Flickering vs double buffering
Hello,
flickering is a common problem and is prevented by using offscreen images. And that's what I'm doing (though, I'm not sure whether I'm doing it right). Now, there's a cycle of images displayed as an animation in my program and the flickering is really obvious while the first cycle is being displayed. It seems more or less OK when it plays further (I'm not realy sure whether it flickers or not, coz the images are being repainted rather fast).
So, my question is: why exactly could the first cycle be displayed so slowly and how could I fix the problem? (perhaps double buffering should fix it and I'm doing it wrong?)
Are you loading all images before showing the animations ? Because if you are loading them as you're showing the animations the loading process will slow your animation down.
Similar Messages
-
Double buffering for shape animation
Hello people,
I'm building an applet which animates some text (a shape with various setting for stroke, fill, etc.) and translating it from x1 to x2 using AffineTransform. How can I clear the screen to create an animation effect and double buffering to avoid flickering? Double buffering can be used with ImageS, but what about ShapeS?
Many thanksDouble buffering is a general concept that applies to all
graphic objects. -
Double buffering still gives flickering graphics.
I copied code from a tutorail which is supposed to illustrate double buffering.
After I run it, it still flickers though.
I use applet viewer, which is part of netbeans to run my applet.
Link to tutorial: http://www.javacooperation.gmxhome.de/TutorialStartEng.html
My questions are:
Is the strategy used for double buffering correct?
Why does it flicker?
Why does the program change the priority a couple of times?
Can you make fast games in JApplets or is there a better way to make games? (I think C++ is too hard)
Here is the code:
package ballspel;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import javax.swing.JApplet;
//import java.applet.*;
* @author Somelauw
public class BallApplet extends /*Applet*/ JApplet implements Runnable {
private Image dbImage;
private Graphics dbg;
private int radius = 20;
private int xPos = 10;
private int yPos = 100;
* Initialization method that will be called after the applet is loaded
* into the browser.
@Override
public void init() {
//System.out.println(this.isDoubleBuffered()); //returns false
// Isn't there a builtin way to force double buffering?
// TODO start asynchronous download of heavy resources
@Override
public void start() {
Thread th = new Thread(this);
th.start();
public void run() {
Thread.currentThread().setPriority(Thread.MIN_PRIORITY);
while (true) {
xPos++;
repaint();
try {
Thread.sleep(20);
} catch (InterruptedException ex) {
ex.printStackTrace();
Thread.currentThread().setPriority(Thread.MAX_PRIORITY);
@Override
public void paint(Graphics g) {
super.paint(g);
//g.clear();//, yPos, WIDTH, WIDTH)
g.setColor(Color.red);
g.fillOval(xPos - radius, yPos - radius, 2 * radius, 2 * radius);
@Override
public void update(Graphics g) {
super.update(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);
// TODO overwrite start(), stop() and destroy() methods
}Somelauw wrote:
I copied code from a tutorail which is supposed to illustrate double buffering.
After I run it, it still flickers though.
I use applet viewer, which is part of netbeans.. AppletViewer is part of the JDK, not NetBeans.
..to run my applet.
Link to tutorial: http://www.javacooperation.gmxhome.de/TutorialStartEng.html
Did you specifically mean the code mentioned on this page?
[http://www.javacooperation.gmxhome.de/BildschirmflackernEng.html]
Don't expect people to go hunting around the site, looking for the code you happen to be referring to.
As an aside, please use the code tags when posting code, code snippets, XML/HTML or input/output. The code tags help retain the formatting and indentation of the sample. To use the code tags, select the sample and click the CODE button.
Here is the code you posted, as it appears in code tags.
package ballspel;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Image;
import javax.swing.JApplet;
//import java.applet.*;
* @author Somelauw
public class BallApplet extends /*Applet*/ JApplet implements Runnable {
private Image dbImage;
private Graphics dbg;
private int radius = 20;
private int xPos = 10;
private int yPos = 100;
* Initialization method that will be called after the applet is loaded
* into the browser.
@Override
public void init() {
//System.out.println(this.isDoubleBuffered()); //returns false
// Isn't there a builtin way to force double buffering?
// TODO start asynchronous download of heavy resources
@Override
public void start() {
Thread th = new Thread(this);
th.start();
public void run() {
Thread.currentThread().setPriority(Thread.MIN_PRIORITY);
while (true) {
xPos++;
repaint();
try {
Thread.sleep(20);
} catch (InterruptedException ex) {
ex.printStackTrace();
Thread.currentThread().setPriority(Thread.MAX_PRIORITY);
@Override
public void paint(Graphics g) {
super.paint(g);
//g.clear();//, yPos, WIDTH, WIDTH)
g.setColor(Color.red);
g.fillOval(xPos - radius, yPos - radius, 2 * radius, 2 * radius);
@Override
public void update(Graphics g) {
super.update(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);
// TODO overwrite start(), stop() and destroy() methods
}Edit 1:
- For animation code, it would be typical to use a javax.swing.Timer for triggering updates, rather than implementing Runnable (etc.)
