I have my own custom control which maintains backing image for it's content. This buffer is of type BufferedImage.
ATTENTION! The usage of backing image is due to requirements. Don't teach me to draw within paintComponent()
Currently I am resizing image in the following way:
#Override
public void setBounds(int x, int y, int width, int height) {
if( bufferedImage == null ) {
bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
}
else {
if( bufferedImage.getWidth() < width || bufferedImage.getHeight() < height ) {
BufferedImage newImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
newImage.createGraphics().drawImage(bufferedImage, 0, 0, null);
bufferedImage = newImage;
}
}
super.setBounds(x, y, width, height);
}
unfortunately, this requires to create new BufferedImage object and hence makes previously obtained Graphics object invalid.
So I have to have my own method
public Graphics2D createImageGraphics() {
if( bufferedImage != null ) {
return bufferedImage.createGraphics();
}
else {
return null;
}
}
although I would like to override getGraphics().
Is it possible to resize image so that it conserve Graphics object?
Here is small example of how you perform custom painting in Swing:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import javax.swing.AbstractAction;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class JFrameTest {
private boolean drawOval = false;
protected void initUI() {
final JPanel panel = new JPanel() {
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (drawOval) {
g.setColor(Color.BLUE);
g.drawOval(0, 0, 100, 100);
}
}
#Override
public Dimension getPreferredSize() {
return new Dimension(100, 100);
}
};
AbstractAction drawAction = new AbstractAction("Draw") {
#Override
public void actionPerformed(ActionEvent e) {
drawOval = true;
panel.repaint();
}
};
JButton drawButton = new JButton(drawAction);
JPanel buttonPanel = new JPanel();
buttonPanel.add(drawButton);
JFrame frame = new JFrame();
frame.add(panel, BorderLayout.CENTER);
frame.add(buttonPanel, BorderLayout.SOUTH);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new JFrameTest().initUI();
}
});
}
}
Related
I want to have a text field to input an integer, then select 1) Grow or 2) Shrink, and then click the button so that the circle gets redrawn on the screen based on the selected options.
I don't know why it isn't repaining. (Don't worry about the layout, just want to get it to work first)
My Frame:
public class Main {
public static void main(String[] args) {
var frame = new JFrame();
frame.setSize(400,400);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
var circleComp = new circleComponent();
var panel1 = new JPanel();
var multiplierLabel = new JLabel("Grow Multiplier");
var multiplierField = new JTextField(20);
var radio1 = new JRadioButton("Grow Circle");
var radio2 = new JRadioButton("Shrink Circle");
var bg = new ButtonGroup();
bg.add(radio1);
bg.add(radio2);
JButton button = new JButton("Rivizato");
button.addActionListener(
new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
if(radio1.isSelected()){
rrComp.repaint(0,0,Integer.parseInt(multiplierField.getText())*rrComp.getWidth(), Integer.parseInt(multiplierField.getText())*rrComp.getHeight());
}
else if(radio2.isSelected()){
rrComp.repaint(0,0,Integer.parseInt(multiplierField.getText())/rrComp.getWidth(), Integer.parseInt(multiplierField.getText())/rrComp.getHeight());
}
}
}
);
panel1.add(multiplierLabel);
panel1.add(multiplierField);
panel1.add(button);
panel1.add(radio1);
panel1.add(radio2);
frame.add(panel1);
frame.add(circleComp);
}
}
My CircleComponent class:
public class CircleComponent extends JComponent {
public void paintComponent(Graphics g){
super.paintComponent(g);
var g2 = (Graphics2D) g;
var circle = new Ellipse2D.Double(0,0,100,100);
g2.draw(circle);
}
}
var circle = new Ellipse2D.Double(0,0,100,100); means that your circle will never change size.
You should also be careful with repaint(x, y, width, height) as it could leave regions of your component "dirty". Better to just use repaint.
As a conceptual example...
