Legend Added repeatedly when an actor was added again

[zhengliuX]

Hi, I am building an app using Pyvista. I encountered an weird problem. I created a dict, consists of some actors, like

actor = dict()
# create some mesh
mesh = ....
for label in labels:
    actor[label] = plotter.add_mesh(mesh[label])
    plotter.add_legend()

When I set a button to choose whether to remove an actor or add it again, the number of the legend of the re-added actor increased. When I did remove_actor, I did do plotter.remove_legend(), and the label of the actor is the same, so I'm not sure why this happened.

[banesullivan]

Try saving the plotter.add_legend() call until after your for loop. This is expected behavior as calling plotter.add_legend() multiple times would imply that multiple legends should be added

[zhengliuX]

Hi Thank you for your reply
you mean like lengend_actor[label] = plotter.add_legend()

[banesullivan]

Something like:

actor = dict()
# create some mesh
mesh = ....
for label in labels:
    actor[label] = plotter.add_mesh(mesh[label], label=label)
plotter.add_legend()

See https://docs.pyvista.org/api/plotting/_autosummary/pyvista.Plotter.add_legend.html?highlight=add_legend#pyvista.Plotter.add_legend

[zhengliuX]

Hi, still added repeatly.
This is what I did:
I havce some checkboxes with the name of some rois, and the rois is removed or added by clicking the checkboxes, also the legend related.
If I set some checkboxes checked, then uncheck them, then set them checked again.
In the BackgroundPlotter the should show uo, disappear, and show up again.

[zhengliuX]

OK, I think this might because that whenever I added some rois again, I created a new mesh and add_mesh with a same label, if I add a judgement statement to check if this actor is created before to decide add_actor or add_mesh, this problem might disappear.

[zhengliuX]

OK, the error fixed!