Can WPF render a line path with 300,000 points on it in a performance-sensitive environment?

Question

A simple XY line graph: The X axis will represent the complete range of possible rating percentages, from 0% on one end to 100% on the other. Specifically, the X value will

Answer 1

I just stumbled upon this post and am building a line graph control myself that needs to be very performant as we update the points on our lines in a real-time manner.

If performance and number of Visual(s) are what you are after ... I doubt you will find a more performant approach than programming directly against WPF's Visual layer (links: 1, 2). My initial results from using this approach have been very positive.

This will be even more performant than overriding OnRender as it will encourage you to take advantage of WPF's retained mode drawing subsystem (where all the drawing instructions are cached).

That is, if all you have to update is a point on the line, then updating the point will force the line Visual to update but won't force the rest of the graph (axes, gridlines, ...) to update ... as the drawing instructions for these are retained and will be reused (since they aren't updating).

Chapter 14 in Pro WPF in C# 2008 by Matthew MacDonald has a great section (titled 'Visuals') on programming against WPF's Visual layer. Chapter 2 of WPF Control Development Unleashed also has section on page 13 where he discusses how a DrawingVisual approach would be perfect for a charting component. Finally, Charles Petzold wrote a MSDN Magazine article where the best overall solution to a scatter plot was a DrawingVisual approach.

(Now, I know that your question mentioned the axes will also be updating ... and so my answer is really for the general case ... but I still think that this approach will be the most performant ... as only the things that need updating ... will update.)