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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;
}
}
}

How to obtain new height and width of resized image?

i am trying to save new resized image but i exactly don't have any idea to get the new height & width or axis of image.
if anyone knows it then i will be so thankful.
my code to resize image or to scale image is as follows :
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Cursor;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.RenderingHints;
import java.awt.Transparency;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class ImageViewer {
public static void main(String[] args) {
new ImageViewer();
}
public ImageViewer() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new ViewPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class ViewPane extends JPanel {
public ViewPane() {
setLayout(null);
ImagePane imagePane = new ImagePane();
imagePane.setSize(imagePane.getPreferredSize());
imagePane.setLocation(0, 0);
add(imagePane);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
}
public static class ImagePane extends JPanel {
private BufferedImage bg;
private BufferedImage scaled;
public ImagePane() {
try {
bg = ImageIO.read(new File("src.jpg"));
scaled = getScaledInstanceToFit(bg, new Dimension(100, 100));
} catch (IOException ex) {
ex.printStackTrace();
}
setBackground(Color.BLACK);
MouseHandler handler = new MouseHandler();
addMouseListener(handler);
addMouseMotionListener(handler);
}
#Override
public Dimension getPreferredSize() {
return bg == null ? new Dimension(200, 200) : new Dimension(scaled.getWidth(), scaled.getHeight());
}
#Override
public void invalidate() {
super.invalidate();
scaled = getScaledInstanceToFit(bg, getSize());
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
int x = (getWidth() - scaled.getWidth()) / 2;
int y = (getHeight() - scaled.getHeight()) / 2;
g2d.drawImage(scaled, x, y, this);
g2d.dispose();
}
public enum MouseAction {
Move(Cursor.getPredefinedCursor(Cursor.MOVE_CURSOR)),
ResizeSouth(Cursor.getPredefinedCursor(Cursor.S_RESIZE_CURSOR)),
ResizeNorth(Cursor.getPredefinedCursor(Cursor.N_RESIZE_CURSOR)),
ResizeEast(Cursor.getPredefinedCursor(Cursor.E_RESIZE_CURSOR)),
ResizeWest(Cursor.getPredefinedCursor(Cursor.W_RESIZE_CURSOR)),
ResizeNorthEast(Cursor.getPredefinedCursor(Cursor.NE_RESIZE_CURSOR)),
ResizeNorthWest(Cursor.getPredefinedCursor(Cursor.NW_RESIZE_CURSOR)),
ResizeSouthEast(Cursor.getPredefinedCursor(Cursor.SE_RESIZE_CURSOR)),
ResizeSouthWest(Cursor.getPredefinedCursor(Cursor.SW_RESIZE_CURSOR));
private Cursor cursor;
private MouseAction(Cursor cursor) {
this.cursor = cursor;
}
public Cursor getCursor() {
return cursor;
}
}
public class MouseHandler extends MouseAdapter {
private MouseAction action;
private Point clickPoint;
private Point offset;
private boolean ignoreMoves;
protected void updateAction(MouseEvent e) {
int x = e.getX();
int y = e.getY();
int width = getWidth();
int height = getHeight();
if (x < 10 && y < 10) {
action = MouseAction.ResizeNorthWest;
} else if (x > width - 10 && y < 10) {
action = MouseAction.ResizeNorthWest;
} else if (y < 10) {
action = MouseAction.ResizeNorth;
} else if (x < 10 && y > height - 10) {
action = MouseAction.ResizeSouthWest;
} else if (x > width - 10 && y > height - 10) {
action = MouseAction.ResizeSouthEast;
} else if (y > height - 10) {
action = MouseAction.ResizeSouth;
} else if (x < 10) {
action = MouseAction.ResizeWest;
} else if (x > width - 10) {
action = MouseAction.ResizeEast;
} else {
