Re: Graphics "goes away" - New Information


"jw" <jw@xxxxxxxxxxxxx> wrote in message
news:amlke.2774$yO1.2136@xxxxxxxxxxx
> I have written a program in C that generates up to 100 data points and
> plots a line to a Dialog within a Tabbed Folder using MoveToEx() -
LineTo()
> functions.
> The program can plot up to 1000 of these lines on the graph.
> My problem is that on my XP SP1 machine sometimes the program simply stops
> drawing at some point.
> Sometimes after around 150 lines and sometimes after over 500 lines --
it's
> not the same each time.
> Most of the time it doesn't stop at all and draw all 1000 lines. And it
is
> not crashing -- if I wait the program comes back after it would normally
> have plotted all of the lines.
> It seems as if the program decided it doesn't want to show the lines
anymore
> or is drawing them off screen somewhere. I'm pretty sure that isn't
> happening because I can set it to plot the same 1000 lines. Most of the
> time it does -- every now and then it doesn't
> Does anyone have any suggestions, as to what is happening. The code is
> calculation intensive and scattered over many thousands of lines of C and
> many- many functions.
> Is it an XP thing where I need to do something to keep XP from swapping it
> out? It happens even if it is the only application running.
>
> Thanks for any direction.
>
> JW
>
>

I have found some new information so I'm guessing this is the correct way to
present it.
I have no idea why I haven't discovered this before.
If I click the mouse off the window containing the dialog, for instance on
the desktop, after about 75 lines it stops showing the lines. So this
apparently is a "focus" issue.
If I click back on the dialog after it stops showing the lines I get a
"Program not responding" message. But the program comes back after it is
done "drawing."
So I guess when the dialog loses focus windows stops showing the lines, even
though it is going through the code that draws them. I know the points are
not out of bounds because I put a check in the program.
So my question now is how do I fix this? Can I force the program not to
give up focus while it is drawing?
Does it send a message other than KILLFOCUS and what can I do if it does. I
monitored KILLFOCUS but it does not seem like I get it right away.

Thanks,

JW


.

Relevant Pages

  • Re: Graphics "goes away"
    ... > You mention that you use MoveToEx and LineTo... ... > Are you drawing in a WM_PAINT block or directly to the dialog? ... >> The program can plot up to 1000 of these lines on the graph. ... I am in a WM_PAINT and I do use BeginPaint and EndPaint. ...
    (microsoft.public.win32.programmer.gdi)
  • Re: Graphics "goes away"
    ... You mention that you use MoveToEx and LineTo... ... Are you drawing in a WM_PAINT block or directly to the dialog? ... > The program can plot up to 1000 of these lines on the graph. ...
    (microsoft.public.win32.programmer.gdi)
  • Re: Graphics "goes away"
    ... deleting them? ... Chris ... > The program can plot up to 1000 of these lines on the graph. ... > or is drawing them off screen somewhere. ...
    (microsoft.public.win32.programmer.gdi)
  • Graphics "goes away"
    ... plots a line to a Dialog within a Tabbed Folder using MoveToEx() - LineTo ... The program can plot up to 1000 of these lines on the graph. ... or is drawing them off screen somewhere. ...
    (microsoft.public.win32.programmer.gdi)
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