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Flickering problem in sim

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  Flickering problem in sim "Qu0ll" <qu0ll@THRWHITE.remove-dii-this> - 2011-04-27 15:38 +0000
    Re: Flickering problem in "Roedy Green" <roedy.green@THRWHITE.remove-dii-this> - 2011-04-27 15:38 +0000
      Re: Flickering problem in "Qu0ll" <qu0ll@THRWHITE.remove-dii-this> - 2011-04-27 15:38 +0000
        Re: Flickering problem in "Roedy Green" <roedy.green@THRWHITE.remove-dii-this> - 2011-04-27 15:38 +0000
          Re: Flickering problem in "Qu0ll" <qu0ll@THRWHITE.remove-dii-this> - 2011-04-27 15:38 +0000
      Re: Flickering problem in "Andrew Thompson" <andrew.thompson@THRWHITE.remove-dii-this> - 2011-04-27 15:38 +0000
        Re: Flickering problem in "Qu0ll" <qu0ll@THRWHITE.remove-dii-this> - 2011-04-27 15:38 +0000
          Re: Flickering problem in "Lew" <lew@THRWHITE.remove-dii-this> - 2011-04-27 15:38 +0000
            Re: Flickering problem in "Qu0ll" <qu0ll@THRWHITE.remove-dii-this> - 2011-04-27 15:38 +0000
              Re: Flickering problem in "Lew" <lew@THRWHITE.remove-dii-this> - 2011-04-27 15:38 +0000
                Re: Flickering problem in "Qu0ll" <qu0ll@THRWHITE.remove-dii-this> - 2011-04-27 15:38 +0000
                  Re: Flickering problem in "Lew" <lew@THRWHITE.remove-dii-this> - 2011-04-27 15:38 +0000
                  Re: Flickering problem in "Andrew Thompson" <andrew.thompson@THRWHITE.remove-dii-this> - 2011-04-27 15:38 +0000
                    Re: Flickering problem in "Qu0ll" <qu0ll@THRWHITE.remove-dii-this> - 2011-04-27 15:38 +0000
            Re: Flickering problem in "Roedy Green" <roedy.green@THRWHITE.remove-dii-this> - 2011-04-27 15:38 +0000
          Re: Flickering problem in "Andrew Thompson" <andrew.thompson@THRWHITE.remove-dii-this> - 2011-04-27 15:38 +0000

#2368 — Flickering problem in sim

  To: comp.lang.java.gui
I am trying to implement very simple double buffering in an applet.  To do 
this I have overidden update() so that it won't clear the display but still 
there is noticeable flickering when the applet is resized.  Clearly 
something is clearing the screen on resize but I can't figure out where it 
is.

What is causing this screen clear?  How can I stop it?  I want smooth 
flicker-free resizing.

Here's the simple applet - it just paints a big blue rectangle.  Resize it 
and notice that the screen is cleared before repainting.

import java.applet.Applet;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;

public class TestApplet extends Applet {

 private Image buffer;
 private int bufferWidth;
 private int bufferHeight;

 @Override
 public void init() {
  resetBuffer();
 }

 public void resetBuffer() {
  buffer = createImage(getWidth(), getHeight());
  bufferWidth = getWidth();
  bufferHeight = getHeight();
 }

 @Override
 public void update(Graphics g){
        paint(g);
    }

 @Override
 public void paint(Graphics g) {
  if (bufferWidth != getWidth() || bufferHeight != getHeight()) {
   resetBuffer();
  }
  Graphics2D g2d = (Graphics2D)buffer.getGraphics();
  g2d.setColor(Color.BLUE);
  g2d.fillRect(10, 10, getWidth() - 20, getHeight() - 20);
  g.drawImage(buffer, 0, 0, null);
 }
}

-- 
And loving it,

-Q
_________________________________________________
Qu0llSixFour@gmail.com
(Replace the "SixFour" with numbers to email me)

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#2371 — Re: Flickering problem in

  To: comp.lang.java.gui
On Wed, 5 Sep 2007 01:31:41 +1000, "Qu0ll" <Qu0llSixFour@gmail.com>
wrote, quoted or indirectly quoted someone who said :

>
>What is causing this screen clear? 

setOpaque( true ) 
See http://mindprod.com/jgloss/flicker.html
-- 
Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com

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#2372 — Re: Flickering problem in

  To: comp.lang.java.gui
"Roedy Green" <see_website@mindprod.com.invalid> wrote in message 
news:it2sd39vk7bobli9cp0hpcgs6k0s4v9dfs@4ax.com...

