Develop Reference

How can I display two JPanels with images on a JFrame, and both of the img to be visible?

I am trying to set as background an aquarium (which is a class that extends JPanel and contain the aquarium img), and on top a fish (which is also a class that extends a JPanel and contain the fish img).
The problem is that it shows only one image instead of fish in top of the aquarium (either aquarium, or fish depending on which one is added first to the JFrame).
Main
public class Core {
JFrame window;
JLabel label;
ImageIcon img;
Aquarium aquarium = new Aquarium();
JavaFish javaFish = new JavaFish();
public void start() {
window = new JFrame();
window.setPreferredSize(new Dimension(600, 400));
window.setVisible(true);
window.setTitle("Java Game");
aquarium.add(javaFish);
window.add(aquarium);
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args) {
Core c = new Core();
c.start();
}
}
Aquarium
public class Aquarium extends JPanel {
private BufferedImage img;
//Initiate aquarium width
public int width;
//Initiate aquarium height
public int height;
#Override
protected void paintComponent(Graphics g) {
width = getSize().width;
height = getSize().height;
try {
img = ImageIO.read(new File("img/AquariumBackground.png"));
} catch (IOException e) {
e.printStackTrace();
System.out.println("Image not fount!");
}
g.drawImage(img, 0, 0, width, height, this);
}
}
Fish
public class JavaFish extends JPanel {
BufferedImage img;
int xPos = 50;
int yPos = 50;
public JavaFish() {
this.setOpaque(false);
}
#Override
protected void paintComponent(Graphics g) {
BufferedImage JavaFish = LoadImage("img/JavaFish.png");
Graphics2D g2d = (Graphics2D) g;
g2d.drawImage(JavaFish, xPos, yPos, 100, 100, null);
repaint();
}
BufferedImage LoadImage(String FileName) {
img = null;
try {
img = ImageIO.read(new File (FileName));
} catch (IOException e) {
e.printStackTrace();
}
return img;
}
}

The problem is that it shows only one image instead of fish in top of the aquarium (either aquarium, or fish depending on which one is added first to the JFrame).
By default a JPanel uses a FlowLayout which respects the preferred size of any component added to it.
By default a JFrame uses a BorderLayout and if you don't specify a constraint the component gets added to the CENTER of the BorderLayout, which means the component is automatically resized to fill the space of the frame.
So the component you add to the frame will be sized to fill the frame. The component you add to the panel will have a size of (0, 0) so there is nothing to paint.
So some custom painting tips:
Override the getPreferredSize() method of the panel to return the size of the image so the layout manager can do its job
Invoke super.paintComponent(..) as the first statement to make sure the background gets cleared.
Don't read the image in the paintComponent() method. This method can be called whenever Swing determines the component needs to be repainted, so it not efficient to keep reading the image. Instead the image should be read in the constructor of the class.
Don't invoke repaint() in a painting method. This will cause an infinite painting loop.
Also, components should be added to the frame BEFORE you make the frame visible.
Having said all of the above, Alerra's suggestion in the comment to paint both images in the same panel is a good idea. It simplifies the painting and you can even paint multiple fish easily by keeping an ArrayList of imgages that you want to paint. Then you would just paint the background and then iterates through the ArrayList to paint the individual fish.
Check out Custom Painting Approaches for a working example. The example only draws Rectangle, but the concept is the same.

How to put transparent JPanel over an opaque JPanel?

I have added webcam to my software using com.github.sarxos.webcam. It has a JPanel named WebcamPanel and has predefined webcam sizes while I need my custom size of pictures. I managed to crop the images taken from webcam at 640 x 480. I want to put a red rectangle over the WebcamPanel to show that this part of the image will be saved.
public class CardPanel {
Dimension panelDim = new Dimension(640, 480);
public Cardpanel(){
//....Button Defined earlier
btnTakePhoto.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
webcameFrame();
}
});
}
private void webcamFrame(){
imageFrame = new JFrame("Photo Capture");
// Did some calculations to put window at center
imageFrame.setBounds(screenSize.width / 2 - frameWidth / 2, screenSize.height / 2 - frameHeight / 2, frameWidth,
frameHeight);
imageFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
imageFrame.setContentPane(contentPane);
JPanel webcamWindow = new JPanel();
RedHighlighter redHighlighter = new RedHighlighter();
Webcam webcam = Webcam.getDefault();
webcam.setViewSize(WebcamResolution.VGA.getSize());
webcamPanel = new WebcamPanel(webcam);
webcamPanel.setFillArea(true);
webcamPanel.setMirrored(false);
webcamPanel.setPreferredSize(panelDim);
webcamWindow.add(webcamPanel);
webcamWindow.add(redHighlighter);
hBox.add(webcamWindow);
}
// Sub Class just for drawing the rectangle
public class RedHighlighter extends JPanel{
public RedHighlighter() {
// If you delete the following line, nothing will appear
setPreferredSize(new Dimension(400, 400));
}
#Override
public void paint(Graphics g) {
g.setColor(Color.RED);
g.drawRect(100, 100, 200, 200);
}
}
}
I used JLayeredPanes but no matter what you do it will cover whole size and will show only one item at a time.
Overriding paint method helped me draw the rectangle but it's on side and not on top.
As you can see the rectangle has pushed WebcamPanel towards left. I want webcamPanel to remain in it's position while the rectangle on top of it at center. Please suggest an efficient approach to this problem. Thanks!

