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Grid drawn on A JPanel is not visible completely

I have a panel which extends JPanel and overrides method paintComponent(Graphics g) which draw some squares.
public class Painter extends JPanel{
private static final Color orange = new Color(225, 95, 0);
private Block[][] blocks;
private int sizeBlock;
public Painter() {
this.setBackground(Color.WHITE);
}
public void setBlocks(Block[][] blocks) {
this.blocks = blocks;
}
public void setSizeBlock(int size) {
this.sizeBlock = size;
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
for(Block[] cols : blocks) {
for(Block block : cols) {
switch(block.getType()) {
case Block.wall: {
paintBlockLineBorder(g, block.getX()*(sizeBlock-1),
block.getY()*(sizeBlock-1), orange);
break;
}
default: {break;}
}
}
}
}
private void paintBlockLineBorder(Graphics g, int x, int y, Color color) {
//background
g.setColor(color);
g.fillRect(x, y, sizeBlock, sizeBlock);
//border
g.setColor(Color.BLACK);
g.drawRect(x, y, sizeBlock-1, sizeBlock-1);
}
}
I add this JPanel (Painter) into other JPanel (painterPanel) which is added to a JFrame with layout GridBagLayout.
The result is not how I want:
This is what I want:
Here is a little use-case which reproduces the problem:
public static void main(String[] args) {
JFrame mainFrame = new JFrame();
mainFrame.setLayout(new GridBagLayout());
mainFrame.setBounds(100, 100, 500, 400);
mainFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
GridBagConstraints gbc = new GridBagConstraints();
gbc.anchor = GridBagConstraints.NORTHWEST;
gbc.fill = GridBagConstraints.NONE;
gbc.gridx = 0; gbc.gridy = 0;
gbc.weighty = 1; gbc.weightx = 1;
JPanel painterPanel = new JPanel();
painterPanel.setBorder(BorderFactory.createLineBorder(Color.black));
mainFrame.add(painterPanel, gbc);
Painter apainter = new Painter();
painterPanel.add(apainter);
Block[][] ablock = new Block[2][2];
ablock[0][0] = new Block(0, 0, Block.wall);
ablock[0][1] = new Block(0, 1, Block.wall);
ablock[1][0] = new Block(1, 0, Block.wall);
ablock[1][1] = new Block(1, 1, Block.wall);
apainter.setBlocks(ablock);
apainter.setSizeBlock(25);
apainter.repaint();
mainFrame.setVisible(true);
}
and here is Block class:
public class Block {
public static final String wall = "wall";
private int x;
private int y;
private String type;
public Block(int x, int y, String type) {
this.x = x;
this.y = y;
this.type = type;
}
//getters & setters
}
Why is my Painter not completely visible?

Try the following :
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Main{
public static void main(String[] args) throws InterruptedException{
JFrame mainFrame = new JFrame();
Block[][] ablock = new Block[2][2];
ablock[0][0] = new Block(0, 0, Block.wall);
ablock[0][1] = new Block(0, 1, Block.wall);
ablock[1][0] = new Block(1, 0, Block.wall);
ablock[1][1] = new Block(1, 1, Block.wall);
Painter apainter = new Painter();
mainFrame.add(apainter);
apainter.setBlocks(ablock);
apainter.setSizeBlock(25);
mainFrame.pack();
mainFrame.setVisible(true);
}
}
class Painter extends JPanel{
private static final Color orange = new Color(225, 95, 0);
private Block[][] blocks;
private int sizeBlock;
public Painter() {
setBackground(Color.WHITE);
setBorder(BorderFactory.createLineBorder(Color.black));
setPreferredSize(new Dimension(400, 300));
}
public void setBlocks(Block[][] blocks) {
this.blocks = blocks;
}
public void setSizeBlock(int size) {
sizeBlock = size;
//you may want to update Preferred Size
}
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
for(Block[] cols : blocks) {
for(Block block : cols) {
switch(block.getType()) {
case Block.wall: {
paintBlockLineBorder(g, block.getX()*(sizeBlock-1),
block.getY()*(sizeBlock-1), orange);
break;
}
default: {break;}
}
}
}
}
private void paintBlockLineBorder(Graphics g, int x, int y, Color color) {
//background
g.setColor(color);
g.fillRect(x, y, sizeBlock, sizeBlock);
//border
g.setColor(Color.BLACK);
g.drawRect(x, y, sizeBlock-1, sizeBlock-1);
}
}
class Block {
public static final String wall = "wall";
private final int x;
private final int y;
private final String type;
public Block(int x, int y, String type) {
this.x = x;
this.y = y;
this.type = type;
}
int getX() {return x; }
int getY() {return y; }
String getType() { return type;}
}
Don't hesitate to ask for clarifications as needed.
Also consider making a grid using GridLayout : 1 2

At advice of #CarlosHeuberger I overrided getPreferredSize, getMinimumSize and getMaximumSize which return a Dimension with values based on lengths of blocks and value of sizeBlock

Generating specific shapes with random dimensions using a JComboBox to select shapes

