu.add(item2);
frame.setJMenuBar(menuBar);
contentPane.add(panel);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
try {
SwingUtilities.invokeAndWait(new Runnable() {
#Override
public void run() {
ImageMain img = new ImageMain();
}
});
} catch (InvocationTargetException | InterruptedException e) {
e.printStackTrace();
}
}
#Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == item1) {
if (fc == null)
fc = new JFileChooser();
int retVal = fc.showOpenDialog(null);
if (retVal == JFileChooser.APPROVE_OPTION) {
File file = fc.getSelectedFile();
try {
image = ImageIO.read(file);
height = image.getHeight();
width = image.getWidth();
// final int[][] pixelData = new int[height * width][3];
// int[] rgb;
for (int i = 0; i < height; i++) {
for (int j = 0; j < width; j++) {
System.out.println(i + " " + j);
Color c = new Color(image.getRGB(j, i));
panel.setBackground(c);
panel.invalidate();
panel.validate();
panel.repaint();
}
}
} catch (IOException e1) {
System.out.println("IO::" + e1.getMessage());
} catch (Exception e1) {
System.out.println("Exception::" + e1.getMessage());
}
}
}
if (e.getSource() == item2) {
System.exit(0);
}
}}
Inside ActionPerformed, I got Color object by reading RGB values and then I am stuck at displaying them to JApplet. Suggestion are welcome if there is a better way to achieve this.
Thanks in advance.