action = MouseAction.Move;
}
setCursor(action.getCursor());
}
#Override
public void mouseMoved(MouseEvent e) {
if (!ignoreMoves) {
updateAction(e);
}
}
#Override
public void mousePressed(MouseEvent e) {
updateAction(e);
ignoreMoves = true;
clickPoint = e.getPoint();
}
#Override
public void mouseReleased(MouseEvent e) {
clickPoint = null;
ignoreMoves = false;
}
#Override
public void mouseDragged(MouseEvent e) {
switch (action) {
case Move: {
Point p = e.getPoint();
p.x -= clickPoint.x;
p.y -= clickPoint.y;
p = SwingUtilities.convertPoint(ImagePane.this, p, getParent());
setLocation(p);
}
break;
case ResizeWest: {
Point p = e.getPoint();
int xDelta = p.x - clickPoint.x;
int width = getWidth() - xDelta;
int x = getX() + xDelta;
setSize(width, getHeight());
setLocation(x, getY());
revalidate();
}
break;
case ResizeEast: {
Point p = e.getPoint();
int xDelta = p.x - clickPoint.x;
int width = getWidth() + xDelta;
setSize(width, getHeight());
revalidate();
clickPoint = p;
}
break;
case ResizeNorth: {
Point p = e.getPoint();
int yDelta = p.y - clickPoint.y;
int height = getHeight() - yDelta;
int y = getY() + yDelta;
setSize(getWidth(), height);
setLocation(getX(), y);
revalidate();
}
break;
case ResizeSouth: {
Point p = e.getPoint();
int yDelta = p.y - clickPoint.y;
int height = getHeight() + yDelta;
setSize(getWidth(), height);
revalidate();
clickPoint = p;
}
break;
}
}
#Override
public void mouseExited(MouseEvent e) {
}
}
}
public static BufferedImage getScaledInstanceToFit(BufferedImage img, Dimension size) {
double scaleFactor = getScaleFactorToFit(img, size);
return getScaledInstance(img, scaleFactor);
}
public static BufferedImage getScaledInstance(BufferedImage img, double dScaleFactor) {
BufferedImage imgBuffer = null;
imgBuffer = getScaledInstance(img, dScaleFactor, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
return imgBuffer;
}
protected static BufferedImage getScaledInstance(BufferedImage img, double dScaleFactor, Object hint) {
BufferedImage imgScale = img;
int iImageWidth = (int) Math.round(img.getWidth() * dScaleFactor);
int iImageHeight = (int) Math.round(img.getHeight() * dScaleFactor);
if (dScaleFactor <= 1.0d) {
imgScale = getScaledDownInstance(img, iImageWidth, iImageHeight, hint);
} else {
imgScale = getScaledUpInstance(img, iImageWidth, iImageHeight, hint);
}
return imgScale;
}
protected static BufferedImage getScaledDownInstance(BufferedImage img,
int targetWidth,
int targetHeight,
Object hint) {
// System.out.println("Scale down...");
int type = (img.getTransparency() == Transparency.OPAQUE)
? BufferedImage.TYPE_INT_RGB : BufferedImage.TYPE_INT_ARGB;
BufferedImage ret = (BufferedImage) img;
if (targetHeight > 0 || targetWidth > 0) {
int w, h;
// Use multi-step technique: start with original size, then
// scale down in multiple passes with drawImage()
// until the target size is reached
w = img.getWidth();
h = img.getHeight();
do {
if (w > targetWidth) {
w /= 2;
if (w < targetWidth) {
w = targetWidth;
}
}
if (h > targetHeight) {
h /= 2;
if (h < targetHeight) {
h = targetHeight;
}
}
BufferedImage tmp = new BufferedImage(Math.max(w, 1), Math.max(h, 1), type);
Graphics2D g2 = tmp.createGraphics();
g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION, hint);
g2.drawImage(ret, 0, 0, w, h, null);
g2.dispose();
ret = tmp;
} while (w != targetWidth || h != targetHeight);
} else {
ret = new BufferedImage(1, 1, type);
}
return ret;
}
protected static BufferedImage getScaledUpInstance(BufferedImage img,
int targetWidth,
int targetHeight,
Object hint) {
