Develop Reference

How do I fire MouseMotionListener events in real-time?

I am trying to create a graphics drawing program that allows the user to draw red pixels on the screen by dragging their mouse over it. So in a way, you can think of this program as Microsoft's Paint program but with only the pencil drawing tool and color red.
Unfortunately the mouseDragged() function in my program is not working properly. It will skip some of the pixels on the screen if I move my mouse too fast, like this:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class FrameView extends JFrame {
JPanel panel;
Graphics2D drawingContext;
public static void main(String[] args) {
new FrameView();
}
public FrameView() {
panel = new JPanel();
panel.addMouseMotionListener(new MouseControls());
panel.setBackground(Color.WHITE);
this.add(panel);
this.setSize(new Dimension(500, 500));
this.setTitle("Drawing Program");
this.setVisible(true);
drawingContext = (Graphics2D)panel.getGraphics();
}
private class MouseControls extends MouseAdapter {
#Override
public void mouseDragged(MouseEvent e) {
int x = e.getX();
int y = e.getY();
final int WIDTH = 1;
final int HEIGHT = 1;
Shape pixel = new Rectangle(x, y, WIDTH, HEIGHT);
drawingContext.setColor(Color.RED);
drawingContext.draw(pixel);
}
}
}

getGraphics is NOT how painting works in Swing, instead, you should be overriding the paintComponent method of the component and performing your custom painting there.
Painting is destructive, it is expected that when ever paintComponent is called, you will completely repaint the current state of the component.
Have a look at Painting in AWT and Swing and Performing Custom Painting for more details
As to you "mouse" problem, this is actually how it works, you won't be notified of EVERY pixel position the mouse has to pass through, your mouse would lag horribly across the screen if it did. Instead, the OS moves the mouse in ever increasing steps based on the speed of the movement of the user input.
Instead of drawing just the points, draw lines between them, for example
nb: I've deliberately painted the points larger so you can see where they are been reported, you will see that all the dots (for a single drag) are connected
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Line2D;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private List<List<Point>> points = new ArrayList<>(25);
private List<Point> activeList;
public TestPane() {
MouseAdapter ma = new MouseAdapter() {
#Override
public void mouseDragged(MouseEvent e) {
if (activeList != null) {
activeList.add(e.getPoint());
repaint();
}
}
#Override
public void mousePressed(MouseEvent e) {
activeList = new ArrayList<>(25);
points.add(activeList);
}
#Override
public void mouseReleased(MouseEvent e) {
if (activeList != null && activeList.isEmpty()) {
points.remove(activeList);
}
activeList = null;
}
};
addMouseMotionListener(ma);
addMouseListener(ma);
}
#Override
public Dimension getPreferredSize() {
return new Dimension(200, 200);
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
g2d.setColor(Color.RED);
for (List<Point> group : points) {
Point previous = null;
for (Point p : group) {
// You can get rid of this, it's simply to show
// where the points would actually be rendered
g2d.fill(new Ellipse2D.Float(p.x - 2, p.y - 2, 4, 4));
if (previous != null) {
g2d.draw(new Line2D.Float(previous, p));
}
previous = p;
}
}
g2d.dispose();
}
}
}

java custom shaped frame using image [duplicate]

This question already has answers here:
Image/Graphic into a Shape
(3 answers)
Closed 8 years ago.
i like to create a java jframe look like this image.i have already crated jframes with different shapes like triangles ,circles ,polygons and some crazy shapes .but the problem it's too hard[99% impossible ] to create shape like this image.so how can i make a jframe like this.i used this code for create shaped window..
setUndecorated(true);
Polygon polygon = new Polygon();
polygon.addPoint(0, 0);
polygon.addPoint(100,100);
GeneralPath path = new GeneralPath();
path.append(polygon, true);
setShape(path);
now can i convert this image to a shape .then set setshapes.any idea?
or is there anyway to make jframe's fully transperent and jlable which hold image completely visible?