The one JPanel is being pushed over due to the layout managers that you are using. If you want one JPanel to overly another, you'll want to consider using a JLayeredPane, with the video images in the lower level, perhaps the JLayeredPane.DEFAULT layer, and the drawing JPanel above it.
Other options and issues:
You could potentially draw in the same JPanel that the image is being displayed in by displaying the image in a paintComponent method as well as the drawing (in lines of code after the image is displayed.
Look into use of a JLayer as a way of adding a drawing "decoration" over your image.
Always override paintComponent, not paint
Always call the super's painting method within your override.

It worked!
public class MyWebcamPanel extends WebcamPanel {
/**
*
*/
private static final long serialVersionUID = 2808353446021354508L;
public MyWebcamPanel(Webcam webcam) {
super(webcam);
}
#Override
protected void paintComponent(Graphics g) {
int x = 180;
int y = 87;
super.paintComponent(g);
g.setColor(Color.RED);
g.drawRect(x, y, 640-2*x, 480-2*y);
}
}

How to draw rectangle in JPanel from button click event

I am relatively new to Java Graphics. I want to draw 20 x 80 rectangle at (X,Y) coordinates in JPanel when user clicks a JButton. (where 'X' and 'Y' are coming from 2 JTextFields) .
I have read many questions and tutorial, but could not solve a problem. In some cases, I can draw rectangle but cannot draw new rectangle without emptying JPanel.
Here is my code :
public class CustomPanel extends JPanel {
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g); // first draw a clear/empty panel
g.draw3DRect(Integer.parseInt(x.getText()),Integer.parseInt(y.getText()), 20, 80, true);
// then draw using your custom logic.
}
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
//Code for frame
//Code for JTextfields x and y
JButton btnDraw = new JButton("Draw");
btnDraw.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
panel= new CustomPanel();
panel.setBounds(406, 59, 407, 297);
frame.getContentPane().add(panel);
frame.revalidate();
}
});
btnDraw.setBounds(286, 339, 89, 23);
frame.getContentPane().add(btnDraw);
}

You ActionListener code is wrong. You don't want to create a new panel, you want to add a Rectangle to the existing panel.
When you create the GUI you should add two panels to the GUI:
The first panel will be an empty panel that will do your custom painting. You would generally add this to the CENTER of the frame
The second panel will contain the "Draw" button. You would generally add this panel to the PAGE_END. Then when you click the Draw button you invoke a method like addRectangle(...) in your custom painting panel so the panel can paint the Rectangle.
Check out Custom Painting Approaches for the two common ways to do custom painting:
Keep a List of Object to paint and then in the paintComponent() method you iterate the LIst an paint each object.
Create a BufferedImage and then just paint the Rectangle onto the BufferedImage, then you can just paint the BufferedImage either in a JLabel or in your paintComponent() method.

How do I call a graphical class in Java?

I've been coding a simulation for a traffic flow network in Java, and the class that is supposed to graphically model the network looks as follows:
public class Map extends JPanel {
BufferedImage truck1;
public Map() throws IOException{
truck1 = ImageIO.read(getClass().getResource("Truck.png"));
}
protected void paintcomponent (Graphics g) {
super.paintComponent(g);
g.drawImage(truck1, 50, 100, 300, 300, this);
}
}
In my main() function, I instance the object as follows at the very beginning of the function:
Frame F1 = new Frame();
F1.setLayout(new FlowLayout());
F1.setSize(500,500);
F1.setVisible(true);
Map map = new Map();
map.setOpaque(true);
F1.add(map);
F1.setVisible(true);
However, when I run the program, the only output is a blank window with a slightly darker grey small square exactly in the middle at the top of the window. I've added Truck.png to the project, and I can't see any reason why it shouldn't display properly. What am I doing wrong?

Components should be added to the frame before the frame is made visible.
You are using a FlowLayout for your frame. A FlowLayout respects the preferred size of all components. Your Map class doesn't have a preferred size so the size defaults to (0, 0) so there is nothing to paint. Override the getPreferredSize() method of the Map class to return the appropriate size for the component.

