Spacing in AWT?

Hi, I've just finished a project which required a GUI, and I used a combination of the standard FlowLayout with a few panels using BorderLayout. What would have been useful would have been a way to insert just white space to space out components of the GUI. Is this possible in the AWT or Swing?

The constructor for BorderLayout:
public BorderLayout(int�hgap,
int�vgap)
Constructs a border layout with the specified gaps between components. The horizontal gap is specified by hgap and the vertical gap is specified by vgap.
Parameters:
hgap - the horizontal gap.
vgap - the vertical gap.
Since:
JDK1.0
As for flow layouts... I never touch em.

Similar Messages

JLabel spacing

I have a component with a JLabel above it. Both of these components are centered relative to the component that is next to it. However, it is not coming out quite right. It appears that the JLabel has 4 pixels of extra space above it. This spacing I believe is due to the font and not from the insets of the GridBagLayout. If I double the size of the JLabel's font, the spacing increases to 8 pixels. I also tested this with a small program that adds a single JLabel to a JFrame:
public class MainClass {
public static void main(String[] args) {
    javax.swing.JFrame frame = new javax.swing.JFrame();
    javax.swing.JLabel label = new javax.swing.JLabel("Environment-gy");
    label.setBackground(java.awt.Color.RED);
    frame.getContentPane().add(label);
    frame.getContentPane().setBackground(java.awt.Color.RED);
    frame.setDefaultCloseOperation(javax.swing.JFrame.EXIT_ON_CLOSE);
    frame.pack();
    frame.setVisible(true);
}If you run this, you will notis that the "gy" in the label has only a single pixel of spacing below, but there are 4 pixels of spacing above the text. Is there any way to remove these 4 pixels? The components do not center correctly with them in there. Even in the test program, the label does not appear to be centered exactly. It appears to be too far down from the top, albeit subtely.
I cannot just kludge this, however, because this application will be run on a number of different environments and there is no way to know what exact font and font size will be used.

In the future Swing related questions should be posted in the Swing forum.
If the past you have been given a link to the Swing tutorial, specifically you have been given the link on "How to Use Layout Managers". So read the tutorial, choose the appropriate layout manager and use the appropriate methods to control the spacing.

Is it possible to insert spacing between two TextFields (for visibility)?

In my program, I have multiple TextFields on top of each other, and I want some separation between them just so it looks better. Is there any way to insert a line, or just add more spacing between rows? I am using a Flow Layout (is there something better than this for what I need?).
Thanks.

import javax.swing.*;
import java.awt.*;
public class DMtest extends JApplet
     private TextField Field1;
     private TextField Field2;
     public void init()
          Field1 = new TextField ("asdf");
          Field2 = new TextField ("asdf2");
          Container mainWindow = getContentPane();
          mainWindow.setLayout(new FlowLayout());
          mainWindow.add(Field1);
          mainWindow.add(Field2);
}I want a space between Field1 and Field2, each on a separate row.

JScrollPane and TitledBorder spacing

Hello,
I have an issue with using a TitledBorder on a JScrollPane. The problem is that the border is noticeably larger than the JScrollPane inside of it. The problem can be clearly seen in these two images:
What the problem looks like: http://www.areath.com/images/ex1.jpg
What it should look like: http://www.areath.com/images/ex2.jpgIf the title is placed on top of the border, the problem is fixed, but it just doesn't look 'right' in this context. Obviously, the title in the border is interfering with the spacing inside of the border, but I was hoping to find a simple way to work around the problem without creating a custom border.
I am using the JGoodies Looks look and feel version 1.3.1 (http://www.jgoodies.com/downloads/libraries.html)
Thanks!

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.applet.Applet;
import javax.swing.BorderFactory;
import javax.swing.border.*;
public class TestBorderClass extends JApplet {
 private class CustomTitledBorder extends TitledBorder{
 int offset = 0;
 String secondTitle = "";
 public CustomTitledBorder(Border border,
 String title,
 int titleJustification,
 int titlePosition,
 Font titleFont,
 Color titleColor){
 super( border,"", titleJustification, titlePosition, titleFont, titleColor);
 this.titleColor = titleColor;
 this.offset = offset;
 this.secondTitle = title;
 public void paintBorder(Component c,
 Graphics g,
 int x,
 int y,
 int width,
 int height){
 //super.paintBorder(c, g, x, y, width, height);
 FontMetrics fontmetric = getFontMetrics(titleFont);
 Color color = g.getColor();
 Color lineColor = color;
 if((border.getClass())== javax.swing.border.LineBorder.class){
 LineBorder lineb = (LineBorder) border;
 lineColor = lineb.getLineColor();
 g.setFont(titleFont);
 int x1, y1, x2, y2;
 x1 = x + 2;
 y1 = y + 2;
 x2 = width - 4;
 y2 = height - 4;
 int half = (int)(fontmetric.getHeight()/2);
 g.setColor(lineColor);
 g.drawLine(x1, y1, 10, y1 );
 g.setColor(getTitleColor());
 g.drawString(secondTitle, 10, half);
 g.setColor(lineColor);
 g.drawLine(10 + fontmetric.stringWidth(secondTitle),y1, x2, y1);
 g.drawLine(x2, y1, x2, y2 );
 g.drawLine(x2, y2, x1, y2 );
 g.drawLine(x1, y2, x1, y1 );
 public void init() {
 JEditorPane area = new JEditorPane("text/html", "");
 area.setEditable(false);
 area.setOpaque(false);
 area.setText("<html><center>** This is the non-opaque JEditorPane ** With HTML formatting!</center> ");
 JScrollPane scroller = new JScrollPane(area,
 JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
 JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
 scroller.setOpaque(false);
 scroller.getViewport().setOpaque(false);
 scroller.setPreferredSize(new Dimension(698, 110));
 scroller.setBorder(new CustomTitledBorder(BorderFactory.createLineBorder(Color.white), "Titled Border Test", TitledBorder.LEFT, TitledBorder.TOP,
 new Font("Times New Roman", Font.BOLD, 14), Color.white));
 setContentPane(scroller);
}