int type = BufferedImage.TYPE_INT_ARGB;
BufferedImage ret = (BufferedImage) img;
int w, h;
w = img.getWidth();
h = img.getHeight();
do {
if (w < targetWidth) {
w *= 2;
if (w > targetWidth) {
w = targetWidth;
}
}
if (h < targetHeight) {
h *= 2;
if (h > targetHeight) {
h = targetHeight;
}
}
BufferedImage tmp = new BufferedImage(w, h, type);
Graphics2D g2 = tmp.createGraphics();
g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION, hint);
g2.drawImage(ret, 0, 0, w, h, null);
g2.dispose();
ret = tmp;
tmp = null;
} while (w != targetWidth || h != targetHeight);
return ret;
}
public static double getScaleFactorToFit(BufferedImage img, Dimension size) {
double dScale = 1;
if (img != null) {
int imageWidth = img.getWidth();
int imageHeight = img.getHeight();
dScale = getScaleFactorToFit(new Dimension(imageWidth, imageHeight), size);
}
return dScale;
}
public static double getScaleFactorToFit(Dimension original, Dimension toFit) {
double dScale = 1d;
if (original != null && toFit != null) {
double dScaleWidth = getScaleFactor(original.width, toFit.width);
double dScaleHeight = getScaleFactor(original.height, toFit.height);
dScale = Math.min(dScaleHeight, dScaleWidth);
}
return dScale;
}
public static double getScaleFactor(int iMasterSize, int iTargetSize) {
double dScale = 1;
if (iMasterSize > iTargetSize) {
dScale = (double) iTargetSize / (double) iMasterSize;
} else {
dScale = (double) iTargetSize / (double) iMasterSize;
}
return dScale;
}
}
i can also move my image easily and also make alteration in size, but now i want to save new image but i have to get first of all its new height and width , if i will get it then i will easily save it.
anyone can assist me ???

Depending on what it's you want to achieve, I would be tempted to add a method to the ImagePane called (something like) save...
public void save(String path, String name) throws IOException {
if (scaled != null) {
name += scaled.getWidth() + "x" + scaled.getHeight();
ImageIO.write(scaled, "png", new File(path + File.separator + name + ".png"));
} else {
throw new NullPointerException("Scaled instance is null");
}
}
Take a look at Writing/Saving an Image
You could also simply pass back a scaled instance based on the ImagePane's state...
public BufferedImage getScaledInstance() {
return getScaledInstanceToFit(bg, getSize());
}
I wouldn't return the scaled object because you don't want people messing with it if you can help it...

Position Image in any Screen Resolution

I have a problem with my program. Every time when I change my screen resolution, my image starts to move out of position. Any suggestions on how to make my image stay in the same location even though I change to any other resolution?
p2 = new JPanel();
p2.setLayout(new FlowLayout());
ImageIcon img2 = new ImageIcon("C:\\Drum\\Invisible4.png");
jbtn2 = new JLabel(img2);
p2.add(jbtn2);
add(jbtn2);
jbtn2.setSize(jbtn2.getPreferredSize());
jbtn2.setLocation(140, 380);

I prefer to always try and work within boundaries of the framework where I can, it makes life generally easier in the long run.
Swing has begin designed to work with LayoutManagers, this means that the way that Swing updates it's components and communicates these changes is based on the use of the LayoutManagers (more or less).
The following example uses pieces from Java: maintaining aspect ratio of JPanel background image to scale the images and a PropertionalLayoutManager which is designed to try and scale not only the size, but also the position of the components based on the size of the parent container.
