I have a JFrame with BorderLayout, there are panels on all sides (North, East ,...). In the panels there are labels and buttons mostly.
Now I want the frame to have a background image, some research told me that i had to change the content pane of my frame.
When I try this however, the content gets put in the background and isn't visible. Also, I don't know how to resize the image if the frame is resized.
Is there an easy fix for this or will I have to rework most of my code?
put JPanel (or JComponent) with background Image to the BorderLayout.CENTER, then this JPanel fills whole JFrame area, rest of yout JComponents put to this JPanel
there are Jpanels on all sides (North, East ,...). In the Jpanels there are Jlabels and Jbuttons mostly.
these JComponents covered all available Rectangle for JFrame, then Background Image (from my 1st point) never will be dispalyed, because these JComponents are on_top JFrame and could be hide this Image as well,
add JPanel with Background Image (from my 1st point), then put there another JPanel(s) with JPanel#setOpaque(false);, then this JPanel will be transparent, notice JPanel has implemented by default FlowLayout
frame.getContentPane().add(new JPanel() {
public void paintComponent(Graphics g) {
g.drawImage(img, 0, 0, this.getWidth(), this.getHeight());
}
});
This example will get you started. Use it like any JPanel.
public class JPanelWithBackground extends JPanel {
Image imageOrg = null;
Image image = null;
{
addComponentListener(new ComponentAdapter() {
public void componentResized(ComponentEvent e) {
int w = JPanelWithBackground.this.getWidth();
int h = JPanelWithBackground.this.getHeight();
image = w>0&&h>0?imageOrg.getScaledInstance(w,h,
java.awt.Image.SCALE_SMOOTH):imageOrg;
JPanelWithBackground.this.repaint();
}
});
}
public JPanelWithBackground(Image i) {
imageOrg=i;
image=i;
setOpaque(false);
}
public void paint(Graphics g) {
if (image!=null) g.drawImage(image, 0, 0, null);
super.paint(g);
}
}
Usage Example:
Image image = your image
JFrame f = new JFrame("");
JPanel j = new JPanelWithBackground(image);
j.setLayout(new FlowLayout());
j.add(new JButton("YoYo"));
j.add(new JButton("MaMa"));
f.add(j);
f.setVisible(true);
Related
I am trying to draw an image to a JPanel which in turn is added to a JFrame, see here:
JFrame screen;
public void welcome(){
screen = new JFrame("Welcome");
screen.setVisible(true);
screen.pack();
screen.setBackground(Color.darkGray);
screen.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
// in the original code there is series of methods here that eventually calls the drawBoard() method
public void drawBoard(){
try {
final BufferedImage gboard = ImageIO.read(new File("cutsomGameBoard.jpg"));
final BufferedImage featPanel = ImageIO.read(new File("extraPanel.png"));
board = new JPanel(){
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(gboard, 0, 0, this);
}
};
extra = new JPanel(){
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(featPanel, 0, 0, this);
}
};
board.setSize(480, 480);
extra.setSize(480, 320);
}
catch (IOException e) {
e.printStackTrace();
}
}
gameScreen.add(toolbar, BorderLayout.PAGE_START);
gameScreen.add(board, BorderLayout.EAST);
gameScreen.add(extra, BorderLayout.WEST);
gameScreen.setVisible(true);
screen.add(gameScreen);
}
My problem is that when running the code, only a small corner of the buffered image is visible and I am not sure if it is a problem with the frame layout, the panel size or the drawImage method arguments, ideas?
P.S. The output: screenshot of java window
You didn't override the getPreferredSize() method of your custom component so the default size is basically (10, 10) which is the size of a panel using a FlowLayout with no added components.
Don't use a JPanel to display an image. Or if you do want to use a JPanel then you need to implement the getPreferredSize() method to return the size of your image.
The easiest solution is to just use a JLabel with an ImageIcon.
Read the section from the Swing tutorial on How to Use Icons for more information and working examples.
I have two panels defined like:
public class JPanel_with_BG extends JPanel
{
private Image bg_image;
public JPanel_with_BG(Image bg_image)
{
this.bg_image = bg_image;
}
public void paintComponent(Graphics g)
{
super.paintComponent(g);
if (bg_image != null)
{
g.drawImage(bg_image, 0, 0, this);
}
}
}
and,
public class MPanel extends JPanel
{
public void paint(Graphics g)
{
super.paint(g);
// draw something...
