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Drawing an Oscilloscope (flickerfree & fast)

carlosn
carlosn asked
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Last Modified: 2013-11-19
I want to display an oscilloscope in a window.  This oscilloscope would have a fixed grid, some fixed text, and the moving signal display.

Ideally the grid and text should be displayed BEHIND the signal, but this is not critical.

The grid and text should be flicker-free.

Finally the scope should not take too much processor time.  It is displaying the result of a fairly intensive calculation process, and I don't want to spend half my time just painting.

What is the best way to implement something like this in MFC?

Carlos
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Commented:
Also take a quick look at DrawDibDraw and it's associated functions in the Video for Windows SDK.  I've used them briefly, but if you have a lot of images to display in a row it could be useful.

Also (and possibly best) you may want to choose your signal wisely, if you use the XOR pen to draw your data, then you can just erase the signal with another XOR drawing.  Then you won't have to redraw the entire bitmap at all.  Just XOR on and XOR off the signal.

Phillip

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Commented:
Thank you, I'll have to check the XOR idea.

I have started using some of the memory DC, and found that the BitBlt was incredibly slow.  Is this normal?  Copying over a bitmap thats about 300x200 pixels, it was taking about 6% of the softwares time (according to the profiler).  Each BitBlt ran for about 2 ms, and the window is getting updated every 50 ms or so.

Commented:
Yes, BitBlt is slow.  DrawDibDraw was created to be faster.

Good luck.

Phillip
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