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.Ellipse2D;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public final class Main {
public static void main(String[] args) {
new Main();
}
public Main() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
frame.add(new MainPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class MainPane extends JPanel {
private CirclePane circlePane;
public MainPane() {
setLayout(new BorderLayout());
JPanel actionsPane = new JPanel(new GridBagLayout());
JButton growButton = new JButton("Grow");
growButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
circlePane.grow();
}
});
JButton shrinkButton = new JButton("Shrink");
shrinkButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
circlePane.shrink();
}
});
actionsPane.add(growButton);
actionsPane.add(shrinkButton);
circlePane = new CirclePane();
add(circlePane);
add(actionsPane, BorderLayout.SOUTH);
}
}
public class CirclePane extends JPanel {
private Ellipse2D circle;
public CirclePane() {
circle = new Ellipse2D.Double(0, 0, 100, 100);
}
public void grow() {
double width = circle.getWidth() + 10;
double height = circle.getHeight() + 10;
circle.setFrame(0, 0, width, height);
repaint();
}
public void shrink() {
double width = Math.max(0, circle.getWidth() - 10);
double height = Math.max(0, circle.getHeight() - 10);
circle.setFrame(0, 0, width, height);
repaint();
}
#Override
public Dimension getPreferredSize() {
return new Dimension(400, 400);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
double x = (getWidth() - circle.getWidth()) / 2d;
double y = (getHeight() - circle.getHeight()) / 2d;
g2d.translate(x, y);
g2d.draw(circle);
g2d.dispose();
}
}
}
nb: I know I've not used JTextField to specify the size of the circle, that's on purpose. You will need to adapt your requirements to work in a similar way - can you see where you might pass parameters to the CirclePane?
After learning that dispose() should be called on Graphics/Graphics2D object after use, I went about changing my game to incorporate this.
When I added g2d.dispose() in overridden paintComponent(Graphics g) of JPanel, my components which I added (extensions of JLabel class) where not rendered I was able to still click on them etc but they would not be painted.
I tested with a normal JLabel and JButton with same effect (though JButton is rendered when mouse is over it).
So my question is why does this happen?
Here is an SSCCE to demonstrate:
after uncommenting call to dispose() in paintComponent of MainMenuPanel class:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.event.FocusAdapter;
import java.awt.event.FocusEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;
import java.net.URL;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class Test {
public Test() {
try {
initComponents();
} catch (Exception ex) {
Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex);
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new Test();
}
});
}
private void initComponents() throws Exception {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setResizable(false);
MainMenuPanel mmp = new MainMenuPanel();
frame.add(mmp);
frame.pack();
frame.setVisible(true);
}
}
class MainMenuPanel extends JPanel {
//create labels for Main Menu
private PopUpJLabel versusesModeLabel;
private PopUpJLabel singlePlayerModeLabel;
private PopUpJLabel optionsLabel;
private PopUpJLabel helpLabel;
private PopUpJLabel aboutLabel;
//create variable to hold background
private Image background;
private Dimension preferredDimensions;
public static String gameType;
public static final String SINGLE_PLAYER = "Single Player", VERSUS_MODE = "VS Mode";
/**
* Default constructor to initialize double buffered JPanel with
* GridBagLayout
*/
public MainMenuPanel() {
super(new GridBagLayout(), true);
try {
initComponents();
} catch (Exception ex) {
JOptionPane.showMessageDialog(null, "Could not load main menu background!", "Main Menu Error: 0x004", JOptionPane.ERROR_MESSAGE);
System.exit(4);
}
}
/*
* Create JPanel and its components
*/
private void initComponents() throws Exception {
//set prefered size of JPanel
preferredDimensions = new Dimension(800, 600);