I am trying to create a program that uses a JComboBox containing specific shapes (Circle, Square, Oval, Rectangle). After the user clicks on a specified shape, the Panel will display 20 of that shape in random dimensions and locations.
I am having trouble on how to make the shapes have random dimensions and locations. Here is my code so far. Any advice or sources to look at would be appreciated.
Thank you.
import javax.swing.*;
import java.awt.*;
import java.awt.geom.*;
import java.util.*;
import java.awt.event.*;
public class HW1b extends JFrame
{
public HW1b()
{
super("Shapes");
final ComboPanel comboPanel = new ComboPanel();
String[] shapeItems = {"Circle", "Square", "Oval", "Rectangle"};
JComboBox shapeBox = new JComboBox<String>(shapeItems);
shapeBox.addItemListener(new ItemListener()
{
public void itemStateChanged(ItemEvent ie)
{
if (ie.getStateChange() == ItemEvent.SELECTED)
{
String item = (String)ie.getItem();
if(shapeBox.getSelectedItem().equals("Circle"))
comboPanel.makeCircles();
if(shapeBox.getSelectedItem().equals("Square"))
comboPanel.makeSquares();
if(shapeBox.getSelectedItem().equals("Oval"))
comboPanel.makeOvals();
if(shapeBox.getSelectedItem().equals("Rectangle"))
comboPanel.makeRectangles();
}
}
});
JPanel southPanel = new JPanel();
southPanel.add(shapeBox);
setDefaultCloseOperation(EXIT_ON_CLOSE);
getContentPane().add(comboPanel, "Center");
getContentPane().add(southPanel, "South");
setSize( 400, 400 );
setLocation( 200, 200 );
setVisible( true );
}
private class ComboPanel extends JPanel
{
int w, h;
Random rand;
static final int OVAL = 0;
static final int RECTANGLE = 1;
int shapeType = -1;
public ComboPanel()
{
rand = new Random();
setBackground(Color.white);
}
public void paintComponent(Graphics g)
{
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
int width = getWidth();
int height = getHeight();
int x, y;
Shape s = null;
for (int i = 0; i < 20; i++)
{
x = rand.nextInt(width - w);
y = rand.nextInt(width - h);
switch(shapeType)
{
case OVAL: s = new Ellipse2D.Double(x,y,w,h);
break;
case RECTANGLE: s = new Rectangle2D.Double(x,y,w,h);
break;
}
if (shapeType > -1)
g2d.draw(s);
}
}
public void makeCircles()
{
shapeType = OVAL;
w = 75;
h = 75;
repaint();
}
public void makeSquares()
{
shapeType = RECTANGLE;
w = 50;
h = 50;
repaint();
}
public void makeOvals()
{
shapeType = OVAL;
w = 80;
h = 60;
repaint();
}
public void makeRectangles()
{
shapeType = RECTANGLE;
w = 80;
h = 40;
repaint();
}
}
public static void main(String[] args)
{
new HW1b();
}
}

You're hard-coding w and h in your code, and so there's no way for this to vary among your shapes. Instead of doing this, use your Random variable, rand, to select random w and h values that are within some desired range. Myself, I wouldn't create my shapes within the paintComponent method since painting is not fully under my control and can occur when I don't want it to. For instance, in your code, your shapes will vary tremendously if the GUI is resized. Instead I'd create a collection such as an ArrayList<Shape> and fill it with created Shape objects (i.e., Ellipse2D for my circles) when desired, and then iterate through that collection within your paintComponent method, drawing your shapes.
for example...
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.Shape;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.awt.geom.Ellipse2D;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import javax.swing.*;
public class SomeShapes extends JPanel {
private ShapePanel shapePanel = new ShapePanel();
private JComboBox<MyShape> myShapeCombo = new JComboBox<>(MyShape.values());
public SomeShapes() {
myShapeCombo.setSelectedIndex(-1);
myShapeCombo.addItemListener(new ComboListener());
JPanel bottomPanel = new JPanel();
bottomPanel.add(myShapeCombo);
setLayout(new BorderLayout());
add(shapePanel, BorderLayout.CENTER);
add(bottomPanel, BorderLayout.PAGE_END);
}
private class ComboListener implements ItemListener {
#Override
public void itemStateChanged(ItemEvent e) {
MyShape myShape = (MyShape) e.getItem();
shapePanel.drawShapes(myShape);
}
}
private static void createAndShowGui() {
JFrame frame = new JFrame("SomeShapes");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new SomeShapes());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
enum MyShape {
OVAL("Oval"), RECTANGLE("Rectangle"), SQUARE("Square"), CIRCLE("Circle");
private String name;
private MyShape(String name) {
this.name = name;
}
public String getName() {
return name;
}
#Override
public String toString() {
return getName();
}
}
class ShapePanel extends JPanel {
private static final int PREF_W = 600;
private static final int PREF_H = PREF_W;
private static final Color SHAPE_COLOR = Color.BLUE;
private static final int SHAPE_COUNT = 20;
private static int MIN = 5;
private static int MAX = 200;
private List<Shape> shapeList = new ArrayList<>();
private Random random = new Random();
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
}
return new Dimension(PREF_W, PREF_H);
}
public void drawShapes(MyShape myShape) {
shapeList.clear(); // empty the shapeList
switch (myShape) {
case OVAL:
drawOval();
break;
case RECTANGLE:
drawRectangle();
break;
// etc...
default:
break;
}
repaint();
}
private void drawOval() {
// for loop to do this times SHAPE_COUNT(20) times.
for (int i = 0; i < SHAPE_COUNT; i++) {
// first create random width and height
int w = random.nextInt(MAX - MIN) + MIN;
int h = random.nextInt(MAX - MIN) + MIN;
// then random location, but taking care so that it
// fully fits into our JPanel
int x = random.nextInt(getWidth() - w);
int y = random.nextInt(getHeight() - h);
// then create new Shape and place in our shapeList.
shapeList.add(new Ellipse2D.Double(x, y, w, h));
}
}
private void drawRectangle() {
// .... etc
}
//.. .. etc
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D)g;
// set rendering hints for smooth ovals
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setColor(SHAPE_COLOR);
// iterate through the shapeList ArrayList
for (Shape shape : shapeList) {
g2d.draw(shape); // and draw each Shape it holds
}
}
}