Dynamic JSlider tick spacing

I run several times into the situation where I needed to hardcode a JSlider tick spacing into my program. I always found it difficult to define the tick spacing because a good looking tick spacing depends on the current size of the JSlider on screen and its maximum value.
For my purposes I created a short function that automatically sets a "good looking" tick spacing (labels do not cover more than half of the slider width and use familiar spacing values like 1,2,5,10,20,50,...).
I wanted to share this little piece of code with you, maybe it helps someone...
Here it is:
 private void setMajorTickSpacing(JSlider slider, int maxValue) {
 Graphics graphics = slider.getGraphics();
 FontMetrics fontMetrics = graphics.getFontMetrics();
 int width = slider.getWidth();
 // try with the following values:
 // 1,2,5,10,20,50,100,200,500,...
 int tickSpacing = 1;
 for (int i = 0, tmpWidthSum = width + 1; tmpWidthSum > (width / 2);
 i++) {
 tickSpacing = (int) Math.pow(10, (i / 3));
 switch (i % 3) {
 case 1:
 tickSpacing *= 2;
 break;
 case 2:
 tickSpacing *= 5;
 tmpWidthSum = 0;
 for (int j = 0; j < maxValue; j += tickSpacing) {
 Rectangle2D stringBounds = fontMetrics.getStringBounds(
 String.valueOf(j), graphics);
 tmpWidthSum += (int) stringBounds.getWidth();
 if (tmpWidthSum > (width / 2)) {
 // the labels are longer than the slider
 break;
 slider.setMajorTickSpacing(tickSpacing);
 slider.setLabelTable(createLabels(slider, tickSpacing));
 }To have your tick spacing dynamically adopted when the user resizes the window, you should use a code snippet similar to the following one:
 jSlider.addComponentListener(new java.awt.event.ComponentAdapter() {
 public void componentResized(java.awt.event.ComponentEvent evt) {
 setMajorTickSpacing(jSlider, maxValue);
 });There is still room for improvement, like handling minimum values etc.
Feel free to improve the code. And please share it with us! :-)

OK, I added some dukes. They will be spend on code improvements. ;-)

Weird font spacing - help needed

Hi,
I've been struggling with this for a while so would appreciate any help, I imagine this is quite a common problem. Basically, I'm developing a website which has quite a complex architecture and will involve generating graphs/charts as png images on the fly, dependent on user input.
To do this we're running weblogic 6.1, jdk 1.3, solaris 8 and an application called netcharts server (which is the charting engine). When a user requests a chart, the charting engine takes the parameters, does its thing to bring back the data and calls a servlet which uses AWT to generate the png image.
On windows, everything is fine, the images look great. However, seeing as the solaris box is running remotely without a display we use xvfb (running on display :1) to simulate an X server. The problem is that the fonts on the generated graphs look very weird - they're not the fonts I expect, and the spacing is very irregular, making the charts look really bad.
Does anyone know how to configure either the fonts.properties or set up solaris properly so it outputs nice looking fonts? I dont know if theres any patches to fix this - if someone could point me in the right direction I would be very grateful!!

What have you done between when it worked fine and when it doesn't? Do you have the same system version on both machines? Have you done any regular maintenance of the computer? Have you tried deleting the Font cache? Onyx is a free application that you can use for maintenance.

If Statement in java.awt paint

import java.applet.Applet; //bring in the applet class
import java.awt.*; //bring in the graphics class
import java.awt.event.*; //bring in the event class
import java.text.DecimalFormat; //bring in the decimal format class
import java.lang.Float; //bring in the float class
public class Bmi extends Applet implements ActionListener { //begin program and start ActionListener
Label weight, height; //define Label variable
TextField weighttext, heighttext; //define TextField variables
Button calculate; //define button variables
float index, wt, ht, max, min; //define float variables
DecimalFormat fmt2 = new DecimalFormat("#.00"); //set decimal format for reals
public void init() { //begin init()
weight = new Label("Please enter your weight in Kg. (2 decimal places): "); //define content of Label weight
weighttext = new TextField(6); //define size of TextField
height = new Label("Please enter your height in Metres (2 decimal places): "); //define content of Label height
heighttext = new TextField(5); //define size of TextField
calculate = new Button("Calculate!!"); //define content of Button
add(weight); //add Label weight to the GUI
add(weighttext); //add TextField weighttext to the GUI
add(height); //add Label height to the GUI
add(heighttext); //add TextField heighttext to the GUI
add(calculate); //add button calculate to the GUI
calculate.addActionListener(this); //wait for button to be returned
wt = 0; //reset wt to 0
index = 0; //reset index to 0
ht = 0; //reset ht to 0
max = 0; //reset max to 0
min = 0; //reset min to 0
public void actionPerformed( ActionEvent e ) { //run upon return of button
wt = Float.parseFloat(weighttext.getText()); //convert weighttext from String to Float
ht = Float.parseFloat(heighttext.getText()); //covert heighttext from String to Float
repaint(); //refresh paint area
public float indexer() //begin indexer method
 float ind; //delare local variable ind
 ind = wt/(ht*ht); //perform calculation
 return ind; //make indexer() the value of variable ind
} // end of indexer method
public float maxWeight() //begin maxWeight method
 float maxwt; //declare local variable maxwt
 final float UPPER = 25.0f; //declare variable UPPER as a float with a decimal value of 25.0
 maxwt = UPPER*ht*ht; //perform calculation
 return maxwt; //make maxWeight() the value of variable maxwt
} // end of maxWeight method
public float minWeight() //begin minWeight method
 float minwt; //declare local variable minwt
 final float LOWER= 20.0f; //declare variable LOWER as a float with a decimal value of 20.0
 minwt = LOWER*ht*ht; //perform calculation
 return minwt; //make minWeight() the value of variable minwt
} // end of minWeight method
public void paint(Graphics g) //begin paint method, define g as Graphics
 index=indexer(); //covert method indexer() to variable index
 max=maxWeight(); //convert method maxWeight() to variable max
 min=minWeight(); //convert method minWeight() to variable min
 g.setFont(new Font("Verdana", Font.ITALIC, 15)); //define font, weight and size
 g.setColor(new Color(90,90,90)); //set new colour
 g.drawRect(5,100,300,75); //define size of rectangle
 g.setColor(new Color(255,107,9)); //set new colour
 g.drawString("BMI is " + fmt2.format(index) + " for " + fmt2.format(wt) + "kg",20,120); //create string in paint, define its on screen position
 g.drawString("Maximum bodyweight is " + fmt2.format(max) + "kg", 20,140); //create string in paint, define its on screen position
 g.drawString("Minimum bodyweight is " + fmt2.format(min) + "kg", 20,160); //create string in paint, define its on screen position
} // end of paint method
} // end of Bmi classI have written the above code to calculate someones BMI (Body Mass Index). Basically as you can see it recieves a weight and height from the user and calculates the rest. But whilst that good I would like to know how I can make it tell the user something to the effect of "Your overweight" or "Your underweight". The if statement runs like this:
if (wt > max)This forum doesn't quite handle <> properly. The greater and less than symbols. So above you will see > this is the html character code for a greater than symbol so please read it as such.
And then if wt is greater than max then it will say "Your overweight".
But I can't figure out how to include it in the above program. Becuase it won't run in paint, atleast it won't the way I have done it previously. So can you think of any other ways?
Help much appreciated,
Simon

