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How is it possible to make an image follow the framesize in Java? [duplicate]

When a user clicks on the corner of a JFrame to resize and drags the mouse around, the JFrame redraws based on the current position of the mouse as the user drags. How can you listen to these events?
Below is the what I have currently tried:
public final class TestFrame extends JFrame {
public TestFrame() {
this.addComponentListener(new ComponentAdapter() {
public void componentResized(ComponentEvent e) {
// This is only called when the user releases the mouse button.
System.out.println("componentResized");
}
});
}
// These methods do not appear to be called at all when a JFrame
// is being resized.
#Override
public void setSize(int width, int height) {
System.out.println("setSize");
}
#Override
public void setBounds(Rectangle r) {
System.out.println("setBounds A");
}
#Override
public void setBounds(int x, int y, int width, int height) {
System.out.println("setBounds B");
}
}
How can I determine and constrain how the user resizes a window (based on the current aspect ratio of the window) as they are dragging around the mouse around?

You can add a component listener and implement the componentResized function like that:
JFrame component = new JFrame("My Frame");
component.addComponentListener(new ComponentAdapter()
{
public void componentResized(ComponentEvent evt) {
Component c = (Component)evt.getSource();
//........
}
});
EDIT: Apparently, for JFrame, the componentResized event is hooked to the mouseReleased event. That's why the method is invoked when the mouse button is released.
One way to achieve what you want, is to add a JPanel that will cover the whole area of your JFrame. Then add the componentListener to the JPanel (componentResized for JPanel is called even while your mouse is still dragging). When your frame is resized, your panel will also be resized too.
I know, this isn't the most elegant solution, but it works!

Another workaround (which is very similar to Alex's but a little more straightforward) is to listen to the events from the JFrame's root pane instead:
public final class TestFrame extends JFrame {
public TestFrame() {
this.getRootPane().addComponentListener(new ComponentAdapter() {
public void componentResized(ComponentEvent e) {
// This is only called when the user releases the mouse button.
System.out.println("componentResized");
}
});
}
}
Depending on other implementation details, it's possible that the root pane might be changed. If that's a possibility then you could override setRootPane() and deal with that. Since setRootPane() is protected and only called from the constructor though, it's unlikely you'll need to do that.

You probably need to override something like validate (don't forget to call the super). Of course, that still may not work if you are using a windowing system to configured to drag outlines.

public class MouseDrag extends Component implements MouseListener,
MouseMotionListener {
/** The Image we are to paint */
Image curImage;
/** Kludge for showStatus */
static Label status;
/** true if we are in drag */
boolean inDrag = false;
/** starting location of a drag */
int startX = -1, startY = -1;
/** current location of a drag */
int curX = -1, curY = -1;
// "main" method
public static void main(String[] av) {
JFrame f = new JFrame("Mouse Dragger");
Container cp = f.getContentPane();
if (av.length < 1) {
System.err.println("Usage: MouseDrag imagefile");
System.exit(1);
}
Image im = Toolkit.getDefaultToolkit().getImage(av[0]);
// create a MouseDrag object
MouseDrag j = new MouseDrag(im);
cp.setLayout(new BorderLayout());
cp.add(BorderLayout.NORTH, new Label(
"Hello, and welcome to the world of Java"));
cp.add(BorderLayout.CENTER, j);
cp.add(BorderLayout.SOUTH, status = new Label());
status.setSize(f.getSize().width, status.getSize().height);
f.pack();
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
// "Constructor" - creates the object
public MouseDrag(Image i) {
super();
curImage = i;
setSize(300, 200);
addMouseListener(this);
addMouseMotionListener(this);
}
public void showStatus(String s) {
status.setText(s);
}
// Five methods from MouseListener:
/** Called when the mouse has been clicked on a component. */
public void mouseClicked(MouseEvent e) {
}
/** Called when the mouse enters a component. */
public void mouseEntered(MouseEvent e) {
}
/** Called when the mouse exits a component. */
public void mouseExited(MouseEvent e) {
}
// And two methods from MouseMotionListener:
public void mouseDragged(MouseEvent e) {
Point p = e.getPoint();
// System.err.println("mouse drag to " + p);
showStatus("mouse Dragged to " + p);
curX = p.x;
curY = p.y;
if (inDrag) {
repaint();
}
}
public void paint(Graphics g) {
int w = curX - startX, h = curY - startY;
Dimension d = getSize();
g.drawImage(curImage, 0, 0, d.width, d.height, this);
if (startX < 0 || startY < 0)
return;
System.err.println("paint:drawRect #[" + startX + "," + startY
+ "] size " + w + "x" + h);
g.setColor(Color.red);
g.fillRect(startX, startY, w, h);
}
}

