Disable component preview if there's nothing to preview

Hi everyone,

does anyone around here happen to know of a way to disable the preview of (all) components that are currently not (or won't ever be) outputting geometry?
The question first arose when I disabled the preview of a ListLength component for the Nth time (where N is quite a large number...), but I think it would be handy for other components too.

I meant to: try to GH_Convert.ToGeometricGoo() all data (as a first attempt), and disable the preview for components where the conversion fails (for example because it's just integers, or some doubles, booleans, colors, ID's, matrices a.s.o.),
but I got stuck before getting to that: I don't know how to access the output of the components on the canvas.
I can get the type of the outputs, but that's not sufficient to decide what components' preview to disable (i.e. what to do when output type is Param_GenericObject is ambiguous).

Could someone help me, or point me in the right direction please (if this is at all possible)?

Kind regards, Pieter

Replies to This Discussion

Permalink Reply by Pieter Segeren on November 11, 2016 at 8:32am

Thanks for taking the time to explain David. Yet I can't think of a scenario where I would need internalised points in a ListLength component, or did I misundertsand what you meant by: "didn't come from elsewhere"?

Permalink Reply by David Rutten on November 11, 2016 at 10:18am

Oh sure it would be a vanishingly rare case, but the algorithm that decides whether to allow preview on a component only deals in absolutes.

A component only draws previews for input parameters that have internal data, if the data is inherited via a wire the input is not drawn, even if a data conversion or post-process took place.