Thanks very much that works well.
Simon
My code now looks like this: import java.applet.Applet; //bring in the applet class
import java.awt.*; //bring in the graphics class
import java.awt.event.*; //bring in the event class
import java.text.DecimalFormat; //bring in the decimal format class
import java.lang.Float; //bring in the float class
public class Bmi extends Applet implements ActionListener { //begin program and start ActionListener
Label weight, height; //define Label variable
TextField weighttext, heighttext; //define TextField variables
Button calculate; //define button variables
float index, wt, ht, max, min; //define float variables
DecimalFormat fmt2 = new DecimalFormat("#.00"); //set decimal format for reals
public void init() { //begin init()
weight = new Label("Please enter your weight in Kg. (2 decimal places): "); //define content of Label weight
weighttext = new TextField(6); //define size of TextField
height = new Label("Please enter your height in Metres (2 decimal places): "); //define content of Label height
heighttext = new TextField(5); //define size of TextField
calculate = new Button("Calculate!!"); //define content of Button
add(weight); //add Label weight to the GUI
add(weighttext); //add TextField weighttext to the GUI
add(height); //add Label height to the GUI
add(heighttext); //add TextField heighttext to the GUI
add(calculate); //add button calculate to the GUI
calculate.addActionListener(this); //wait for button to be returned
wt = 0; //reset wt to 0
index = 0; //reset index to 0
ht = 0; //reset ht to 0
max = 0; //reset max to 0
min = 0; //reset min to 0
public void actionPerformed( ActionEvent e ) { //run upon return of button
wt = Float.parseFloat(weighttext.getText()); //convert weighttext from String to Float
ht = Float.parseFloat(heighttext.getText()); //covert heighttext from String to Float
repaint(); //refresh paint area
public float indexer() //begin indexer method
 float ind; //delare local variable ind
 ind = wt/(ht*ht); //perform calculation
 return ind; //make indexer() the value of variable ind
} // end of indexer method
public float maxWeight() //begin maxWeight method
 float maxwt; //declare local variable maxwt
 final float UPPER = 25.0f; //declare variable UPPER as a float with a decimal value of 25.0
 maxwt = UPPER*ht*ht; //perform calculation
 return maxwt; //make maxWeight() the value of variable maxwt
} // end of maxWeight method
public float minWeight() //begin minWeight method
 float minwt; //declare local variable minwt
 final float LOWER= 20.0f; //declare variable LOWER as a float with a decimal value of 20.0
 minwt = LOWER*ht*ht; //perform calculation
 return minwt; //make minWeight() the value of variable minwt
} // end of minWeight method
public void you(Graphics g)
String statement;
if(wt > max) statement="You are very fat";
else if(wt < min) statement="You are very thin";
else statement="You are in the recommended weight range for your height";
g.drawString(statement, 20,210);
public void paint(Graphics g) //begin paint method, define g as Graphics
 you(g);
 index=indexer(); //covert method indexer() to variable index
 max=maxWeight(); //convert method maxWeight() to variable max
 min=minWeight(); //convert method minWeight() to variable min
 g.setFont(new Font("Verdana", Font.ITALIC, 15)); //define font, weight and size
 g.setColor(new Color(90,90,90)); //set new colour
 g.drawRect(5,100,300,75); //define size of rectangle
 g.setColor(new Color(255,107,9)); //set new colour
 g.drawString("BMI is " + fmt2.format(index) + " for " + fmt2.format(wt) + "kg",20,120); //create string in paint, define its on screen position
 g.drawString("Maximum bodyweight is " + fmt2.format(max) + "kg", 20,140); //create string in paint, define its on screen position
 g.drawString("Minimum bodyweight is " + fmt2.format(min) + "kg", 20,160); //create string in paint, define its on screen position
} // end of paint method
} // end of BmiThanks again,
Simon

Can I build a GUI application with SWING only without [import java.awt.*;]

I have seen several threads (in forums), books and tutorials about SWING and I see that they all mix SWING with AWT (I mean they import both Swing and AWT in their code).
The conclusion that comes out is:
It is good to learn about SWING and forget AWT as it won't be supported later. I have decided to do so, and I never include <<import java.awt.*;>> in my code.
But I see that you cannot do much without <<import java.awt.*;>>. For example this line which changes the background color:
<<frame.getContentPane().setBackground(Color.red)>>
works only with <<import java.awt.*;>>. I have seen that codes in this and other forums import awt to change the background. Why is that?
After all, I wonder, what can I do;
My question is, can I change the background (and of course do all other things listener, buttons etc) without using <<import java.awt.*;>>.
I would like to avoid using <<import java.awt.*;>> and using awt since my program will not work later.
In addition, I believe there is no point to learn awt, which later will not exist.
I know, I must have misunderstood something. I would appreceate it very much, if anyone could give me even a short answer.
Thank you in advance,
JMelsi

Since swing is a layer on top of awt, AWT will exist for as long as swing does.
If sun does ever remove AWT they will have to replace it something else swing can layer on to and you will probably only have to replace your import statements.
The main difference is the way there drawn to the screen.
You can do custom drawing on swing components but you can't on AWT.
If your using a desktop PC system it's probably best to use swing just in case you wish to do some custom drawing.
awt uses less memory than swing and is faster but swing can be extended. awt comes only as standard.
Say for example you wish to implement a JButton with a ProgressBar below the button text, this can be done with swing!

In Pages 5.1 how do I change the default spacing after a paragraph? I used to be able to do this with the inspector. I no longer see the option.

In pages 5.1 I was wondering how to change the line spacing after a paragraph.