Only able to add JLabel background or JPanel background

I am making my first game in Java. This is the first time using swing too. I am having difficulties adding objects correctly to the frame.
Some irrelevant code has been removed from other classes. There may be several components missing that are referenced.
Main:
public class Main {
Ball ball = new Ball();
int yBall = 0;
public static void main(String[] args) throws InterruptedException {
Main main = new Main();
main.run();
while (true) {
main.ball(100);
}
}
public void run() throws InterruptedException {
Data data = new Data();
Frame frame = new Frame(700, 500);
test.setAngleX();
frame.add(data, BorderLayout.CENTER);
}
}
When I add ball after data(background) my ball is visible on the frame, overlapping my data. If I would switch position here my data would be visible but not my ball, the ball still exists underneath.
frame.add(ball);
frame.setVisible(true);
public void ball(int yBall) throws InterruptedException {
ball.Ball();
yBall = ball.SendY();
}
This is my frame, no problems in here what I know:
public class Frame extends JFrame {
private int frameWidth;
private int frameHeight;
int yBall = 0;
public Frame(int frameWidth, int frameHeight) {
this.frameWidth=frameWidth;
this.frameHeight = frameHeight;
setSize(new Dimension(frameWidth, frameHeight));
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}
Here's my Ball. paintComponent is at the end, before that it is just working logics that I'm guessing will be irrelevant.
Ball:
public class Ball extends JLabel{
Graphics g1;
int x = 325, y = 225;
int speed = 1;
int angleX = 0;
int angleY = 0;
public Ball() {
}
public void setAngleX() {
angleX = ThreadLocalRandom.current().nextInt(-5, 5 + 1);
angleY = ThreadLocalRandom.current().nextInt(-1, 1 + 1);
if (angleX == 0) {
setAngleX();
}
if (angleY == 0) {
setAngleX();
}
}
public void move() {
if (x + angleX < 0) {
angleX = speed;
} else if (x + angleX > getWidth() - 25) {
angleX = -speed;
} else if (y + angleY < 0) {
angleY = speed;
} else if (y + angleY > getHeight() - 25) {
angleY = -speed;
}
x = x + angleX;
y = y + angleY;
}
public void Ball() throws InterruptedException {
move();
repaint();
int sleepSpeed = angleX * speed;
if (sleepSpeed < 0) {
sleepSpeed = -sleepSpeed;
Thread.sleep(10*sleepSpeed);
}
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.WHITE);
g.fillOval(x, y, 25, 25);
}
public int SendY() {
return y;
}
And finally my Data;
public class Data extends JPanel{
private static final long serialVersionUID = 1L;
private Graphics2D g2;
public Data() {
}
#Override
public void paintComponent(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
g2.setColor(Color.BLACK);
g2.fillRect(0, 0, getSize().width, getSize().height);
g2.setColor(Color.lightGray);
g2.fillRect(350, 0, 10, 400);
}
So what happens is that I either get my data(background) on my frame or I get my Ball bouncing around as it should but on an empty background, depending on which one I add last in my main. I'm guessing it's bcz of overlapping but I can't find a solution working for my code, no matter how much I search..

