[GUI] Canvas overlay / VB

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Permalink Reply by David Rutten on June 30, 2013 at 2:07pm

Well, it can be done, though not in the exact same way as the Disabled Solver graphics. The canvas draws stuff in distinct layers (or "channels") and there are events for each channel that you can handle and draw custom stuff.

These are all the events that are generated given a typical Canvas painting procedure:

1. CanvasPaintBegin
2. CanvasPaintBackground
3. CanvasPrePaintGroups
4. CanvasPostPaintGroups
5. CanvasPrePaintWires
6. CanvasPostPaintWires
7. CanvasPrePaintObjects
8. CanvasPostPaintObjects
9. CanvasPrePaintOverlay
10. CanvasPostPaintOverlay
11. CanvasPrePaintWidgets
12. CanvasPostPaintWidgets
13. CanvasPaintEnd

As you can see quite a few events. I hope the names are self-documenting enough for you to guess what sort of painting goes on in between these events.

You'll want to draw your stuff way at the end so that it doesn't end up underneath any other objects. You can handle CanvasPostPaintWidgets for this (CanvasPaintEnd is too late to start drawing stuff).

Another approach would be to create a custom Widget. The downside of this one is that other widgets (compass, markov chain etc.) may be drawn on top of you. The upside though is that you get to handle mouse events so when someone clicks on your border or icon you can 'eat' the click.

Do you need further example code?

--

David Rutten

david@mcneel.com

Poprad, Slovakia

Permalink Reply by David Rutten on June 30, 2013 at 2:25pm

I implemented the CanvasPostPaintWidgets event approach in the attached file.

--

David Rutten

david@mcneel.com

Tirol, Austria

Attachments:

• PaintHandler.gh, 4 KB

Permalink Reply by Thibault Schwartz on June 30, 2013 at 2:32pm

Wow

That was fast!

It's exactly what I needed, huge thanks, this is a great example!

Have a nice evening!

Thibault.