I want to paint the contents of a JFrame onto another frame. Currently, I only get it to work if the JFrame is visible.Is there a way to paint a hidden JFrame?
Additional info:In my project I need to be able to rotate and scale windows. I do not want to write my own window-api, so I thought I might be able to just paint JFrames or similar container classes in a rotated way (which the Graphics2D-API supports perfectly well). It would be awesome to be able to use standard JFrames for that, but a custom frame extending a JFrame would also be OK..
public class JFTest extends JFrame {
private JFrame frameToPaint = null;
public static void main (String[] args) {
new JFTest ();
}
public JFTest () {
// some basic initialization
super ("Container");
setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
setExtendedState (JFrame.MAXIMIZED_BOTH);
add (new JPanel () {
#Override public void paintComponent (Graphics g) {
super.paintComponent (g);
// painting the child frame's contents onto this frame
if (frameToPaint != null) frameToPaint.getRootPane().paintAll (g);
}
});
setVisible (true);
// initializing some test-frame that will get painted onto the container
frameToPaint = new JFrame ("child");
frameToPaint.setSize (200, 100);
frameToPaint.add (new JLabel ("test"));
frameToPaint.addComponentListener (new ComponentAdapter() {
#Override public void componentResized (ComponentEvent e) { repaint (); }
#Override public void componentHidden (ComponentEvent e) { repaint (); }
});
// magic line. an invisible frame will not get painted! why??
frameToPaint.setVisible (true);
}
}
Hint 1: JFrame's setDefaultLookAndFeelDecorated(false)/setUndecorated(true) might be of use for a window without caption and borders;
Hint 2: as setGlassPane/setLayeredPane/setOpaque(false) might be of use for a second "layer".
I want to get the graphical contents of a frame without having to make the frame visible for the user
The Screen Image class should help. Although I think it will only work for the "content pane" of the frame and not the entire frame (with the title bar and borders) unless you use a decorated frame.
1) you have to use proper LayoutManager, not setSize() or setBounds()
2) if is there null LayoutManager used then Container returns any size after setVisible(true);
3) if is there used proper LayoutManager, then Container return its Size after call pack();, in other hands this container couldn't be visible on the screen ( meaning setVisible(true); )
4) JComponents must to returns PrefferedSize for example
Related
I have a JScrollPanel and a JPanel added to it. I would like to draw to the JPanel and make the scrollbars of the JScrollPane appear whenever the drawing exceeds the size of the panel and be able to scroll the drawing both vertically and horizontally.
I have tried consulting with various forums and the official docs and tried a few things (setting the borders, the preferred size, etc.) but none seems to yield the desired effects.
I have a JFrame (with GridBagLayout, btw.) :
JFrame frame1 = new JFrame("Application");
frame1.setVisible(true);
frame1.setMinimumSize(new Dimension(580,620));
frame1.setResizable(false);
frame1.setLocationRelativeTo(null);
frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
The relevant components are :
JPanel panel1 = new JPanel();
JScrollPane scrollPane = new JScrollPane(panel1);
frame1.add(scrollPane, gbc_panel1); //added with layout constraints
JPanel :
panel1.setBackground(Color.BLACK);
panel1.setPreferredSize(new Dimension(500,500));
panel1.setMinimumSize(new Dimension(360,360));
panel1.setMaximumSize(new Dimension(1000,1000));
JScrollPane :
scrollPane.setAutoscrolls(true);
The relevant code from the action event
of a button that does the drawing :
Graphics g;
g = panel1.getGraphics();
panel1.paint(g);
g.setColor(new Color(0,128,0));
/* this is followed by some more code that
does the drawing of a maze with g.drawLine() methods */
The code does the drawing perfectly, I just can't seem to figure it out how to make the scrolling and dynamic resizing happen.
I would appreciate any helpful comments or remarks!
Thank you!
Ultimately rewriting the paint method did the trick as #MadProgrammer suggested. I was just hoping that I could do the painting without having to define my custom JPanel class, but looks like it doesn't work that way.
The custom class looks like this:
class Drawing extends JPanel {
int mazeSize;
public Drawing(JTextField jtf)
{
try {
this.mazeSize = Integer.parseInt(jtf.getText());
}
catch (Exception e)
{
JOptionPane.showMessageDialog(this, "ERROR! Invalid size value!");
}
} // the constructor gets the size of the drawing from a textField
public Dimension getPreferredSize() {
return new Dimension(mazeSize*10,mazeSize*10);
} //getPreferredSize - this method is used by the scroll pane to adjust its own size automatically
public void drawMaze (Graphics g)
{
/* some irrelevant code that does the desired drawing to the panel by calling g.drawLine()*/
} // drawMaze method that does the de facto drawing
#Override
public void paintComponent(Graphics g)
{
super.paintComponent(g);
drawMaze(g);
}// paintComponent() #Override method - this was the tricky part
}//Drawing JPanel subclass
It is also worth noting (if some noob like myself happens to stumble upon this question), that after instantiating the new JPanel subclass in the action event, I had to add it to the JScrollPanel in the following way, instead of just simply using its add() method:
Drawing drawPanel = new Drawing(textfield1);
scrollPane.getViewport().add(drawPanel);
Again, thanks for the suggestion!