that I either get my data(background) on my frame or I get my Ball bouncing around as it should but on an empty background, depending on which one I add last in my main.
You can't add both components to the frame. you need to have a parent/child relationship.
So the logic should be something like:
background.add( ball );
frame.add( background );
Then the frame will be painted, then the background and finally the ball.
Also, the Ball class will need to implement the getPreferredSize() method so component has a reasonable size. You should be painting the Ball at offset (0, 0) in the paint component method. When you want to move the ball on the background panel, then you just use setLocation(...) on the ball to reposition it on the background. When you create the Ball you would also need to set the size of the Ball to the preferred size so the Ball has a size/location to be painted on the background panel. The layout of the background panel would need to be set to null, so you can freely move the ball around the panel.
You should NOT be extending JLabel, you are not using any features of the JLabel. You are doing custom painting so just extend JPanel or JComponent. Read the section from the Swing tutorial on Custom Painting for more information and working examples.
Also, method names should NOT start with an upper case character. Ball() is not a proper method name. It looks like the class name. The method should be more descriptive.
Or the other approach, instead of having two components, is to have a single component. Then the paintComopnent(...) method of that component would paint both:
the background
the ball
Then this way you would paint the Ball relative to the background panel which is how your logic currently works.

animation using repaint()

I am trying to create a simple animation which draws random rectangles when a button is pressed. So far I managed to create rectangle on the press of a button. I want to further develop the code so that when I press the button, more than multiple random rectangles are created. I tried to create a for loop which asks the inner class to repaint itself but it still didn't work. can anyone help me please.
public class TwoButtonsRandomRec {
JFrame frame;
private int width = 500;
private int height = 500;
private DrawPanel dp;
public int getWidth() {
return width;
}
public void setWidth(int width) {
this.width = width;
}
public int getHeight() {
return height;
}
public void setHeight(int height) {
this.height = height;
}
public static void main (String[] args)
{
TwoButtonsRandomRec test = new TwoButtonsRandomRec();
test.go();
}
public void go()
{
dp = new DrawPanel();
JButton start = new JButton("Start");
start.addActionListener(new startListener());
JButton stop = new JButton("Stop");
stop.addActionListener(new stopListener());
frame = new JFrame();
frame.setSize(getWidth(), getHeight());
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(BorderLayout.NORTH, start);
frame.getContentPane().add(BorderLayout.SOUTH, stop);
}
class startListener implements ActionListener{
public void actionPerformed(ActionEvent event){
frame.getContentPane().add(BorderLayout.CENTER, dp);
frame.repaint();
frame.getRootPane().revalidate();
for(int i=0; i<10; i++){
dp.repaint();
}
}
}
class stopListener implements ActionListener{
public void actionPerformed(ActionEvent event){
System.out.println("stop");
}
}
class DrawPanel extends JPanel{
public void paintComponent(Graphics g){
int w = 5+(int)(Math.random() * width-5);
int h = 5+(int)(Math.random() * height-5);
int maxX = width-w; // diffX & diffY are used to ensure that rectangle is
int maxY = width-h; // draw completely inside the window
int x = (int)(Math.random() * maxX);
int y = (int)(Math.random() * maxY);
Color color = new Color((int) (Math.random()*256), // random red
(int) (Math.random()*256), // random green
(int) (Math.random()*256));// random blue
g.setColor(color);
g.fillRect(x,y,w,h);
}
}
}

repaint() simply tells Swing "when you'll have time, please repaint this area". So if you add rectangles in a loop and call repaint at each iteration, all the rectangles will only appear after the loop has finished, and the action event has been handled.
To have an animation, you need to loop in a separate thread. The easiest way to do that is to use a Swing Timer. When the Start button is started, start a timer which adds a random rectangle and calls repaint() every X milliseconds. When the Stop button is pressed, stop the timer.

