Double Buffering and Components
Hello I am wondering how do I turn off double buffering for my components. This is important for printing as double buffering makes the print job alot of MB
/** The speed and quality of printing suffers dramatically if
* any of the containers have double buffering turned on.
* So this turns if off globally.
* @see enableDoubleBuffering
public static void disableDoubleBuffering(Component c) {
RepaintManager currentManager = RepaintManager.currentManager(c);
currentManager.setDoubleBufferingEnabled(false);
/** Re-enables double buffering globally. */
public static void enableDoubleBuffering(Component c) {
RepaintManager currentManager = RepaintManager.currentManager(c);
currentManager.setDoubleBufferingEnabled(true);
}
Similar Messages
-
Problem with Double Buffering and Swing
Hi
I made a game and basically it works pretty well, my only problem is it flickers really badly right now. I read up on a whole lot of forums about double buffering and none of those methods seemed to work. Then I noticed that Swing has double buffering built in so I tried that but then I get compilation errors and I'm really not sure why. My original code was a console application and worked perfectly, then I ported it into a JApplet and it still works but it flickers and thats what I'm tryign to fix now.
The code below is in my main class under the constructor.
Heres the double buffering code I'm trying to use, I'm sure you all seen it before lol
public void update(Graphics g)
// initialize buffer
if (dbImage == null)
dbImage = createImage(this.getSize().width, this.getSize().height);
dbg = dbImage.getGraphics();
// clear screen in background
dbg.setColor(getBackground());
dbg.fillRect(0, 0, this.getSize().width, this.getSize().height);
// draw elements in background
dbg.setColor(getForeground());
paint(dbg);
// draw image on the screen
g.drawImage(dbImage, 0, 0, this);
}My paint is right under neath and heres how it looks
This snipet of code works but when I change the method to
public paintComponent(Graphics g){
super.paintComponent(g)...
everythign stops working and get a compilation error and says that it can't find paintComponent in javax.swing.JFrame.
public void paint(Graphics g)
super.paint(g);
//if game starting display menue
if (show_menue)
//to restart lives if player dies
lives = 3;
menue.draw_menue(g);
menue_ufo1.draw_shape(g);
menue_ufo2.shape_color = Color.DARK_GRAY;
menue_ufo2.draw_shape(g);
menue_ufo3.shape_color = Color.BLUE;
menue_ufo3.draw_shape(g);
menue_ufo4.shape_color = new Color(82, 157, 22);
menue_ufo4.draw_shape(g);
menue_ufo5.draw_shape(g);
menue_ufo6.shape_color = new Color(130, 3, 3); ;
menue_ufo6.draw_shape(g);
menue_turret.draw_ship(g);
menue_ammo.draw_ammo(g);
else
//otherwise redraw game objects
gunner.draw_ship(g);
y_ammo.draw_ammo(g);
grass.draw_bar(g);
o_ufo.draw_shape(g);
b_ufo.draw_shape(g);
m_ufo.draw_shape(g);
s_ufo.draw_shape(g);
z_ufo.draw_shape(g);
xx_ufo.draw_shape(g);
info.draw_bar(g);
live_painter.draw_lives(g, lives);
score_painter.draw_score(g, score);
level_display.draw_level(g, level);
explosion.draw_boom(g);
}I just want to get rid of the flickering for now so any help will be greatly appreciated. Depending which will be simpler I can either try to double buffer this program or port it all to swing but I'm not sure which elements are effected by AWT and which by Swing. Also I read some of the Java documentation but couldn't really understand how to implement it to fix my program.
