I have no idea what the heck is going on while I'm trying to render an image on a JPanel in a JFrame. In fact I just want an image displayed in a fixed position on my JFrame.To achieve this I have a JPanel of a fixed size (min, max, pref size set) on my JFrame. On press of a button, I add another panel to mentioned panel, having the same size. The "child" panel has an overriden paint method to draw an image. So far so good, once I press the button and add that child panel, nothing happens at all. If I then click on the empty panel, the image is drawn as it should be, not overflowing the bounds of the child panel. However, all other components width increases drastically, stretching them out of the JFrames bounds. One would think that at least a scrollbar would appear, but no, the components are then out of reach. I'm attaching two screenshots displaying that very logic behavior.
The code is as follows:
void setPoster(BufferedImage poster) {
ImagePanel ip = new ImagePanel(poster);
ip.setSize(new Dimension(222, 327));
panelPoster.add(ip);
ip.setSize(new Dimension(222, 327));
}
Inside ImagePanel:
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(image, 0, 0, this);
System.out.println("Paiting imagepanel with size " + getSize());
}
Before screenshot:
After screenshot:
Could anyone enlighten me on what could possibly occur here?
I fixed the strange resizing by setting the layout to null on both the JFrame and the JPanel inside my tabbed pane.
setLayout(null);
jPanel4.setLayout(null);
Anyway, that's not needed when using the JLabel instead of the JPanel to hold the image.
However, my ImagePanel would not draw the image anymore, so I replaced it by a JLabel which draws the image just fine:
void setPoster(BufferedImage poster) {
JLabel imageLabel = new JLabel(new ImageIcon(poster));
panelPoster.add(imageLabel);
imageLabel.setSize(new Dimension(222, 327));
}
Note that without setting the size of the JLabel, it won't display anything.
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.
I've spent a fair bit of time researching how to change the background color of JFrame, but haven't managed to make anything work. My code in its current state looks like this:
final ImageIcon cardIcon = new ImageIcon("cardImages/aceSpades.gif");
JPanel panel = new JPanel()
{
public void paintComponent(Graphics g) {
super.paintComponent(g);
cardIcon.paintIcon(this, g, 20, 20);
}
};
JFrame window = new JFrame("Deck of Cards");
window.add(panel);
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
window.setPreferredSize(new Dimension(200,200));
window.pack();
window.getContentPane().setBackground(Color.green);
window.setVisible(true);
This is the result of all of the searches I've done on stackoverflow, so some help would be appreciated. I know I need to change the content pane instead of the actual frame, but all of my efforts seem to result in the default grey background. Thanks in advance.
edit: panel is for an image that's being loaded in.
edit 2: Sounds like panel is blocking the background from changing.
The JPanel you're adding to the frame is blocking the background color. Either set the panel's background color via panel.setBackground or make the panel transparent by setting panel.setOpaque(false).
I have created a custom JPanel class called ImagePanel. I override the paintComponent method like this...
public void paintComponent(Graphics g)
{
super.paintComponent(g);
g.drawImage(image, 0,0, null);
}
The purpose of the custom panel is to simply draw an image.
In my JFrame, I create a ScollPane that is added to the JFrame. When I created the ScrollPane though, I pass in the instance of my imagePanel, like this...
ip = new ImagePanel();
JScrollPane jsp = new JScrollPane(ip);
this.add(jsp);
Now all I want as an easy to use way of using the scroll bars to scroll over my image. Right now the image is very large and scrollbars do not appear. I use the policy to make them visible, but the handles to the scrollbars are not there.
Does anyone know an easy way to do this?
Try with JPanel#setPreferredSize() that will force the JScrollPane to show the scroll bar if needed.
public void paintComponent(Graphics g)
{
super.paintComponent(g);
g.drawImage(image, 0,0, null);
// set the size of the panel based on image size
setPreferredSize(new Dimension(image.getWidth(), image.getHeight()));
}
EDIT
Setting setPreferredSize() inside overridden paintComponent() is not a good way.
You can do it in a simpler way using JLabel as suggested by #mKorbel. For more info have a look at the comments below.
BufferedImage image = ...
JLabel label = new JLabel(new ImageIcon(image)); // set the icon
JScrollPane jsp = new JScrollPane(label);
Screenshot:
I have some Graphics2D graphics displayed in my frame, and then I added a JPanel to the entire frame so that I can add a mouselistener to clicks anywhere in the panel. However, the graphics disappear, I assume blocked out by the frame. I tried setting the panel to visible false, but that didnt do anything. How can I keep my mouselistener listening on the entire window, and still display my graphics?
EDIT:
Heres a bit of code: EDIT:(and some more)
//adding the panel and mouselistener
JPanel allPanel = new JPanel();
allPanel.addMouseListener(this);
frame.add(allPanel);
//...
//drawing some of the graphics
public void draw() {
frame.add(new CustomPaintComponent());
// Display the frame
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
frame.setVisible(true);
JPanel allPanel = new JPanel();
allPanel.addMouseListener(this);
frame.add(allPanel);
}
static class CustomPaintComponent extends Component {
private static final long serialVersionUID = 1L;
public void paint(Graphics g) {
Graphics2D g2d = (Graphics2D)g;
g2d.fillRoundRect(10, 10, 50, 50, 10,10);
//...
Three problems jump out...
First, JFrame uses a BorderLayout as its default layout manager, this means that only one component can occupy any of its available five positions. By using add(Component) you add each component to the CENTRE position, overriding the first component you added to it...
Second, JPanel is opaque by default, meaning, even if you did get both components to occupy the same space, the top component would block the lower one
Third, you should be using paintComponent instead of paint
Take a look at Performing Custom Painting for more details
The solution could be to add the MouseListener directly to the custom component
Another choice would be to use a BorderLayout on the lower component, make the top component transparent (using setOpaque(false)) and add it to the lower component directly...
I believe your problem is that JFrame can have only one component added to it (by default). You add a CustomPaintComponent, which paints your graphics. Then, you add the JPanel, which automatically removes the CustomPaintComponent
Are you trying to paint the custom drawing on top of the JPanel? If that is the case, simply move that code over to the JPanel (but instead of using a CustomPaintComponent, put it in the paintComponent(Graphics g) method of the JPanel)
So I have big panel with: setLayout(null). Then I want to add button to it. In big panel's constructor I add such code:
JButton button = new JButton("eeee");
button.setBounds(100, 100, 100, 50);
add(button);
And it's okay. But when I repaint big panel button hides. It appears again when I move mouse to place where it should be... How to prevent this strange behaviour? Maybe its connected with the fact I add button in constrcutor?
you need to let the paint panel components first with "super.paint (g)" if you do not it does not draw the components added
#Override
public void paint(Graphics g){
super.paint(g); //draw your button as default
// hear, you can draw others things
}