What you should do is to put the loop inside paintComponent method and not call repaint in the loop.
So your paintComponent method should look like this:
public void paintComponent(Graphics g){
for (int i = 0; i < 10; i++) {
int w = 5+(int)(Math.random() * width-5);
int h = 5+(int)(Math.random() * height-5);
int maxX = width-w; // diffX & diffY are used to ensure that rectangle is
int maxY = width-h; // draw completely inside the window
int x = (int)(Math.random() * maxX);
int y = (int)(Math.random() * maxY);
Color color = new Color((int) (Math.random()*256), // random red
(int) (Math.random()*256), // random green
(int) (Math.random()*256));// random blue
g.setColor(color);
g.fillRect(x,y,w,h);
}
}
And your action performed should look like this:
public void actionPerformed(ActionEvent event){
frame.getContentPane().add(BorderLayout.CENTER, dp);
frame.repaint();
frame.getRootPane().revalidate();
dp.repaint();
}

Well,here I have done a short EG for you.It displays random rectangles, random times on random screen location.
(You can set your own value of randomization, and the screen location max bound,as per your requirements.)
And also note
int i=(int)(Math.random()*10);
int j=(int)(Math.random()*10);
for(;i<j;i++)
Where at times i may be > than j.So,loop may not work on one or two cliks.Change as per your need.
Here is the working code:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class SimpleStamper extends JApplet {
public void init() {
Display display = new Display();
setContentPane(display);
}
class Display extends JPanel implements MouseListener {
Display() {
setBackground(Color.black);
addMouseListener(this);
}
public void mousePressed(MouseEvent evt) {
if ( evt.isShiftDown() ) {
repaint();
return;
}
int x = evt.getX();
int y = evt.getY();
Graphics g = getGraphics();
//***MODIFY THE FOLLOWING LINES****//
int i=(int)(Math.random()*10);
int j=(int)(Math.random()*10);
for(;i<j;i++)
{ g.setColor(Color.red);
x=(int)(Math.random()*100);
y=(int)(Math.random()*100);
g.fillRect( x , y , 60, 30 );
g.setColor(Color.black);
g.drawRect(x , y , 60, 30 );}
g.dispose();
}
public void mouseEntered(MouseEvent evt) { }
public void mouseExited(MouseEvent evt) { }
public void mouseClicked(MouseEvent evt) { }
public void mouseReleased(MouseEvent evt) { }
}
}

JLabel Overlapping

I have created a label with overriding its paintComponent (to paint it in a different format with an arc) and located them on a panel. Everything worked fine, however the labels which are located in same location (by .setlocation) are creating problems.
Lets say I have 3 labels at the same location with different shapes. A-B-C
A is first created, then B is created and lastly c is created.
When I click on A, my function paints A and displays "youve clicked A"
But when I click on B or C, it acts like i have clicked on A.
(I'm adding labels in a panel stacked in scroll pane )
Here is the code where i make labels
for(int i=0;i<rowcount;i++){
arcstart = Rawazimuth(azimuth[i]);
//custom JLabel to paint it like an arc
MyLabel FLabel = new MyLabel(100, 50, (int)arcstart,cellid[i],lon[i],lat[i]);
FLabel.setOpaque(true);
Dimension LabelSize = new Dimension( 100,50);
FLabel.setSize(LabelSize);
//locate the JLabel to labels location. it might be same or not
FLabel.setLocation(lon[i], lat[i]);
MyPanel.add(FLabel);
}
this is my custom jlabel class
public MyLabel(int W, int H, int start,int outcellid,int lonn, int latt) {
addMouseListener(this);
arcsizeW = W;
arcsizeH = H;
arcstart = start;
cellid = outcellid;
clicked = false;
lon = lonn;
lat = latt;
}
#Override
public void paintComponent(Graphics g){
// true if button is clicked, so paint acordingly
if(clicked ==true){
g.setColor(dummyg.getColor());
}else{
g.setColor(Color.blue);
}
// draw the arc
g.fillArc(0, 0,arcsizeW , arcsizeH, arcstart, 60);
}
//if cell is clicked, change its color to red and print its cellid
#Override
public void mouseClicked(MouseEvent e) {
System.out.println(cellid);
dummyg = this.getGraphics();
dummyg.setColor(Color.red);
this.paintComponent(dummyg);
clicked = true;
}// other listener stuff}
so how do i prevent this?
i think i can use jlayerpane, but i will need at least 4 layers ( dunno if its ok ).