- Attempting to set the thread priority will throw a SecurityException, though oddly it occurs when attempting to set the Thread priority to maximum, whereas the earlier call to set the Thread priority to minimum passed without comment (exception).
- The paint() method of that applet is not double buffered.
- It is generally advisable to override paintComponent(Graphics) in a JPanel that is added to the top-level applet (or JFrame, or JWindow, or JDialog..) rather than the paint(Graphics) method of the top-level container itself.
Edited by: AndrewThompson64 on Jan 22, 2010 12:47 PM -
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 -
I was searching through posts to find an answer to my problem of getting double buffering working without flickering when I came across this response:
Upgrade your SDK, early 1.4 implementations had this problem on Windows2k (It's a bug). Pretty much the second buffer will point to an empty portion of video memory always, the solution to this without updating is to fill the entire backbuffer completely, flip it, fill it again, and then flip it again. You should then be able to use it normaly.
-Jason Thomas.
Since I am on dialup I can't really download the SDK, so could someone give me some code to do what Jason has suggested?
Jonathan O'BrienNo I am not recreating the bufferstrategy every frame. Overriding update didn't work either. Here is my code for main:
GraphicsEnvironment env = GraphicsEnvironment.getLocalGraphicsEnvironment();
GraphicsDevice device = env.getDefaultScreenDevice();
GraphicsConfiguration gc = device.getDefaultConfiguration();
Frame myFrame = new Frame(gc);
BufferCapabilities bufferCaps = gc.getBufferCapabilities();
boolean multiBuffer = bufferCaps.isMultiBufferAvailable();
boolean fullScreen = device.isFullScreenSupported();
System.out.println("Full screen supported = " + fullScreen);
System.out.println("Multi buffer available = " + multiBuffer);
System.out.println("Page flipping = " + bufferCaps.isPageFlipping());
myFrame.setUndecorated(true);
myFrame.setIgnoreRepaint(true);
if ((fullScreen) && (multiBuffer))
device.setFullScreenWindow(myFrame);
device.setDisplayMode(new DisplayMode(800, 600, 16, 0));
rectBounds = myFrame.getBounds();
myFrame.createBufferStrategy(2);
bufferStrategy = myFrame.getBufferStrategy();
bufferReady = true;
Game thisGame = new Game(args[0]);
myFrame.add(thisGame);
// myFrame.getContentPane().add(thisGame);
myFrame.show();
And here is the relevant code for my run method:
if (bufferReady)
Graphics g = bufferStrategy.getDrawGraphics();
if (!bufferStrategy.contentsLost()) {
g.fillRect(0,0,getWidth(),getHeight());
g.dispose();
bufferStrategy.show(); -
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 -
Double Buffering in Java Swing
Hi sir,
Here i want to know about what is exactly double buffering?
I have learned that double buffering is automatic in swing components.
But i have some problem with my JButtons it is FLICKERING a bit.Where u need to scroll the mouse to see it.Can be provide any idea for this.
And also give some sample examples related to double buffering.
Thanx,
m.ananthuHi sir,
I have a problem with repainting and validate methods.
In my project when i click a startbutton it will show a row of 4 buttons and when i click it again that 4 buttons should disappear.All this features are working well.But when i again click the startbutton
the 4 buttons are not showing in the second time but when i use the
mouse and scroll over 4 buttons area it is showing the 4 buttons.
I have used repaint() and validate() methods still there is no use.
so Pls. do help me.Is it any thing to do with double buffering ?It is
Urgent.Here is my problem code:-
Here is the code where MenuOptionList is a class that contains 4 buttons I have used the instance of the MenuoptionList here.Here when i click the "Start" which is for the start button Menuoptionlist will show which contains the row of 4 buttons as u can see there i have used a Flag=false for the first click (ie) to show the row of 4 buttons and in the next i have set the Flag=true to make the 4 buttons disappear all this features are working fine where jp.add(mol) means "jp" is a panel which is set it in the beginning of my home page with setBounds in to it i am adding the mol(instance of MenuoptionList).Here the problem is when i click the StartButton the 4 button are displaying & when i click it next time they are disappearing that all works fine.But when i click it for the next the 4 buttons should show.The problwem is they are showing but they are invisible in such a case if scroll the mouse over the 4 buttons area they are visible.What is the problem here.I have used repaint(),validate() methods still no use.Is the problem is to do with any instance removal.Pls.do help me.It is Urgent
public void actionPerformed(ActionEvent e)
changeCenterPanel(e.getActionCommand());
private void changeCenterPanel(String buttonEvent){
if((buttonEvent.equals("Start"))&&(Flag==false)){
mol=new MenuOptionList(jp,jp1,jp2);//Which contains the 4 buttons
mol.setBounds(150,1,500,600);
Color c1=new Color(116,121,184);
mol.setBackground(c1);
mol.validate();
mol.repaint();
jp.add(mol);
jp.validate();
jp.repaint();
Flag=true;
else if((buttonEvent.equals("Start"))&&(Flag==true))
mol.removeAll();//removing the 4 buttons
mol.validate();
mol.repaint();
Flag=false;
Thanx,
m.ananthu -
Need help with double buffering
Hi!