dynamically update JPanel background does't work

After reading image from JFilechooser, I am trying to read pixel of an image one by one and display it to JPanel after some delay in sequential manner. can't update the background of JPanel.
public class ImageMain extends JFrame implements ActionListener {
/**
*
*/
private static final long serialVersionUID = 2916361361443483318L;
private JFileChooser fc = null;
private JMenuItem item1, item2;
private BufferedImage image = null;
private JPanel panel = null;
private int width = 0;
private int height = 0;
private BorderLayout card;
private Container contentPane;
//private int loopcount = 0;
//private int counter = 0;
public ImageMain() {
JFrame frame = new JFrame("Image Extraction Tool");
frame.setExtendedState(Frame.MAXIMIZED_BOTH);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
contentPane = frame.getContentPane();
panel = new JPanel();
card = new BorderLayout();
panel.setLayout(card);
panel.setBackground(Color.white);
JMenuBar menuBar = new JMenuBar();
JMenu menu = new JMenu("Menu");
menuBar.add(menu);
item1 = new JMenuItem("Browse an image");
item2 = new JMenuItem("Exit");
item1.addActionListener(this);
item2.addActionListener(this);
menu.add(item1);
menu.add(item2);
frame.setJMenuBar(menuBar);
contentPane.add(panel);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
try {
SwingUtilities.invokeAndWait(new Runnable() {
#Override
public void run() {
ImageMain img = new ImageMain();
}
});
} catch (InvocationTargetException | InterruptedException e) {
e.printStackTrace();
}
}
#Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == item1) {
if (fc == null)
fc = new JFileChooser();
int retVal = fc.showOpenDialog(null);
if (retVal == JFileChooser.APPROVE_OPTION) {
File file = fc.getSelectedFile();
try {
image = ImageIO.read(file);
height = image.getHeight();
width = image.getWidth();
// final int[][] pixelData = new int[height * width][3];
// int[] rgb;
for (int i = 0; i < height; i++) {
for (int j = 0; j < width; j++) {
System.out.println(i + " " + j);
Color c = new Color(image.getRGB(j, i));
panel.setBackground(c);
panel.invalidate();
panel.validate();
panel.repaint();
}
}
} catch (IOException e1) {
System.out.println("IO::" + e1.getMessage());
} catch (Exception e1) {
System.out.println("Exception::" + e1.getMessage());
}
}
}
if (e.getSource() == item2) {
System.exit(0);
}
}}
Inside ActionPerformed, I got Color object by reading RGB values and then I am stuck at displaying them to JApplet. Suggestion are welcome if there is a better way to achieve this.
Thanks in advance.