To make a transparent window, you need to set the frames background color's alpha to 0. This is probably the most counter intuitive call I've seen in a while, as if you do this to any other Swing component, you will completely screw up the paint process.
You don't want to change the opacity of the window, as it effectives the entire window and it's contents equally.
For example...
JWindow frame = new JWindow();
frame.setBackground(new Color(0, 0, 0, 0));
You don't have to use a JWindow, but this means I don't need to undecorate it myself...
You also need to make sure that whatever content you add to the window is transparent (opaque = false), so that it doesn't "hide" what's underneath it...
import java.awt.Color;
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.image.BufferedImage;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JButton;
import javax.swing.JPanel;
import javax.swing.JWindow;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.CompoundBorder;
import javax.swing.border.EmptyBorder;
import javax.swing.border.LineBorder;
public class LeafWindow {
public static void main(String[] args) {
new LeafWindow();
}
public LeafWindow() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JWindow frame = new JWindow();
frame.setBackground(new Color(0, 0, 0, 0));
frame.setContentPane(new LeafPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
frame.setAlwaysOnTop(true);
}
});
}
public class LeafPane extends JPanel {
private BufferedImage leaf;
public LeafPane() {
setBorder(new CompoundBorder(
new LineBorder(Color.RED),
new EmptyBorder(0, 0, 250, 0)));
try {
leaf = ImageIO.read(getClass().getResource("/Leaf.png"));
} catch (IOException ex) {
ex.printStackTrace();
}
setOpaque(false);
setLayout(new GridBagLayout());
JButton button = new JButton("Close");
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
});
add(button);
}
#Override
public Dimension getPreferredSize() {
return leaf == null ? new Dimension(200, 200) : new Dimension(leaf.getWidth(), leaf.getHeight());
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (leaf != null) {
Graphics2D g2d = (Graphics2D) g.create();
g2d.drawImage(leaf, 0, 0, this);
g2d.dispose();
}
}
}
}
This example deliberate adds a line border to the content as you can see what the original window bounds would be. It also uses a EmptyBorder to force the JButton onto the graphics, but this is just an example...

You'll have to create a shape based on your image. There are different threads here on SO that provide some way how to do this. The best one (based on the description, I didn't try it myself) might be Java - Create a shape from border around image. Another option for more complex images could be Image/Graphic into a Shape.
Another solution might be to use an undecorated frame along with "per-pixel transparency", as explained by Oracle here: http://docs.oracle.com/javase/tutorial/uiswing/misc/trans_shaped_windows.html

Layering text over JLabel

This is how I want my app to look like.
Trouble is, if I drag the JLabel with the "Hello, I'm Myra" over another JLabel (whose icon is the speech bubble), rather than superimposing or layering, NetBeans shifts the JLabels to be adjacent.
How do I superimpose ie. place the text JLabel on top of another JLabel?
Do note, I'm using NetBeans. It doesn't allow me to edit much of the JFrame or JLabel code.

Netbeans won't let you add components to a JLabel, it doesn't see them as a valid Container.
This won't be easily achieved using component labels, as the icon placement is outside of your control. A better solution might be to use a custom component, such as a JPanel and manually draw the speech bubble image yourself, then using a combination of Border and LayoutManager it would allow you to add other components to it
This is a very basic example...
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import java.awt.image.BufferedImage;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.border.EmptyBorder;
public class SpeechBubble {
public static void main(String[] args) {
new SpeechBubble();
}
public SpeechBubble() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
SpeechBubblePane bubble = new SpeechBubblePane();
JLabel hello = new JLabel("Hello, I'm Myra");
hello.setFont(hello.getFont().deriveFont(28f));
hello.setForeground(Color.CYAN);
JLabel message = new JLabel("<html>What would you like to know today?</html>");
message.setFont(message.getFont().deriveFont(22f));
message.setForeground(Color.WHITE);
bubble.setLayout(new GridLayout(2, 1));
bubble.add(hello);
bubble.add(message);
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setBackground(Color.BLACK);
frame.add(bubble);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class SpeechBubblePane extends JPanel {
private BufferedImage background;
public SpeechBubblePane() {
setOpaque(false);
try {
background = ImageIO.read(getClass().getResource("/speechbubble.png"));
} catch (IOException ex) {
ex.printStackTrace();
}
setBorder(new EmptyBorder(19, 19, 66, 19));
}
#Override
public Dimension getPreferredSize() {
Dimension size = new Dimension(200, 200);
if (background != null) {
size = new Dimension(background.getWidth(), background.getHeight());
}
return size;
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (background != null) {
Graphics2D g2d = (Graphics2D) g.create();
int x = (getWidth() - background.getWidth()) / 2;
int y = (getHeight()- background.getHeight()) / 2;
g2d.drawImage(background, x, y, this);
g2d.dispose();
}
}
}
}
If I was doing this, I would consider developing up a "9-path" which would allow you to break the image down into 9 parts and scale the outer sections based on what the content requires, for example...