The PropertionalLayoutManager demonstrated here will try and layout the components around the center of the parent container. You can change this, but it looks weird - IMHO
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.LayoutManager2;
import java.awt.RenderingHints;
import java.awt.Transparency;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.util.Map;
import java.util.WeakHashMap;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class Drums {
protected static BufferedImage SYMBOL;
protected static BufferedImage DRUM;
public static void main(String[] args) {
new Drums();
}
public Drums() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
public TestPane() {
setLayout(new PropertionalLayoutManager(400, 400));
add(new Symbol(), new PropertionalConstraint(0f, 0));
add(new Symbol(), new PropertionalConstraint(0.67f, 0));
add(new Symbol(), new PropertionalConstraint(0f, 0.4675f));
add(new Symbol(), new PropertionalConstraint(0.67f, 0.4675f));
add(new Drum(), new PropertionalConstraint(0.205f, 0.1f));
add(new Drum(), new PropertionalConstraint(0.5f, 0.1f));
add(new Drum(), new PropertionalConstraint(0f, 0.33f));
add(new Drum(), new PropertionalConstraint(0.705f, 0.33f));
}
}
public class PropertionalConstraint {
private float x;
private float y;
public PropertionalConstraint(float x, float y) {
this.x = x;
this.y = y;
}
public float getX() {
return x;
}
public float getY() {
return y;
}
}
public class PropertionalLayoutManager implements LayoutManager2 {
private Map<Component, PropertionalConstraint> constraints;
private Dimension defaultSize;
public PropertionalLayoutManager(int defaultWidth, int defaultHeight) {
constraints = new WeakHashMap<>(25);
defaultSize = new Dimension(defaultWidth, defaultHeight);
}
#Override
public void addLayoutComponent(Component comp, Object constraint) {
if (constraint instanceof PropertionalConstraint) {
constraints.put(comp, ((PropertionalConstraint) constraint));
}
}
#Override
public Dimension maximumLayoutSize(Container target) {
return preferredLayoutSize(target);
}
#Override
public float getLayoutAlignmentX(Container target) {
return 0.5f;
}
#Override
public float getLayoutAlignmentY(Container target) {
return 0.5f;
}
#Override
public void invalidateLayout(Container target) {
}
#Override
public void addLayoutComponent(String name, Component comp) {
}
#Override
public void removeLayoutComponent(Component comp) {
constraints.remove(comp);
}
#Override
public Dimension preferredLayoutSize(Container parent) {
return defaultSize;
}
#Override
public Dimension minimumLayoutSize(Container parent) {
return preferredLayoutSize(parent);
}
#Override
public void layoutContainer(Container parent) {
int width = parent.getWidth();
int height = parent.getHeight();
double dScaleWidth = getScaleFactor(defaultSize.width, width);
double dScaleHeight = getScaleFactor(defaultSize.height, height);
double scaleSize = Math.min(dScaleHeight, dScaleWidth);
int minRange = Math.min(width, height);
if (width > 0 && height > 0) {
int maxY = 0;
int maxX = 0;
for (Component comp : parent.getComponents()) {
PropertionalConstraint p = constraints.get(comp);
if (p != null) {
Dimension prefSize = comp.getPreferredSize();
prefSize.width *= scaleSize;
prefSize.height *= scaleSize;
int x = Math.round(minRange * p.getX());
int y = Math.round(minRange * p.getY());
comp.setBounds(x, y, prefSize.width, prefSize.height);
maxX = Math.max(maxX, x + prefSize.width);
maxY = Math.max(maxY, y + prefSize.height);
} else {
comp.setBounds(0, 0, 0, 0);