Drawing from another class wont take the right dimensions of the JPanel

Ok i have a JPanel such as this one :
public class GUI {
JFrame frame = new JFrame("Net");
JPanel panel = new JPanel();
public GUI()
{
frame.setSize(835,650);
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.setVisible(true);
frame.add(panel);
panel.setSize(600,600);
panel.setLocation(215,5);
panel.add(new DrawPlanes(300,300,200,Color.BLACK));}
There are some other panels in there tables etc. My main is this one :
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable(){
#Override
public void run(){
//new GUI();
new GUI().buildTable();
}
});
And there i another class this one :
public class DrawPlanes extends JPanel
{
private static int centreX, centreY, radius;
private Color colour;
public DrawPlanes()
{
centreX = 300;
centreY = 300;
radius = 200;
colour = Color.BLACK;
}
public DrawPlanes(int centreX,int centreY, int radius, Color colour)
{
this.centreX = centreX;
this.centreY = centreY;
this.radius = radius;
this.colour = colour;
}
#Override
protected void paintComponent(Graphics g)
{
super.paintComponent(g);
System.out.println("ppp");
Graphics2D g2D = (Graphics2D) g;
g2D.setStroke(new BasicStroke(2F));
g.setColor(Color.BLACK);
g.drawOval(centreX - radius , centreY - radius, radius * 2 , radius * 2);
......
}
}
Ok so i ve setted the background colour of my panel red to see whats going on the whole panel its red but there is a small grey square where i believe the drawings are. I ve tried to change opaque as there might be an incompatibility issue but nothing changed at all.Any suggestions,is there anything that i m missing?
link of what is the result of
panel.add(new DrawPlanes(300,300,200,Color.BLACK))
http://dc626.4shared.com/img/FeYopZC1/s7/142d22f1be0/2013-12-08_142846.png?async&rand=0.9010817544924218
what does the DrawPlanes class draws when i checked it having the main and a panel etc in the DrawPlanes itself http://dc626.4shared.com/img/NPDkiQRJ/s7/142d22f23b0/1451491_586878858047235_191988.jpg?async&rand=0.27479583155781395 .When i apply a layout manager that grey square just moves to the center when i use getPreferredSize overriden or not the whole red panel appears grey.

frame.add(component) function eventually add your component to frame's content pane which has BorderLayout as default layout manager.
A JPanel uses FlowLayout as default layout which respect component's preferred size.
As your 'panel' and 'frame' is satisfying above two as a default, size hint with setSize(Dimension) or setBounds(Dimenstion) to component won't have effect.
You should provide size hint using setPreferredSize(Dimenstion)(to DrawPanel instance of your context) and if specifying minimum/maximum size is needed setMinimumSize(Dimenstion) and setMaximumSize(Dimenstion).
However it is considered as a better practice to override getXXXSize(Dimenstion): xxx represents Preferred/Minimmum/Maximum always which allows to adjust size of component with it's content.
Instead of calling setSize(Dimension) on a window it is preferable to call pack() at the end of addition of child components.
We should call setVisible(true) after finishing addition of all of the child components and following above point, after pack().
Please, start with the tutorial: Laying Out Components Within a Container
Edit:
Let us edit your GUI() constructor code and see what happens:
public GUI()
{
frame.setSize(835,650);
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
//frame.setVisible(true); // <<--- call it at the end of the code
frame.add(panel);
//panel.setSize(600,600); <<--- removing set size
panel.add(new DrawPlanes(300,300,200,Color.BLACK));
frame.setVisible(true);
}
And the DrawPnales will extend JComponent:
public class DrawPlanes extends JComponent{
public DrawPlanes(int centreX,int centreY, int radius, Color colour)
{
this.centreX = centreX;
this.centreY = centreY;
this.radius = radius;
this.colour = colour;
}
#Override
public Dimension getPreferredSize() {
return new Dimenstion(width, height);
// ^ provide your required size
}
}
If this still doesn't make any sense to you, then please try learning Swing layout managers a little bit further. Otherwise no matter how hard we hit our head on the table, possibly we won't be able to achieve any thing.

You're missing the fact that panels are laid out inside their container using a LayoutManager. The default layout manager of JPanel is a FlowLayout. The FlowLayout uses the preferred width and height of the components it lays out to decide where to place them in the container, and which size they should have. But your DrawPlanes panel doesn't override getPreferredSize(), so its preferred size is the default one.
Every time you use setSize() on a component or frame, you have a 99.9% probability of doing something wrong. Learn layout managers. If you design a custom component like your DrawPlanes component, which is not just a container for other components, but has a custom paintComponent() method, then override getPreferredSize(), getMaximumSize() and getMinimumSize() to tell the layout managers how they should display your component, and to make sure your custom component always has the appropriate size. You never set the size of a JButton, right? That's because the JButton itself decides, based on the text and icon it contains, which size it should have.