This is from the online Pages Help . You have the option to the Help in your Pages Help menu
Adjust line spacing
You can adjust the spacing between lines in a paragraph, and change the amount of space before or after a paragraph.
Click in the paragraph whose spacing you want to change, or select one or more paragraphs.
In the Text pane of the Format inspector, click Style.
Click the disclosure triangle next to Spacing, then choose an option from the pop-up menu:
Lines: Choose when the distance between ascenders (parts of letters that extend to the top of the line) and descenders (parts of letters that extend below the line) should stay the same. The space between lines is proportional to the font size.
At least: Choose when the distance between lines should remain fixed (but not to overlap if the text gets large).The distance from one line to the next will never be less than the value you set, but it may be larger for larger fonts to prevent overlapping text lines.
Exactly: The distance between the baselines.
Between: The value you set increases the space between the lines, instead of increasing the height of the lines. By contrast, double-spacing doubles the height of each line.
Click the arrows next to the spacing field to set the amount of space for the option you chose.
To adjust the amount of space before and after the selected paragraph, click the arrows for Before Paragraph and After Paragraph

The method add() in java.awt.Container made me in confuse

Here is my two java code file:
//MyContainer.java
package sam.gui;
import java.awt.Dimension;
import java.awt.Graphics;
import javax.swing.JApplet;
import javax.swing.JFrame;
public class MyContainer extends JApplet {
 private MyButton[] myButton = new MyButton[2];
 private static int counter = 0;
 public MyContainer() {
 myButton[0] = new MyButton(5, 5, 200, 30);
 myButton[1] = new MyButton(5, 40, 200, 30);
 for (int i = 0; i < myButton.length; i++) {
 add(myButton);
 public void paint(Graphics g) {
 for (int i = 0; i < myButton.length; i++) {
 System.out.println("MyButton : " + (i+1));
 myButton[i].draw(g);
 public static void main(String[] args) {
 MyContainer container = new MyContainer();
 JFrame f = new JFrame();
 f.getContentPane().add(container);
 f.pack();
 f.setSize(new Dimension(300, 200));
 f.show();
//MyButton.java
package sam.gui;
import java.awt.Color;
import java.awt.Component;
import java.awt.Graphics;
import java.awt.Graphics2D;
public class MyButton extends Component {
 private Color m_rectColor = new Color(128, 73, 0);
 public MyButton(int x, int y, int width, int height) {
 setBounds(x, y, width, height);
 public void draw(Graphics g) {
 Graphics2D g2 = (Graphics2D)g;
 g.setColor(m_rectColor);
 g.fillRect(0, 0,
 getBounds().width, getBounds().height);
 System.out.println("x = " + getBounds().x);
 System.out.println("y = " + getBounds().y);
 System.out.println("width = " + getBounds().width);
 System.out.println("height = " + getBounds().height);
I thinked the runned result should be below:
MyButton : 1
x = 5
y = 5
width = 200
height = 30
MyButton : 2
x = 5
y = 40
width = 200
height = 30But in fact, its result is here:
MyButton : 1
x = 5
y = 5
width = 200
height = 30
MyButton : 2
x = 0
y = 0
width = 292
height = 173I don't know why the result would like this? I have used add(...) method to add two component MyButton to the container MyContainer, But the bounds of the second component is not I want.
So this problem made me go into confuse.

You need to learn how layout managers work. The default layout manager of a JApplet and JFrame is BorderLayout .
/Kaj

Using List Class in java.awt / java.util ?

have a program that:
import java.util.*;
List list = new LinkedList();
list = new ArrayList();
... read a file and add elements to array
use a static setter
StaticGettersSetters.setArray(list);
next program:
import java.awt.*;
public static java.util.List queryArray =
StaticGettersSetters.getArray();
If I don't define queryArray with the package and class, the compiler
gives an error that the List class in java.awt is invalid for queryArray.
If I import the util package, import java.util.*; , the compiler
gives an error that the list class is ambiguous.
Question:
If you using a class that exists in multiple packages, is the above declaration of queryArray the only way to declare it ?
Just curious...
Thanks for your help,
YAM-SSM

So what you have to do is explicitly tell the compiler which one you really want by spelling out the fully-resolved class name:
import java.awt.*;
import java.sql.*;
import java.util.*;
public class ClashTest
    public static void main(String [] args)
        java.util.Date today    = new java.util.Date();
        java.util.List argsList = Arrays.asList(args);
        System.out.println(today);
        System.out.println(argsList);
}No problems here. - MOD

Custom graphics in java.awt.ScrollPane

Hi all,
I have to draw a custom created image in a scroll pane. As the image is very large I want to display it in a scroll pane. As parts of the image may change within seconds, and drawing the whole image is very time consuming (several seconds) I want to draw only the part of the image that is currently visible to the user.
My idea: creating a new class that extends from java.awt.ScrollPane, overwrite the paint(Graphics) method and do the drawings inside. Unfortunately, it does not work. The background of the scoll pane is blue, but it does not show the red box (the current viewport is not shown in red).
Below please find the source code that I am using:
package graphics;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.ScrollPane;
import java.awt.event.AdjustmentEvent;
public class CMyComponent extends ScrollPane {
 /** Listener to force a component to repaint when a scroll bar changes its
 * position.
 private final class ScrollBarAdjustmentListener implements java.awt.event.AdjustmentListener {
 /** The component to force to repaint. */
 private final Component m_Target;
 /** Default constructor.
 * @param Target The component to force to repaint.
 private ScrollBarAdjustmentListener(Component Target) { m_Target = Target; }
 /** Forces to component to repaint upon adjustment of the scroll bar.
 * @see java.awt.event.AdjustmentListener#adjustmentValueChanged(java.awt.event.AdjustmentEvent)
 public void adjustmentValueChanged(AdjustmentEvent e) { m_Target.paint(m_Target.getGraphics()); }
 public CMyComponent() {
 // Ensure that the component repaints upon changing of the scroll bars
 ScrollBarAdjustmentListener sbal = new ScrollBarAdjustmentListener(this);
 getHAdjustable().addAdjustmentListener(sbal);
 getVAdjustable().addAdjustmentListener(sbal);
 public void paint(Graphics g) {
 setBackground(Color.BLUE);
 g.setColor(Color.RED);
 g.fillRect(getScrollPosition().x, getScrollPosition().y, getViewportSize().width, getViewportSize().height);
 public final static void main(String[] args) {
 java.awt.Frame f = new java.awt.Frame();
 f.add(new CMyComponent());
 f.pack();
 f.setVisible(true);
}