}
}
Then, I want to add the second panel over the bg_pnl. The top panel is smaller like bg_pnl.size = pnl + 2*padding.
MPanel pnl = new MPanel();
JPanel bg_pnl = new JPanel_with_BG(image);
int pad = 50;
bg_pnl.setBorder(new EmptyBorder(pad, pad, pad, pad));
bg_pnl.add(pnl);
The problem is that what I'm drawing on the top panel is not visible. What I can see is only the background image. Any ideas? Thanks.
You Code seems ok. I tried this at my end and I can see a small area on my UI showing MPanel. You need to validate the size of your panel on which you are showing this component.
It might happen that the area is not visible because of the dimension of the window. Also a panel's default layout is flow layout and it arranges the components added on it based on their size and if they are really small, It might not be visible
MASSIVE EDIT: I added more descritpion and code.
I recently encounter a problem where a panel that I added to another panel won't display properly (only display a black dot instead of the image). The flow of the code is: the Menu class has a button panel. When the button start is press, the Menu remove the button panel, create a Board object(that implement panel) and add it to Menu. In Board constructor, an image is loaded (a .png), then a PlayerPanel (that implement panel) is added to the board panel. In PlayerPanl constructor, an image is loaded.
The plan is to make the menu repaint() method able to call Board paintcomponent. Board will then ask PlayerPanel to paintComponent. PlayerPanel paint his image, Board paint his image and that's it, both image should display.
public class Menu extends JFrame implements ActionListener
{
Board theBoard;
JPanel pnlButton = new JPanel();
JButton btnStart = new Jbutton("Start");
public Menu(String s)
{
pnlButton.add(btnStart);
super.add(pnlButton);
super.setLocation(0,0);
super.setSize(600, 500);
super.setResizable(false);
super.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
#Override
public void actionPerformed(ActionEvent evt)
{
if(evt.getSource() == btnStart)
{
theBoard = new Board ("TestBoard");
super.remove(pnlButton);
super.add(theBoard);
super.repaint();
}
}
}
public class Board extends JPanel
{
BufferedImage boardImage;
PlayerPanel playerPanel;
public Board (String boardName)
{
boardImage = Tools.loadImage(boardName);
playerPanel = new PlayerPanel();
this.add(playerPanel);
}
#Override
public void paintComponent(Graphics g)
{
g.drawImage(boardImage, 0, 200, null);
}
}
public class PlayerPanel extends JPanel
{
BufferedImage playerImage;
public PlayerPanel()
{
playerImage = Tools.loadImage("TestPlayer");
}
#Override
public void paintComponent(Graphics g)
{
g.drawImage(playerImage, 0, 0, null);
}
}
Both image load successfully as tested, but when the repaint() is call from the JFrame holding the Board panel, only the image in Board is painted, and the image in PlayerPanel is replace with a black dot.
Any help? Thanks!
Your problem seems to be due to the size of your PlayerPanel JPanel. Sometimes it helps to debug things by testing to see what size things are when they're rendered. For instance, if you change your Board paintComponent method to this:
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
if (boardImage != null) {
g.drawImage(boardImage, 0, 200, null);
}
System.out.printf("Board size: [%d, %d]%n", getWidth(), getHeight());
System.out.printf("Player size: [%d, %d]%n", playerPanel.getWidth(), playerPanel.getHeight());
}
it will tell you exactly what the sizes are of itself and its constituent playerPanel.
To solve the issue, you could give Board a layout manager that expands its constituent components such as a BorderLayout. Another possible solution is to give PlayerPanel its own getPreferredSize() method override, especially if you want it to size itself to its image. e.g.,
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
if (playerImage != null) {
g.drawImage(playerImage, 0, 0, null);
}
}
Alternatively, you could use a JLabel that holds an ImageIcon rather than draw in the JPanel.
Note, you should swap views with a CardLayout rather than calling remove(...), add(...), revalidate(), repaint()
I'm trying to add a JScrollPane to an JPanel from a separate class. And thanks to some questions, which were asked so far, I could help myself create them. But my problem is still a little bit special.
I want to display an image on a JPanel and if the image is to large for the panel, I want to add scrollbars. But the scrollbars won't appear.
(When I set the ScrollPaneConstants to ****_SCROLLBAR_ALWAYS the frame of the bar appears, but without the bars to scroll).
I guess i have to connect the imagesize with the bars, so that they appear?