background = scaleImage(800, 600, ImageIO.read(new URL("http://photos.appleinsider.com/12.08.30-Java.jpg")));
//create label instances
singlePlayerModeLabel = new PopUpJLabel("Single Player Mode");
singlePlayerModeLabel.setEnabled(false);
versusesModeLabel = new PopUpJLabel("Versus Mode");
optionsLabel = new PopUpJLabel("Options");
helpLabel = new PopUpJLabel("Help");
aboutLabel = new PopUpJLabel("About");
//create new constraints for gridbag
GridBagConstraints gc = new GridBagConstraints();
gc.fill = GridBagConstraints.HORIZONTAL;
gc.ipady = 50;//vertical spacing
//add newGameLabel to panel with constraints
gc.gridx = 0;
gc.gridy = 0;
add(singlePlayerModeLabel, gc);
gc.gridy = 1;
add(versusesModeLabel, gc);
//add optionsLabel to panel with constraints (x is the same)
gc.gridy = 2;
add(optionsLabel, gc);
//add helpLabel to panel with constraints (x is the same)
gc.gridy = 3;
add(helpLabel, gc);
//add aboutLabel to panel with constraints (x is the same)
gc.gridy = 4;
add(aboutLabel, gc);
}
public static BufferedImage scaleImage(int w, int h, BufferedImage img) throws Exception {
BufferedImage bi;
//bi = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
bi = new BufferedImage(w, h, img.getType());
Graphics2D g2d = (Graphics2D) bi.createGraphics();
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2d.addRenderingHints(new RenderingHints(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY));
g2d.drawImage(img, 0, 0, w, h, null);
g2d.dispose();
return bi;
}
/*
* Will return the preffered size of JPanel
*/
#Override
public Dimension getPreferredSize() {
return preferredDimensions;
}
/*
* Will draw the background to JPanel with anti-aliasing on and quality rendering
*/
#Override
protected void paintComponent(Graphics grphcs) {
super.paintComponent(grphcs);
//convert graphics object to graphics2d object
Graphics2D g2d = (Graphics2D) grphcs;
//set anti-aliasing on and rendering etc
//GamePanel.applyRenderHints(g2d);
//draw the image as the background
g2d.drawImage(background, 0, 0, null);
//g2d.dispose();//if I uncomment this no LAbels will be shown
}
}
class PopUpJLabel extends JLabel {
public final static Font defaultFont = new Font("Arial", Font.PLAIN, 50);
public final static Font hoverFont = new Font("Arial", Font.BOLD, 70);
PopUpJLabel(String text) {
super(text);
setHorizontalAlignment(JLabel.CENTER);
setForeground(Color.ORANGE);
setFont(defaultFont);
//allow component to be focusable
setFocusable(true);
//add focus adapter to change fints when focus is gained or lost (used for transversing labels with keys)
addFocusListener(new FocusAdapter() {
#Override
public void focusGained(FocusEvent fe) {
super.focusGained(fe);
if (isEnabled()) {
setFont(getHoverFont());
}
}
#Override
public void focusLost(FocusEvent fe) {
super.focusLost(fe);
setFont(getDefaultFont());
}
});
addMouseListener(new MouseAdapter() {
#Override
public void mouseEntered(MouseEvent me) {
super.mouseEntered(me);
if (isEnabled()) {
setFont(getHoverFont());
}
//call for focus mouse is over this component
requestFocusInWindow();
}
});
}
Font getDefaultFont() {
return defaultFont;
}
Font getHoverFont() {
return hoverFont;
}
}
The thing is that the Graphics context you are using in paintComponent is created and provided by the caller (the framework), which is also responsible for disposing of it.
You only need to dispose of Graphics when you actually create it yourself (for example by calling Component.getGraphics()). In your case, you're not creating it, you're just casting it, so do not call dispose in this case.
Because .dispose() releases your resources. Yes, everything.
After learning that dispose() should be called on Graphics/Graphics2D object after use, I went about changing my game to incorporate this.
When I added g2d.dispose() in overridden paintComponent(Graphics g) of JPanel, my components which I added (extensions of JLabel class) where not rendered I was able to still click on them etc but they would not be painted.
I tested with a normal JLabel and JButton with same effect (though JButton is rendered when mouse is over it).
So my question is why does this happen?