Dear all,
I used the last days and tried several things. I think now I have a quite good working solution (just one bug remains) and it is very performant. To give others a chance to see what I have done I post the source code of the main class (a canvas drawing and implementing scrolling) here. As soon as the sourceforge project is accepted, I will publish the whole sources at there. Enjoy. And if you have some idea for my last bug in getElementAtPixel(Point), then please tell me.
package internetrail.graphics.hexgrid;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Point;
import java.awt.Polygon;
import java.awt.event.ComponentEvent;
import java.awt.event.ComponentListener;
import java.awt.geom.Area;
import java.awt.image.BufferedImage;
import java.util.WeakHashMap;
import java.util.Map;
/** Hex grid view.
* Visualizes a {@link IHexGridModel}.
* @version 0.1, 03.06.2006
* @author Bjoern Wuest, Germany
public final class CHexGridView extends Canvas implements ComponentListener, IHexGridElementListener {
 /** Serial version unique identifier. */
 private static final long serialVersionUID = -965902826101261530L;
 /** Instance-constant parameter for the width of a hex grid element. */
 public final int CONST_Width;
 /** Instance-constant parameter for 1/4 of the width of a hex grid element. */
 public final int CONST_Width1fourth;
 /** Instance-constant parameter for 3/4 of the width of a hex grid element. */
 public final int CONST_Width3fourth;
 /** Instance-constant parameter for 1.5 times of the width of a hex grid element. */
 public final int CONST_Width1dot5;
 /** Instance-constant parameter for 4 times of the width of a hex grid element. */
 public final int CONST_Widthquad;
 /** Instance-constant parameter for the height of a hex grid element. */
 public final int CONST_Height;
 /** Instance-constant parameter for 1/2 of the height of a hex grid element. */
 public final int CONST_Heighthalf;
 /** Instance-constant parameter for the double height of a hex grid element. */
 public final int CONST_Heightdouble;
 /** The steepness of a side of the hex grid element (calculated for the upper left arc). */
 public final double CONST_Steepness;
 /** The model of this hex grid */
 private final IHexGridModel m_Model;
 /** A cache for already created images of the hex map. */
 private final Map<Point, Image> m_Cache = new WeakHashMap<Point, Image>();
 /** The graphical area to draw the selection ring around a hex element. */
 private final Area m_SelectionRing;
 /** The image of the selection ring around a hex element. */
 private final BufferedImage m_SelectionRingImage;
 /** The current position of the hex grid in pixels (top left visible corner). */
 private Point m_ScrollPosition = new Point(0, 0);
 /** Flag to define if a grid is shown ({@code true}) or not ({@code false}). */
 private boolean m_ShowGrid = true;
 /** Flag to define if the selected hex grid element should be highlighted ({@code true}) or not ({@code false}). */
 private boolean m_ShowSelected = true;
 /** The offset of hex grid elements shown on the screen, measured in hex grid elements. */
 private Point m_CurrentOffset = new Point(0, 0);
 /** The offset of the image shown on the screen, measured in pixels. */
 private Point m_PixelOffset = new Point(0, 0);
 /** The index of the currently selected hex grid element. */
 private Point m_CurrentSelected = new Point(0, 0);
 /** The width of a buffered pre-calculated image in pixel. */
 private int m_ImageWidth;
 /** The height of a buffered pre-calculated image in pixel. */
 private int m_ImageHeight;
 /** The maximum number of columns of hex grid elements to be shown at once on the screen. */
 private int m_MaxColumn;
 /** The maximum number of rows of hex grid elements to be shown at once on the screen. */
 private int m_MaxRow;
 /** Create a new hex grid view.
 * The hex grid view is bound to a {@link IHexGridModel} and registers at
 * that model to listen for {@link IHexGridElement} updates.
 * @param Model The model backing this view.
 public CHexGridView(IHexGridModel Model) {
 // Set the model
 m_Model = Model;
 CONST_Width = m_Model.getElementsWidth();
 CONST_Height = m_Model.getElementsHeight();
 CONST_Width1fourth = CONST_Width/4;
 CONST_Width3fourth = CONST_Width*3/4;
 CONST_Width1dot5 = CONST_Width*3/2;
 CONST_Heighthalf = CONST_Height/2;
 CONST_Widthquad = CONST_Width*4;
 CONST_Heightdouble = CONST_Height*2;
 CONST_Steepness = (double)CONST_Heighthalf / CONST_Width1fourth;
 m_ImageWidth = getSize().width+CONST_Widthquad;
 m_ImageHeight = getSize().height+CONST_Heightdouble;
 m_MaxColumn = m_ImageWidth / CONST_Width3fourth;
 m_MaxRow = m_ImageHeight / CONST_Height;
 // Register this canvas for various notifications
 m_Model.addElementListener(this);
 addComponentListener(this);
 // Create the selection ring to highlight hex grid elements
 m_SelectionRing = new Area(new Polygon(new int[]{-1, CONST_Width1fourth-1, CONST_Width3fourth+1, CONST_Width+1, CONST_Width3fourth+1, CONST_Width1fourth-1}, new int[]{CONST_Heighthalf, -1, -1, CONST_Heighthalf, CONST_Height+1, CONST_Height+1}, 6));
 m_SelectionRing.subtract(new Area(new Polygon(new int[]{2, CONST_Width1fourth+2, CONST_Width3fourth-2, CONST_Width-2, CONST_Width3fourth-2, CONST_Width1fourth+2}, new int[]{CONST_Heighthalf, 2, 2, CONST_Heighthalf, CONST_Height-2, CONST_Height-2}, 6)));
 m_SelectionRingImage = new BufferedImage(CONST_Width, CONST_Height, BufferedImage.TYPE_INT_ARGB);
 Graphics2D g = m_SelectionRingImage.createGraphics();
 g.setColor(Color.WHITE);
 g.fill(m_SelectionRing);
 @Override public synchronized void paint(Graphics g2) {
 // Caculate the offset of indexes to show
 int offsetX = 2 * (m_ScrollPosition.x / CONST_Width1dot5) - 2;
 int offsetY = (int)(Math.ceil(m_ScrollPosition.y / CONST_Height) - 1);
 m_CurrentOffset = new Point(offsetX, offsetY);
 // Check if the image is in the cache
 Image drawing = m_Cache.get(m_CurrentOffset);
 if (drawing == null) {
 // The image is not cached, so draw it
 drawing = new BufferedImage(m_ImageWidth, m_ImageHeight, BufferedImage.TYPE_INT_ARGB);
 Graphics2D g = ((BufferedImage)drawing).createGraphics();
 // Draw background
 g.setColor(Color.BLACK);
 g.fillRect(0, 0, m_ImageWidth, m_ImageHeight);
 // Draw the hex grid
 for (int column = 0; column <= m_MaxColumn; column += 2) {
 for (int row = 0; row <= m_MaxRow; row++) {
 // Draw even column
 IHexGridElement element = m_Model.getElementAt(offsetX + column, offsetY + row);
 if (element != null) { g.drawImage(element.getImage(m_ShowGrid), (int)(column*(CONST_Width3fourth-0.5)), CONST_Height*row, null); }
 // Draw odd column
 element = m_Model.getElementAt(offsetX + column+1, offsetY + row);
 if (element!= null) { g.drawImage(element.getImage(m_ShowGrid), (int)(column*(CONST_Width3fourth-0.5)+CONST_Width3fourth), CONST_Heighthalf*(row*2+1), null); }
 // Put the image into the cache
 m_Cache.put(m_CurrentOffset, drawing);
 // Calculate the position of the image to show
 offsetX = CONST_Width1dot5 + (m_ScrollPosition.x % CONST_Width1dot5);
 offsetY = CONST_Height + (m_ScrollPosition.y % CONST_Height);
 m_PixelOffset = new Point(offsetX, offsetY);
 g2.drawImage(drawing, -offsetX, -offsetY, null);
 // If the selected element should he highlighted, then do so
 if (m_ShowSelected) {
 // Check if the selected element is on screen
 if (isElementOnScreen(m_CurrentSelected)) {
 // Correct vertical offset for odd columns
 if ((m_CurrentSelected.x % 2 == 1)) { offsetY -= CONST_Heighthalf; }
 // Draw the selection circle
 g2.drawImage(m_SelectionRingImage, (m_CurrentSelected.x - m_CurrentOffset.x) * CONST_Width3fourth - offsetX - ((m_CurrentSelected.x + 1) / 2), (m_CurrentSelected.y - m_CurrentOffset.y) * CONST_Height - offsetY, null);
 @Override public synchronized void update(Graphics g) { paint(g); }
 public synchronized void componentResized(ComponentEvent e) {
 // Upon resizing of the component, adjust several pre-calculated values
 m_ImageWidth = getSize().width+CONST_Widthquad;
