On the Workbench Canvas Performance

Some people might have noticed that Workbench runs very slowly and flickers a lot in their machines. Other people will be able to work without noticing any significant sluggishness with the diagram graphics. The difference is because Workbench’s custom canvas may use hardware accelerated OpenGL graphics or non-accelerated software rendering, depending on the system (ie, whether or not a 3D accelerated graphics card is available or not). We were expecting that the most reasonably recent machines (maybe 5 years old or less) would have at least some basic graphics acceleration, but for some reason, that seems to not always be the case. Apparently, some people that have decent systems with ATI or Intel cards seem to get the fallback software rendered canvas, which will result in sluggish graphics.

We are still not sure why Cairo/Glitz (the underlying graphics library used by our drawing canvas) is not working as intended for everyone, but we are working on getting this performance problem solved in at least two fronts:

  • one is to add support for the Windows GDI backend of Cairo, which seems to be faster than the software based OpenGL rendering provided by Mesa. We already use that for Windows printing, so we get that for almost free;
  • another thing that’s being worked on is general drawing optimization, so that the number of redundant drawing operations is minimized. Those changes should make Workbench work much faster and smoother for everyone, as we intended to have from the beginning.

So expect future versions to have an improved canvas and Workbench will be much faster when you work on larger models.