The main problem is your performing a long running task within the context of the Event Dispatching Thread, which is responsible for, amongst other things, processing repaint requests.
#Override
public void actionPerformed(ActionEvent e) {
//...
// Nothing will be updated until after the
// actionPerformed method exists
for (int i = 0; i < height; i++) {
for (int j = 0; j < width; j++) {
System.out.println(i + " " + j);
Color c = new Color(image.getRGB(j, i));
panel.setBackground(c);
panel.invalidate();
panel.validate();
panel.repaint();
}
}
The other problem you have is that you are required to only modify the state of the UI from within the context of the EDT
Depending on your exact needs, you could use a SwingWorker, which would allow you to process the pixels in the background while updating the UI from within the context of the EDT, however, because SwingWorker consolidates it's updates, you could miss color changes.
A better solution might be to use a java.swing.Timer which would allow you to trigger updates at a specified period, which are triggered within the context of the EDT.
See Concurrency in Swing for more details...
Updated with example
In order to draw pixels, you need something to draw them on. Now, you could simply add each pixel you want to paint to an array and loop that array each time you need to repaint the component, but that's kind of expensive...
Instead, it would be simpler to have a backing buffer of some kind, onto which you paint the pixels and then paint that buffer to the component, which should be faster.
Basically, the allows you to supply the height and width of the expected image and then supply each pixel as you need..
public class ImagePane extends JPanel {
private BufferedImage img;
public ImagePane() {
}
public void reset(int width, int height) {
img = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
revalidate();
}
public void reset() {
img = null;
revalidate();
}
public void setPixelAt(int x, int y, int pixel) {
img.setRGB(x, y, pixel);
}
#Override
public Dimension getPreferredSize() {
return img == null ? new Dimension(200, 200) : new Dimension(img.getWidth(), img.getHeight());
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
if (img != null) {
int x = (getWidth() - img.getWidth()) / 2;
int y = (getHeight() - img.getHeight()) / 2;
g2d.drawImage(img, x, y, this);
}
g2d.dispose();
}
}
Take a look at Performing Custom Painting for more details...
Then you need some way to process the original image and update the image panel...Now, based on the updated requirements, I would use a SwingWorker, the reason for this, is that the SwingWorker can cache what is passed back to the EDT, this allows the background thread to continue processing and caching the output until the EDT (and system) is ready to process it...
public class PixelExposerWorker extends SwingWorker<Void, Pixel> {
private final BufferedImage img;
private final ImagePane imagePane;
private final List<Point> points;
public PixelExposerWorker(BufferedImage img, ImagePane imagePane) {
this.img = img;
this.imagePane = imagePane;
points = new ArrayList<>(img.getWidth() * img.getHeight());
for (int x = 0; x < img.getWidth(); x++) {
for (int y = 0; y < img.getHeight(); y++) {
points.add(new Point(x, y));
}
}
}
#Override
protected void process(List<Pixel> chunks) {
System.out.println("Publish " + chunks.size());
for (Pixel pixel : chunks) {
imagePane.setPixelAt(pixel.getX(), pixel.getY(), pixel.getColor());
}
imagePane.repaint();
}
#Override
protected Void doInBackground() throws Exception {
int pixelCount = (int) (points.size() * 0.005);
while (!points.isEmpty()) {
for (int count = 0; count < pixelCount && !points.isEmpty(); count++) {
int index = (int) (Math.random() * (points.size() - 1));
Point p = points.remove(index);
Pixel pixel = new Pixel(p.x, p.y, img.getRGB(p.x, p.y));
publish(pixel);
}
Thread.yield();
}
return null;
}
}
Basically, this SwingWorker builds a List of "pixel points", it uses the list to randomly remove points from the list, generate a virtual Pixel and publish back to the EDT for processing. The worker will process around 0.5% of the pixels at a time, meaning that the work is always trying to send a "bunch" of pixels back to the EDT, rather the one at a time.
Finally, it will yield to allow other threads to run (and the hopefully for the EDT to update it self)