I'm trying to write an animated applet the shows the Java Duke waving.
No problem getting it to work, but the applet is flickering and I sence the need for double buffering.
I've tried to use "traditional" double buffering techniques without success. Something like this:
currentDuke = bufferGraphics.getGraphics();
public void update(Graphics g) {
bufferGraphics.clearRect(0, 0, this.getWidth(), this.getHeight());
paint(g);
public void paint(Graphics g) {
bufferGraphics.drawImage(nextDuke, 0, 0, this);
g.drawImage(currentDuke, 0, 0, this);
}Didn't help...
Here's my current code:
import javax.swing.*;
import java.awt.*;
* This is a simple animation applet showing Duke waving.
* @author Andrew
* @version 1.0 2002-07-04
public class WavingDuke extends JApplet implements Runnable {
private Image[] duke;
private Image currentDuke;
private Thread wave;
* Called by the browser or applet viewer to inform this applet that it has
* been loaded into the system.
public void init() {
loadDuke();
currentDuke = this.createImage(this.getWidth(), this.getHeight());
* Called by the browser or applet viewer to inform this applet that it
* should start its execution.
public void start() {
if (wave == null) {
wave = new Thread(this);
wave.start();
* Loads all the duke images into a <code>Image</code> array.
private void loadDuke() {
duke = new Image[10];
for (int i = 0; i < 10; i++) {
duke[i] = this.getImage(this.getCodeBase(), "images/duke"+i+".gif");
* Method cycles through different images and calls <code>repaint</code>
* to make an animation. After each call to <code>repaint</code> the thread
* sleeps for predefined amount of time.
public void run() {
while (true) {
for (int i = 0; i < 10; i++) {
currentDuke = duke;
repaint();
paus(150);
* Method makes the current thread to sleep for tha amount of time
* specified in parameter <code>ms</code>.
* @param ms The time to wait specified in milliseconds.
private void paus(int ms) {
try {
Thread.sleep(ms);
} catch (InterruptedException ie) {
System.err.println(ie.getMessage());
* Updates this component.
* @param g The specified context to use for updating.
public void update(Graphics g) {
paint(g);
* Paints this component.
* @param g The graphics context to use for painting.
public void paint(Graphics g) {
g.clearRect(0, 0, this.getWidth(), this.getHeight());
g.drawImage(currentDuke, 0, 0, this);
Thanks in advance!
/AndrewI've solved it!
/Andrew -
JNI native drawing - Double Buffering issue
Hi,
I use JNI to paint from a C++ DLL onto a canvas, which works fine.
The problem is that double buffering is not working though.
In C++ I create an offscreen HDC, draw something on it and finally i bitblit the offscreen HDC to the parent window HDC.
That is how double buffering is supposed to work. But each time i repaint my Canvas in Java, i see flickering:
the background color is displayed first, then the C++ paintings are drawn.
Since i already do double buffering in my C++ drawings, i don't know why there still is flickering.
Should i do double buffering on my canvas also?
How would this work, since my paint method looks like;
private native void drawChart(Graphics g);
public void paint(Graphics g)
drawChart(g);
}this is my lucky day :)
the following thread on http://forum.java.sun.com/thread.jspa?threadID=562392&messageID=2767046 suggested to override the update method on the canvas, which works.
// overridden to eliminate flicker
public void update(Graphics g)
paint(g);
} -
High CPU usage with double buffering enabled
Hello all,
My GUI application is using 100% of the CPU with double buffering (DB) enabled, about 20% with it disabled?
Also with DB enabled is visible slower than without, although there are some flickers.
Java 1.7.0_21
2 NVIDIA Quadro NVS 420
Windows 7
Any ideas?Try tinkering with the Java2D system flags:
http://docs.oracle.com/javase/1.5.0/docs/guide/2d/flags.html -
How to draw a point without double buffering?
Hello all,
I am drawing points as small red circles, but they are a bit ugly without double buffering. Am I able to draw the points to be nice? I mean not to draw them as just circles, but some special circle with light border that will looks much more nicer?