Make sure you are calling super.paintComponent. This is important to ensure that the component is painting correcting.
Mouse events are like rain. They will hit the first component registered to receive mouse events and stop (like rain hitting an umbrella).
If you have components that overlap, where they overlap, the mouse events go to the first component registered to handle them (in this case A).
Here's a quick example to show what I mean...
As you hover over each circle, it will highlight, try hovering over the middle...
public class OverlappingMouseTest {
public static void main(String[] args) {
new OverlappingMouseTest();
}
public OverlappingMouseTest() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException ex) {
} catch (InstantiationException ex) {
} catch (IllegalAccessException ex) {
} catch (UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new BackgroundPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
protected class BackgroundPane extends JLayeredPane {
private CirclePane redPane;
private CirclePane greenPane;
private CirclePane bluePane;
public BackgroundPane() {
redPane = new CirclePane(Color.RED);
greenPane = new CirclePane(Color.GREEN);
bluePane = new CirclePane(Color.BLUE);
add(redPane);
add(greenPane);
add(bluePane);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
#Override
public void doLayout() {
Dimension size = new Dimension(100, 100);
int width = getWidth() - 1;
int height = getHeight() - 1;
Point p = new Point();
p.x = (width / 2) - 50;
p.y = (height / 2) - 75;
redPane.setBounds(new Rectangle(p, size));
p.x = (width / 2) - 75;
p.y = (height / 2) - 25;
bluePane.setBounds(new Rectangle(p, size));
p.x = (width / 2) - 25;
p.y = (height / 2) - 25;
greenPane.setBounds(new Rectangle(p, size));
}
}
protected class CirclePane extends JPanel {
private boolean mouseHover = false;
public CirclePane(Color background) {
setOpaque(false);
setBackground(background);
addMouseListener(new MouseAdapter() {
#Override
public void mouseExited(MouseEvent me) {
mouseHover = false;
repaint();
}
#Override
public void mouseEntered(MouseEvent me) {
mouseHover = true;
repaint();
}
});
}
#Override
public Dimension getPreferredSize() {
return new Dimension(100, 100);
}
#Override
protected void paintComponent(Graphics grphcs) {
super.paintComponent(grphcs);
Graphics2D g2d = (Graphics2D) grphcs.create();
if (!mouseHover) {
g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 0.5f));
}
g2d.setColor(getBackground());
g2d.fill(new Ellipse2D.Float(0, 0, getWidth() - 1, getHeight() - 1));
g2d.dispose();
}
}
}

Everything worked fine, however the JLabel's which are located in same
location ( by .setlocation ) are creating problems.
Lets say i have 3 Jlabels at the same location with different shapes.
A-B-C A is first created, then B is created and lastly c is created.
there are tree ways, to use
JLayer (Java7), based on JXLayer (Java6)
OverlayLayout
JLayeredPane

I have solved my problem.
The real problem that i found was, Java is interpreting each component with their x,y location and width & height. So even if your label does not overlap ( graphically ) they can be interpreted as same component.
To solve my problem,
I found the angle between mouse click point and component center; then calculated the closest component and reached it.
Layers and such doesn't work in this situation, the only other way around is possibly overriding the contains method for the actualy shape.

Listen to JFrame resize events as the user drags their mouse?

When a user clicks on the corner of a JFrame to resize and drags the mouse around, the JFrame redraws based on the current position of the mouse as the user drags. How can you listen to these events?
Below is the what I have currently tried:
public final class TestFrame extends JFrame {
public TestFrame() {
this.addComponentListener(new ComponentAdapter() {
public void componentResized(ComponentEvent e) {
// This is only called when the user releases the mouse button.
System.out.println("componentResized");
}
});
}
// These methods do not appear to be called at all when a JFrame
// is being resized.
#Override
public void setSize(int width, int height) {
System.out.println("setSize");
}
#Override
public void setBounds(Rectangle r) {
System.out.println("setBounds A");
}
#Override
public void setBounds(int x, int y, int width, int height) {
System.out.println("setBounds B");
}
}
How can I determine and constrain how the user resizes a window (based on the current aspect ratio of the window) as they are dragging around the mouse around?