 m_ImageHeight = getSize().height+CONST_Heightdouble;
 m_MaxColumn = m_ImageWidth / CONST_Width3fourth;
 m_MaxRow = m_ImageHeight / CONST_Height;
 // And flush the cache
 m_Cache.clear();
 public void componentMoved(ComponentEvent e) { /* do nothing */ }
 public void componentShown(ComponentEvent e) { /* do nothing */ }
 public void componentHidden(ComponentEvent e) { /* do nothing */ }
 public synchronized void elementUpdated(IHexGridElement Element) {
 // Clear cache where the element may be contained at
 for (Point p : m_Cache.keySet()) { if (isElementInScope(Element.getIndex(), p, new Point(p.x + m_MaxColumn, p.y + m_MaxRow))) { m_Cache.remove(p); } }
 // Update the currently shown image if the update element is shown, too
 if (isElementOnScreen(Element.getIndex())) { repaint(); }
 /** Returns the model visualized by this grid view.
 * @return The model visualized by this grid view.
 public IHexGridModel getModel() { return m_Model; }
 /** Returns the current selected hex grid element.
 * @return The current selected hex grid element.
 public IHexGridElement getSelected() { return m_Model.getElementAt(m_CurrentSelected.x, m_CurrentSelected.y); }
 /** Sets the current selected hex grid element by its index.
 * If the selected hex grid element should be highlighted and is currently
 * shown on the screen, then this method will {@link #repaint() redraw} this
 * component automatically.
 * @param Index The index of the hex grid element to become the selected one.
 * @throws IllegalArgumentException If the index refers to a non-existing hex
 * grid element.
 public synchronized void setSelected(Point Index) throws IllegalArgumentException {
 // Check that the index is valid
 if ((Index.x < 0) || (Index.y < 0) || (Index.x > m_Model.getXElements()) || (Index.y > m_Model.getYElements())) { throw new IllegalArgumentException("There is no hex grid element with such index."); }
 m_CurrentSelected = Index;
 // If the element is on screen and should be highlighted, then repaint
 if (m_ShowSelected && isElementOnScreen(m_CurrentSelected)) { repaint(); }
 /** Moves the visible elements to the left by the number of pixels.
 * To move the visible elements to the left by one hex grid element, pass
 * {@link #CONST_Width3fourth} as the parameter. The component will
 * automatically {@link #repaint()}.
 * @param Pixels The number of pixels to move to the left.
 * @return The number of pixels moved to the left. This is always between 0
 * and {@code abs(Pixels)}.
 public synchronized int moveLeft(int Pixels) {
 int delta = m_ScrollPosition.x - Math.max(0, m_ScrollPosition.x - Math.max(0, Pixels));
 if (delta != 0) {
 m_ScrollPosition.x -= delta;
 repaint();
 return delta;
 /** Moves the visible elements up by the number of pixels.
 * To move the visible elements up by one hex grid element, pass {@link
 * #CONST_Height} as the parameter. The component will automatically {@link
 * #repaint()}.
 * @param Pixels The number of pixels to move up.
 * @return The number of pixels moved up. This is always between 0 and {@code
 * abs(Pixels)}.
 public synchronized int moveUp(int Pixels) {
 int delta = m_ScrollPosition.y - Math.max(0, m_ScrollPosition.y - Math.max(0, Pixels));
 if (delta != 0) {
 m_ScrollPosition.y -= delta;
 repaint();
 return delta;
 /** Moves the visible elements to the right by the number of pixels.
 * To move the visible elements to the right by one hex grid element, pass
 * {@link #CONST_Width3fourth} as the parameter. The component will
 * automatically {@link #repaint()}.
 * @param Pixels The number of pixels to move to the right.
 * @return The number of pixels moved to the right. This is always between 0
 * and {@code abs(Pixels)}.
 public synchronized int moveRight(int Pixels) {
 int delta = Math.min(m_Model.getXElements() * CONST_Width3fourth + CONST_Width1fourth - getSize().width, m_ScrollPosition.x + Math.max(0, Pixels)) - m_ScrollPosition.x;
 if (delta != 0) {
 m_ScrollPosition.x += delta;
 repaint();
 return delta;
 /** Moves the visible elements down by the number of pixels.
 * To move the visible elements down by one hex grid element, pass {@link
 * #CONST_Height} as the parameter. The component will automatically {@link
 * #repaint()}.
 * @param Pixels The number of pixels to move down.
 * @return The number of pixels moved down. This is always between 0 and
 * {@code abs(Pixels)}.
 public synchronized int moveDown(int Pixels) {
 int delta = Math.min(m_Model.getYElements() * CONST_Height + CONST_Heighthalf - getSize().height, m_ScrollPosition.y + Math.max(0, Pixels)) - m_ScrollPosition.y;
 if (delta != 0) {
 m_ScrollPosition.y += delta;
 repaint();
 return delta;
 /** Checks if the hex grid element of the given index is currently
 * displayed on the screen (even just one pixel).
 * The intention of this method is to check if a {@link #repaint()} is
 * necessary or not.
 * @param ElementIndex The index of the element to check.
 * @return {@code true} if the hex grid element of the given index is
 * displayed on the screen, {@code false} if not.
 public synchronized boolean isElementOnScreen(Point ElementIndex) { return isElementInScope(ElementIndex, m_CurrentOffset, new Point(m_CurrentOffset.x + m_MaxColumn, m_CurrentOffset.y + m_MaxRow)); }
 /** Checks if the hex grid element of the given index is within the given
 * indexes.
 * The intention of this method is to check if a {@link #repaint()} is
 * necessary or not.
 * @param ElementIndex The index of the element to check.
 * @param ReferenceIndexLeftTop The left top index of the area to check.
 * @param ReferenceIndexRightBottom The right bottom index of the area to check.
 * @return {@code true} if the hex grid element of the given index is within
 * the given area, {@code false} if not.
 public synchronized boolean isElementInScope(Point ElementIndex, Point ReferenceIndexLeftTop, Point ReferenceIndexRightBottom) { if ((ElementIndex.x >= ReferenceIndexLeftTop.x) && (ElementIndex.x <= ReferenceIndexRightBottom.x) && (ElementIndex.y >= ReferenceIndexLeftTop.y) && (ElementIndex.y <= (ReferenceIndexRightBottom.y))) { return true; } else { return false; } }
 /** Return the {@link IHexGridElement hex grid element} shown at the given
 * pixel on the screen.
 * Remark: There seems to be a bug in retrieving the proper element,
 * propably caused by rounding errors and unprecise pixel calculations.
 * @param P The pixel on the screen.
 * @return The {@link IHexGridElement hex grid element} shown at the pixel.
 public synchronized IHexGridElement getElementAtPixel(Point P) {
 // @FIXME Here seems to be some bugs remaining
 int dummy = 0; // Variable for warning to indicate that there is something to do :)
 // Calculate the pixel on the image, not on the screen
 int px = P.x + m_PixelOffset.x;
 int py = P.y + m_PixelOffset.y;
 // Determine the x-index of the column (is maybe decreased by one)
 int x = px / CONST_Width3fourth + m_CurrentOffset.x;
 // If the column is odd, then shift the y-pixel by half element height
 if ((x % 2) == 1) { py -= CONST_Heighthalf; }
 // Determine the y-index of the row (is maybe decreased by one)
 int y = py / CONST_Height + m_CurrentOffset.y;
 // Normative coordinates to a single element
 px -= (x - m_CurrentOffset.x) * CONST_Width3fourth;
 py -= (y - m_CurrentOffset.y) * CONST_Height;
 // Check if the normative pixel is in the first quarter of a column
 if (px < CONST_Width1fourth) {
 // Adjustments to the index may be necessary
 if (py < CONST_Heighthalf) {
 // We are in the upper half of a hex-element
 double ty = CONST_Heighthalf - CONST_Steepness * px;
 if (py < ty) { x--; }
 } else {
 // We are in the lower half of a hex-element
 double ty = CONST_Heighthalf + CONST_Steepness * px;
 if (py > ty) {
 x--;
 y++;
 return m_Model.getElementAt(x, y);
}Ah, just to give you some idea: I use this component to visualize a hex grid map with more than 1 million grid elements. And it works, really fast, and requires less than 10 MByte of memory.

