I have a GUI, which consists of a JFrame and Menu bar. Inside the JFrame is my custom Panel (extending JPanel), which is initially hidden. The user chooses an image (JFileChooser), this image is passed to the panel and drawn (using paintIcon). The panel is resized to fit the image and then set visible. I want to resize my JFrame to fit the panel, but I cannot seem to get it to work. I have tried using the pack() method, but this just makes a tiny GUI, that is the size of the JMenu! I have also tried resizing both the frame and the JPanel using the getIconWidth() and getIconHeight() properties of the ImageIcon, but while this correctly sizes the panel it does not size the JFrame. Any ideas as to how I would do this correctly?
The block of code where I am setting the size of the JFrame is here:
#Override
public void actionPerformed(ActionEvent e)
{
JFileChooser imgChooser = new JFileChooser();
JMenuItem evtSource = (JMenuItem) e.getSource();
String srcText = evtSource.getText();
if (srcText.equals("Add Image..."))
{
imgChooser = new JFileChooser();
imgChooser.showOpenDialog(frmMain);
chosenImage = imgChooser.getSelectedFile();
try
{
loadedImage = ImageIO.read(chosenImage);
}
catch (IOException ex)
{
String errorMsg = ex.getMessage();
JOptionPane.showMessageDialog(frmMain, "Error while loading file: " + errorMsg, "Error!", JOptionPane.ERROR_MESSAGE);
}
panelImage = new ImageIcon(loadedImage);
frmMain.setSize(panelImage.getIconWidth(), panelImage.getIconHeight() + mbMenu.getHeight());
displayImage.loadImage(panelImage);
displayImage.setVisible(true);
}
}
The code from the relevant sections of the "displayImage" custom panel is below:
public void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
if (imgIsLoaded)
{
panelImage.paintIcon(this,g2,0,0);
resizePanel(panelImage.getIconWidth(), panelImage.getIconHeight());
}
}
public void loadImage(ImageIcon i)
{
panelImage = i;
imgIsLoaded = true;
}
public void resizePanel(int w, int h)
{
this.setSize(w, h);
}
Override getPreferredSize() in the panel to return a default value (e.g. 400x400) if it has no image, and the size of the image otherwise.
After setting an image, call frame.pack().
BTW - if all the panel does is paint the image, I'd opt for a JLabel instead.
Related
I have trouble with my IT class project in NetBeans and jFrame. When I set the background image, there is a weird rectangle, after changing it via menu bar and menu item. There is no jPanel or other components that could cover it.
This is how I set the background:
private void jMenuItem3ActionPerformed(java.awt.event.ActionEvent evt) {
Graphics x= this.getGraphics();
Image img = null;
try
{img = ImageIO.read(new File("noga1.jpg"));
x.drawImage(img, 0, 0, rootPane);}
catch (Exception e) {}
}
And that's what we can see after performing an action:
I am facing an issue that I am not able to draw an png image into my swing GUI into JPanel (which I am adding into JScrollPane after).
Here is my code I am trying to use for this.
if(processCreated == true){
System.out.println("updating tree of organisms");
processCreated = false;
updateTree();
try {
Thread.sleep(100);
} catch (InterruptedException ex) {
Logger.getLogger(Svet.class.getName()).log(Level.SEVERE, null, ex);
}
tree = new File(path+"/out.png"); //File
try {
treeImage = ImageIO.read(tree); //BufferedImage
tp = new TreePane(treeImage.getScaledInstance( 500, 500 ,treeImage.SCALE_SMOOTH)); // my class, implementation below
treeOutput.add(tp); //adding "JPanel" with picture into GUI
treeOutput.repaint();
} catch (IOException ex) {
Logger.getLogger(Svet.class.getName()).log(Level.SEVERE, null, ex);
}
}
After this the JScrollPane remains empty. Is there anything wrong with my code? You can find what is what in comments.
Here is my TreePane class
public class TreePane extends JPanel{
Image img;
public TreePane( Image img ){
this.img = img;
}
public void paintComponent(Graphics g){
super.paintComponent(g);
int imgX = 0;
int imgY = 0;
g.drawImage(img, imgX, imgY, this);
}
}
Very likely your TreePane is layed out to size 0,0 and therefore you'll never see anything. Try adding a breakpoint and inspecting in paintComponent - it might not even ever get called.
To fix, you should explicitly set the size of your TreePane before adding it to the JScrollPane.
tp = new TreePane(treeImage.getScaledInstance( 500, 500 ,treeImage.SCALE_SMOOTH)); // my class, implementation below
tp.setSize(myWidth, myHeight);
treeOutput.add(tp); //adding "JPanel" with picture into GUI
treeOutput.repaint();
Code works, my bad. But I'm still open to suggestions on how to improve or make the code more elegant.