An image of 650x975 takes roughly 1m and 10s to fully renderer
And the full code...
import core.util.StopWatch;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.List;
import javax.imageio.ImageIO;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.SwingWorker;
import javax.swing.Timer;
public class PixelShower implements ActionListener {
private static final long serialVersionUID = 2916361361443483318L;
private JFileChooser fc = null;
private JMenuItem item1, item2;
private BufferedImage image = null;
private ImagePane panel = null;
private int width = 0;
private int height = 0;
private BorderLayout card;
private Container contentPane;
public PixelShower() {
JFrame frame = new JFrame("Image Extraction Tool");
frame.setExtendedState(Frame.MAXIMIZED_BOTH);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
contentPane = frame.getContentPane();
panel = new ImagePane();
card = new BorderLayout();
panel.setLayout(card);
panel.setBackground(Color.white);
JMenuBar menuBar = new JMenuBar();
JMenu menu = new JMenu("Menu");
menuBar.add(menu);
item1 = new JMenuItem("Browse an image");
item2 = new JMenuItem("Exit");
item1.addActionListener(this);
item2.addActionListener(this);
menu.add(item1);
menu.add(item2);
frame.setJMenuBar(menuBar);
contentPane.add(panel);
frame.setVisible(true);
}
public static void main(String[] args) {
try {
SwingUtilities.invokeAndWait(new Runnable() {
#Override
public void run() {
PixelShower img = new PixelShower();
}
});
} catch (InvocationTargetException | InterruptedException e) {
e.printStackTrace();
}
}
#Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == item1) {
if (fc == null) {
fc = new JFileChooser();
}
int retVal = fc.showOpenDialog(null);
if (retVal == JFileChooser.APPROVE_OPTION) {
File file = fc.getSelectedFile();
try {
image = ImageIO.read(file);
panel.reset(image.getWidth(), image.getHeight());
PixelExposerWorker worker = new PixelExposerWorker(image, panel);
worker.execute();
} catch (IOException e1) {
e1.printStackTrace();
} catch (Exception e1) {
e1.printStackTrace();
}
}
}
if (e.getSource() == item2) {
System.exit(0);
}
}
public class ImagePane extends JPanel {
private BufferedImage img;
public ImagePane() {
}
public void reset(int width, int height) {
img = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
revalidate();
}
public void reset() {
img = null;
revalidate();
}
public void setPixelAt(int x, int y, int pixel) {
img.setRGB(x, y, pixel);
}
#Override
public Dimension getPreferredSize() {
return img == null ? new Dimension(200, 200) : new Dimension(img.getWidth(), img.getHeight());
}
#Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g.create();
if (img != null) {
int x = (getWidth() - img.getWidth()) / 2;
int y = (getHeight() - img.getHeight()) / 2;
g2d.drawImage(img, x, y, this);
}
g2d.dispose();
}
}
public class Pixel {
private int x;
private int y;
private int color;
public Pixel(int x, int y, int color) {
this.x = x;
this.y = y;
this.color = color;
}
public int getColor() {
return color;
}
public int getX() {
return x;
}
public int getY() {
return y;
}
}
public class PixelExposerWorker extends SwingWorker<Void, Pixel> {
private final BufferedImage img;
private final ImagePane imagePane;
private final List<Point> points;
public PixelExposerWorker(BufferedImage img, ImagePane imagePane) {
this.img = img;
this.imagePane = imagePane;
points = new ArrayList<>(img.getWidth() * img.getHeight());
for (int x = 0; x < img.getWidth(); x++) {
for (int y = 0; y < img.getHeight(); y++) {
points.add(new Point(x, y));
}
}
}
#Override
protected void process(List<Pixel> chunks) {
System.out.println("Publish " + chunks.size());
for (Pixel pixel : chunks) {
imagePane.setPixelAt(pixel.getX(), pixel.getY(), pixel.getColor());
}
imagePane.repaint();
}
#Override
protected Void doInBackground() throws Exception {
StopWatch sw = StopWatch.newInstance().start();
int pixelCount = (int) (points.size() * 0.005);
System.out.println("pixelCount = " + pixelCount + "; " + points.size());
while (!points.isEmpty()) {
StopWatch sw1 = StopWatch.newInstance().start();
for (int count = 0; count < pixelCount && !points.isEmpty(); count++) {
int index = (int) (Math.random() * (points.size() - 1));
Point p = points.remove(index);
Pixel pixel = new Pixel(p.x, p.y, img.getRGB(p.x, p.y));
publish(pixel);
}
Thread.yield();
}
System.out.println("Took " + sw.stop());
return null;
}
}
}