Useless code in java.awt.image.SampleModel.java?

Hey there,
i just looked up the sourcecode of java.awt.image.SampleModel.java in JDK 6
I discovered two issues i'd like to discuss.
1) on lines 736 to 739 this code is stated:
if (iArray != null)
pixels = iArray;
else
pixels = new int[numBands * w * h];
I asked myself, why does this code exist? while the getPixels() method is overwritten twice by double[] getPixels() and float[] getPixels, it is impossible to reach the part of the java code that initializes the pixels-array. One could only step into that line if "null" is given for the i/d/fArray-parameter. but if one would do so, the Java parser couldn't determine, which method is to use. so this part of code is just useless IMHO.
the java developers could get a little more performance out of this method if the if statement would be cut out - especially when reading a lot of very small rasters
or, on the other hand, they could replace this piece of code by an explicit bounds check.
When somebody touches this code, i would appreciate it if the errormessage "index out of bounds!" could be rewritten to be a little more verbose, like: Index out of bounds(x=123; y=456, maxX=100, maxY=400)!(numbers are just examples)
I hope i didn't miss something very basic and could help improving this class a little bit.
2) the local variable Offset(line 734) is coded against code conventions which say, variables shall start with a lowercase letter. Offset obviously doesn't fit that convention.
best regards
kdot

One could only step into that line if "null" is given for the i/d/fArray-parameter. but if one would do so, the Java parser couldn't determine, which method is to use. so this part of code is just useless IMHO. You can have
sampleModel.getPixels(x,y,w,h,(int[]) null, dataBuffer);No ambiguity on which method to use.
the local variable Offset(line 734) is coded against code conventions which say, variables shall start with a lowercase letter. Offset obviously doesn't fit that convention. You're correct, offset is against coding conventions. So are many other examples scattered throughout the jdk source code. For example, Hashtable should be called HashTable. In some cases the coding conventions might not have been established when the original code was written. In other cases it might have been human error. In yet other cases the conventions were probably ignored. The person who wrote the SampleModel class did so some 10+ years ago (Java 1.2). Who knows what he/she was thinking at the time, and in all honesty - does it really matter in this case?
Did you know there are some classes that declare unused local variables (ahem ColorConvertOp)? Some also have unused imports ( *** cough *** BufferedImage *** cough *** ). In essence, the jdk source code is not the epidemy of code correctness. But it's still pretty good.