}
}
for (Component comp : parent.getComponents()) {
System.out.println("maxX = " + maxX);
System.out.println("maxY = " + maxY);
if (comp.getWidth() > 0 && comp.getHeight() > 0) {
int x = ((width - maxX) / 2) + comp.getX();
int y = ((height - maxY) / 2) + comp.getY();
comp.setLocation(x, y);
}
}
} else {
for (Component comp : parent.getComponents()) {
comp.setBounds(0, 0, 0, 0);
}
}
}
}
public abstract class AbstractKitPiecePane extends JPanel {
private BufferedImage scaled;
public AbstractKitPiecePane() {
setOpaque(false);
}
public abstract BufferedImage getKitImage();
#Override
public Dimension getPreferredSize() {
return new Dimension(getKitImage().getWidth(), getKitImage().getHeight());
}
#Override
public void invalidate() {
super.invalidate();
if (getWidth() > 0 && getHeight() > 0) {
scaled = getScaledInstanceToFit(getKitImage(), getSize());
} else {
scaled = null;
}
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (scaled != null) {
int x = (getWidth() - scaled.getWidth()) / 2;
int y = (getHeight() - scaled.getHeight()) / 2;
g.drawImage(scaled, x, y, this);
}
}
}
public class Drum extends AbstractKitPiecePane {
#Override
public BufferedImage getKitImage() {
return DRUM;
}
}
public class Symbol extends AbstractKitPiecePane {
#Override
public BufferedImage getKitImage() {
return SYMBOL;
}
}
protected static BufferedImage getScaledInstance(BufferedImage img, double dScaleFactor) {
BufferedImage imgScale = img;
int iImageWidth = (int) Math.round(img.getWidth() * dScaleFactor);
int iImageHeight = (int) Math.round(img.getHeight() * dScaleFactor);
if (dScaleFactor <= 1.0d) {
imgScale = getScaledDownInstance(img, iImageWidth, iImageHeight, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
} else {
imgScale = getScaledUpInstance(img, iImageWidth, iImageHeight, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
}
return imgScale;
}
protected static BufferedImage getScaledDownInstance(BufferedImage img,
int targetWidth,
int targetHeight,
Object hint) {
// System.out.println("Scale down...");
int type = (img.getTransparency() == Transparency.OPAQUE)
? BufferedImage.TYPE_INT_RGB : BufferedImage.TYPE_INT_ARGB;
BufferedImage ret = (BufferedImage) img;
if (targetHeight > 0 || targetWidth > 0) {
int w, h;
w = img.getWidth();
h = img.getHeight();
do {
if (w > targetWidth) {
w /= 2;
if (w < targetWidth) {
w = targetWidth;
}
}
if (h > targetHeight) {
h /= 2;
if (h < targetHeight) {
h = targetHeight;
}
}
BufferedImage tmp = new BufferedImage(Math.max(w, 1), Math.max(h, 1), type);
Graphics2D g2 = tmp.createGraphics();
g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION, hint);
g2.drawImage(ret, 0, 0, w, h, null);
g2.dispose();
ret = tmp;
} while (w != targetWidth || h != targetHeight);
} else {
ret = new BufferedImage(1, 1, type);
}
return ret;
}
protected static BufferedImage getScaledUpInstance(BufferedImage img,
int targetWidth,
int targetHeight,
Object hint) {
int type = BufferedImage.TYPE_INT_ARGB;
BufferedImage ret = (BufferedImage) img;
int w, h;
w = img.getWidth();
h = img.getHeight();
do {
if (w < targetWidth) {
w *= 2;
if (w > targetWidth) {
w = targetWidth;
}
}
if (h < targetHeight) {
h *= 2;
if (h > targetHeight) {
h = targetHeight;
}
}
BufferedImage tmp = new BufferedImage(w, h, type);
Graphics2D g2 = tmp.createGraphics();
g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION, hint);
g2.drawImage(ret, 0, 0, w, h, null);
g2.dispose();
ret = tmp;
tmp = null;
} while (w != targetWidth || h != targetHeight);