Undesirable repaint of a JPanel when dynamically updated

I have a window that dynamically updates the buffered image set on a JPanel using javax.swing.Timer
Everything works as expected but every time I invoke the dynamic update there seems to be another buffered image displayed below the currently updating one.
The image of the window before and after clicking the train button (which triggers the dynamic update) is given below.
Since the image below the dynamically updating image looks like the initial screen. I rechecked the following
Whether I'm adding two dynamic lattice objects to the same panel
Multiple calls of repaint()
Unwanted initialization of the dynamic lattice
I could not find any of these in my code. I cannot post the code since it is huge and whenever I'm creating a minimal set to reproduce the same behavior it is not there. So I'm sure I'm missing something or doing something on my project code which triggers this behavior. Any suggestions on how to debug this or why it is doing something like this?
Thank you
EDIT
SSCCE is give below. If executing, click the load button followed by the train button to get the error.
(MapScreen.java - Main Class)
package test;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JLabel;
import javax.swing.SwingUtilities;
import javax.swing.Timer;
import java.awt.Font;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import test.DisplayLattice;
import test.SelfOrganizingMap;
public class MapScreen extends JFrame {
private double NUM_ITERATIONS = 0.0;
private double ETA = 0.0;
private double SPREAD_FACTOR = 0.0;
private double RADIUS = 0.0;
private int WIDTH = 0;
private int HEIGHT = 0;
private SelfOrganizingMap SOM = null;
private Timer REFRESH_TIMER = null;
private JPanel pnlMap;
private JButton btnLoadParameters;
private JButton btnTrain;
private DisplayLattice displayScreen;
public MapScreen(double iterations, double learningRate, double spreadFactor, double radius, int option, int width, int height, int mapOption) {
NUM_ITERATIONS = iterations;
ETA = learningRate;
SPREAD_FACTOR = spreadFactor;
RADIUS = radius;
WIDTH = width;
HEIGHT = height;
setType(Type.UTILITY);
setResizable(false);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setTitle("Map");
setSize(650, 800);
setLocation(150,150);
getContentPane().setLayout(null);
displayScreen = new DisplayLattice();
pnlMap = displayScreen;
pnlMap.setBounds(6, 130, 600, 600);
getContentPane().add(pnlMap);
btnLoadParameters = new JButton("Load Parameters");
btnLoadParameters.setFont(new Font("Tahoma", Font.PLAIN, 11));
btnLoadParameters.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0)
{
SOM = new SelfOrganizingMap(10000,0,0,13,displayScreen);
}
});
btnLoadParameters.setBounds(192, 46, 126, 23);
getContentPane().add(btnLoadParameters);
btnTrain = new JButton("Train");
btnTrain.setFont(new Font("Tahoma", Font.PLAIN, 11));
btnTrain.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
initialObjectSetUp();
}
});
btnTrain.setBounds(192, 72, 62, 23);
getContentPane().add(btnTrain);
}
private void initialObjectSetUp()
{
SOM.initTrainSOM(null, 100, 0.25);
REFRESH_TIMER = new Timer(100, SOM);
REFRESH_TIMER.start();
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
MapScreen frame = new MapScreen(100,0.25,0.0,0.0,1,100,0,0);
frame.setVisible(true);
}
});
}
}
(SelfOrganizingMap.java)
package test;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
public class SelfOrganizingMap implements ActionListener {
private Node[][] SOM = null;
private double[][] NORM_MAP = null; //holds the L2 norm of each vector in the SOM[][].
#SuppressWarnings("unused")
private int GRID_OPTION = 0;
private int INPUT_DIMENSION = 0;
private int NUMER_OF_ITERATIONS = 0;
private int CURRENT_ITERATION=0;
private int SOM_HORIZONTAL_LENGTH = 0;
private int SOM_VERTICAL_LENGTH = 0;
private double INITIAL_LEARNING_RATE = 0.0;
private double LEARNING_RATE = 0.0;
private double MAX_RADIUS = 0.0; //radius at first epoch (t = 0)
private double RADIUS = 0.0;
private double TIME_STEP = 0.0; //lambda of X(t) = t0 * exp(-t/lambda)
private String INPUT_SAMPLES = null;
private DisplayLattice DISPLAY_SCREEN = null;
public SelfOrganizingMap(int numberOfNodes, int depth, int grid, int inputDimensison, DisplayLattice screen)
{
INPUT_DIMENSION = inputDimensison;
if(grid == 0)
{
int side = (int)Math.sqrt(numberOfNodes);
SOM = new Node[side][side];
NORM_MAP = new double[side][side];
GRID_OPTION = grid;
MAX_RADIUS = side/2;
DISPLAY_SCREEN = screen;
}
RADIUS = MAX_RADIUS;
}
public void initTrainSOM(String input, int iterations, double learningRate)
{
NUMER_OF_ITERATIONS = iterations;
INITIAL_LEARNING_RATE = learningRate;
LEARNING_RATE = INITIAL_LEARNING_RATE;
TIME_STEP = NUMER_OF_ITERATIONS/Math.log(MAX_RADIUS);
INPUT_SAMPLES = input;
}
private void singleCompleteRun()
{
DISPLAY_SCREEN.render();
System.out.println(CURRENT_ITERATION);
}
#Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
if(CURRENT_ITERATION <= NUMER_OF_ITERATIONS)
{
singleCompleteRun();
CURRENT_ITERATION++;
}
}
}
(DisplayLattice.java)
package test;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import javax.swing.*;
#SuppressWarnings("serial")
public class DisplayLattice extends JPanel {
private BufferedImage img = new BufferedImage(500, 500, 1);
public void paintComponent(Graphics g) {
if (img == null)
super.paintComponents(g);
else
g.drawImage(img, 0, 0, this);
}
public void render() {
float cellWidth = 100;
float cellHeight = 100;
int imgW = img.getWidth();
int imgH = img.getHeight();
float r, g, b;
Graphics2D g2 = img.createGraphics();
g2.setBackground(Color.black);
g2.clearRect(0,0,imgW,imgH);
for (int x=0; x<100; x++) {
for (int y=0; y<100; y++) {
r = (float)Math.random();
g = (float)Math.random();
b = (float)Math.random();
g2.setColor(new Color(r,g,b));
g2.fillRect((int)(x*cellWidth), (int)(y*cellHeight),
(int)cellWidth+1, (int)cellHeight+1);
}
}
g2.setColor(Color.black);
g2.dispose();
repaint();
}
public BufferedImage getImage() {
if (img == null)
img = (BufferedImage)createImage(500, 500);
return img;
}
public void setImage(BufferedImage bimg) {
img = bimg;
}
}
(Node.java - Structure class for the SOM)
package test;
public class Node {
private int DIMENSION = 0;
private int POSITION_X = 0;
private int POSITION_Y = 0;
private double ACTIVATION_VALUE = 0.0;
public Node(int Dimensions, int x, int y)
{
DIMENSION = Dimensions;
setWeightVector();
POSITION_X = x;
POSITION_Y = y;
}
public int getX() {
return POSITION_X;
}
public int getY() {
return POSITION_Y;
}
public double getACTIVATION_VALUE() {
return ACTIVATION_VALUE;
}
public void setPOSITION_X(int x) {
POSITION_X = x;
}
public void setPOSITION_Y(int y) {
POSITION_Y = y;
}
public void setACTIVATION_VALUE(double y) {
ACTIVATION_VALUE= y;
}
private void setWeightVector()
{
double temp[] = new double[DIMENSION];
for(int i = 0; i<temp.length ; i++)
{
temp[i] = Math.random();
}
}
}

