`CanvasPanelInputProvider`'s `ICanvasRaycastFilter` blocks raycasts to child Unity UI elements

[claytercek]

Description:

Standard Unity UI elements (Buttons, Toggles, etc.) nested as children of a RiveCanvasRenderer cannot receive pointer events.

CanvasPanelInputProvider implements ICanvasRaycastFilter, which Unity's GraphicRaycaster checks on the target and all its parents. When a child UI element is hit-tested, Unity walks up to the panel's filter, and IsRaycastLocationValid returns false (no Rive widget at that position), rejecting the child's raycast.

This is also broken with PointerInputMode.DisablePointerInput — the panel correctly disables raycastTarget on its Image, but IsRaycastLocationValid still unconditionally returns false, so children are blocked regardless.

There is no configuration that allows standard Unity UI elements to receive pointer events when nested inside a RivePanel.

Question:

Is mixing standard Unity UI elements as children of a RiveCanvasRenderer a supported use case? It's unclear in the documentation

Possible Fix:

One approach might be moving the hit-test logic from the panel down to individual Rive widget hitboxes, so the panel itself doesn't need to implement ICanvasRaycastFilter. I haven't fully evaluated the trade-offs of this approach, but it would eliminate the parent filter walk problem and allow Unity UI elements to coexist naturally alongside Rive widgets.

[damzobridge]

Is mixing standard Unity UI elements as children of a RiveCanvasRenderer a supported use case? It's unclear in the documentation

Hello, this isn't a supported use case as it can lead to unexpected results. Thanks for bringing it up. We'll update the docs.

The RivePanel is intended to be a self-contained component, but uGUI doesn't have an automatic way to restrict it from containing non-RiveWidget gameobjects. To work around this, we might log a warning instead if we detect you're trying to use Unity UI Elements under a panel.

Also, can you elaborate a bit more on why your use case requires Unity's UI components under a panel?

[claytercek]

Gotcha! Totally makes sense.

I'm migrating bits and pieces of a uGUI UI that were manually animated over to rive components, and was trying to see if I could wrap the whole camera-space canvas in a single Panel element, as is recommended in the best-practices docs (though I now understand that's referencing a single panel for a UI built out of widgets, not mixed widgets/uGUI elements)

Thanks for the quick reply!