>>What is causing this screen clear?
>
> setOpaque( true )
> See http://mindprod.com/jgloss/flicker.html

There is no setOpaque() method in Applet (note this is not a JApplet);

-- 
And loving it,

-Q
_________________________________________________
Qu0llSixFour@gmail.com
(Replace the "SixFour" with numbers to email me)

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#2375 — Re: Flickering problem in

  To: comp.lang.java.gui
On Wed, 5 Sep 2007 12:56:43 +1000, "Qu0ll" <Qu0llSixFour@gmail.com>
wrote, quoted or indirectly quoted someone who said :

>> See http://mindprod.com/jgloss/flicker.html
>
>There is no setOpaque() method in Applet (note this is not a JApplet);

in that case read the list of other causes of flicker at
http://mindprod.com/jgloss/flicker.html

I suspect you don't understand the relationship of paint and update.
see http://mindprod.com/jgloss/paint.html
http://mindprod.com/jgloss/update.html
-- 
Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com

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#2377 — Re: Flickering problem in

  To: comp.lang.java.gui
"Roedy Green" <see_website@mindprod.com.invalid> wrote in message 
news:8afsd3tem9bip83n1jgceqdvqc5ido9ls5@4ax.com...

> in that case read the list of other causes of flicker at
> http://mindprod.com/jgloss/flicker.html

I have read this helpful list but none of those things apply in this case. 
In fact I am doing all the things suggested in that list.

> I suspect you don't understand the relationship of paint and update.
> see http://mindprod.com/jgloss/paint.html
> http://mindprod.com/jgloss/update.html

I do understand the relationships and have implemented the recommendations. 
I have even tried ignoring repaints and scheduling all painting myself but 
something still clears the screen when resizing happens.  While the window 
edge is being dragged for a resize the screen is blank.  I do not want this 
and I am hoping it can be overridden somehow.

-- 
And loving it,

-Q
_________________________________________________
Qu0llSixFour@gmail.com
(Replace the "SixFour" with numbers to email me)

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#2373 — Re: Flickering problem in

  To: comp.lang.java.gui
Roedy Green wrote:
>>What is causing this screen clear? 
>
>setOpaque( true ) 

There is no setOpaque(boolean) method in java.applet.Applet.

But to the OP.

- Why are you writing to the root component,
rather than do custom rendering in a Panel/JPanel?
- Why are you using AWT?
- Why are you using AWT in combination with color
constants that were defined in J2SE 1.4?
- Why are you writing these test cases as applets?
- Why are you programming applets, again?

-- 
Andrew Thompson
http://www.athompson.info/andrew/

Message posted via JavaKB.com
http://www.javakb.com/Uwe/Forums.aspx/java-gui/200709/1

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#2376 — Re: Flickering problem in

  To: comp.lang.java.gui
"Andrew Thompson" <u32984@uwe> wrote in message news:77be6bcb49755@uwe...

> But to the OP.
>
> - Why are you writing to the root component,
> rather than do custom rendering in a Panel/JPanel?

No particular reason - it's just a test applet and it makes no difference if 
I write to a panel instead.

> - Why are you using AWT?

Well there's no law against it and I would like to try a few things without 
the overhead of Swing.  Again, I am just testing the waters at this stage.

> - Why are you using AWT in combination with color
> constants that were defined in J2SE 1.4?

It's just a test.  I had to use some colours and they were the most 
convenient ones available.

> - Why are you writing these test cases as applets?

I like applets and this problem is only evident in applets.  If I use a 
Frame the problem does not occur.

> - Why are you programming applets, again?

I like applets.

-- 
And loving it,

-Q
_________________________________________________
Qu0llSixFour@gmail.com
(Replace the "SixFour" with numbers to email me)

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#2379 — Re: Flickering problem in

  To: comp.lang.java.gui
"Andrew Thompson" wrote:
>> - Why are you using AWT?

Qu0ll wrote:
> Well there's no law against it and I would like to try a few things 
> without the overhead of Swing.  Again, I am just testing the waters at 
> this stage.

Does Swing have more "overhead" than AWT?

What is the nature of that extra overhead?

These are things I don't know.