Thanks in advance
SebastianThis is a simple animation example quickly thrown together. I have two classes, an animation panel which is a JPanel subclass that overrides paintComponent and draws the animation, and a JApplet subclass that simply holds the animation panel in the applet's contentpane:
SimpleAnimationPanel.java
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.JPanel;
import javax.swing.Timer;
class SimpleAnimationPanel extends JPanel
private static final int DELAY = 20;
public static final int X_TRANSLATION = 2;
public static final int Y_TRANSLATION = 2;
private Point point = new Point(5, 32);
private BufferedImage duke = null;
private Timer timer = new Timer(DELAY, new TimerAction());
public SimpleAnimationPanel()
try
// borrow an image from sun.com
duke = ImageIO.read(new URL(
"http://java.sun.com/products/plugin/images/duke.wave.med.gif"));
catch (MalformedURLException e)
e.printStackTrace();
catch (IOException e)
e.printStackTrace();
setPreferredSize(new Dimension(600, 400));
timer.start();
// do our drawing here in the paintComponent override
@Override
protected void paintComponent(Graphics g)
super.paintComponent(g);
if (duke != null)
g.drawImage(duke, point.x, point.y, this);
private class TimerAction implements ActionListener
@Override
public void actionPerformed(ActionEvent e)
int x = point.x;
int y = point.y;
Dimension size = SimpleAnimationPanel.this.getSize();
if (x > size.width)
x = 0;
else
x += X_TRANSLATION;
if (y > size.height)
y = 0;
else
y += Y_TRANSLATION;
point.setLocation(new Point(x, y)); // update the point
SimpleAnimationPanel.this.repaint();
}AnimationApplet.java
import java.lang.reflect.InvocationTargetException;
import javax.swing.JApplet;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
public class AnimationApplet extends JApplet
public void init()
try
SwingUtilities.invokeAndWait(new Runnable()
public void run()
// construct the panel
JPanel simpleAnimation = new SimpleAnimationPanel();
// put it in the contentPane of the JApplet
getContentPane().add(simpleAnimation);
setSize(simpleAnimation.getPreferredSize());
catch (InterruptedException e)
e.printStackTrace();
catch (InvocationTargetException e)
e.printStackTrace();
}Here's a 3rd bonus class that shows how to put the JPanel into a stand-alone program, a JFrame. It's very similar to doing it in the JApplet:
AnimationFrame.java
import javax.swing.JFrame;
public class AnimationFrame
private static void createAndShowUI()
JFrame frame = new JFrame("SimpleAnimationPanel");
frame.getContentPane().add(new SimpleAnimationPanel());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
public static void main(String[] args)
java.awt.EventQueue.invokeLater(new Runnable()
public void run()
createAndShowUI();
}Edited by: Encephalopathic on Mar 15, 2008 11:01 PM -
Double buffering method - confusion
Hello everyone,
I've been messing around with Applets and animation in them and needed a method to reduce/remove flicker, so I decided on double buffering and looked up a tutorial on it. I understand the concept of it clearly, however the code doesn't make too much sense to me even after reading paint/graphics pages. What confuses me is:
Why is the "g.drawString()" in update method if it already paints the dbg graphics? I commented it out, and the ball won't move. In addition, in the drawImage method it draws dbImage which is only altered once (see when it was null), so how are we using it to double buffer if we never write to it except once?
import java.applet.*;
import java.awt.*;
public class BallBasic extends Applet implements Runnable {
int x_pos = 10;
int y_pos = 10;
int radius = 20;
private Image dbImage;
private Graphics dbg;
public void init() {
setBackground(Color.blue);
public void start() {
Thread th = new Thread(this);
th.start();
public void stop() {
public void destroy() {
public void run() {
Thread.currentThread().setPriority(Thread.MIN_PRIORITY);
while (true) {
x_pos++;
repaint();
try {
Thread.sleep(20);
} catch (InterruptedException ex) {
Thread.currentThread().setPriority(Thread.MAX_PRIORITY);
public void update(Graphics g) {
if (dbImage == null) {
System.out.println("dbImage was null");
dbImage = createImage(this.getSize().width, this.getSize().height);
dbg = dbImage.getGraphics();
dbg.setColor(getBackground());
dbg.fillRect(0, 0, this.getSize().width, this.getSize().height);
dbg.setColor(getForeground());
paint(dbg);
g.drawImage(dbImage, 0, 0, this);
public void paint(Graphics g) {
g.setColor(Color.red);
g.fillOval(x_pos - radius, y_pos - radius, 2 * radius, 2 * radius);
}Thanks for reading, hope you can help.
Note: I understand how the panting process works, how it ties into update, ectcetera, please do not post explanations of how painting/applets work, just looking for heavy comments on what is happening throughout the update/paint method.Patrick_Ritchie wrote:
I want to understand the concepts of this and how to use just plain ol' applets. I need to learn these things ;)Most people skip the old AWT. Did you learn how steam engines worked before you learned to drive a car? -
Which is better, Double Buffering 1, or Double Buffering 2??