Here is an SSCCE to demonstrate:
after uncommenting call to dispose() in paintComponent of MainMenuPanel class:
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.event.FocusAdapter;
import java.awt.event.FocusEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;
import java.net.URL;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class Test {
public Test() {
try {
initComponents();
} catch (Exception ex) {
Logger.getLogger(Test.class.getName()).log(Level.SEVERE, null, ex);
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new Test();
}
});
}
private void initComponents() throws Exception {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setResizable(false);
MainMenuPanel mmp = new MainMenuPanel();
frame.add(mmp);
frame.pack();
frame.setVisible(true);
}
}
class MainMenuPanel extends JPanel {
//create labels for Main Menu
private PopUpJLabel versusesModeLabel;
private PopUpJLabel singlePlayerModeLabel;
private PopUpJLabel optionsLabel;
private PopUpJLabel helpLabel;
private PopUpJLabel aboutLabel;
//create variable to hold background
private Image background;
private Dimension preferredDimensions;
public static String gameType;
public static final String SINGLE_PLAYER = "Single Player", VERSUS_MODE = "VS Mode";
/**
* Default constructor to initialize double buffered JPanel with
* GridBagLayout
*/
public MainMenuPanel() {
super(new GridBagLayout(), true);
try {
initComponents();
} catch (Exception ex) {
JOptionPane.showMessageDialog(null, "Could not load main menu background!", "Main Menu Error: 0x004", JOptionPane.ERROR_MESSAGE);
System.exit(4);
}
}
/*
* Create JPanel and its components
*/
private void initComponents() throws Exception {
//set prefered size of JPanel
preferredDimensions = new Dimension(800, 600);
background = scaleImage(800, 600, ImageIO.read(new URL("http://photos.appleinsider.com/12.08.30-Java.jpg")));
//create label instances
singlePlayerModeLabel = new PopUpJLabel("Single Player Mode");
singlePlayerModeLabel.setEnabled(false);
versusesModeLabel = new PopUpJLabel("Versus Mode");
optionsLabel = new PopUpJLabel("Options");
helpLabel = new PopUpJLabel("Help");
aboutLabel = new PopUpJLabel("About");
//create new constraints for gridbag
GridBagConstraints gc = new GridBagConstraints();
gc.fill = GridBagConstraints.HORIZONTAL;
gc.ipady = 50;//vertical spacing
//add newGameLabel to panel with constraints
gc.gridx = 0;
gc.gridy = 0;
add(singlePlayerModeLabel, gc);
gc.gridy = 1;
add(versusesModeLabel, gc);
//add optionsLabel to panel with constraints (x is the same)
gc.gridy = 2;
add(optionsLabel, gc);
//add helpLabel to panel with constraints (x is the same)
gc.gridy = 3;
add(helpLabel, gc);
//add aboutLabel to panel with constraints (x is the same)
gc.gridy = 4;
add(aboutLabel, gc);
}
public static BufferedImage scaleImage(int w, int h, BufferedImage img) throws Exception {
BufferedImage bi;
//bi = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
bi = new BufferedImage(w, h, img.getType());
Graphics2D g2d = (Graphics2D) bi.createGraphics();
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2d.addRenderingHints(new RenderingHints(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY));
g2d.drawImage(img, 0, 0, w, h, null);
g2d.dispose();
return bi;
}
/*
* Will return the preffered size of JPanel
*/
#Override
public Dimension getPreferredSize() {
return preferredDimensions;
}
/*
* Will draw the background to JPanel with anti-aliasing on and quality rendering
*/
#Override
protected void paintComponent(Graphics grphcs) {
super.paintComponent(grphcs);
//convert graphics object to graphics2d object
Graphics2D g2d = (Graphics2D) grphcs;
//set anti-aliasing on and rendering etc
//GamePanel.applyRenderHints(g2d);
//draw the image as the background
g2d.drawImage(background, 0, 0, null);
//g2d.dispose();//if I uncomment this no LAbels will be shown
}
}
class PopUpJLabel extends JLabel {
public final static Font defaultFont = new Font("Arial", Font.PLAIN, 50);
public final static Font hoverFont = new Font("Arial", Font.BOLD, 70);
PopUpJLabel(String text) {
super(text);
setHorizontalAlignment(JLabel.CENTER);
setForeground(Color.ORANGE);
setFont(defaultFont);
//allow component to be focusable
setFocusable(true);
//add focus adapter to change fints when focus is gained or lost (used for transversing labels with keys)
addFocusListener(new FocusAdapter() {
#Override
public void focusGained(FocusEvent fe) {
super.focusGained(fe);
if (isEnabled()) {
setFont(getHoverFont());
}
}
#Override
public void focusLost(FocusEvent fe) {
super.focusLost(fe);
setFont(getDefaultFont());
}
});
addMouseListener(new MouseAdapter() {
#Override
public void mouseEntered(MouseEvent me) {
super.mouseEntered(me);
if (isEnabled()) {
setFont(getHoverFont());
}
//call for focus mouse is over this component
requestFocusInWindow();
}
});
}
Font getDefaultFont() {
return defaultFont;
}
Font getHoverFont() {
return hoverFont;
}
}
The thing is that the Graphics context you are using in paintComponent is created and provided by the caller (the framework), which is also responsible for disposing of it.
