How to get rid of graph flicker?

[Mehrdad]

Hi all,

I am programing for a user controll which is refreshing every 0.05 of a
second. the client area is flickering. I used the below code in the
constructor:
--------------------------
SetStyle(ControlStyles.OptimizedDoubleBuffer |
ControlStyles.AllPaintingInWmPaint, true);
--------------------------
It made it so much better, but it is still flickering. Is there any other
way to completely get rid of it?

Thank you in advance,
Mehrdad

[Peter Duniho]

On Sat, 21 Jun 2008 07:54:08 -0700, Mehrdad <ga****@irandoc.ac.irwrote:

I am programing for a user controll which is refreshing every 0.05 of a
second. the client area is flickering. I used the below code in the
constructor:
--------------------------
SetStyle(ControlStyles.OptimizedDoubleBuffer |
ControlStyles.AllPaintingInWmPaint, true);
--------------------------
It made it so much better, but it is still flickering. Is there any other
way to completely get rid of it?

I don't understand how "it made it so much better, but it is still
flickering". "Flickering" isn't generally a matter of degrees. It's
caused by erasing on-screen and then drawing over the erased area
on-screen. You can eliminate it, but to simply "reduce" it would mean
that sometimes the control is being double-buffered and sometimes it's
not. That seems like an unlikely scenario to me.

Now, all that said...have you tried simply setting the DoubleBuffered
property to "true"? I don't ever use the control styles to control
double-buffering.

Pete

[Mehrdad]

Thank you for your answer. Yes, I set the double buffering to true. I think
when the OnPaint methode is triggering, it clears the client area before
fetching the buffered information into it. Is it true? If yes, how can I
prevent it to clear?

Thanks again,
Mehrdad

"Peter Duniho" <Np*********@nnowslpianmk.comwrote in message
news:op***************@petes-computer.local...

On Sat, 21 Jun 2008 07:54:08 -0700, Mehrdad <ga****@irandoc.ac.irwrote:

>I am programing for a user controll which is refreshing every 0.05 of a
second. the client area is flickering. I used the below code in the
constructor:
--------------------------
SetStyle(ControlStyles.OptimizedDoubleBuffer |
ControlStyles.AllPaintingInWmPaint, true);
--------------------------
It made it so much better, but it is still flickering. Is there any other
way to completely get rid of it?

I don't understand how "it made it so much better, but it is still
flickering". "Flickering" isn't generally a matter of degrees. It's
caused by erasing on-screen and then drawing over the erased area
on-screen. You can eliminate it, but to simply "reduce" it would mean
that sometimes the control is being double-buffered and sometimes it's
not. That seems like an unlikely scenario to me.

Now, all that said...have you tried simply setting the DoubleBuffered
property to "true"? I don't ever use the control styles to control
double-buffering.

Pete

[Chris Jobson]

Thank you for your answer. Yes, I set the double buffering to true. I

think when the OnPaint methode is triggering, it clears the client area
before fetching the buffered information into it. Is it true? If yes, how
can I prevent it to clear?

I'm not sure about this, but I seem to remember something about overriding
OnPaintBackground with a method that does nothing.

Chris Jobson

[Peter Duniho]

On Sun, 22 Jun 2008 02:05:53 -0700, Mehrdad <ga****@irandoc.ac.irwrote:

Thank you for your answer. Yes, I set the double buffering to true.

That statement is ambiguous. "set the double buffering to true" could
mean anything. As opposed to "Set the Control.DoubleBuffered property to
true", which is very specific. So what did you actually do?

I think
when the OnPaint methode is triggering, it clears the client area before
fetching the buffered information into it. Is it true? If yes, how can I
prevent it to clear?

If you set the DoubleBuffered property to true, then even though the
background is cleared before OnPaint() is called, it's cleared in the
back-buffer, not on-screen. There should be no flickering.

On the other hand, if you use some other technique to try to enable
double-buffering (such as the code you posted), then you are responsible
for handling all of the double-buffering. This includes not erasing the
on-screen image (which is what Chris is talking about) and making sure
that you paint the entire control in the OnPaint() method, and do it all
at once (i.e. draw into your own back buffer and then copy that to the
screen Graphics instance provided in the PaintEventArgs).

Pete

[Mehrdad]

Thank you very much,

Actually, as a part of a project, I am creating a histogram component which
its graphs should be as soft as possible.

Thank you for your complete answer :)
Mehrdad

"Peter Duniho" <Np*********@nnowslpianmk.comwrote in message
news:op***************@petes-computer.local...

On Sun, 22 Jun 2008 02:05:53 -0700, Mehrdad <ga****@irandoc.ac.irwrote:

>Thank you for your answer. Yes, I set the double buffering to true.

That statement is ambiguous. "set the double buffering to true" could
mean anything. As opposed to "Set the Control.DoubleBuffered property to
true", which is very specific. So what did you actually do?

>I think
when the OnPaint methode is triggering, it clears the client area before
fetching the buffered information into it. Is it true? If yes, how can I
prevent it to clear?

If you set the DoubleBuffered property to true, then even though the
background is cleared before OnPaint() is called, it's cleared in the
back-buffer, not on-screen. There should be no flickering.

On the other hand, if you use some other technique to try to enable
double-buffering (such as the code you posted), then you are responsible
for handling all of the double-buffering. This includes not erasing the
on-screen image (which is what Chris is talking about) and making sure
that you paint the entire control in the OnPaint() method, and do it all
at once (i.e. draw into your own back buffer and then copy that to the
screen Graphics instance provided in the PaintEventArgs).

Pete