vc++ graphic performance

I want to build开发者_如何学编程 a obj to draw a realtime graph but I have performance limitations size of graph is static.

in repaint the graph I can redraw all the needed line. I have other way that save the graph on bitmap memory and each time copy it on the screen which way is better? what is faster copy bitmap or draw lines?

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I guess it depends on what you are trying to display. Showing a few lines should not pose any performance problems (if done well), but doing anything more graphics-intensive can be more problematic.

It also depends on what you use for drawing. GDI is easy but slow; GDI+ is also easy, can be prettier (antialiasing, etc.) but is also quite slow (or used to be when I tried it); OpenGL is fast but a bit trickier.

So it's a question with no easy answer, not knowing all the details of your needs. I think I would draw directly, and if it's not fast enough then check other options. What you'll probably need anyway is a double-buffering system, to avoid flickering (check http://www.codeproject.com/KB/GDI/flickerfree.aspx)

You can take a look at http://www.codeproject.com/KB/miscctrl/High-speedCharting.aspx. It's a charting control which seems to be quite fast.