You only need to dispose of Graphics when you actually create it yourself (for example by calling Component.getGraphics()). In your case, you're not creating it, you're just casting it, so do not call dispose in this case.
Because .dispose() releases your resources. Yes, everything.
I created one JFrame. and set layout shown in below code
this.setLayout(new GridLayout());
JPanel panel=new JPanel();
panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
panel.add(new PicturePanel1());
JTabbedPane jtp=new JTabbedPane();
jtp.addTab("show Images", panel);
jtp.addTab("Compare Image", new JButton());
this.add(jtp);
I created another class that draws Images from particular location.
protected void paintComponent(Graphics g) {
super.paintComponents(g);
Graphics2D g2 = (Graphics2D) g;
int k = 20,y=10;
for (int j = 0; j <= listOfFiles.length - 1; j++) {
g2.drawImage(b[j], k, y, 100, 100, null);
// add(new javax.swing.JCheckBox());
k = k + 120;
if(k>=960)
{
k=20;
y=y+120;
}
}
Its working fine. I want to delete Images when user clicks on particular Image.
This is my output window. I want to delete Image from list.
Here is an example I made (bored and tired of studying :)). It is by no means the best just a quick thing to show you an example, click the image you want to delete and then press the delete button or DEL to remove and image from the panel:
When app starts up (orange just shows focused label for hovering):
Image to delete is selected by clicking on the Label (Border becomes green highlighted and will remain this way until another label is clicked):
After delete button or key is pressed:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.FocusAdapter;
import java.awt.event.FocusEvent;
import java.awt.event.KeyEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;
import java.net.URL;
import java.util.ArrayList;
import javax.imageio.ImageIO;
import javax.swing.AbstractAction;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.KeyStroke;
import javax.swing.SwingUtilities;
import javax.swing.border.LineBorder;
public class JavaApplication5 {
public static void main(String[] args) {
createAndShowJFrame();
}
public static void createAndShowJFrame() {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = createJFrame();
frame.setVisible(true);
}
});
}
private static JFrame createJFrame() {
JFrame frame = new JFrame();
//frame.setResizable(false);//make it un-resizeable
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setTitle("Test");
ArrayList<BufferedImage> images = null;
try {
images = getImagesArrayList();
} catch (Exception ex) {
ex.printStackTrace();
}
final ImageViewPanel imageViewPanel = new ImageViewPanel(images);
JScrollPane jsp = new JScrollPane(imageViewPanel);
jsp.setPreferredSize(new Dimension(400, 400));
frame.add(jsp);
JPanel controlPanel = new JPanel();
JButton addLabelButton = new JButton("Delete Selected Image");
addLabelButton.addActionListener(new AbstractAction() {
#Override
public void actionPerformed(ActionEvent e) {
imageViewPanel.removeFocusedImageLabel();
}
});
controlPanel.add(addLabelButton);
frame.add(controlPanel, BorderLayout.SOUTH);
frame.pack();
return frame;
}
private static ArrayList<BufferedImage> getImagesArrayList() throws Exception {
ArrayList<BufferedImage> images = new ArrayList<>();
images.add(resize(ImageIO.read(new URL("http://icons.iconarchive.com/icons/deleket/sleek-xp-software/256/Yahoo-Messenger-icon.png")), 100, 100));
images.add(resize(ImageIO.read(new URL("https://upload.wikimedia.org/wikipedia/commons/6/64/Gnu_meditate_levitate.png")), 100, 100));
return images;
}
public static BufferedImage resize(BufferedImage image, int width, int height) {