OutOfMemory error in java.awt.image.DataBufferInt. init

We have an applet application that performs Print Preview of the images in the canvas. The images are like a network of entities (it has pictures of the entities involve (let's say Person) and how it links to other entities). We are using IE to launch the applet.
We set min heap space to 128MB, JVM max heap space to 256MB, java plugin max heap space to 256MB using the Control Panel > Java.
When the canvas width is about 54860 and height is 1644 and perform Print Preview, it thows an OutOfMemoryError in java.awt.image.DataBufferInt.<int>, hence, the Print Preview page is not shown. The complete stack trace (and logs) is as follows:
Width: 54860 H: 1644
Max heap: 254 # using Runtime.getRuntime().maxMemory()
javaplugin.maxHeapSize: 256M # using System.getProperties("javaplugin.maxHeapSize")
n page x n page : 1x1
Exception in thread "AWT-EventQueue-2" java.lang.OutOfMemoryError: Java heap space
 at java.awt.image.DataBufferInt.<init>(Unknown Source)
 at java.awt.image.Raster.createPackedRaster(Unknown Source)
 at java.awt.image.DirectColorModel.createCompatibleWritableRaster(Unknown Source)
 at java.awt.image.BufferedImage.<init>(Unknown Source)
 at com.azeus.gdi.chart.GDIChart.preparePreview(GDIChart.java:731)
 at com.azeus.gdi.chart.GDIChart.getPreview(GDIChart.java:893)
 at com.azeus.gdi.ui.GDIUserInterface.printPreviewOp(GDIUserInterface.java:1526)
 at com.azeus.gdi.ui.GDIUserInterface$21.actionPerformed(GDIUserInterface.java:1438)
 at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
 at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
 at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
 at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
 at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
 at java.awt.Component.processMouseEvent(Unknown Source)
 at javax.swing.JComponent.processMouseEvent(Unknown Source)
 at java.awt.Component.processEvent(Unknown Source)
 at java.awt.Container.processEvent(Unknown Source)
 at java.awt.Component.dispatchEventImpl(Unknown Source)
 at java.awt.Container.dispatchEventImpl(Unknown Source)
 at java.awt.Component.dispatchEvent(Unknown Source)
 at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
 at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
 at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
 at java.awt.Container.dispatchEventImpl(Unknown Source)
 at java.awt.Component.dispatchEvent(Unknown Source)
 at java.awt.EventQueue.dispatchEvent(Unknown Source)
 at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
 at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
 at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
 at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
 at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
 at java.awt.EventDispatchThread.run(Unknown Source)
Drilling down the cause of the problem. The OutOfMemory occurred in the constructor of DataBufferInt when it tried to create an int array:
public DataBufferInt(int size) {
super(STABLE, TYPE_INT, size);
data = new int[size]; # this part produce out of memory error when size = width X height
bankdata = new int[1][];
bankdata[0] = data;
The OutOfMemory error occurred when size is width * height (54860 X 1644) which is 90,189,840 bytes (~86MB).
I can replicate the OutOfMemory error when initiating an int array using a test class when it uses the default max heap space but if I increase the heap space to 256MB, it cannot be replicated in the test class.
Using a smaller width and height with product not exceeding 64MB, the applet can perform Print Preview successfully.
Given this, I think the java applet is not using the value assigned in javaplugin.maxHeapSize to set the max heap space, hence, it still uses the default max heap size and throws OutOfMemory in int array when size exceeds the default max heap space which is 64MB.
For additional information, below is some of the java properties (when press S in java applet console):
browser = sun.plugin
browser.vendor = Sun Microsystems, Inc.
browser.version = 1.1
java.awt.graphicsenv = sun.awt.Win32GraphicsEnvironment
java.awt.printerjob = sun.awt.windows.WPrinterJob
java.class.path = C:\PROGRA~1\Java\jre6\classes
java.class.version = 50.0
java.class.version.applet = true
java.runtime.name = Java(TM) SE Runtime Environment
java.runtime.version = 1.6.0_17-b04
java.specification.version = 1.6
java.vendor.applet = true
java.version = 1.6.0_17
java.version.applet = true
javaplugin.maxHeapSpace = 256M
javaplugin.nodotversion = 160_17
javaplugin.version = 1.6.0_17
javaplugin.vm.options = -Xms128M -Djavaplugin.maxHeapSpace=256M -Xmx256m -Xms128M
javawebstart.version = javaws-1.6.0_17
Kindly advise if this is a bug in JRE or wrong setting. If wrong setting, please advise on the proper way to set the heap space to prevent OutOfMemory in initializing int array.
Thanks a lot.
Edited by: rei_xanther on Jun 28, 2010 12:01 AM
Edited by: rei_xanther on Jun 28, 2010 12:37 AM

rei_xanther wrote:
..But the maximum value of the int data type is 2,147,483,647. That is the maximum positive integer value that can be stored in (the 4 bytes of) a signed int, but..
..The value that I passed in the int array size is only 90,189,840...its only connection with RAM is that each int requires 4 bytes of memory to hold it.
new int[size] -- size is 90,189,840Sure. So the number of bytes required to hold those 90,189,840 ints is 360,759,360.
I assumed that one element in the int array is 1 byte. ..Your assumption is wrong. How could it be possible to store 32 bits (4 bytes) in 8 bits (1 byte)? (a)
a) Short of some clever compression algorithm applied to the data.

Display image in java.awt.List

hello guys,
How i can display image in java.awt.List means listbox. give me sample code. if you have
Waiting for your favorable reply.
Regards,
Bhavesh Kharwa

java.awt.List you can not.
javax.swing.JLast you can.

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