Once finished with the program (a random maze generator that uses a recursive backtracking algorithm), I will make the source code available at my github profile.
This is my first java project and I am trying to draw a simple rectangle on my JPanel inside my JFrame. Been trying to solve this issue with the help of the same topics on stackoverflow but still no success.
The exception I get when I run the program is java.lang.NullPointerException. From my understanding I can not draw on the JPanel itself? which is created in mainWindow.
Main:
public class Main {
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
GameBoard game = new GameBoard();
mainWindow view = new mainWindow(game);
mainModel model = new mainModel();
mainController cont = new mainController(model, view, game);
cont.controllerInit();
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
}
View:
public class mainWindow{
public JFrame frame;
public JPanel panel;
GameBoard game = new GameBoard();
frame = new JFrame();
frame.getContentPane().setBackground(SystemColor.control);
frame.setBounds(100, 100, 728, 435);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(game);
frame.getContentPane().setLayout(null);
panel = new JPanel();
FlowLayout flowLayout = (FlowLayout) panel.getLayout();
panel.setBounds(166, 44, 550, 349);
frame.getContentPane().add(panel);
frame.setVisible(true);
}
Game:
public class GameBoard extends JPanel{
#Override
public void paintComponent(Graphics g)
{
super.paintComponent(g);
g.setColor(Color.BLUE);
g.drawRect(200, 200, 200, 200);
}
}
Never, ever call paintComponent directly, no external source has any reason to do so. Also, what do you thing would happen if you passed it null?
You should start by having a look at Performing Custom Painting and Painting in AWT and Swing to get a better understand of how paint in Swing works.
The Swing API basically uses a delegate model, where the system delegates responsibility of the paint of each component to the component. This is achieved by the system calling the components paint method, which in-turn calls (among a few others) paintComponent.
Swing also uses a passive rendering approaching, meaning that painting occurs at the discretion of the paint system. You component is notified of the need when its paint method is called. This may occur at any time.
In order for a component to be painted, it must first be added to container which is realised on the screen (has a native peer), in most cases, this means that the component hierarchy needs to resolve to some kind of window based class, like JFrame.
So, the answer to your question is:
Read the above documentation (and get a better understanding of how the API works)
Add your GameBoard to a container which can be resolved to a window based class
Never call paint or paintComponent directly
Reflection....
private mainWindow view;
private mainModel model;
public GameBoard(mainModel m, mainWindow v)
{
view = v;
model = m;
}
To me, this makes no sense. There is no reasonable reason why GameBoard needs a reference to mainWindow. GameBoard is, in of itself, a "view". If anything, the only thing you "should" be passing to GameBoard (assuming you're trying to use a MVC) is a controller
The problem is, I am unable to make it a dimension with 800x600. In other words, when I run the program, the frame is so small that I can not do anything with it.
How can I make the frame larger?
I have set the preferred size already ans set the canvas bounds.
Then what is the problem?
public class GameCanvas extends Canvas
{
private BufferStrategy buffer = null;
public GameCanvas()
{
setBounds(0, 0, 800, 600);
setIgnoreRepaint(true);
addKeyListener(new KeyInputHandler());
requestFocus();
}
public void addNotify()
{
super.addNotify();
this.createBufferStrategy(2);
buffer = this.getBufferStrategy();
setBounds(0, 0, 800, 600);
}
}
public class GameGuiFrame extends JFrame
{
private JPanel panel = new JPanel();
private GameCanvas canvas = new GameCanvas();
public GameGuiFrame()
{
this.setName("My Game");
this.pack();
this.setResizable(false);
this.setVisible(true);
panel = (JPanel) this.getContentPane();
panel.setPreferredSize(new Dimension(750,500));
panel.setLayout(null);
panel.add(canvas);
}
}
public class GameManager
{
public static void runGameLoop()
{
GameGuiFrame container = new GameGuiFrame();
container.addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
});
}
}
public class Main
{
public static void main(String [] args)
{
GameManager.runGameLoop();
}
}
Try packing the Frame after you set the preferred size of the content pane.
Not related to your question but based on the code you posted it looks like you've copied some old AWT code and are trying to use it in a Swing application.