BufferedImage bi = new BufferedImage(width, height, BufferedImage.TRANSLUCENT);
Graphics2D g2d = (Graphics2D) bi.createGraphics();
g2d.addRenderingHints(new RenderingHints(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY));
g2d.drawImage(image, 0, 0, width, height, null);
g2d.dispose();
return bi;
}
}
class ImageViewPanel extends JPanel {
JLabel NO_IMAGES = new JLabel("No Images");
ArrayList<BufferedImage> images;
ArrayList<MyLabel> imageLabels;
public ImageViewPanel(ArrayList<BufferedImage> images) {
this.images = images;
imageLabels = new ArrayList<>();
for (BufferedImage bi : images) {
imageLabels.add(new MyLabel(new ImageIcon(bi), this));
}
layoutLabels();
getInputMap(JComponent.WHEN_IN_FOCUSED_WINDOW).put(KeyStroke.getKeyStroke(KeyEvent.VK_DELETE, 0, true), "Delete pressed");
getActionMap().put("Delete pressed", new AbstractAction() {
#Override
public void actionPerformed(ActionEvent e) {
removeFocusedImageLabel();
}
});
}
void removeFocusedImageLabel() {
if (focusedLabel == null) {
return;
}
imageLabels.remove(focusedLabel);
remove(focusedLabel);
layoutLabels();
}
private void layoutLabels() {
if (imageLabels.isEmpty()) {
add(NO_IMAGES);
} else {
remove(NO_IMAGES);
for (JLabel il : imageLabels) {
add(il);
}
}
revalidate();
repaint();
}
private MyLabel focusedLabel;
void setFocusedLabel(MyLabel labelToFocus) {
if (focusedLabel != null) {
focusedLabel.setBorder(null);
focusedLabel.setClicked(false);
}
focusedLabel = labelToFocus;
focusedLabel.setBorder(new LineBorder(Color.GREEN));
}
}
class MyLabel extends JLabel {
private final ImageViewPanel imageViewPanel;
private boolean clicked = false;
public MyLabel(Icon image, ImageViewPanel imageViewPanel) {
super(image);
this.imageViewPanel = imageViewPanel;
initLabel();
}
public MyLabel(String text, ImageViewPanel imageViewPanel) {
super(text);
this.imageViewPanel = imageViewPanel;
initLabel();
}
private void initLabel() {
setFocusable(true);
addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
super.mouseClicked(e);
clicked = true;
imageViewPanel.setFocusedLabel(MyLabel.this);
}
#Override
public void mouseEntered(MouseEvent me) {
super.mouseEntered(me);
if (clicked) {
return;
}
setBorder(new LineBorder(Color.ORANGE));
//call for focus mouse is over this component
requestFocusInWindow();
}
});
addFocusListener(new FocusAdapter() {
#Override
public void focusLost(FocusEvent e) {
super.focusLost(e);
if (clicked) {
return;
}
setBorder(null);
}
});
}
public void setClicked(boolean clicked) {
this.clicked = clicked;
}
public boolean isClicked() {
return clicked;
}
}
simply find the location (x, and y) and the size(width, and height) of image, then with the Graphics object (g2) fill a rectangle over the image drawn, like this
g2.setColor(this.getBackground());//set the color you want to clear the bound this point to JFrame/JPanel
g2.fillRect(x, y, width, height);
where x and y where is the location that images is located, and width and height are size of the picture
I am writing a program in which I paint on a JPanel. How do I get an Image of the JPanel which is painted on it?
I tried this code but all I get is a blank image with the Background color of my JPanel.
The BufferedImage does not contain what is painted on my panel.
private BufferedImage createImage(JPanel panel) {
int w = panel.getWidth();
int h = panel.getHeight();
BufferedImage bi = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
Graphics2D g = bi.createGraphics();
panel.paint(g);
return bi;
}
What am I doing wrong?
Here is an SSCCE illustrating that it works. A common mistake is to pass null as the ImageObserver of the drawImage method, because the loading of the image is asynchronous.
