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Can I have two message pumps in the same form?

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inma (VIP)

I have one chart in a form and some buttons. The chart shows a huge number of
points and the redrawing takes about 2 seconds. The problem is that while the
chart is redrawing the form gets frozen.

The problem comes from the fact that there is only one message pump in the
form and the processing time of the refresh chart message takes 2 seconds.
During that time the pump is not attending messages from other controls.

How can I solve the problem?. Can I have two message pumps in the same form?

Thanks in advance
Inma

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AlexS

inma,

your problem is not as much related to message pump as to non-optimal
drawing code. Since Windows 1.0 it was always a pain in "brain" to make
Paint sufficiently quick for complex graphics.
Before going for "heavy-duty" solutions like another message pump, I would
profile painting code and optimized it. You might be surprised with results.
Start with checking if you really need to repaint whole graph, Maybe
scrolling dc or redrawing only portion of graph will do the magic?

Btw, you will never have another message pump on same thread in foreseeable
future. It's too non-Windows.

HTH
Alex

"inma" <Click here to reveal e-mail address> wrote in message
news:Click here to reveal e-mail address...
> I have one chart in a form and some buttons. The chart shows a huge number
of
> points and the redrawing takes about 2 seconds. The problem is that while
the
[Original message clipped]

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inma (VIP)

Thanks for your answer AlexS but my problem is not the time it takes the
chart to refresh. I don't care even if it takes 1 minute. My problem is that
during that period of time the entire form is not responsive.
Anyway I can't optimize the chart because It is a closed code one.

Regards
Inma

"AlexS" wrote:

[Original message clipped]

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Niall

Can you have the chart render to an image in a separate thread, instead of
directly to the GUI? Then you can push the image onto the form...

Niall

"inma" <Click here to reveal e-mail address> wrote in message
news:Click here to reveal e-mail address...
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inma (VIP)

I have to recognize that it is an interesting approach but It has an
important disadvantage. If you deal with an image you loose the chart
interaction capabilities. For example, zooming, rotating or showing labels as
the mouse icon moves over the chart. Also if you click in the chart, throws
an event that gives you information about whereabout in the chart you clicked
(not only x-y coords).

As you pointed out , I think the solution is in multithreading but I
really don't know how to run the drawing code in a diferent thread.

Many thanks for your answer Niall
Inma

"Niall" wrote:

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