Hi,
I came across a book that uses a completely different approach to double buffering. I use this method:
private Graphics dbg;
private Image dbImage;
public void update() {
if (dbImage == null) {
dbImage = createImage(this.getSize().width, this.getSize().height);
dbg = dbImage.getGraphics();
dbg.setColor(this.getBackground());
dbg.fillRect(0, 0, this.getSize().width, this.getSize().height);
dbg.setColor(this.getForeground());
paint(dbg);
g.drawImage(dbImage, 0, 0, this);
}that was my method for double buffering, and this is the books method:
import java.awt.*;
public class DB extends Canvas {
private Image[] backing = new Image[2];
private int imageToDraw = 0;
private int imageNotDraw = 1;
public void update(Graphics g) {
paint(g);
public synchronized void paint(Graphics g) {
g.drawImage(backing[imageToDraw], 0, 0, this);
public void addNotify() {
super.addNotify();
backing[0] = createImage(400, 400);
backing[1] = createImage(400, 400);
setSize(400, 400);
new Thread(
new Runnable() {
private int direction = 1;
private int position = 0;
public void run() {
while (true) {
try {
Thread.sleep(10);
}catch (InterruptedException ex) {
Graphics g = backing[imageNotDraw].getGraphics();
g.clearRect(0, 0, 400, 400);
g.setColor(Color.black);
g.drawOval(position, 200 - position, 400 - (2 * position), 72 * position);
synchronized (DB.this) {
int temp = imageNotDraw;
imageNotDraw = imageToDraw;
imageToDraw = temp;
position += direction;
if (position > 199) {
direction = -1;
}else if (position < 1) {
direction = 1;
repaint();
).start();
public static void main(String args[]) {
Frame f = new Frame("Double Buffering");
f.add(new DB(), BorderLayout.CENTER);
f.pack();
f.show();
}which is better? I noticed smoother animation with the later method.
Is there no difference? Or is it just a figment of my imagination??To be fair if you download an applet all the class files are stored in your .jpi_cache, and depending on how that game requests its graphics sometimes they are stored there to, so really if you have to download an applet game twice, blame the programmer (I've probably got that dead wrong :B ).
But, what's wrong with Jars. They offer so much more.
No offence meant by this Malohkan but if you can't organize your downloaded files the internet must really be a landmine for you :)
Personally I'd be happy if I never seen another applet again, it seems java is tied to this legacy, and to the average computer user it seems that is all java is capable of.
Admitidly there are some very funky applets out here using lots of way over my head funky pixel tricks, but they would look so much better running full screen and offline. -
Is dictionary cache double buffered (shared pool, buffer cache)
Hi,
I'm trying to get idea about how dictionary cache is buffered .
Let us say we're talking about dc_objects .
It is dba_tables view related so all underlying sys.obj$ sys.user$ ... tables block are cached in buffer cache.
So why we are caching them in dictionary cache space in shared pool additionally ?
Looks like double buffering and wasting SGA .
Please explain .
Regards
GregGHI,
Dictionary cache will not cache data of tables, rather it will cache the structural information of table (in your case).
If i will do "select ename from emp", during statement compilation, it needs to check whether "ename" is a real column? and for this it needs to query data dictionary information (from using physical read of system data file or from data dictionary cache if information is there). It also need to check whether i have (logged in user) rights to access this table/column and all this information comes from data dictionary.
This is a simple example, otherwise dictionary cache need to store a lot of other information also (but purely the information present in data dictionary)
Salman -
Custom RepaintManager can't support true double-buffering?
RepaintManager doesn't provide a way to set bufferStrategyType. Custom RepaintManager can't support true double-buffering and 'gray rect' problem again?
Well looking at the source code, I was wrong... nevermind
-
Panel refreshing and double buffering
Hi all swing experts
Could any one solve the problem.I have an application,which is having a JSplit pane.
On the left of the JSplit pane , there is a tree. When u click a node from the tree
that will be selected and you can place that node into the right side panel.
And the same way you can click an another node (redirection or sink) and drop into the
panel.you can draw a line by clicking the source and the sink / or redirection.
The line is getting drawn dynamically by getting the x,y coordinates of the node.
once the line is drawn am storing the line into vector, since this is getting drawn
dynamically once if i minimize and maxmize it will disappear.
For avoiding this am trying to redraw the old line from the vector when the window
is getting activated, here the problem starts it draws the line but the line
is getting disappeared immly.
HOW DO I SOLVE THIS?
is it possible to solve this problem with double buffering tech? if so how?
PL HELP.