The problem is your DiaplyLattice class.
You overrode paintComponent but you invoke super.paintComponents(g). Notice the extra s you have at the end of paintComponents! This of course is unwanted and should be super.paintComponent(g);
I would have you method as follow:
#Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
if (img != null) {
g.drawImage(img, 0, 0, this);
}
}
Now, just as a good advice/tip to give, don't use null layout and rather use LayoutManager's and possibly use several level of nesting. It's always easier.
Also, you missed an important thing in SSCCE: the SHORT part. Meaning that you should remove anything unnecessary and have a single file to copy/paste.

Java JScrollBar Design

I want customize the JScrollBar Design. I use Mac to develop the app with eclipse. I already tried to scrollPane.getVerticalScrollBar().setBackground(Color.BLACK); but nothing happen.
My code:
scrollPane = new JScrollPane(scriptView);
scrollPane.setBorder(BorderFactory.createEmptyBorder());
scrollPane.getVerticalScrollBar().setUnitIncrement(6);
window.getContentPane().add(scrollPane);
The Object scriptView is from the class JEditorPane.
How it should look:
Thanks for every help.

I guess you are looking for a transparent scrollbar.
This is just presented as an idea(NOT tested code):
import java.awt.*;
import javax.swing.*;
import javax.swing.border.*;
import javax.swing.plaf.basic.*;
public class TranslucentScrollBarTest {
public JComponent makeUI() {
JTextArea cmp = new JTextArea();
String str = "1234567890abcdefghijklmnopqrstuvwxyz";
for(int i=0; i<20; i++) {
cmp.append(str+str+"\n");
}
cmp.setForeground(Color.WHITE);
cmp.setBackground(Color.BLACK);
cmp.setOpaque(true);
JScrollPane scrollPane = new JScrollPane(
cmp, ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS,
ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
scrollPane.setComponentZOrder(scrollPane.getVerticalScrollBar(), 0);
scrollPane.setComponentZOrder(scrollPane.getViewport(), 1);
scrollPane.getVerticalScrollBar().setOpaque(false);
scrollPane.setLayout(new ScrollPaneLayout() {
#Override
public void layoutContainer(Container parent) {
JScrollPane scrollPane = (JScrollPane)parent;
Rectangle availR = scrollPane.getBounds();
availR.x = availR.y = 0;
Insets insets = parent.getInsets();
availR.x = insets.left;
availR.y = insets.top;
availR.width -= insets.left + insets.right;
availR.height -= insets.top + insets.bottom;
Rectangle vsbR = new Rectangle();
vsbR.width = 12;
vsbR.height = availR.height;
vsbR.x = availR.x + availR.width - vsbR.width;
vsbR.y = availR.y;
if(viewport != null) {
viewport.setBounds(availR);
}
if(vsb != null) {
vsb.setVisible(true);
vsb.setBounds(vsbR);
}
}
});
scrollPane.getVerticalScrollBar().setUI(new BasicScrollBarUI() {
private final Dimension d = new Dimension();
#Override protected JButton createDecreaseButton(int orientation) {
return new JButton() {
#Override public Dimension getPreferredSize() {
return d;
}
};
}
#Override protected JButton createIncreaseButton(int orientation) {
return new JButton() {
#Override public Dimension getPreferredSize() {
return d;
}
};
}
#Override
protected void paintTrack(Graphics g, JComponent c, Rectangle r) {}
#Override
protected void paintThumb(Graphics g, JComponent c, Rectangle r) {
Graphics2D g2 = (Graphics2D)g.create();
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
Color color = null;
JScrollBar sb = (JScrollBar)c;
if(!sb.isEnabled() || r.width>r.height) {
return;
}else if(isDragging) {
color = new Color(200,200,100,200);
}else if(isThumbRollover()) {
color = new Color(255,255,100,200);
}else {
color = new Color(220,220,200,200);
}
g2.setPaint(color);
g2.fillRoundRect(r.x,r.y,r.width,r.height,10,10);
g2.setPaint(Color.WHITE);
g2.drawRoundRect(r.x,r.y,r.width,r.height,10,10);
g2.dispose();
}
#Override
protected void setThumbBounds(int x, int y, int width, int height) {
super.setThumbBounds(x, y, width, height);
scrollbar.repaint();
}
});
return scrollPane;
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override public void run() {
createAndShowGUI();
}
});
}
public static void createAndShowGUI() {
JFrame f = new JFrame();
f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
f.getContentPane().add(new TranslucentScrollBarTest().makeUI());
f.setSize(320, 240);
f.setLocationRelativeTo(null);
f.setVisible(true);
}
}

