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| 1 | +import { type PointerEvent, useRef } from "react"; |
| 2 | +import { type Vector2, vector2 } from "../common/vector2"; |
| 3 | + |
| 4 | +const DRAG_THRESHOLD = 5; |
| 5 | + |
| 6 | +export type UseDraggableProps = { |
| 7 | + onClick?(e: PointerEvent): void; |
| 8 | + onDragStart?(e: PointerEvent): void; |
| 9 | + onDrag?(e: PointerEvent): void; |
| 10 | + onDragEnd?(e: PointerEvent): void; |
| 11 | +}; |
| 12 | + |
| 13 | +export function useDraggable(props: UseDraggableProps) { |
| 14 | + const { onClick, onDragStart, onDrag, onDragEnd } = props; |
| 15 | + |
| 16 | + const dragStateRef = useRef<{ |
| 17 | + pointerId: number; |
| 18 | + initialPosition: Vector2; |
| 19 | + isDragging: boolean; |
| 20 | + } | null>(null); |
| 21 | + |
| 22 | + return { |
| 23 | + onPointerDown: (e: PointerEvent) => { |
| 24 | + if (!(e.buttons & 1)) return; |
| 25 | + dragStateRef.current = { |
| 26 | + pointerId: e.pointerId, |
| 27 | + initialPosition: vector2.fromDomEvent(e.nativeEvent), |
| 28 | + isDragging: false, |
| 29 | + }; |
| 30 | + onDragStart?.(e); |
| 31 | + e.currentTarget.setPointerCapture(e.pointerId); |
| 32 | + }, |
| 33 | + onPointerMove: (e: PointerEvent) => { |
| 34 | + if (!dragStateRef.current) return; |
| 35 | + if (dragStateRef.current.pointerId !== e.pointerId) return; |
| 36 | + if (dragStateRef.current.isDragging) { |
| 37 | + onDrag?.(e); |
| 38 | + return; |
| 39 | + } |
| 40 | + |
| 41 | + const currentPosition = vector2.fromDomEvent(e.nativeEvent); |
| 42 | + const distance = vector2.distance( |
| 43 | + dragStateRef.current.initialPosition, |
| 44 | + currentPosition, |
| 45 | + ); |
| 46 | + if (distance > DRAG_THRESHOLD) { |
| 47 | + dragStateRef.current.isDragging = true; |
| 48 | + onDragStart?.(e); |
| 49 | + onDrag?.(e); |
| 50 | + } |
| 51 | + }, |
| 52 | + onPointerUp: (e: PointerEvent) => { |
| 53 | + if (!dragStateRef.current) return; |
| 54 | + if (dragStateRef.current.pointerId !== e.pointerId) return; |
| 55 | + e.currentTarget.releasePointerCapture(e.pointerId); |
| 56 | + }, |
| 57 | + onLostPointerCapture: (e: PointerEvent) => { |
| 58 | + if (!dragStateRef.current) return; |
| 59 | + if (dragStateRef.current.isDragging) onDragEnd?.(e); |
| 60 | + else onClick?.(e); |
| 61 | + dragStateRef.current = null; |
| 62 | + }, |
| 63 | + }; |
| 64 | +} |
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