-- 
Lew

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#2380 — Re: Flickering problem in

  To: comp.lang.java.gui
"Lew" <lew@lewscanon.com> wrote in message 
news:XaWdnccpX9GsNUPbnZ2dnUVZ_o_inZ2d@comcast.com...

> Does Swing have more "overhead" than AWT?
>
> What is the nature of that extra overhead?
>
> These are things I don't know.

Lew,

It's just my poor choice of words on this occasion.  There is absolutely 
nothing wrong with Swing (in fact I love it).  I am simply experimenting 
with the possibilities of AWT at this stage.  Anyway, what does it matter 
*why* I am doing what I am doing?  I have encountered a problem and am 
looking for assistance.  I don't think I need to justify the purpose of my 
activities.

-- 
And loving it,

-Q
_________________________________________________
Qu0llSixFour@gmail.com
(Replace the "SixFour" with numbers to email me)

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#2382 — Re: Flickering problem in

  To: comp.lang.java.gui
"Lew" wrote:
>> Does Swing have more "overhead" than AWT?
>>
>> What is the nature of that extra overhead?
>>
>> These are things I don't know.

Qu0ll wrote:
> Lew,
> 
> It's just my poor choice of words on this occasion.  
> There is absolutely nothing wrong with Swing (in fact I love it).  
> I am simply experimenting with the possibilities of AWT at this stage.  
> Anyway, what does it matter *why* I am doing what I am doing?  
> I have encountered a problem and am looking for assistance.  
> I don't think I need to justify the purpose of my activities.

How do you get a question of "why" from my request for information about 
Swing's overhead?  I didn't ask you why you chose to do what you're doing, nor 
did I ask you to justify your decision, nor did I offer any opinion about the 
relative superiority of either widget set.  I asked for technical information 
about Swing and AWT.

To answer your direct question, it doesn't matter to my question why you are 
doing what you're doing.  I agree that you do not need to justify the purpose 
of your activities; in fact, I am not actually interested in that purpose nor 
its justification.

I offer thanks to Roedy for the information I requested.

-- 
Lew

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#2384 — Re: Flickering problem in

  To: comp.lang.java.gui
"Lew" <lew@lewscanon.com> wrote in message 
news:HeSdnTSDGscjREPbnZ2dnUVZ_oTinZ2d@comcast.com...

>> It's just my poor choice of words on this occasion.  There is absolutely 
>> nothing wrong with Swing (in fact I love it).  I am simply experimenting 
>> with the possibilities of AWT at this stage.  Anyway, what does it matter 
>> *why* I am doing what I am doing?  I have encountered a problem and am 
>> looking for assistance.  I don't think I need to justify the purpose of 
>> my activities.
>
> How do you get a question of "why" from my request for information about 
> Swing's overhead?  I didn't ask you why you chose to do what you're doing, 
> nor did I ask you to justify your decision, nor did I offer any opinion 
> about the relative superiority of either widget set.  I asked for 
> technical information about Swing and AWT.
>
> To answer your direct question, it doesn't matter to my question why you 
> are doing what you're doing.  I agree that you do not need to justify the 
> purpose of your activities; in fact, I am not actually interested in that 
> purpose nor its justification.
>
> I offer thanks to Roedy for the information I requested.

My response on the "why" question was just continuation of my answer to 
Andrew's questions.  It wasn't directed at you.

-- 
And loving it,

-Q
_________________________________________________
Qu0llSixFour@gmail.com
(Replace the "SixFour" with numbers to email me)

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#2386 — Re: Flickering problem in

  To: comp.lang.java.gui
Qu0ll wrote:
> My response on the "why" question was just continuation of my answer to 
> Andrew's questions.  It wasn't directed at you.

Perhaps you should quote the material to which you are responding instead of 
an unrelated message, to avoid such confusion.  Naturally since your response 
quoted my message in its entirety, and no one else's, I concluded that your 
comments were related to my post.

Actually, Andrew's questions are useful.  Knowing why you're doing something 
is a beginning to understanding how to advise you to do it.  Perhaps you 
should consider answering his questions instead of being aggrieved.

-- 
Lew

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#2388 — Re: Flickering problem in

  To: comp.lang.java.gui
Qu0ll wrote:
..
>...It wasn't directed at you.

Why /stress/ over it?

This is not email, & both my, and Lew's questions 
were (perhaps in a round about way) aimed at 
understanding the 'problem domain' (to put it a 
fancy way) well enough to provide the best technical 
information.