Software - Visual Tool
Last Modified -7/23/01
sami
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;
import javax.swing.*;
import javax.swing.border.TitledBorder;
import javax.swing.event.TreeSelectionEvent;
import javax.swing.event.TreeSelectionListener;
import javax.swing.plaf.FontUIResource;
import javax.swing.tree.*;
import java.lang.System;
import java.net.*;
import java.awt.image.*;
import javax.swing.event.*;
public class CompTree extends JFrame implements TreeSelectionListener,WindowListener{
// Swing components declarations
public JSplitPane jSplitPane1,jSplitPaneTop;
public JScrollPane treeScrollPane,splitScrollPane;
public JTree mainTree,jtree ;
public static DefaultMutableTreeNode topchildnode1, topchildnode2, topchildnode3,toptreenode;
DrawPanel dp = new DrawPanel();
public int i=0;
public int j=0;
public int flag = 1 ;
public String var,S,R,D;
Frame fr = new Frame("GUI TOOL");
public CompTree()
File nFile = null ;
mainTree = DrawTree(nFile,"N") ;
mainTree.updateUI();
mainTree.setBackground(new Color(105,205,159));
// Tree is getting added into scroll pane
treeScrollPane = new JScrollPane(mainTree);
treeScrollPane.setVerticalScrollBarPolicy(javax.swing.JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
treeScrollPane.setHorizontalScrollBarPolicy(javax.swing.JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
splitScrollPane = new JScrollPane();
splitScrollPane.setViewportView(dp.panel1);
splitScrollPane.setVerticalScrollBarPolicy(javax.swing.JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
splitScrollPane.setHorizontalScrollBarPolicy(javax.swing.JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
jSplitPane1 = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,treeScrollPane,splitScrollPane);
jSplitPane1.setOneTouchExpandable(true);
jSplitPane1.setContinuousLayout(true);
jSplitPane1.addComponentListener(new ComponentAdapter(){
public void componentResized(ComponentEvent e) {
System.out.println("Componenet resized");
flag = 1;
paint(dp.panel1.getGraphics());
//Provide minimum sizes for the two components in the split pane
Dimension minimumSize = new Dimension(150,75);
splitScrollPane.setMinimumSize(minimumSize);
//Provide a preferred size for the split pane
jSplitPane1.setPreferredSize(new Dimension(700, 500));
//setContentPane(jSplitPane1);
fr.add(jSplitPane1);
fr.setSize(700,500);
fr.setVisible(true);
fr.addWindowListener(this);
public void windowActivated(WindowEvent we){
System.out.println("activated");
dp.draw();
public void windowClosed(WindowEvent we){System.out.println("closed");}
public void windowIconified(WindowEvent we){System.out.println("iconified");}
public void windowDeiconified(WindowEvent we){
dp.draw();
System.out.println("deiconified");
public void windowDeactivated(WindowEvent we){System.out.println("deactivated");}
public void windowOpened(WindowEvent we){
dp.repaint();
System.out.println("opened");
public void windowClosing(WindowEvent we){
System.exit(0);
System.out.println("closing");
public void valueChanged(TreeSelectionEvent e) {
DefaultMutableTreeNode node = (DefaultMutableTreeNode)
mainTree.getLastSelectedPathComponent();
String strRootNode = "" ;
try{
Object rootNode = node.getRoot();
strRootNode = rootNode.toString() ;
catch(Exception eRoot)
System.out.println("Error in geting Root Node");
if (node == null) return;
Object nodeInfo = node.getUserObject();
TreeNode ParentNode = node.getParent();
final String strParentName = node.toString() ;
if (strParentName.equals("Source"))
System.out.println("Before source");
var = "S";
System.out.println("This is source");
else if (strParentName.equals("Redirection"))
var ="R";
else if (strParentName.equals("Sink") )
var ="D";
else
if ( strRootNode != strParentName){
public JTree DrawTree( File file, String strIsValid)
jtree = new JTree();
toptreenode = new DefaultMutableTreeNode("Start");
topchildnode1 = new DefaultMutableTreeNode("Source");
topchildnode2 = new DefaultMutableTreeNode("Sink");
topchildnode3 = new DefaultMutableTreeNode("Redirection");
toptreenode.add(topchildnode1);
toptreenode.add(topchildnode2);
toptreenode.add(topchildnode3);
jtree.putClientProperty("JTree.lineStyle", "Angled");
DefaultTreeModel defaulttreemodel = new DefaultTreeModel(toptreenode);
jtree.setModel(defaulttreemodel);
DefaultTreeSelectionModel defaulttreeselectionmodel = new DefaultTreeSelectionModel();
defaulttreeselectionmodel.setSelectionMode(1);
jtree.setSelectionModel(defaulttreeselectionmodel);
jtree.addTreeSelectionListener(this);
jtree.setEditable(true);
return jtree;
public static void main(String args[]){
CompTree ct = new CompTree();
* This class contains all the component related to panel 1
* this can be used for .....