I have created this layout and I want to be able to draw a circle whenever the user clicks on the white area.
Couldn't post an image, so here is the link
The white area is basically a rectangle. But something with my code isn't working, it just doesn't respond to mouse clicks. When I tried to see if it responds to mouseDragged it worked perfectly but this isn't what I need.
Here is my code, some "tests" are put as /comments/ but neither of them work as intended.
I would be very grateful for help. Here is my code:
import java.awt.*;
import java.awt.Graphics;
import javax.swing.*;
public class CitiesMapPanel extends JPanel implements MouseListener {
private JButton cmdAddWay, cmdFindPath, cmdClearMap, cmdClearPath;
private JLabel lblFrom, lblTo;
private JTextField txtFrom, txtTo;
public CitiesMapPanel() {
cmdAddWay = new JButton("Add Way");
cmdFindPath = new JButton("Find Path");
cmdClearMap = new JButton("Clear Map");
cmdClearPath = new JButton("Clear Path");
lblFrom = new JLabel("From");
lblTo = new JLabel("To");
txtFrom = new JTextField(6);
txtTo = new JTextField(6);
this.addMouseListener(this);
setLayout(new BorderLayout());
add(buildGui(), BorderLayout.SOUTH);
}
private JPanel buildGui() {
JPanel buttonsBar = new JPanel();
//The "south" of the BorderLayout consist of a (2,4) GridLayout.
buttonsBar.setLayout(new GridLayout(2,4));
buttonsBar.add(lblFrom);
buttonsBar. add(txtFrom);
buttonsBar.add(lblTo);
buttonsBar.add(txtTo);
buttonsBar.add(cmdAddWay);
buttonsBar.add(cmdFindPath);
buttonsBar.add(cmdClearMap);
buttonsBar.add(cmdClearPath);
return buttonsBar;
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.white);
g.fillRect(0, 0, this.getSize().height, this.getSize().width);
}
public static void main(String[] args) {
JFrame frame = new JFrame("layout");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(530, 550);
CitiesMapPanel gui = new CitiesMapPanel();
frame.add(gui);
frame.setVisible(true);
}
/*abstract private class MyMouseListner implements MouseListener{
public void mouseClicked(MouseEvent e){
int x = e.getX();
int y = e.getY();
Graphics g = getGraphics();
g.setColor(Color.black);
g.fillOval(x,y,15,15);
}
}*/
#Override
public void mouseClicked(MouseEvent e) {
int x = e.getX();
int y = e.getY();
Graphics g = getGraphics();
g.setColor(Color.black);
g.fillOval(x,y,15,15);
System.out.println("test");
}
#Override
public void mouseEntered(MouseEvent e) {
// TODO Auto-generated method stub
}
#Override
public void mouseExited(MouseEvent e) {
// TODO Auto-generated method stub
}
#Override
public void mousePressed(MouseEvent e) {
// TODO Auto-generated method stub
}
#Override
public void mouseReleased(MouseEvent e) {
// TODO Auto-generated method stub
}
}
The click listener is not the problem. Your approach to painting is simply wrong. You can't do a getGraphic, paint on it, and expect the result to be presented. In Swing (AWT) things work fundamentally different. You need to either create an off screen image that you paint to and that you then present on screen in your paintComponent method, or you need to track the objects you want to paint in a data structure and paint those in your paintComponent method. You can trigger a repaint in your click listener by calling repaint so the UI subsystems knows about the changed state that requires a repaint of your component.
Read more about the basics in the Swing painting tutorial.
I need some help with painting an Image object upon/inside/on a BufferedImage and then painting that BufferedImage on a JPanel.
I've prepared a small program to illustrate my problem. Just a frame with a panel accompanied by an ImageLoader.
The image is placed in the same folder as the code. The sten Image is painted successfully when just painted, but not when I try painting it with the BufferedImage, which you'll notice if you try to run the program. just create the Test object and the constructor does the rest.
Thanks in advance!