The main problem is your performing a long running task within the context of the Event Dispatching Thread, which is responsible for, amongst other things, processing repaint requests.
#Override
public void actionPerformed(ActionEvent e) {
//...
// Nothing will be updated until after the
// actionPerformed method exists
for (int i = 0; i < height; i++) {
for (int j = 0; j < width; j++) {
System.out.println(i + " " + j);
Color c = new Color(image.getRGB(j, i));
panel.setBackground(c);
panel.invalidate();
panel.validate();
panel.repaint();
}
}
The other problem you have is that you are required to only modify the state of the UI from within the context of the EDT
Depending on your exact needs, you could use a SwingWorker, which would allow you to process the pixels in the background while updating the UI from within the context of the EDT, however, because SwingWorker consolidates it's updates, you could miss color changes.
A better solution might be to use a java.swing.Timer which would allow you to trigger updates at a specified period, which are triggered within the context of the EDT.
See Concurrency in Swing for more details...
Updated with example
In order to draw pixels, you need something to draw them on. Now, you could simply add each pixel you want to paint to an array and loop that array each time you need to repaint the component, but that's kind of expensive...
Instead, it would be simpler to have a backing buffer of some kind, onto which you paint the pixels and then paint that buffer to the component, which should be faster.
Basically, the allows you to supply the height and width of the expected image and then supply each pixel as you need..
public class ImagePane extends JPanel {
private BufferedImage img;
public ImagePane() {
}
public void reset(int width, int height) {
img = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
revalidate();
}
public void reset() {
img = null;
revalidate();
}
public void setPixelAt(int x, int y, int pixel) {
img.setRGB(x, y, pixel);
}
#Override
public Dimension getPreferredSize() {
return img == null ? new Dimension(200, 200) : new Dimension(img.getWidth(), img.getHeight());
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
if (img != null) {
int x = (getWidth() - img.getWidth()) / 2;
int y = (getHeight() - img.getHeight()) / 2;
g2d.drawImage(img, x, y, this);
}
g2d.dispose();
}
}
Take a look at Performing Custom Painting for more details...
Then you need some way to process the original image and update the image panel...Now, based on the updated requirements, I would use a SwingWorker, the reason for this, is that the SwingWorker can cache what is passed back to the EDT, this allows the background thread to continue processing and caching the output until the EDT (and system) is ready to process it...
public class PixelExposerWorker extends SwingWorker<Void, Pixel> {
private final BufferedImage img;
private final ImagePane imagePane;
private final List<Point> points;
public PixelExposerWorker(BufferedImage img, ImagePane imagePane) {
this.img = img;
this.imagePane = imagePane;
points = new ArrayList<>(img.getWidth() * img.getHeight());
for (int x = 0; x < img.getWidth(); x++) {
for (int y = 0; y < img.getHeight(); y++) {
points.add(new Point(x, y));
}
}
}
#Override
protected void process(List<Pixel> chunks) {
System.out.println("Publish " + chunks.size());
for (Pixel pixel : chunks) {
imagePane.setPixelAt(pixel.getX(), pixel.getY(), pixel.getColor());
}
imagePane.repaint();
}
#Override
protected Void doInBackground() throws Exception {
int pixelCount = (int) (points.size() * 0.005);
while (!points.isEmpty()) {
for (int count = 0; count < pixelCount && !points.isEmpty(); count++) {
int index = (int) (Math.random() * (points.size() - 1));
Point p = points.remove(index);
Pixel pixel = new Pixel(p.x, p.y, img.getRGB(p.x, p.y));
publish(pixel);
}
Thread.yield();
}
return null;
}
}
Basically, this SwingWorker builds a List of "pixel points", it uses the list to randomly remove points from the list, generate a virtual Pixel and publish back to the EDT for processing. The worker will process around 0.5% of the pixels at a time, meaning that the work is always trying to send a "bunch" of pixels back to the EDT, rather the one at a time.
Finally, it will yield to allow other threads to run (and the hopefully for the EDT to update it self)
An image of 650x975 takes roughly 1m and 10s to fully renderer
And the full code...
import core.util.StopWatch;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.List;
import javax.imageio.ImageIO;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.SwingWorker;
import javax.swing.Timer;
public class PixelShower implements ActionListener {
private static final long serialVersionUID = 2916361361443483318L;
private JFileChooser fc = null;
private JMenuItem item1, item2;
private BufferedImage image = null;
private ImagePane panel = null;
private int width = 0;
private int height = 0;
private BorderLayout card;
private Container contentPane;
public PixelShower() {
JFrame frame = new JFrame("Image Extraction Tool");
frame.setExtendedState(Frame.MAXIMIZED_BOTH);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
contentPane = frame.getContentPane();
panel = new ImagePane();
card = new BorderLayout();
panel.setLayout(card);
panel.setBackground(Color.white);
JMenuBar menuBar = new JMenuBar();
JMenu menu = new JMenu("Menu");
menuBar.add(menu);
item1 = new JMenuItem("Browse an image");
item2 = new JMenuItem("Exit");
item1.addActionListener(this);
item2.addActionListener(this);
menu.add(item1);
menu.add(item2);
frame.setJMenuBar(menuBar);
contentPane.add(panel);
frame.setVisible(true);
}
public static void main(String[] args) {
try {
SwingUtilities.invokeAndWait(new Runnable() {
#Override
public void run() {
PixelShower img = new PixelShower();
}
});
} catch (InvocationTargetException | InterruptedException e) {
e.printStackTrace();
}
}
#Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == item1) {
if (fc == null) {
fc = new JFileChooser();
}
int retVal = fc.showOpenDialog(null);
if (retVal == JFileChooser.APPROVE_OPTION) {
File file = fc.getSelectedFile();
try {
image = ImageIO.read(file);
panel.reset(image.getWidth(), image.getHeight());
PixelExposerWorker worker = new PixelExposerWorker(image, panel);
worker.execute();
} catch (IOException e1) {
e1.printStackTrace();
} catch (Exception e1) {
e1.printStackTrace();
}
}
}
if (e.getSource() == item2) {
System.exit(0);
}
}
public class ImagePane extends JPanel {
private BufferedImage img;
public ImagePane() {
}
public void reset(int width, int height) {
img = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
revalidate();
}
public void reset() {
img = null;
revalidate();
}
public void setPixelAt(int x, int y, int pixel) {
img.setRGB(x, y, pixel);
}
#Override
public Dimension getPreferredSize() {
return img == null ? new Dimension(200, 200) : new Dimension(img.getWidth(), img.getHeight());
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
if (img != null) {
int x = (getWidth() - img.getWidth()) / 2;
int y = (getHeight() - img.getHeight()) / 2;
g2d.drawImage(img, x, y, this);
}
g2d.dispose();
}
}
public class Pixel {
private int x;
private int y;
private int color;
public Pixel(int x, int y, int color) {
this.x = x;
this.y = y;
this.color = color;
}
public int getColor() {
return color;
}
public int getX() {
return x;
}
public int getY() {
return y;
}
}
public class PixelExposerWorker extends SwingWorker<Void, Pixel> {
private final BufferedImage img;
private final ImagePane imagePane;
private final List<Point> points;
public PixelExposerWorker(BufferedImage img, ImagePane imagePane) {
this.img = img;
this.imagePane = imagePane;
points = new ArrayList<>(img.getWidth() * img.getHeight());
for (int x = 0; x < img.getWidth(); x++) {
for (int y = 0; y < img.getHeight(); y++) {
points.add(new Point(x, y));
}
}
}
#Override
protected void process(List<Pixel> chunks) {
System.out.println("Publish " + chunks.size());
for (Pixel pixel : chunks) {
imagePane.setPixelAt(pixel.getX(), pixel.getY(), pixel.getColor());
}
imagePane.repaint();
}
#Override
protected Void doInBackground() throws Exception {
StopWatch sw = StopWatch.newInstance().start();
int pixelCount = (int) (points.size() * 0.005);
System.out.println("pixelCount = " + pixelCount + "; " + points.size());
while (!points.isEmpty()) {
StopWatch sw1 = StopWatch.newInstance().start();
for (int count = 0; count < pixelCount && !points.isEmpty(); count++) {
int index = (int) (Math.random() * (points.size() - 1));
Point p = points.remove(index);
Pixel pixel = new Pixel(p.x, p.y, img.getRGB(p.x, p.y));
publish(pixel);
}
Thread.yield();
}
System.out.println("Took " + sw.stop());
return null;
}
}
}