public class DrawPanel extends JPanel implements ActionListener,
ComponentListener,MouseListener,KeyListener{
public JRadioButton uniRadio,multiRadio,show;
public JButton sBut,rBut,dBut;
public int flag = 1 ;
public int Radio = 1;
public boolean sIndicator = true;
public boolean rIndicator = true;
public boolean isDestSelected = false;
public boolean isDestFirstTime = true;
public int x1 = 0 ;
public int y1 = 0 ;
public int x2 = 0 ;
public int y2 = 0;
public int x3 = 0;
public int y3 = 0;
public int k=0;
public int l = 40;
public int b = 40;
public String connection1,connection2,connection3,destination1,destination2;
public int locX;
public int locY;
public JPanel panel1 = new JPanel ();
public JPanel panel2 = new JPanel ();
Vector lines = new Vector();
Vector colors = new Vector();
Vector obj = new Vector();
Vector source = new Vector();
Vector loc = new Vector();
BasicStroke stroke = new BasicStroke(2.0f);
Icon compImage = new ImageIcon("network1.gif"); //new
Icon workImage = new ImageIcon("tconnect02.gif");
Icon lapImage = new ImageIcon("server02.gif");
public DrawPanel(){
am adding radio button for checking the mode unicast and broad cast mode -- new
uniRadio = new JRadioButton("Unicast Mode");
uniRadio.setMnemonic(KeyEvent.VK_B);
uniRadio.setSelected(true);
multiRadio = new JRadioButton("Broadcast Mode");
multiRadio.setMnemonic(KeyEvent.VK_C);
show = new JRadioButton("show Panel");
show.setMnemonic(KeyEvent.VK_C);
ButtonGroup group = new ButtonGroup();
group.add(uniRadio);
group.add(multiRadio);
group.add(show);
/* Border border = ButtonGroup.getBorder();
Border margin = new EmptyBorder(10,10,10,10);
ButtonGroup.setBorder(new CompoundBorder(border,margin)); */
uniRadio.addActionListener(this);
multiRadio.addActionListener(this);
show.addActionListener(this);
panel1.add(uniRadio);
panel1.add(multiRadio);
panel1.add(show);
uniRadio.setBounds(150,15,100,40);
multiRadio.setBounds(260,15,120,40);
show.setBounds(390,15,100,40);
uniRadio.setBackground(new Color(105,200,205));
multiRadio.setBackground(new Color(105,200,205));
show.setBackground(new Color(105,200,205));
/*****************PANEL 1*********************/
panel1.setLayout(null);
panel1.setBounds(new Rectangle(0,0,400,400));
panel1.setBackground(new Color(105,100,205));
panel1.addComponentListener(this);
panel1.addMouseListener(this);
public void sourceObject(String name)
sBut = new JButton(compImage);
panel1.add(sBut);
sBut.setMnemonic(KeyEvent.VK_F);
sBut.setBounds(new Rectangle(locX,locY,l,b));
sBut.addActionListener(this);
sBut.addMouseListener(this);
sBut.addKeyListener(this);
System.out.println("am inside the source object") ;
sBut.setBackground(new Color(105,100,205));
System.out.println("key number" +sBut.getMnemonic());
System.out.println("MY LOCATION : SBUT : "+ sBut.getLocation());
public void redirectionObject(String name)
rBut = new JButton(workImage);
panel1.add(rBut);
rBut.setBounds(new Rectangle(locX,locY,l,b));
rBut.addActionListener(this);
rBut.addMouseListener(this);
rBut.addKeyListener(this);
rBut.setBackground(new Color(105,100,205));
System.out.println("am inside the redirection :" + j) ;
System.out.println("MY LOCATION : RBUT : "+ rBut.getLocation());
public void destinationObject(String name){
dBut = new JButton(lapImage);
panel1.add(dBut);
dBut.setBackground(new Color(105,100,205));
System.out.println("am inside the destination object") ;
dBut.setBounds(new Rectangle(locX,locY,l,b));
System.out.println("am inside the destination:" + j) ;
dBut.addActionListener(this);
dBut.addMouseListener(this);
dBut.addKeyListener(this);
System.out.println("MY LOCATION : DBUT : "+ dBut.getLocation());
public void paintComponent(Graphics g){
super.paintComponent(g);
System.out.println("inside paint");
Graphics2D g2 = (Graphics2D) g;
g2.setStroke(stroke);
if(flag == 1){
/* this is for drawing current line, this will be drawn when component event happens */
g.setColor(getForeground());
System.out.println("inside flag");
int np = lines.size();
System.out.println("Total number of lines present the buffer to draw :" + np);
for (int I=0; I < np; I++) {
Rectangle p = (Rectangle)lines.elementAt(I);
g2.setColor((Color)colors.elementAt(I));
System.out.println("width" + p.width);
g2.setColor(Color.red);
// g2.setPaint(p.x,p.y,p.width,p.height);
g2.drawLine(p.x,p.y,p.width,p.height);
System.out.println("$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$");
System.out.println(obj.elementAt(I));
System.out.println("$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$");
System.out.println(p.x +"," +","+ p.y + ","+ ","+ p.width+ "," + ","+ p.height);
flag = -1;
}else if(flag == -1){
