Module machine 

A formal state machine for pointer-driven drag gestures.

The lifecycle every synthesized drag goes through - press, threshold promotion, tracking, release or abort - is modeled here as a pure transition function over explicit states and events, so every edge (stray pointer ids, release before the threshold, cancellation mid-drag) is an exhaustive match arm with a test, not an ad-hoc if.

crate::core::Draggable drives this machine; you can drive it yourself to build custom pointer interactions with the same rigor:

use dioxus_dnd::core::{transition, GestureEffect, GesturePhase, GestureEvent, Point};

let mut phase = GesturePhase::Idle;
let (next, fx) = transition(phase, GestureEvent::Down { at: Point::new(10.0, 10.0), pointer_id: 1 }, 8.0);
phase = next;
assert_eq!(fx, GestureEffect::None); // pressed, not yet a drag

let (next, fx) = transition(phase, GestureEvent::Move { at: Point::new(30.0, 10.0), pointer_id: 1 }, 8.0);
assert!(matches!(fx, GestureEffect::Begin { .. })); // crossed the threshold

Enums

GestureEffect

What the caller should do after a transition.

GestureEvent

An input to the machine.

GesturePhase

Where a pointer gesture currently stands.

Promotion

How a press gets promoted to a drag - the policy half of the touch auto-sensor.

Functions

transition

Advance the machine with the default Promotion::Distance policy. Pure: same inputs, same outputs, no side effects.

transition_with

Advance the machine under an explicit Promotion policy. Pure: same inputs, same outputs, no side effects.