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class TestPrint {
protected static void initUI() throws MalformedURLException {
final ImageIcon image = new ImageIcon(new URL("http://www.travelblog.org/Wallpaper/pix/tb_fiji_sunset_wallpaper.jpg"));
JPanel panel = new JPanel() {
#Override
protected void paintComponent(java.awt.Graphics g) {
super.paintComponent(g);
g.drawImage(image.getImage(), 0, 0, this);
};
};
panel.setPreferredSize(new Dimension(image.getIconWidth(), image.getIconHeight()));
panel.setSize(panel.getPreferredSize());
BufferedImage bi = new BufferedImage(panel.getWidth(), panel.getHeight(), BufferedImage.TYPE_INT_RGB);
Graphics g = bi.createGraphics();
panel.print(g);
g.dispose();
try {
ImageIO.write(bi, "png", new File("test.png"));
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
try {
initUI();
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
}
}
Here's a quick example method that you can add to any of your Java 2/JDK 1.2 applications. Simply pass in the component you want to snapshot and the filename you want to save into.
public void saveComponentAsJPEG(Component myComponent, String filename) {
Dimension size = myComponent.getSize();
BufferedImage myImage = new BufferedImage(size.width, size.height, BufferedImage.TYPE_INT_RGB);
Graphics2D g2 = myImage.createGraphics();
myComponent.paint(g2);
try {
OutputStream out = new FileOutputStream(filename);
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
encoder.encode(myImage);
out.close();
} catch (Exception e) {
System.out.println(e);
}
}
This method is very versatile. It can be used to take snapshots of a wide variety of Java application components. Please do be forewarned, however, that you use com.sun.image.codec.jpeg at some risk to the portability of your code.
EDIT:
I tested the code to make sure and all seems fine:
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
import java.awt.*;
import java.awt.geom.Ellipse2D;
import java.awt.image.BufferedImage;
import java.io.FileOutputStream;
import java.io.OutputStream;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class ScreenCapture extends JFrame {
public ScreenCapture() {
createAndShowUI();
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
ScreenCapture screenCapture = new ScreenCapture();
}
});
}
private void createAndShowUI() {
setTitle("Test Screen Capture");
setSize(300, 300);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
getContentPane().add(new DrawingPanel());
setVisible(true);
saveComponentAsJPEG(this, "C:/test.jpg");
}
public void saveComponentAsJPEG(Component myComponent, String filename) {
Dimension size = myComponent.getSize();
BufferedImage myImage = new BufferedImage(size.width, size.height, BufferedImage.TYPE_INT_RGB);
Graphics2D g2 = myImage.createGraphics();
myComponent.paint(g2);
try {
OutputStream out = new FileOutputStream(filename);
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
encoder.encode(myImage);
out.close();
} catch (Exception e) {
System.out.println(e);
}
}
class DrawingPanel extends JPanel {
public DrawingPanel() {
setDoubleBuffered(true);
}
#Override
public void paintComponent(Graphics grphcs) {
super.paintComponents(grphcs);
Graphics2D g2d = (Graphics2D) grphcs;
RenderingHints rhints = g2d.getRenderingHints();
boolean antialiasOn = rhints.containsValue(RenderingHints.VALUE_ANTIALIAS_ON);
if (!antialiasOn) {
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
}
Shape circle = new Ellipse2D.Float(100.0f, 100.0f, 100.0f, 100.0f);
g2d.setColor(Color.RED);
g2d.draw(circle);
g2d.fill(circle);
}
}
}
Your code works for me.
Here is a simple example. Resize the frame to see the panel change size and the image move around.
public static void main(String[] args) {
JFrame frame = new JFrame("Test");
JPanel panel = new JPanel();
panel.setBackground(Color.BLUE);
JLabel label = new JLabel("Image");
label.setForeground(Color.RED);
panel.add(label);
frame.add(panel, BorderLayout.NORTH);
frame.pack();
JLabel image = new JLabel(new ImageIcon(createImage(panel)));
frame.add(image, BorderLayout.SOUTH);
frame.pack();
label.setText("Original");
frame.setVisible(true);
}
private static BufferedImage createImage(JPanel panel) {
int w = panel.getWidth();
int h = panel.getHeight();
BufferedImage bi = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
Graphics2D g = bi.createGraphics();
panel.paint(g);
return bi;
}
So your problem must be elsewhere. Make sure your panel has positive size at the point that you create an image of it.