if(x1 != 0 && y1 != 0 && x2 != 0 && y2 != 0 ){
connection1 = "source to redirection";
g2.setColor(Color.red);
g2.drawLine(x1,y1,x2,y2);
lines.addElement(new Rectangle(x1,y1,x2,y2));
colors.addElement(getForeground());
obj.addElement(connection1);
x1 = 0 ;y1 = 0 ;
x2 = 0 ;y2 = 0 ;
else if (x2 != 0 && y2 != 0 && x3 != 0 && y3 != 0 )
connection2 = "Redirection to Destination";
g2.setColor(Color.green);
g2.drawLine(x2,y2,x3,y3);
colors.addElement(getForeground());
lines.addElement(new Rectangle(x2,y2,x3,y3));
obj.addElement(connection2);
x2 = 0; y2 = 0 ;
x3 = 0 ; y3 = 0 ;
else if (x1 != 0 && y1 != 0 && x3 != 0 && y3 != 0)
connection3 = "Source to Destination";
g2.setColor(Color.red);
g2.drawLine(x1,y1,x3,y3);
colors.addElement(getForeground());
lines.addElement(new Rectangle(x1,y1,x3,y3));
obj.addElement(connection3);
x1 = 0; y1 = 0 ;
x3 = 0 ; y3 = 0 ;
/* Image offscreen = panel1.createImage(400,400);
Graphics og = offscreen.getGraphics();
og.drawLine(200,200,500,500);
g.drawImage(offscreen,0,0,null); */
// Component Listener's method
public void componentHidden(ComponentEvent e) {
if(e.getSource().equals(panel1)){System.out.println("Componenet Hidden");}
System.out.println("Componenet Hidden");
public void componentMoved(ComponentEvent e) {
System.out.println("Componenet moved");
draw();
public void componentResized(ComponentEvent e) {
System.out.println("Componenet resized");
flag = 1;
paintComponent(panel1.getGraphics());
public void componentShown(ComponentEvent e) {
System.out.println("Componenet Shown");
// Mouse Listerner's Method
public void mouseClicked(MouseEvent me){
if (me.getSource().equals(panel1))
System.out.println("inside mouse clicked");
if(var == "S"){
the boolean sIndicator will allow the usage of source object only once
This is the case for both unicast and multi cast.It has been restricted
to single use.
if (sIndicator){
System.out.println("inside mouse clicked");
System.out.println("locX" + locX);
locX = me.getX();
locY = me.getY();
sourceObject("Source");
sIndicator = false;
}else{}
}else if (var == "R")
if(rIndicator){
if(!isDestSelected){
System.out.println("redirection" + locX);
locX = me.getX();
locY = me.getY();
redirectionObject("Redirection");
rIndicator = false;
}else{}
} else{}
}else if(var == "D"){
if(Radio == 1 && isDestSelected == false){
System.out.println("Destination -- uni cast mode" + locX);
locX = me.getX();
locY = me.getY();
destinationObject("Sink");
isDestSelected = true;
} else if (Radio == 2)
System.out.println("Destination -- Multicast mode" + locX);
locX = me.getX();
locY = me.getY();
destinationObject("Sink");
isDestSelected = true;
public void mousePressed(MouseEvent me){System.out.println("am inside mouse pressed"); }
public void mouseReleased(MouseEvent me){
System.out.println("am inside mouse released");
paintComponent(panel1.getGraphics());
public void mouseEntered(MouseEvent me){}
public void mouseExited(MouseEvent me){}
// key Listener
public void keyReleased(KeyEvent e) {
Component compo =(JButton)e.getSource();
if (e.getKeyChar() == e.VK_DELETE){
remove(compo);
public void keyTyped(KeyEvent e) {}
public void keyPressed(KeyEvent e){}
public void remove(Component comp){
System.out.println("inside delete key" );
panel1.remove(comp);
panel1.repaint();
public void draw(){
super.paint(panel1.getGraphics());
System.out.println("inside draw");
flag = 1;
paintComponent(panel1.getGraphics());
public void actionPerformed(ActionEvent e)
if(e.getSource().equals(sBut)){
System.out.println("am s button");
x1 = sBut.getX() + l;
y1 = sBut.getY() + (b/2);
else if(e.getSource().equals(rBut)){
System.out.println("am r button");
x2 = rBut.getX() ;
y2 = rBut.getY()+ b/2;
System.out.println("x2 : " + x2 + "y2 :" +y2 );
else if(e.getSource().equals(dBut)){
System.out.println("am d button");
x3 = dBut.getX();
y3 = dBut.getY()+ b/2;
else if (e.getSource().equals(uniRadio)){
System.out.println("uni radio");
Radio = 1 ;
} else if (e.getSource().equals(multiRadio)){
System.out.println("multi radio");
Radio = 2;
} else if (e.getSource().equals(show)){
System.out.println("inside show");
*********************************************ok
i don't take a long time tracing your code, but i think u have to overwrite the repaint methode so it 's call the methode which will paint the line each time.
hope this will help! -
I am trying to write a double buffered data acquisition program using MFC and a callback function.
i am trying to do a double buffer data acquisition using MFC application framework in Visual Studio.i want to use a callback function to notify when the buffer is half full.do you have some sample reference program that can help me?