Some pieces of my code:
MainWindow
public class Deconvolutioner extends JFrame
{
Draw z;
Picturearea picturearea;
class Draw extends JPanel
{
public void paint(Graphics g)
{
}
}
public Deconvolutioner()
{
setTitle("Deconvolutioner");
setLocation(30,1);
setSize(1300,730);
super.setFont(new Font("Arial",Font.BOLD,11));
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setResizable(false);
FlowLayout flow = new FlowLayout(FlowLayout.CENTER);
this.setLayout(flow);
picturearea = new Picturearea();
picturearea.setLayout(new GridBagLayout());
JScrollPane scrollPane = new JScrollPane(picturearea,
ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED,
ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED);
scrollPane.setPreferredSize(new Dimension(1000, 664));
getContentPane().add(scrollPane, flow); // add scrollpane to frame
add(z = new Draw());
setVisible(true);
}
}
JPanel Class
public class Picturearea extends JPanel
{
BufferedImage image;
int panelWidth, panelHeight, imageWidth, imageHeight;
public Picturearea()
{
setBackground(new Color(210,210,210));
setBorder(LineBorder.createBlackLineBorder());
setVisible(true);
}
#Override
public void paintComponent(Graphics g)
{
super.paintComponent(g);
g.drawImage(image, 0, 0, this);
}
public void setPicture(BufferedImage picture)
{
try
{
image = picture;
}
catch (Exception e)
{
System.err.println("Some IOException accured (did you set the right path?): ");
System.err.println(e.getMessage());
}
repaint();
}
}
Thanks for your time.
The problem is that the JScrollPane has no way to know if it should display scroll bars or not, since the Picturearea it contains doesn't tell anything about its preferred size (or rather, it returns the preferred size based on its layout and on the components it contains. But since it doesn't contain any component, the returned preferred size is probably (0, 0)).
I would simply use a JLabel instead of the custom Picturearea class. A JLabel can display an image just fine, and it returns the appropriate Dimension when asked for its preferred size.
You can create a JLabel first and then add the Label to JPanel picturearea before creating instance for JScrollPane .
Have a try and it will work.
Example code is as follows:
JLabel imageLabel = new JLabel(new ImageIcon("d:\\099.jpg"));
picturearea.add(imageLabel);**
JScrollPane scrollPane = new JScrollPane(picturearea,
ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED,
ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED);
I'm currently trying to draw shapes on a JPanel, which is within another JPanel, within a JFrame.
I've searched Google and Youtube and found out how to draw shapes within a JFrame that has one panel, but have found nothing which can help me with what I'm doing. (maybe I'm not seeing something).
Code I've seen so far:
public class GameScreen
{
public void paintComponent(Graphics g)
{
super.paintComponent(g);
g.setColor(Color.red);
g.drawRect(100, 10, 30, 40);
}
public static void main(String[] args)
{
GameScreen gs = new GameScreen();
JFrame f = new JFrame();
f.setTitle("");
f.setSize(400,400);
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(gs);
}
This is all good for when I'm dealing with just one panel, but I wanna display shapes on a panel which is within the 1'st panel I've created.
Add a JPanel to the JFrame in the same way as you're doing now, but do it with your own subclass of JPanel.
class MyPanel extends JPanel {
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.red);
g.drawRect(100, 10, 30, 40);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(400,400); // As suggested by camickr
}
}
You can add this to a JPanel which sits within the JFrame
public static void main(String[] args)
{
MyPanel mp = new MyPanel();
JPanel jp = new JPanel();
jp.add(mp);
JFrame f = new JFrame();
f.setTitle("");
f.setSize(400,400);
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(jp);
}
This can work for components within components, if you add them as children components. The key is to extend the component and override the methods you wish to change.
This is all good for when I'm dealing with just one panel,
The code you posted works fine because a frame uses a BorderLayout. So, when you add your panel to the frame is will increase in size and your custom painting will be seen.
I wanna display shapes on a panel which is within the 1'st panel I've created.
When you create a panel it uses a FlowLayout by default. When you add a custom painting panel to that panel it will be displayed at its preferred size, which will be (0, 0) since you didn't specify the preferred size.
On the panels that do custom painting you also need to implement the getPreferredSize() method so the layout manager knows how to arrange the panels. For example:
public Dimension getPreferredSize()
{
return new Dimension(200, 200);
}