Or what radius and position of the circle must be to be a nice small circle containing only 5 pixels? (upper, lower, right, left, middle)
ps - they are ugly in the way of having a strange dot on the left sideI use this method:
private static final float POINT_RADIUS = 2f;
private static final float POINT_DIAMETER = POINT_RADIUS * 2;
private void drawPoint(float x, float y, Color c) {
Ellipse2D point = new Ellipse2D.Float(x - POINT_RADIUS, -y
- POINT_RADIUS, POINT_DIAMETER, POINT_DIAMETER);
graphics.setStroke(new BasicStroke(0.2f));
graphics.fill(point);
// and points looks like this:
*** -
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));
} -
Using 6533 DIO32HS, is it possible to use double buffered output with varying pauses?
I'm using Level-Ack handshaking to transmit data. Currently, I'm hooked up to a loop-back on the DIO32HS card.
If I don't use double-buffering, I end up with pauses in data transmission, so I need to use double buffering. Unfortunately, I can't seem to set up a delay in the middle of a double buffered scheme.
What I need to do is this:
Transmit 64 packets of data (16 bits each) on group 2 / Receive 64 packets of data (16 bits each) on group 1
Delay for .2 ms
Transmit the same packets again / receive
The delay in the middle will need to be varied, from .2 to 20 ms.
I'm programming in Visual C++ 6.0 under Windows 2000, with (as suggested above) group1 c
onfigured as input (DIOA and DIOB) and group2 set up as output (DIOC and DIOD). Due to the speed of transmission (256kHz) and the small size of the data set, the program I wrote, no matter how tight I try to make it, cannot insert the proper delay and start the next send on time.
Does anyone have any idea if such a pause is possible? Anyone know how to do it, or any suggestions on what to try?
Thanks!.2 ms is a very small time delay to use in software. Windows usually isn't more accurate than about 10 or 20 ms. If you need to have small, precise delays you could either use a real time OS, like pharlap and LabVIEW RT, or use extra hardware to generate the delays correctly.
I would recommend using a separate MIO or counter/timer board (like a 660x) to generate timing pulses for the DIO32HS. This gives you precise timing control at high speed. If the 32HS is in Level ACK Mode, it will respond to external ACK and REQ signals. This is covered in more detail on page 5-10 of the PCI-DIO32HS User Manual. -
Hi there,
I have a frame F that contains two panels P1 and P2.
P1 uses double buffering for drawing circles and lines.
P2 has buttons and a JList.
When i click on a JList to have popup menu
or when i move the frame F on the screen
the panel P2 lost some of JList drawing.
Actually i iconify the frame in order to oblige
JVM to do repaint.
How can i resolve this problem please.Do not ever mix heavyweight and lightweight, or else
you won't be able to set up the correct zorder.But when i iconfiy and desiconify my frame Java
repaint correctly.
I need a nice tip article of how to simulate
desiconify repainting process.
Thabk u -
HELP!!! lol i'm trying to figure out how to get the whole double buffering thing to work with a picture like a gif image i drew in paint. i can't quite understand anything aobut how to do it. lol i've read some things and looked at some code samples but they all do it with a polygon. i just can't seem to get it right. i learn best from code snipets if that helps. don't give me a whole program i just want some lines that will help me learn it like what i have to import. and other things. i know a little about using images but not a whole lot. if anyone can help it will be appreciated.
andyPsst... Tell you teacher that one can read an image with ImageIO, often in one line:
BufferedImage image = ImageIO.read(file_or_url_or_inputstream);(No need for a MediaTracker!) And the resulting BufferedImage (a subclass of Image)
is easier to work with than Image and has more useful features.
Welcome to Java 2D.
Maybe you are looking for
-
Volumes and raid sets disappeared
I booted my machine and it gave me a question mark folder I booted it off an external drive but the internal bay hdds arent mounting. When I was looking through raid utility it says they are all good and viable disks in roaming but no raid sets or vo
-
IBooks seriously unstable after install of iOS 8
Since installing iOS 8 on my iPad (128 GB) iBooks is showing serious instability. Background: I use my iPad principally as a library. No music, films, videos or games, but a number of mainly productivity apps. iBooks has worked very well. Over severa
-
To_date(to_char(sysdate,'dd/mm/yyyy hh24:mm'),'dd/mm/yyyy hh24:mm')
Hi I am using this conversion to_date(to_char(sysdate,'dd/mm/yyyy hh24:mm'),'dd/mm/yyyy hh24:mm') but it says format string appears twice Could some one please help me with this?
-
Chinese Data in OBIEE Chart Reports
Hello All, I'm facing an issue with OBIEE Chart report . We have some data as Chinese in database. When displaying these on OBIEE Chart , it is shown as boxes. This is happening only with OBIEE Charts . Looks like chinese characters are not supported
-
Remove queries from Portal Roles
Hi, We have a requirement in the portal and BW queries. We want to remove queries from the portal roles. That is the queries must not be physically deleted, but they should not appear in the portal when viewed through Business Explorer. Is this possi