What DAQ board are you using? When you installed NI-DAQ you should have selected to install the support files for VC++. Then there will be several examples on how to do double buffered data acquisition.
If you have already installed NI-DAQ 6.8 or higher and did not select to include the support files, you can run the NI-DAQ setup program and just add them. If you are using an older version, you will have to uninstall and reinstall.
Once you have the support files, follow this path to the examples.
>>Program Files>>National Instruments>>NI-DAQ>>Examaples>>Visual C>>
If you are doing digital acquistion, goto the di folder, if you are doing analog acquisition goto the ai folder.
As for the callback function, you can use the NI-DAQ function Config_DAQ_
Event_Message with DAQEvent Type = 1, where N would equal half your buffer.
Brian -
Can i use double buffering with SCAN_Sequence_Setup and sample rate divisors?
If possible I would like to use double buffering when acquiring multiple channels at different rates using SCAN_Sequence_Setup. What are the tricks to sizing the buffers, if any.
PCI-MIO-16Xe-10 and PCI-6052E are the boards I'm writing for, using Borland C++ builder under Windows2000
Thanks,
BradyHello;
At this time, you can't set up a multiple Scan Rate for different channels at same DAQ board. But, you can set up your Sample Rate to the fastest required to acquire you fastest channel, and then discard the readings of the other channels and only take the values for the different channels at their theoretical rate.
Hope this helps.
Filipe -
Is double buffering incorporated into Jframes? If so how can I implement it?
I don't know the answer to your question. But, looking at your recent threads, I think you need to be told that there is a Swing forum here:
http://forum.java.sun.com/forum.jspa?forumID=57
Most of your questions are related to Swing, and you will get better answers in that forum--where more Swing experts hang out.
Good luck! -
Alternative to Double-Buffered Canvas
I am working on a program in which I use a double-buffered Canvas inside a JScrollPane. The problem is that the Canvas draws over the scrollbars. I have tried extending JComponent, JPanel, JApplet, and Component instead of Canvas, and none of them are double buffered. Here is the code I used to debug this problem:
import java.awt.*;
import java.awt.geom.*;
import java.awt.image.*;
import javax.swing.*;
public class Test implements Runnable
JFrame f;
JScrollPane scroller;
JPanel panel;
TestCanvas canvas;
Thread runner;
BufferStrategy strategy;
public static void main (String[] args) {
Test app = new Test();
app.init();
public void init() {
f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
panel = new JPanel();
canvas = new TestCanvas();
panel.add(canvas);
scroller = new JScrollPane(panel);
scroller.setWheelScrollingEnabled(true);
f.getContentPane().add(scroller);
f.pack();
f.setSize(300,300);
f.setVisible(true);
canvas.createBufferStrategy(2);
strategy = canvas.getBufferStrategy();
runner = new Thread(this);
runner.run();
public void run() {
int x = 0;
while(x != 65536) {
Graphics2D g = (Graphics2D)strategy.getDrawGraphics().create();
g.setColor(new Color(x%256,0,0));
g.fill(new Ellipse2D.Double(0,0,600,600));
strategy.show();
x++;
}Any suggestions?The main culprit is that you are mixing AWT components with Swing ones.
In addition, your are doing so many of useless things and wrong things in your code.
Swing components are defaulted for using double-buffering.
See: http://java.sun.com/products/jfc/tsc/articles/painting/index.html
Try and study this code.
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.awt.image.*;
import javax.swing.*;
public class Fox1229{
JFrame f;
JScrollPane scroller;
TestCanvas canvas;
int x;
Timer t;
public static void main (String[] args) {
Fox1229 app = new Fox1229();
app.init();
public void init() {
x = 0;
f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
canvas = new TestCanvas();
scroller = new JScrollPane(canvas);
scroller.setWheelScrollingEnabled(true);
f.getContentPane().add(scroller, BorderLayout.CENTER);
f.setSize(300, 300);
f.setVisible(true);
t = new Timer(50, new ActionListener(){
public void actionPerformed(ActionEvent e){
canvas.setOc(new Color(x % 256, 0, 0));
canvas.repaint();
if (++x == 1024){
t.stop();
t.start();
class TestCanvas extends JPanel{
Color oc;
public TestCanvas (){
oc = new Color(0, 0, 0);
public void setOc(Color c){
oc = c;
public Dimension getPreferredSize(){
return new Dimension(600, 600);
public void paintComponent(Graphics g){
super.paintComponent(g);
Graphics2D g2d = (Graphics2D)g;
g2d.setColor(Color.blue);
g2d.fill(new Rectangle(0, 0, 600, 600));
g2d.setColor(oc);
g2d.fill(new Ellipse2D.Double(0, 0, 600, 600));
} -
Hi there......