It sounds like you just want to add a z-order. If so, you need a LayeredPane:
http://docs.oracle.com/javase/7/docs/api/index.html
http://docs.oracle.com/javase/7/docs/api/javax/swing/JLayeredPane.html

I'm trying to draw a filled rectangle over an imageIcon using the coordinates of the image and the rectangle appears off

Eventually after I work out this small detail it will receive a building and room number to outline said building and room number so it is easy to locate but I can't get the rectangle to draw even close to acurately over a single room.
package programSTLApp;
/*
Program to request the classroom no. in STLCC and Display the location of
that classroom.
*/
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class STLApp extends JFrame
{
private JLabel imageLabel;
private JButton button;
private JPanel imagePanel;
private JPanel buttonPanel;
public STLApp()
{
super("My STLCC Class Locator");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLayout(new BorderLayout());
buildImagePanel();
buildButtonPanel();
add(imagePanel, BorderLayout.CENTER);
add(buttonPanel,BorderLayout.SOUTH);
pack();
setVisible(true);
}
private void buildImagePanel()
{
imagePanel = new JPanel();
imageLabel = new JLabel("Click the button to see the drawing indicating "
+ "the location of your class");
imagePanel.add(imageLabel);
}
private void buildButtonPanel()
{
buttonPanel = new JPanel();
button = new JButton("Get Image");
button.addActionListener(new ButtonListener());
buttonPanel.add(button);
}
private class ButtonListener implements ActionListener
{
#Override
public void actionPerformed(ActionEvent e)
{
ImageIcon SiteLayoutFV = new ImageIcon("D:\\B120.jpg");
imageLabel.setIcon(SiteLayoutFV);
imageLabel.setText(null);
pack();
}
}
public void paint(Graphics g)
{
super.paint(g);
g.setColor(Color.RED);
g.fillRect(55,740,164,815);
}
public static void main(String[] args)
{
new STLApp();
}
}

As has already being pointed out, top level containers ain't a studiable class for performing custom painting, there is just to much going with these containers to make it easy to paint to.
Instead, create yourself a custom component, extending from something like JPanel, and override it's paintComponent method.
Once you have the floor pane rendered, you can render you custom elements over the top of it.
How you store this information is up to you, but basically, you need some kind of mapping that would allow you to take the floor/room and get the Shape that should be rendered.
Because the floor map might float (it may not always be rendered at 0x0 for example), you need to be able to translate the coordinates so that the Shape will always match.
Take a look at...
Performing Custom Painting
2D Graphics
For more details
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class FloorPlan {
public static void main(String[] args) {
new FloorPlan();
}
public FloorPlan() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private BufferedImage floorPlan;
private Rectangle myOffice = new Rectangle(150, 50, 32, 27);
public TestPane() {
try {
floorPlan = ImageIO.read(new File("floorPlan.png"));
} catch (IOException ex) {
ex.printStackTrace();
}
}
#Override
public Dimension getPreferredSize() {
return floorPlan == null ? new Dimension(200, 200) : new Dimension(floorPlan.getWidth(), floorPlan.getHeight());
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
if (floorPlan != null) {
int x = (getWidth() - floorPlan.getWidth()) / 2;
int y = (getHeight() - floorPlan.getHeight()) / 2;
g2d.drawImage(floorPlan, x, y, this);
g2d.setColor(Color.RED);
g2d.translate(x, y);
g2d.draw(myOffice);
}
g2d.dispose();
}
}
}

