My best advice would be: go away from pixel graphics, especially if this is engineering chart. You can easily render the image our of vector model with blazing speed. It is especially easy if you use WPF; in this case you won't need to take care about rendering, zoom, panning — all this is already done for you.
Few more ideas: you can create/use SVG graphics and convert it to XAML using open-source Incskape, see
http://en.wikipedia.org/wiki/Inkscape[
^],
http://www.inkscape.org/[
^], and you can use XAML in your product during design-time and run-time. You can even allow your user the create custom image in XAML and include them on your charts during run-time; and this is easy to achieve. You actually don't even need to know XAML format to do that.
How about that?
—SA
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