return ret;
}
public static BufferedImage getScaledInstanceToFit(BufferedImage img, Dimension size) {
double scaleFactor = getScaleFactorToFit(img, size);
return getScaledInstance(img, scaleFactor);
}
public static double getScaleFactorToFit(BufferedImage img, Dimension size) {
double dScale = 1;
if (img != null) {
int imageWidth = img.getWidth();
int imageHeight = img.getHeight();
dScale = getScaleFactorToFit(new Dimension(imageWidth, imageHeight), size);
}
return dScale;
}
public static double getScaleFactorToFit(Dimension original, Dimension toFit) {
double dScale = 1d;
if (original != null && toFit != null) {
double dScaleWidth = getScaleFactor(original.width, toFit.width);
double dScaleHeight = getScaleFactor(original.height, toFit.height);
dScale = Math.min(dScaleHeight, dScaleWidth);
}
return dScale;
}
public static double getScaleFactor(int iMasterSize, int iTargetSize) {
double dScale = 1;
if (iMasterSize > iTargetSize) {
dScale = (double) iTargetSize / (double) iMasterSize;
} else {
dScale = (double) iTargetSize / (double) iMasterSize;
}
return dScale;
}
static {
try {
SYMBOL = ImageIO.read(new File("Symbol.png"));
} catch (IOException ex) {
ex.printStackTrace();
}
try {
DRUM = ImageIO.read(new File("Drum.png"));
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
And the images used within the program, for your enjoyment. They live in the same directory the program is run from

create a percentage/ratio of the "normal" screen size to what it currently is and multiply that by the pos. Example if the screen size you are working with was 400x600
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
double width = screenSize.getWidth();
double height = screenSize.getHeight();
double widthRat = width/600
double heightRat = height/400
then
jbtn2.setLocation(140*widthRat, 380*heightRat);
that way say the screen size was doubled to 1200x800 widthRat would = 2 and double the position. This is kind of a sloppy example but gives the idea

I prefer to use Absolute layout. And here are the codes which should work for you.
Toolkit toolkit=Toolkit.getDefaultToolkit();
JPanel1.setSize(toolkit.getScreenSize().width, toolkit.getScreenSize().height);
int w=toolkit.getScreenSize().width;
int h=toolkit.getScreenSize().height;
JPanel1.setBounds(0, 0, w, h);
This code will fetch the current resolution of your computer...

Custom Java Component Not Drawn Correctly

I have a custom button that is not being drawn properly. It shows up as a dot in the upper left hand corner. I have three classes. One for the button, one for the menu or drawing of several buttons and a main class that calls the menu.
Class 1 - button
#Override
protected void paintComponent(Graphics g) {
g.setColor(Color.white);
Graphics2D g2d = (Graphics2D) g;
g2d.drawImage(img, this.x, this.y,this.getWidth(), this.getHeight(), null);
g2d.setFont(this.font);
g2d.drawString(this.label, x, y);
}
Class 2 - menu
public void draw(Graphics g, int width, int height) {
int x, y;
for(int i = 0; i < buttons.length; i++) {
x = (int) (width / 2 - buttons[i].getWidth() / 2);
y = (int) (height / 2 - buttons[i].getHeight() / 2);
buttons[i].setBounds(x, y + (i*60), buttons[i].getWidth(), buttons[i].getHeight());
buttons[i].paintComponent(g);
}
}
Class 3 - main
if(gMenu != null) {
gMenu.draw(g, gWindow.getWidth(), gWindow.getHeight());
}
Edit: To clarify what I'm trying to do is create a popup menu with a few custom buttons (components).
Edit: I got them to draw, but the mouse listener doesn't work.
