on_drag()

void MayaFlux::Portal::Forma::Context::on_drag	(	uint32_t	id,
		IO::MouseButtons	btn,
		MoveFn	fn
	)

Called on each mouse-move event while btn is held, tracking the element where the drag began even when the cursor leaves its bounds.

Drag tracking begins when the element is first hit (either at initial press or first drag motion while button is held). Once tracking starts, the callback continues to fire with the current cursor position until the button is released, regardless of whether the cursor remains over the element.

This matches standard UI expectations for sliders, scrollbars, resize handles, and other controls that must respond continuously during a drag gesture.

Driven by the same motion event as on_move, for every button the window's event source reports as held.

Parameters

id	Element id to bind to.
btn	Mouse button that must be held.
fn	Callback receiving element id and current NDC cursor position (which may be outside the element's bounds during drag).

Definition at line 53 of file Context.cpp.

{
    m_callbacks[id].drag[static_cast<int>(btn)] = std::move(fn);
}

References m_callbacks.

Referenced by MayaFlux::Portal::Forma::Scrollable::indicator(), MayaFlux::Portal::Forma::Geometry::wire_canvas_drag(), and wire_drag().

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