In my previous blog post I had made a simple slider that worked with a click. This week, I also implemented dragging. It required changing the way I was sending the UI elements to ghe renderer again. It worked well, but I am stuck with a bug which seems pretty difficult to solve.
VTK has actors - 2D actors and 3D actors. Now, when you click on the screen, we use a picker (a built in VTK object) which takes in the click coordinates and returns the actor at that coordinate. This is how everything was working for the past 6 weeks. All the UI elements I have are 2D Actors. I have some problem picking the right 2D actor. This seems like a long known yet unsolved issue with VTK-Python :/
We’re working on it right now and if it doesn’t work out, we’ll have to write our own picker.