Here is an improved version I did for a private project. It also supports horizontal scrollbar.
Code:
import javax.swing.*;
import javax.swing.plaf.basic.BasicScrollBarUI;
import java.awt.*;
/**
* This is an implementation of a JScrollPane with a modern UI
*
* #author Philipp Danner
*
*/
public class ModernScrollPane extends JScrollPane {
private static final long serialVersionUID = 8607734981506765935L;
private static final int SCROLL_BAR_ALPHA_ROLLOVER = 100;
private static final int SCROLL_BAR_ALPHA = 50;
private static final int THUMB_SIZE = 8;
private static final int SB_SIZE = 10;
private static final Color THUMB_COLOR = Color.Black;
public ModernScrollPane(Component view) {
this(view, VERTICAL_SCROLLBAR_AS_NEEDED, HORIZONTAL_SCROLLBAR_AS_NEEDED);
}
public ModernScrollPane(int vsbPolicy, int hsbPolicy) {
this(null, vsbPolicy, hsbPolicy);
}
public ModernScrollPane(Component view, int vsbPolicy, int hsbPolicy) {
setBorder(null);
// Set ScrollBar UI
JScrollBar verticalScrollBar = getVerticalScrollBar();
verticalScrollBar.setOpaque(false);
verticalScrollBar.setUI(new ModernScrollBarUI(this));
JScrollBar horizontalScrollBar = getHorizontalScrollBar();
horizontalScrollBar.setOpaque(false);
horizontalScrollBar.setUI(new ModernScrollBarUI(this));
setLayout(new ScrollPaneLayout() {
private static final long serialVersionUID = 5740408979909014146L;
#Override
public void layoutContainer(Container parent) {
Rectangle availR = ((JScrollPane) parent).getBounds();
availR.x = availR.y = 0;
// viewport
Insets insets = parent.getInsets();
availR.x = insets.left;
availR.y = insets.top;
availR.width -= insets.left + insets.right;
availR.height -= insets.top + insets.bottom;
if (viewport != null) {
viewport.setBounds(availR);
}
boolean vsbNeeded = isVerticalScrollBarfNecessary();
boolean hsbNeeded = isHorizontalScrollBarNecessary();
// vertical scroll bar
Rectangle vsbR = new Rectangle();
vsbR.width = SB_SIZE;
vsbR.height = availR.height - (hsbNeeded ? vsbR.width : 0);
vsbR.x = availR.x + availR.width - vsbR.width;
vsbR.y = availR.y;
if (vsb != null) {
vsb.setBounds(vsbR);
}
// horizontal scroll bar
Rectangle hsbR = new Rectangle();
hsbR.height = SB_SIZE;
hsbR.width = availR.width - (vsbNeeded ? hsbR.height : 0);
hsbR.x = availR.x;
hsbR.y = availR.y + availR.height - hsbR.height;
if (hsb != null) {
hsb.setBounds(hsbR);
}
}
});
// Layering
setComponentZOrder(getVerticalScrollBar(), 0);
setComponentZOrder(getHorizontalScrollBar(), 1);
setComponentZOrder(getViewport(), 2);
viewport.setView(view);
}
private boolean isVerticalScrollBarfNecessary() {
Rectangle viewRect = viewport.getViewRect();
Dimension viewSize = viewport.getViewSize();
return viewSize.getHeight() > viewRect.getHeight();
}
private boolean isHorizontalScrollBarNecessary() {
Rectangle viewRect = viewport.getViewRect();
Dimension viewSize = viewport.getViewSize();
return viewSize.getWidth() > viewRect.getWidth();
}
/**
* Class extending the BasicScrollBarUI and overrides all necessary methods
*/
private static class ModernScrollBarUI extends BasicScrollBarUI {
private JScrollPane sp;
public ModernScrollBarUI(ModernScrollPane sp) {
this.sp = sp;
}
#Override
protected JButton createDecreaseButton(int orientation) {
return new InvisibleScrollBarButton();
}
#Override
protected JButton createIncreaseButton(int orientation) {
return new InvisibleScrollBarButton();
}
#Override
protected void paintTrack(Graphics g, JComponent c, Rectangle trackBounds) {
}
#Override
protected void paintThumb(Graphics g, JComponent c, Rectangle thumbBounds) {
int alpha = isThumbRollover() ? SCROLL_BAR_ALPHA_ROLLOVER : SCROLL_BAR_ALPHA;
int orientation = scrollbar.getOrientation();
int x = thumbBounds.x;
int y = thumbBounds.y;
int width = orientation == JScrollBar.VERTICAL ? THUMB_SIZE : thumbBounds.width;
width = Math.max(width, THUMB_SIZE);
int height = orientation == JScrollBar.VERTICAL ? thumbBounds.height : THUMB_SIZE;
height = Math.max(height, THUMB_SIZE);
Graphics2D graphics2D = (Graphics2D) g.create();
graphics2D.setColor(new Color(THUMB_COLOR.getRed(), THUMB_COLOR.getGreen(), THUMB_COLOR.getBlue(), alpha));
graphics2D.fillRect(x, y, width, height);
graphics2D.dispose();
}
#Override
protected void setThumbBounds(int x, int y, int width, int height) {
super.setThumbBounds(x, y, width, height);
sp.repaint();
}
/**
* Invisible Buttons, to hide scroll bar buttons
*/
private static class InvisibleScrollBarButton extends JButton {
private static final long serialVersionUID = 1552427919226628689L;
private InvisibleScrollBarButton() {
setOpaque(false);
setFocusable(false);
setFocusPainted(false);
setBorderPainted(false);
setBorder(BorderFactory.createEmptyBorder());
}
}
}
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setPreferredSize(new Dimension(400, 400));
JPanel content = new JPanel();
content.setBackground(Color.WHITE);
content.setPreferredSize(new Dimension(500, 500));
content.add(new JLabel("test"));
frame.add(new ModernScrollPane(content));
frame.pack();
frame.setVisible(true);
}
}

Custom scrollbar preview :
Custom scrollbar code :
public class CustomScrollBarUI extends BasicScrollBarUI {
private final Dimension d = new Dimension();
#Override
protected JButton createDecreaseButton(int orientation) {
return new JButton() {
private static final long serialVersionUID = -3592643796245558676L;
#Override
public Dimension getPreferredSize() {
return d;
}
};
}
#Override
protected JButton createIncreaseButton(int orientation) {
return new JButton() {
private static final long serialVersionUID = 1L;
#Override
public Dimension getPreferredSize() {
return d;
}
};
}
#Override
protected void paintTrack(Graphics g, JComponent c, Rectangle r) {
}
#Override
protected void paintThumb(Graphics g, JComponent c, Rectangle r) {
Graphics2D g2 = (Graphics2D) g.create();
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
Color color = null;
JScrollBar sb = (JScrollBar) c;
if (!sb.isEnabled() || r.width > r.height) {
return;
} else if (isDragging) {
color = Color.DARK_GRAY; // change color
} else if (isThumbRollover()) {
color = Color.LIGHT_GRAY; // change color
} else {
color = Color.GRAY; // change color
}
g2.setPaint(color);
g2.fillRoundRect(r.x, r.y, r.width, r.height, 10, 10);
g2.setPaint(Color.WHITE);
g2.drawRoundRect(r.x, r.y, r.width, r.height, 10, 10);
g2.dispose();
}
#Override
protected void setThumbBounds(int x, int y, int width, int height) {
super.setThumbBounds(x, y, width, height);
scrollbar.repaint();
}
}
Then use it like this:
YOUR_COMPONENT.getVerticalScrollBar().setUI(new CustomScrollBarUI());

Sadly the proposed solutions will break JTable and won't display the table header, but I found this solution that seems to work.