My replies to you on this, and other applet threads,
have had a certain 'impatience and directness' that I
doubt have helped your responses.

When I 'bump'd that reply the other day, I was aware
that you had not seen it (or at least, strongly suspected),
but had not realised just how many of my *earlier* replies
you had not seen.  That led to that single 'final' reply that
I bumped, being relatively overbearing.  If you maintian 
that thread is finished I'll (try and) accept that, but note 
that I suspect whatever fix happened, was somewhat 
random, and a second IE7/Vista combo. might show 
very different behaviour.

Anyway, hopefully we can get back more on track with 
the technical side of it.

FWIW - I do hope to see you resolve your any, many 
and varied technical issues with applets.  They can be 
fascinating little beasties.

-- 
Andrew Thompson
http://www.athompson.info/andrew/

Message posted via JavaKB.com
http://www.javakb.com/Uwe/Forums.aspx/java-gui/200709/1

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#2389 — Re: Flickering problem in

  To: comp.lang.java.gui
"Andrew Thompson" <u32984@uwe> wrote in message news:77c94443cd883@uwe...

> Why /stress/ over it?
>
> This is not email, & both my, and Lew's questions
> were (perhaps in a round about way) aimed at
> understanding the 'problem domain' (to put it a
> fancy way) well enough to provide the best technical
> information.
>
> My replies to you on this, and other applet threads,
> have had a certain 'impatience and directness' that I
> doubt have helped your responses.
>
> When I 'bump'd that reply the other day, I was aware
> that you had not seen it (or at least, strongly suspected),
> but had not realised just how many of my *earlier* replies
> you had not seen.  That led to that single 'final' reply that
> I bumped, being relatively overbearing.  If you maintian
> that thread is finished I'll (try and) accept that, but note
> that I suspect whatever fix happened, was somewhat
> random, and a second IE7/Vista combo. might show
> very different behaviour.
>
> Anyway, hopefully we can get back more on track with
> the technical side of it.
>
> FWIW - I do hope to see you resolve your any, many
> and varied technical issues with applets.  They can be
> fascinating little beasties.

Well I can happily announce that the problem is solved thanks to an AWT 
engineer who suggested the use of the -Dawt.noerasebackground argument to 
the JVM.  If this is set to true in the Java plug-in then the browser will 
not clear the screen when resizing.  Wonderful!

Andrew, Lew and Roedy: thanks, I appreciate your efforts and input.  I have 
learned a lot in the process.

-- 
And loving it,

-Q
_________________________________________________
Qu0llSixFour@gmail.com
(Replace the "SixFour" with numbers to email me)

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#2381 — Re: Flickering problem in

  To: comp.lang.java.gui
On Wed, 05 Sep 2007 08:59:28 -0400, Lew <lew@lewscanon.com> wrote,
quoted or indirectly quoted someone who said :

>Does Swing have more "overhead" than AWT?
>
>What is the nature of that extra overhead?

Yes.  Swing does its own rendering in Java.  AWT uses the OS to render
which presumably has a lot of hand-tuned assembler.
-- 
Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com

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#2387 — Re: Flickering problem in

  To: comp.lang.java.gui
Qu0ll wrote:
..
>> - Why are you using AWT?
>
>Well there's no law against it and I would like to try a few things without 
>the overhead of Swing.  Again, I am just testing the waters at this stage.
>
>> - Why are you using AWT in combination with color
>> constants that were defined in J2SE 1.4?
>
>It's just a test.  I had to use some colours and they were the most 
>convenient ones available.

OK - often AWT and Applets are associated because the OP
feels it advantageous to target/support Java 1.1*.  If that is not 
the case, I recommend you stick to using Swing (the GUI
toolkit that most people are actively using and familiar with).

* No, it is not.  Not in this day and age.

>> - Why are you writing these test cases as applets?
>
>I like applets and this problem is only evident in applets.  If I use a 
>Frame the problem does not occur.

Really?  Can you produce the equivalent frame source?
Perhaps that will help explain the behaviour.
(Shrugs) I looked at your example, even changed it in 
various ways, but could not get that flickering effect 
out of it.

-- 
Andrew Thompson
http://www.athompson.info/andrew/

Message posted via JavaKB.com
http://www.javakb.com/Uwe/Forums.aspx/java-gui/200709/1

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