Ive created a game that uses double buffering...basically the user hits the ball that is moving around the screen... after 5 goes the program needs to display a graph....
I have got the two components working seperatly... but when i combine that classes into one (the graph + the game) when theg graph is displayed the screen flickers..... and u cant see the graph properly....
How do you stop the screen from trying to keep refreshing and display the final image? (which is no longer animated)
Many thanks....search this site or google
there are hundreds of posts about double buffering -
Drawing with double buffering to a JFrame
I want to create a simple JFrame and draw stuff to it via Graphic object using double buffering.
If I create a loop and draw constantly using JFrame.getGraphic().xxx, am i doing double buffering. ( 'cause i read somewhere that swing components automaticly use double buffering ). And is this the righ approuch ( or whatever it's spelled ) ?I want to create a simple JFrame and draw stuff to it
Don't do that.
If you want to do custom rendering then use JPanel or JComponent, not JFrame.
If I create a loop and draw constantly using JFrame.getGraphic().xxx, am i doing double buffering.
No.
You're also painting outside the standard paint cycle, which is a Bad Idea.
So, essentially, everything your suggesting is the wrong way to go about things.
In its most simple form, double buffering works something like this, though there are a whole load of subtleties to consider (such as component resizing for a start)
public class Foo extends JComponent
private BufferedImage image = null;
protected void paintComponent(Graphics g)
if (image != null)
image = createImage(getWidth(), getHeight());
paintBuffer(ig);
g.drawImage(image, 0, 0, this);
private void paintBuffer()
Graphics ig = image.getGraphics();
// do the rendering
ig.dispose();
} -
Hi all,
I have stumbled on strange swing behavior on Windows, most probably connected to double buffering introduced in java 6.
Once in a while Windows stops redrawing my JFrame. From the java side everything seems ok - all the components are painted (that is, all native methods called), EventQueue normally processed by EDT, but repainted GUI is not shown on the screen. Note that OS has the repainted info - if I cover part of the application window with another window (e.g. explorer), and hid it back, the part that was covered is repainted. This happens even if I have java app halted on debug, so no other java actions can cause this repaint - OS has to have this image, it just does not put it on the screen. When I minimize/maximize the app, everything goes back to normal.
Note that I can normally operate the app "as if" it was painted - I can change tabs, click buttons (even though I can't see them), and results of these actions are painted by java to some offscreen buffer, but are only shown when I cover/uncover my app with another window, or min/max it. Min/Maxing ends this strange state and further repaints are shown normally.
Did any of you have this kind of problem? Any idea how to approach/resolve it or what can be the cause?
Java is 1.6.20, I have seen the behavior on Windows XP, Vista and 2008. It is not reproducible, it just happens sometimes. I haven't seen that on Java 5. Turning off double buffering resolves that, but is not feasible due to degraded user experience.
Thanks in advance for your help!
JakubThanks for your help so far, perhabs this is something with the driver, but I use fairly generic windows distribution.
EDT is not hosed, it is processing events normally (I checked that on debug step-by-step). We do not override any paint methods, and this is rather something on different level - it is not "a component not being repainted" it is "everything is repainted, but not shown on screen". Including tabbedPane's tab changes, menu display, etc. I can even see cursor changing into carret when I hover over "not shown" textfield.
Displaying and then disposing of modal dialog also fixes the state, as do resizing of the JFrame. -
Printing double-buffered component
I have a component that is double-buffered (must be) and when I print it, the quality of that component is pour. Quality of other components is good. So I'm guessing that image that I'm using for buffering is in the different resolution than the graphics that is used for printing, so g.drawImage() has to scale image which causses bad quality. I have seen posts about this problem but I haven't found a solution. Is there a way to fix this?
* The speed and quality of printing suffers dramatically if
* any of the containers have double buffering turned on.
* So this turns if off globally.
* @see enableDoubleBuffering
* @param c processed component
public static void disableDoubleBuffering(Component c) {
RepaintManager currentManager = RepaintManager.currentManager(c);
currentManager.setDoubleBufferingEnabled(false);
* Re-enables double buffering globally.
* @param c processed component
public static void enableDoubleBuffering(Component c) {
RepaintManager currentManager = RepaintManager.currentManager(c);
currentManager.setDoubleBufferingEnabled(true);
regards
Stas
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