here is the menu class
public class Menu extends JComponent {
GameWindow window;
public Menu(GameWindow window) {
this.window = window;
this.setVisible(true);
}
public void addChildToPanel(JComponent child) {
int width = (int) getWidth();
if(child.getWidth() > width) {
width = child.getWidth();
}
int height = (int) getHeight();
height += child.getHeight();
setSize(width, height);
Dimension screen = new Dimension(window.getWidth(), window.getHeight());
int x = (screen.width - width) / 2;
int y = (screen.height - height) / 2;
setBounds(x, y, width, height);
}
}
Here is the button class
public class MenuButton extends JComponent implements MouseListener {
private BufferedImage img;
private BufferedImage img_h;
private int x, y;
private String label;
private Font font;
private int state = 0;
// state 0 = normal
// state 1 = highlight
// state 2 = pressed
public MenuButton(BufferedImage img, BufferedImage img_h, String label, Font font) {
this.setPreferredSize(new Dimension(img.getWidth(), img.getHeight()));
this.img_h = img_h;
this.img = img;
this.label = label;
this.font = font;
setVisible(true);
setBounds(0, 0, img.getWidth(), img.getHeight());
this.addMouseListener(this);
}
#Override
protected void paintComponent(Graphics g) {
g.setColor(Color.white);
Graphics2D g2d = (Graphics2D) g;
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
switch (state) {
case 0:
g2d.drawImage(img, this.getBounds().x, this.getBounds().y,this.getWidth(), this.getHeight(), null);
break;
case 1:
g2d.drawImage(img_h, this.getBounds().x, this.getBounds().y,this.getWidth(), this.getHeight(), null);
break;
case 2:
g2d.drawImage(img, this.x, this.y,this.getWidth(), this.getHeight(), null);
break;
}
g2d.setFont(this.font);
int size = g2d.getFontMetrics(font).stringWidth(this.label);
int x = this.getBounds().x + this.getWidth() - 20 - size;
int y = this.getBounds().y + 29;
g2d.drawString(this.label,x, y);
}
public void setState(int state) {
this.state = state;
}
#Override
public void mouseClicked(MouseEvent e) {
}
#Override
public void mouseEntered(MouseEvent e) {
setState(1);
}
#Override
public void mouseExited(MouseEvent e) {
setState(0);
}
#Override
public void mousePressed(MouseEvent e) {
setState(2);
}
#Override
public void mouseReleased(MouseEvent e) {
setState(1);
}
}
Child class that I call draw on
public class PauseMenu extends Menu {
private int width;
private int height;
private MenuButton[] buttons = new MenuButton[4];
public PauseMenu(GameWindow window) {
super(window);
Font font = null;
BufferedImage img = null;
BufferedImage img_h = null;
try {
InputStream is = getClass().getResourceAsStream("/fonts/ALDOPC.ttf");
font = Font.createFont(Font.TRUETYPE_FONT, is).deriveFont(Font.PLAIN, 24f);
GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
ge.registerFont(font);
img = ImageIO.read(getClass().getResourceAsStream("/gui/bg_menu_button_round.png"));
img_h = ImageIO.read(getClass().getResourceAsStream("/gui/bg_menu_button_round_highlight.png"));
}
catch(Exception e)
{
System.out.print("Failed to load resources");
System.out.println();
}
MenuButton resume = new MenuButton(img, img_h, "CONTINUE", font);
final MenuButton quit = new MenuButton(img, img_h, "QUIT", font);
MenuButton vid = new MenuButton(img, img_h, "VIDEO", font);
MenuButton sound = new MenuButton(img, img_h, "SOUND", font);
buttons[0] = resume;
buttons[1] = vid;
buttons[2] = sound;
buttons[3] = quit;
for(int i = 0; i < buttons.length; i++) {
int x = (window.getWidth() - img.getWidth()) / 2;
int y = (window.getHeight() - img.getHeight()) / 2;
buttons[i].setBounds(x, y + (i * img.getHeight()), img.getWidth(), img.getHeight());
this.addChildToPanel(buttons[i]);
}
}
public void draw(Graphics g) {
for(int i = 0; i < buttons.length; i++)
buttons[i].paintComponent(g);
}
}

How to edit a curve in java

I am making a Java program which is able to draw a curve on JPanel on mouse events.
Now I want to ask after drawing that curve, how can I edit that curve?