The method about ImageIcons does not work

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Cards extends JFrame {
private GridLayout grid1;
JButton []bt=new JButton[52];
ImageIcon tail=new ImageIcon(getClass().getResource("b1fv.png"));
ImageIcon ori;
public Cards(){
grid1=new GridLayout(7,9,2,2);
setLayout(grid1);
for(int i=0;i<bt.length;i++){
ImageIcon c=new ImageIcon(getClass().getResource(i+1+".png"));
bt[i]=new JButton(c);
bt[i].addActionListener(new RatingMouseListener(i));
add( bt[i]);
}
}
public static void main(String[] args){
Cards frame=new Cards();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(1400,700);
frame.setVisible(true);
}
private class RatingMouseListener implements ActionListener {
private int index=0;
public RatingMouseListener(int index) {
this.index = index;
}
public void actionPerformed(ActionEvent e) {
System.out.println("Mouse entered for rating " + index);
ori=new ImageIcon(getClass().getResource(index+1+".png"));
if (bt[index].getIcon()==ori)
bt[index].setIcon(tail);
else
bt[index].setIcon(ori);
}
}
}
When I run this, I expect that the ori and the tail should exchange. But they don't. Can someone help me?

This would be best done via a description tag.
Basically, set the description to the images like below, then swap them if they have the same description.
ori.setDescription("ori");
tail.setDescription("tail");
if ("ori".equals((ImageIcon)bt[index].getIcon()).getDescription())
// The rest is how you had it.

I'm guessing that you want to have playing cards that flip when clicked (but I'm not sure). Again, I recommend that you create your ImageIcons once and at the start of the program. Then you can easily compare if one icon is the same as another by using the equal(...) method or even in this situation the == operator. For example, please have a look at and run this code for an example of what I mean:
import java.awt.GridLayout;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import javax.imageio.ImageIO;
import javax.swing.*;
public class CardsDeck {
public static final String RANKS = "a23456789tjqk";
public static final String SUITS = "cdhs";
public static final String CARDS_IMG_PATH = "http://math.hws.edu/javanotes/source/cards.png";
private static final int BACK_RANK = 2;
private static final int BACK_SUIT = SUITS.length();
private static final String ICON = "icon";
private JPanel panel = new JPanel();
private List<ImageIcon> iconList = new ArrayList<ImageIcon>();
private ImageIcon cardBack;
public CardsDeck() {
try {
URL imgUrl = new URL(CARDS_IMG_PATH);
BufferedImage img = ImageIO.read(imgUrl);
double cardWidth = (double) img.getWidth() / RANKS.length();
double cardHeight = (double) img.getHeight() / (SUITS.length() + 1);
int w = (int) cardWidth;
int h = (int) cardHeight;
for (int rank = 0; rank < RANKS.length(); rank++) {
for (int suit = 0; suit < SUITS.length(); suit++) {
int x = (int) (rank * cardWidth);
int y = (int) (suit * cardHeight);
BufferedImage subImg = img.getSubimage(x, y, w, h);
ImageIcon icon = new ImageIcon(subImg);
iconList.add(icon);
}
}
int x = (int) (BACK_RANK * cardWidth);
int y = (int) (BACK_SUIT * cardHeight);
BufferedImage subImg = img.getSubimage(x, y, w, h);
cardBack = new ImageIcon(subImg);
int hgap = 5;
int vgap = hgap;
panel.setLayout(new GridLayout(SUITS.length(), RANKS.length(), hgap, vgap));
panel.setBorder(BorderFactory.createEmptyBorder(vgap, hgap, vgap, hgap));
MouseListener mouseListener = new MouseAdapter() {
#Override
public void mousePressed(MouseEvent e) {
JLabel label = (JLabel) e.getSource();
Icon currentIcon = label.getIcon();
if (currentIcon.equals(cardBack)) {
Icon icon = (Icon) label.getClientProperty(ICON);
label.setIcon(icon);
} else {
label.setIcon(cardBack);
}
}
};
Collections.shuffle(iconList);
for (int i = 0; i < iconList.size(); i++) {
JLabel label = new JLabel(cardBack);
label.putClientProperty(ICON, iconList.get(i));
label.addMouseListener(mouseListener);
panel.add(label);
}
} catch (MalformedURLException e) {
e.printStackTrace();
System.exit(-1);
} catch (IOException e) {
e.printStackTrace();
System.exit(-1);
}
}
private JComponent getPanel() {
return panel;
}
private static void createAndShowGui() {
CardsDeck cardsDeck = new CardsDeck();
JFrame frame = new JFrame("CardsDeck");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(cardsDeck.getPanel());
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
If run, it will show a 13 x 4 array of cards that can be flipped by clicking on them:

We Keep Coding

Java is a programming language and computing platform first released by Sun Microsystems in 1995.

Image not showing up in Swing? - java

In the main method of Class Lab10, initialize the JPanel before the JFrame and it should work. PS: Make sure the image referenced "houseTyrell.png" exists or use a fully qualified path temporarily for testing (i.e. c://test//houseTyrell.png).

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Show video stream from multiple cameras in jpanel grids in java opencv

dynamically update JPanel background does't work

The method about ImageIcons does not work

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