My code:
public class Test extends JFrame{
static class ImageLoader {
public static Image loadImage(String name){
Image img = null;
img = Toolkit.getDefaultToolkit().getImage(ImageLoader.class.getResource(name));
return img;
}
}
class Panel extends JPanel{
Image sten;
BufferedImage bf = new BufferedImage(500,500,BufferedImage.TYPE_INT_RGB);
public Panel(Image sten){
super();
this.sten = sten;
initBF();
}
private void initBF(){
Graphics2D g = (Graphics2D) bf.createGraphics();
g.drawImage(sten, 0,0,this);
}
public void paintComponent (Graphics g)
{
g.drawImage(bf, 100,100,null);
g.drawImage(sten, 0,0,null);
repaint();
}
}
public Test(){
setSize(new Dimension(500, 500));
setEnabled(true);
this.setBounds(50, 150, 500, 500);
setVisible(true);
Image sten = ImageLoader.loadImage("sten.png");;
Panel panel = new Panel(sten);
panel.setBackground(Color.GREEN);
panel.setSize(500, 500);
this.add(panel);
setDefaultCloseOperation(EXIT_ON_CLOSE);
panel.paintComponent(this.getGraphics());
}
}
The problem is that Toolkit.getDefaultToolkit().getImage loads images asychronously so will not be loaded when paintComponent is invoked. Use a MediaTracker to block until the image has been loaded:
public Image loadImage(String name) {
Image img = null;
MediaTracker tracker = new MediaTracker(myPanel); // pass the panel from ctor
img = Toolkit.getDefaultToolkit().getImage(ImageLoader.class.getResource(name));
tracker.addImage(img, 0);
try {
tracker.waitForID(0);
} catch (InterruptedException e) {
e.printStackTrace();
}
return img;
}
or far simpler:
img = ImageIO.read(ImageLoader.class.getResource(name)));
This will eliminate the need to use MediaTracker.
Some notes:
Don't call paintComponent directly, request repaints by invoking repaint.
Don't use getGraphics for custom painting - this uses a transient Graphics reference.
When using a custom Graphics reference, make sure to call Graphics#dispose when finished using the reference.
In addition of Reimeus' aswer, notice that Toolkit.getDefaultToolkit().getImage() is non-blocking, it loads images asynchronously, so at the point when you call g.drawImage(sten, 0,0,this); sten will probably not still actually be loaded (see the doc of the method). See also this (false) bug report.
I am using Jtree for listing various images of a directory, I want to display image on applet when the user click on the image name displayed in the Tree, the code i'm using is as below, ta is an object of the applet because i'm using it in another class.
private void displayImage(URL furl, String fname) {
ta.Picture = ta.getImage(furl, fname);
prepareImage(ta.Picture, this);
Graphics g = ta.imageCanvas.getGraphics();
g.clearRect(10, 10, 800, 800);
g.drawImage(ta.Picture, 10, 10, this);
} // displayImage
public void valueChanged(TreeSelectionEvent e)
{
// TODO Auto-generated method stub
FileTreeNode node = (FileTreeNode) tree.getLastSelectedPathComponent();
System.out.println("slecte asldf " + node.isLeaf());
if (node.isLeaf())
{
currentFile = node.file;
System.out.println("File name " + currentFile.getName());
try
{
URL furl = new URL("file:/F:/photos");
displayImage(furl, currentFile.getName());
}
catch (MalformedURLException mle)
{
System.out.println("Exception::::::" + mle);
}
}
else
currentFile = null;
}
But its not working.
As you are showing files from the local filesystem, working with URLs is not required. Use
displayImage(currentFile);
and rewrite that method as following:
private void displayImage(File file) {
BufferedImage image = ImageIO.read(file);
ta.image = image;
ta.repaint();
}
where the paint method of the (I an assuming) component ta must be like
BufferedImage image;
public void paint(Graphics g) {
g.clearRect(10, 10, 800, 800);
g.drawImage(ta.Picture, 10, 10, this);
}
Because of security reasons, the applet will only be able to access the file system if signed or running without security manager (most often on the same computer).
But its not working.
This is in no way helpful, do you get exceptions? What happens? Please post an SSCCE for better help sooner
I want to display image on applet when the user click on the image
name displayed in the Tree, the code i'm using is as below, ta is an
object of the applet because i'm using it in another class.
IMO you are going about it wrong using the JPanel object and Component#getGraphics.
Dont use Component#getGraphics() as its not good practice and not persistent thus on next call to repaint() the screen will be cleared.
Dont use Applet with Swing components rather use JApplet.
Add a custom JPanel with getters and setters for BufferedImage variable to the container and than override paintComponnet and draw the BufferedImage there.
Now to change the BufferedImage simply call the setter i.e setBackgroundImage(BufferedImage img) and than call repaint() on JPanel to show the changes. Like so:
public class MyPanel extends JPanel {
private BufferedImage bg;
public MyPanel(BufferedImage bi) {
bg=bi;
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d=(Graphics2D)g;
g2d.addRenderingHints(new RenderingHints(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY));
g2d.addRenderingHints(new RenderingHints(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON));
g2d.drawImage(bg,0,0,this);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(bg.getWidth(),bg.getHeight());
}
public BufferedImage setBackgroundImage(BufferedImage bi) {
bg=bi;
}
}
Now we use it like so:
MyPanel mp=new MyPanel(...);//create the panel with an image
...
add(mp);//add to container
...
mp.setBackgroundImage(..);//change the image being displayed
mp.repaint();//so the new image may be painted