This is my Java program:
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.QuadCurve2D;
import java.awt.image.BufferedImage;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.Vector;
import javax.swing.*;
public class MouseTestHovercraft extends JPanel {
private static final int PREF_W = 600;
private static final int PREF_H = PREF_W;
private static final int MAX_CLR = 5;
private static final Color CURRENT_LIST_COLOR = new Color(190, 190, 255);
private List<Color> colors = new ArrayList<Color>();
private boolean tracking = false;
private List<Point> currentList = null;
private BufferedImage bufferedImage = new BufferedImage(PREF_W, PREF_H,
BufferedImage.TYPE_INT_ARGB);
private Random random = new Random();
This contructor is used to change the color of the curve as soon as mouse is released.
public MouseTestHovercraft() {
for (int redIndex = 0; redIndex < MAX_CLR; redIndex++) {
int r = (redIndex * 256) / (MAX_CLR - 1);
r = (r == 256) ? 255 : r;
for (int greenIndex = 0; greenIndex < MAX_CLR; greenIndex++) {
int g = (greenIndex * 256) / (MAX_CLR - 1);
g = (g == 256) ? 255 : g;
for (int blueIndex = 0; blueIndex < MAX_CLR; blueIndex++) {
int b = (blueIndex * 256) / (MAX_CLR - 1);
b = (b == 256) ? 255 : b;
Color c = new Color(r, g, b);
colors.add(c);
}
}
}
add(new JToggleButton(new AbstractAction("TrackMouse") {
public void actionPerformed(ActionEvent ae) {
trackMouse(ae);
}
}));
add(new JButton(new AbstractAction("Clear Image") {
public void actionPerformed(ActionEvent e) {
bufferedImage = new BufferedImage(getWidth(), getHeight(),
BufferedImage.TYPE_INT_ARGB);
repaint();
}
}));
MyMouseAdapter myMA = new MyMouseAdapter();
addMouseListener(myMA);
addMouseMotionListener(myMA);
}
This is used to listen the event of tracking button.
private void trackMouse(ActionEvent ae) {
JToggleButton toggleBtn = (JToggleButton) ae.getSource();
tracking = toggleBtn.isSelected();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(PREF_W, PREF_H);
}
public void msg(String message) {
System.out.println(message);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(bufferedImage, 0, 0, null);
if (currentList != null) {
drawList(g, currentList, CURRENT_LIST_COLOR, 1f);
}
}
This will draw a curve on jpanel using quadcurve
private void drawList(Graphics g, List<Point> ptList, Color color,
float strokeWidth) {
if (ptList.size() > 1) {
Graphics2D g2 = (Graphics2D) g.create();
// Graphics2D g2 = (Graphics2D) g;
g2.setColor(color);
// g2.setStroke(new BasicStroke(strokeWidth));
QuadCurve2D selectedCurve = null;
for (int j = 0; j < ptList.size() - 1; j++) {
int x1 = ptList.get(j).x;
int y1 = ptList.get(j).y;
int x2 = ptList.get(j + 1).x;
int y2 = ptList.get(j + 1).y;
selectedCurve =new QuadCurve2D.Float(x1, y1, 5, 5, x2,y2);
g2.draw(selectedCurve);
}
g2.dispose();
}
}
On mouse press this code will first add the starting point into currentlist list and after that till mouse released all the points are added into currentlist.
private class MyMouseAdapter extends MouseAdapter {
#Override
public void mousePressed(MouseEvent e) {
if (tracking && e.getButton() == MouseEvent.BUTTON1) {
currentList = new ArrayList<Point>();
currentList.add(e.getPoint());
}
}
#Override
public void mouseReleased(MouseEvent e) {
if (tracking && e.getButton() == MouseEvent.BUTTON1) {
currentList.add(e.getPoint());
Graphics2D g2 = bufferedImage.createGraphics();
Color color = colors.get(random.nextInt(colors.size()));
drawList(g2, currentList, color, 3f);
currentList = null;
repaint();
}
}
#Override
public void mouseDragged(MouseEvent e) {
if (tracking && currentList != null) {
currentList.add(e.getPoint());
repaint();
}
}
}
private static void createAndShowGui() {
MouseTestHovercraft mainPanel = new MouseTestHovercraft();
JFrame frame = new JFrame("MouseMotion Eg");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.setResizable(false);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}