I would suggest you only use Swing components. There is no need to use a Canvas with a BufferStrategy. Just use a JPanel it is double buffered by default. The code snippet you copied is old and that is not the way it is done in Swing.
Don't use a null layout. Swing was designed to be using with layout managers. Then the pack() method will be able to do its job properly.
There is no need to use a WindowListener to close the frame. These days people just use:
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Also, the frame should be made visible AFTER components have been added to the frame.
Generally you should be use Key Bindings, not a KeyListener to listen for key events in a Swing application.
I suggest you look at the Swing tutorial for more information about the above concepts.
You call to pack() will set the frame (and components within it) to their preferred size. However, you haven't specified a preferred size. I would suggest removing your two calls to setBounds() and calling setBounds() within the main method instead of pack().
i found this link.. LINK what i want is there's a JPanel that has a background and another JPanel with half the size of the first JPanel but with an image that is transparent and with a face or a ball at the middle.. :) just like the screenshot from the link.. is that possible to code in java? :) im just thinking it like for web programming. just a sort of DIV's to have that but i dont know in java.. :) sorry for bad english.. :D i have this as a background..
package waterKing;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
#SuppressWarnings("serial")
public class Main extends JFrame {
MainData data = new MainData();
public static void main(String[] args) {
Main frmMain = new Main();
frmMain.setExtendedState(Frame.MAXIMIZED_BOTH);
frmMain.setVisible(true);
}
public Main() {
data.tk = getToolkit();
data.d = data.tk.getScreenSize();
data.jP = new JPanel() {
protected void paintComponent(Graphics g) {
data.e = getSize();
data.iI = new ImageIcon("images/mainBG.png").getImage();
g.drawImage(data.iI,0, 0, data.d.width, data.d.height, null);
super.paintComponent(g);
}
};
data.jP.setOpaque(false);
data.jSp = new JScrollPane(data.jP);
data.jB = new JButton("EXIT");
data.jB.setBounds(10,10,200,40);
data.jB.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
});
data.jP.setLayout(null);
data.jP.add(data.jB);
this.setTitle("Water King Inventory System");
this.setUndecorated(true);
this.getContentPane();
this.add(data.jSp);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setLocationRelativeTo(null);
}
}
i dont know how to add another JPanel to show in the middle with this background
i dont know how to add another JPanel to show in the middle with this background
Its just like adding components to a panel. You need to use a layout manager and then the component will be positioned properly based on the rules of the layout manager. In your case you can set the layout manager of the background panel to be a BorderLayout. Then you can add a JLabel with the appropriate Icon to the center of the BorderLayout.
You will need to set the preferred size (or override the getPreferredSize() method of your panel since you add it to a scroll pane. Scrollbars will only appear when the preferred size of the panel is greater than the size of the scroll pane.
You should not be reading the image in your paintComponent() method since this method is called multiple times.
You should not be using the "screen size" to determine the width/height of the image because the frame will contain a border. You need to use the size of the panel.
Get rid of all the setBounds() code. Learn to use layout managers.
For a general purpose background panel that takes into account most of the suggestions made here check out Background Panel.
I have a JFrame on which I am using overriding the paint method to display some graphics. I also want to add a JPanel to it that will show up on top of the graphics. Right now, all I see is the graphics created from JFrame paint method.
Here's my JPanel:
public class NoteDraw extends JPanel {
public NoteDraw() {
setSize(200, 100);
setBackground(Color.BLACK);
}
#Override public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.red);
g.fillRect(0, 0, 100, 100);
}
}
Here's my JFrame:
public class ui extends JFrame {
public void paint(Graphics g) {
//do some drawing here...
}
}
Here's my main:
public class Main {
static ui main_gui = new ui();
public static void main(String[] args) {
NoteDraw note = new NoteDraw();
main_gui.getContentPane().add(note);
main_gui.setVisible(true);
}
}
You should NEVER override the paint() method of a JFrame (unless you really know what you are doing). This method is responsible for all the optimized painting behaviour of Swing.
Custom painting should always be done by overriding the paintComponent() method of a Swing component like you have done on your NoteDraw panel.
The reason the code in the paint method doesn't show is because the NoteDraw panel is opaque and therefore the panel paints over top of the Graphics code in your paint method.
So the solution is to move the Graphics painting code to the NoteDraw panel.
Or if you are trying to create some kind of background image for your frame then you can try using the Background Panel.
Or if you truly do need custom painting then you create a background panel and override the paintComponent() method. Then you set the layout to a BorderLayout and add this panel to the frame. Then you make your NoteDraw panel non-opaque and add it to the custom background panel. Now the background will show through on the NoteDraw panel.
Remember to call super.paint() when you override your paint() method.
This way, you still use the behavior defined in the parent class, and you can add your modifications safely.
Resources :
sun.com - Using the Keyword super