@antv/g6
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A Graph Visualization Framework in JavaScript
175 lines • 7.08 kB
JavaScript
import { CommonEvent } from '../constants';
/**
* <zh/> 捏合手势处理器
*
* <en/> Pinch gesture handler
* @remarks
* <zh/> 处理双指触摸事件，计算缩放比例并触发回调。通过跟踪两个触摸点的位置变化，计算两点间距离变化率来确定缩放比例。
*
* <en/> Handles two-finger touch events, calculates zoom ratio and triggers callbacks. Tracks position changes of two touch points to determine zoom ratio based on distance variation.
*/
export class PinchHandler {
constructor(emitter, phase, callback) {
this.phase = phase;
/**
* <zh/> 当前跟踪的触摸点集合
*
* <en/> Currently tracked touch points collection
*/
this.pointerByTouch = [];
/**
* <zh/> 初始两点间距离
*
* <en/> Initial distance between two points
*/
this.initialDistance = null;
this.emitter = emitter;
if (PinchHandler.instance) {
PinchHandler.callbacks[this.phase].push(callback);
return PinchHandler.instance;
}
this.onPointerDown = this.onPointerDown.bind(this);
this.onPointerMove = this.onPointerMove.bind(this);
this.onPointerUp = this.onPointerUp.bind(this);
this.bindEvents();
PinchHandler.instance = this;
PinchHandler.callbacks[this.phase].push(callback);
}
bindEvents() {
const { emitter } = this;
emitter.on(CommonEvent.POINTER_DOWN, this.onPointerDown);
emitter.on(CommonEvent.POINTER_MOVE, this.onPointerMove);
emitter.on(CommonEvent.POINTER_UP, this.onPointerUp);
}
/**
* <zh/> 更新指定指针的位置
*
* <en/> Update position of specified pointer
* @param pointerId - <zh/> 指针唯一标识符 | <en/> Pointer unique identifier<sup>1</sup>
* @param x - <zh/> 新的X坐标 | <en/> New X coordinate
* @param y - <zh/> 新的Y坐标 | <en/> New Y coordinate
*/
updatePointerPosition(pointerId, x, y) {
const index = this.pointerByTouch.findIndex((p) => p.pointerId === pointerId);
if (index >= 0) {
this.pointerByTouch[index] = { x, y, pointerId };
}
}
/**
* <zh/> 处理指针按下事件
*
* <en/> Handle pointer down event
* @param event - <zh/> 指针事件对象 | <en/> Pointer event object
* @remarks
* <zh/> 当检测到两个触摸点时记录初始距离
*
* <en/> Record initial distance when detecting two touch points
*/
onPointerDown(event) {
const { x, y } = event.client || {};
if (x === undefined || y === undefined)
return;
this.pointerByTouch.push({ x, y, pointerId: event.pointerId });
if (event.pointerType === 'touch' && this.pointerByTouch.length === 2) {
PinchHandler.isPinching = true;
const dx = this.pointerByTouch[0].x - this.pointerByTouch[1].x;
const dy = this.pointerByTouch[0].y - this.pointerByTouch[1].y;
this.initialDistance = Math.sqrt(dx * dx + dy * dy);
PinchHandler.callbacks.pinchstart.forEach((cb) => cb(event, { scale: 0 }));
}
}
/**
* <zh/> 处理指针移动事件
*
* <en/> Handle pointer move event
* @param event - <zh/> 指针事件对象 | <en/> Pointer event object
* @remarks
* <zh/> 当存在两个有效触摸点时计算缩放比例
*
* <en/> Calculate zoom ratio when two valid touch points exist
*/
onPointerMove(event) {
if (this.pointerByTouch.length !== 2 || this.initialDistance === null)
return;
const { x, y } = event.client || {};
if (x === undefined || y === undefined)
return;
this.updatePointerPosition(event.pointerId, x, y);
const dx = this.pointerByTouch[0].x - this.pointerByTouch[1].x;
const dy = this.pointerByTouch[0].y - this.pointerByTouch[1].y;
const currentDistance = Math.sqrt(dx * dx + dy * dy);
const ratio = currentDistance / this.initialDistance;
PinchHandler.callbacks.pinchmove.forEach((cb) => cb(event, { scale: (ratio - 1) * 5 }));
}
/**
* <zh/> 处理指针抬起事件
*
* <en/> Handle pointer up event
* @param event
* @remarks
* <zh/> 重置触摸状态和初始距离
*
* <en/> Reset touch state and initial distance
*/
onPointerUp(event) {
var _a;
PinchHandler.callbacks.pinchend.forEach((cb) => cb(event, { scale: 0 }));
PinchHandler.isPinching = false;
this.initialDistance = null;
this.pointerByTouch = [];
(_a = PinchHandler.instance) === null || _a === void 0 ? void 0 : _a.tryDestroy();
}
/**
* <zh/> 销毁捏合手势相关监听
*
* <en/> Destroy pinch gesture listeners
* @remarks
* <zh/> 移除指针按下、移动、抬起事件的监听
*
* <en/> Remove listeners for pointer down, move, and up events
*/
destroy() {
this.emitter.off(CommonEvent.POINTER_DOWN, this.onPointerDown);
this.emitter.off(CommonEvent.POINTER_MOVE, this.onPointerMove);
this.emitter.off(CommonEvent.POINTER_UP, this.onPointerUp);
PinchHandler.instance = null;
}
/**
* <zh/> 解绑指定阶段的手势回调
* <en/> Unregister gesture callback for specific phase
* @param phase - <zh/> 手势阶段：开始(pinchstart)/移动(pinchmove)/结束(pinchend) | <en/> Gesture phase: start/move/end
* @param callback - <zh/> 要解绑的回调函数 | <en/> Callback function to unregister
* @remarks
* <zh/> 从指定阶段的回调列表中移除特定回调，当所有回调都解绑后自动销毁事件监听
* <en/> Remove specific callback from the phase's callback list, auto-destroy event listeners when all callbacks are unregistered
*/
off(phase, callback) {
const index = PinchHandler.callbacks[phase].indexOf(callback);
if (index > -1)
PinchHandler.callbacks[phase].splice(index, 1);
this.tryDestroy();
}
/**
* <zh/> 尝试销毁手势处理器
* <en/> Attempt to destroy the gesture handler
* @remarks
* <zh/> 当所有阶段（开始/移动/结束）的回调列表都为空时，执行实际销毁操作
* <en/> Perform actual destruction when all phase (pinchstart/pinchmove/pinchend) callback lists are empty
* <zh/> 自动解除事件监听并重置单例实例
* <en/> Automatically remove event listeners and reset singleton instance
*/
tryDestroy() {
if (Object.values(PinchHandler.callbacks).every((arr) => arr.length === 0)) {
this.destroy();
}
}
}
/**
* <zh/> 是否处于 Pinch 阶段
*
* <en/> Whether it is in the Pinch stage
*/
PinchHandler.isPinching = false;
PinchHandler.instance = null;
PinchHandler.callbacks = { pinchstart: [], pinchmove: [], pinchend: [] };
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