You can add a component listener and implement the componentResized function like that:
JFrame component = new JFrame("My Frame");
component.addComponentListener(new ComponentAdapter()
{
public void componentResized(ComponentEvent evt) {
Component c = (Component)evt.getSource();
//........
}
});
EDIT: Apparently, for JFrame, the componentResized event is hooked to the mouseReleased event. That's why the method is invoked when the mouse button is released.
One way to achieve what you want, is to add a JPanel that will cover the whole area of your JFrame. Then add the componentListener to the JPanel (componentResized for JPanel is called even while your mouse is still dragging). When your frame is resized, your panel will also be resized too.
I know, this isn't the most elegant solution, but it works!

Another workaround (which is very similar to Alex's but a little more straightforward) is to listen to the events from the JFrame's root pane instead:
public final class TestFrame extends JFrame {
public TestFrame() {
this.getRootPane().addComponentListener(new ComponentAdapter() {
public void componentResized(ComponentEvent e) {
// This is only called when the user releases the mouse button.
System.out.println("componentResized");
}
});
}
}
Depending on other implementation details, it's possible that the root pane might be changed. If that's a possibility then you could override setRootPane() and deal with that. Since setRootPane() is protected and only called from the constructor though, it's unlikely you'll need to do that.

You probably need to override something like validate (don't forget to call the super). Of course, that still may not work if you are using a windowing system to configured to drag outlines.

public class MouseDrag extends Component implements MouseListener,
MouseMotionListener {
/** The Image we are to paint */
Image curImage;
/** Kludge for showStatus */
static Label status;
/** true if we are in drag */
boolean inDrag = false;
/** starting location of a drag */
int startX = -1, startY = -1;
/** current location of a drag */
int curX = -1, curY = -1;
// "main" method
public static void main(String[] av) {
JFrame f = new JFrame("Mouse Dragger");
Container cp = f.getContentPane();
if (av.length < 1) {
System.err.println("Usage: MouseDrag imagefile");
System.exit(1);
}
Image im = Toolkit.getDefaultToolkit().getImage(av[0]);
// create a MouseDrag object
MouseDrag j = new MouseDrag(im);
cp.setLayout(new BorderLayout());
cp.add(BorderLayout.NORTH, new Label(
"Hello, and welcome to the world of Java"));
cp.add(BorderLayout.CENTER, j);
cp.add(BorderLayout.SOUTH, status = new Label());
status.setSize(f.getSize().width, status.getSize().height);
f.pack();
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
// "Constructor" - creates the object
public MouseDrag(Image i) {
super();
curImage = i;
setSize(300, 200);
addMouseListener(this);
addMouseMotionListener(this);
}
public void showStatus(String s) {
status.setText(s);
}
// Five methods from MouseListener:
/** Called when the mouse has been clicked on a component. */
public void mouseClicked(MouseEvent e) {
}
/** Called when the mouse enters a component. */
public void mouseEntered(MouseEvent e) {
}
/** Called when the mouse exits a component. */
public void mouseExited(MouseEvent e) {
}
// And two methods from MouseMotionListener:
public void mouseDragged(MouseEvent e) {
Point p = e.getPoint();
// System.err.println("mouse drag to " + p);
showStatus("mouse Dragged to " + p);
curX = p.x;
curY = p.y;
if (inDrag) {
repaint();
}
}
public void paint(Graphics g) {
int w = curX - startX, h = curY - startY;
Dimension d = getSize();
g.drawImage(curImage, 0, 0, d.width, d.height, this);
if (startX < 0 || startY < 0)
return;
System.err.println("paint:drawRect #[" + startX + "," + startY
+ "] size " + w + "x" + h);
g.setColor(Color.red);
g.fillRect(startX, startY, w, h);
}
}