JAVA Showing Image -GUI

I'm trying to make a simple GUI using JAVA
no image is shown
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.io.*;
import javax.swing.*;
import javax.imageio.*;
public class EmiloLadderSnack {
public JFrame frame=new JFrame("EmiloLadderSnack");
public Image img;
public Graphics g;
public EmiloLadderSnack()
{
frame.setBounds(0, 0, Toolkit.getDefaultToolkit().getScreenSize().width, Toolkit.getDefaultToolkit().getScreenSize().height);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
try
{
img= ImageIO.read(new File("/media/01CCE00FA6888D80/Achieve/Eclipse/EmiloLadderSnack/src/photo.jpg"));
g.drawImage(img, 50, 50, null);
}
catch(Exception e)
{
System.out.println(e.toString());
}
}
public static void main(String args[])
{
new EmiloLadderSnack();
}
}
please help me to show an image in my simple GUI using JAVA
I'm using Eclipse

Hovercraft Full Of Eels is right, as he/she usually is. It really did not look like you tried.
Look at the tutorials, but I do believe when Hovercraft Full Of Eels says the correct way, hover means as follows.
Let me explain what I did below. First I created a new class that extended the JFrame. The JFrame is what is suppose to hold all of the components in a window. Then draw on the JPanel so that all of your drawings are contained in a lightweight container. I set the layout with a new layout I just discovered due to StackOverflow which I am very thankful for. The layout is called the MigLayout and it is a third party resource. You have to download it and import it. Please note that you do not have to have the MigLayout, but it is preferable to use due to its ease of use. After I set the Layout Constraint to fill and docked the JPanel in the center I created a new class which extended the JPanel so that I could change the paint method. The #Override lets you, in a way, re create the method for that extended class. As you can see once draw to that one graphics class then you are all set. There is a lot more you should read up on. Read the comments below your post, they suggest fairly good material.
Anything I get wrong Hovercraft will say below in the comments. So look for that as well.
Hovers corrections:
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class GraphicExample extends JPanel {
private static final String IMG_FILE_PATH = "/media/01CCE00FA6888D80/" +
"Achieve/Eclipse/EmiloLadderSnack/src/photo.jpg";
private BufferedImage img;
public GraphicExample(BufferedImage img) {
this.img = img;
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (img != null) {
g.drawImage(img, 0, 0, this);
}
}
#Override
public Dimension getPreferredSize() {
if (img != null) {
return new Dimension(img.getWidth(), img.getHeight());
}
return super.getPreferredSize();
}
private static void createAndShowGui() {
try {
BufferedImage img = ImageIO.read(new File(IMG_FILE_PATH));
JFrame frame = new JFrame("GraphicExample");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new GraphicExample(img));
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
// the easy way to display an image -- in a JLabel:
ImageIcon icon = new ImageIcon(img);
JLabel label = new JLabel(icon);
JOptionPane.showMessageDialog(frame, label);
} catch (IOException e) {
e.printStackTrace();
System.exit(-1);
}
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
My initial recommendations:
import java.awt.Color;
import java.awt.Graphics;
import javax.swing.JFrame;
import javax.swing.JPanel;
import net.miginfocom.swing.MigLayout;
public class DrawCircle extends JFrame {
JPanel panel;
public DrawCircle(String title, int width, int height) {
this.setTitle(title);
this.setSize(width, height);
this.setLocationRelativeTo(null); // Center JFrame
this.setLayout(new MigLayout("fill")); // Download external jar
this.panel = new DrawOval();
this.add(panel, "dock center"); // Link: http://www.miglayout.com/
this.setVisible(true);
}
public class DrawOval extends JPanel {
Color color = new Color(1, 1, 1);
public DrawOval() {
}
#Override
public void paint(Graphics g) {
g.setColor(color.RED);
g.fillOval(0, 0, this.getWidth(), this.getHeight());
}
}
}

I can't imagine that this is compiling. There must be a NullPointerException.
When you want to draw something you usually subclass JPanel and do the drawing in the paintComponent() method, like this:
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.drawImage(img, 50, 50, null);
}