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Mini Shell
Mini Shell
import { frame, isPrimaryPointer, cancelFrame, frameData } from 'motion-dom';
import { pipe, secondsToMilliseconds, millisecondsToSeconds } from 'motion-utils';
import { addPointerEvent } from '../../events/add-pointer-event.mjs';
import { extractEventInfo } from '../../events/event-info.mjs';
import { distance2D } from '../../utils/distance.mjs';
/**
* @internal
*/
class PanSession {
constructor(event, handlers, { transformPagePoint, contextWindow, dragSnapToOrigin = false, } = {}) {
/**
* @internal
*/
this.startEvent = null;
/**
* @internal
*/
this.lastMoveEvent = null;
/**
* @internal
*/
this.lastMoveEventInfo = null;
/**
* @internal
*/
this.handlers = {};
/**
* @internal
*/
this.contextWindow = window;
this.updatePoint = () => {
if (!(this.lastMoveEvent && this.lastMoveEventInfo))
return;
const info = getPanInfo(this.lastMoveEventInfo, this.history);
const isPanStarted = this.startEvent !== null;
// Only start panning if the offset is larger than 3 pixels. If we make it
// any larger than this we'll want to reset the pointer history
// on the first update to avoid visual snapping to the cursoe.
const isDistancePastThreshold = distance2D(info.offset, { x: 0, y: 0 }) >= 3;
if (!isPanStarted && !isDistancePastThreshold)
return;
const { point } = info;
const { timestamp } = frameData;
this.history.push({ ...point, timestamp });
const { onStart, onMove } = this.handlers;
if (!isPanStarted) {
onStart && onStart(this.lastMoveEvent, info);
this.startEvent = this.lastMoveEvent;
}
onMove && onMove(this.lastMoveEvent, info);
};
this.handlePointerMove = (event, info) => {
this.lastMoveEvent = event;
this.lastMoveEventInfo = transformPoint(info, this.transformPagePoint);
// Throttle mouse move event to once per frame
frame.update(this.updatePoint, true);
};
this.handlePointerUp = (event, info) => {
this.end();
const { onEnd, onSessionEnd, resumeAnimation } = this.handlers;
if (this.dragSnapToOrigin)
resumeAnimation && resumeAnimation();
if (!(this.lastMoveEvent && this.lastMoveEventInfo))
return;
const panInfo = getPanInfo(event.type === "pointercancel"
? this.lastMoveEventInfo
: transformPoint(info, this.transformPagePoint), this.history);
if (this.startEvent && onEnd) {
onEnd(event, panInfo);
}
onSessionEnd && onSessionEnd(event, panInfo);
};
// If we have more than one touch, don't start detecting this gesture
if (!isPrimaryPointer(event))
return;
this.dragSnapToOrigin = dragSnapToOrigin;
this.handlers = handlers;
this.transformPagePoint = transformPagePoint;
this.contextWindow = contextWindow || window;
const info = extractEventInfo(event);
const initialInfo = transformPoint(info, this.transformPagePoint);
const { point } = initialInfo;
const { timestamp } = frameData;
this.history = [{ ...point, timestamp }];
const { onSessionStart } = handlers;
onSessionStart &&
onSessionStart(event, getPanInfo(initialInfo, this.history));
this.removeListeners = pipe(addPointerEvent(this.contextWindow, "pointermove", this.handlePointerMove), addPointerEvent(this.contextWindow, "pointerup", this.handlePointerUp), addPointerEvent(this.contextWindow, "pointercancel", this.handlePointerUp));
}
updateHandlers(handlers) {
this.handlers = handlers;
}
end() {
this.removeListeners && this.removeListeners();
cancelFrame(this.updatePoint);
}
}
function transformPoint(info, transformPagePoint) {
return transformPagePoint ? { point: transformPagePoint(info.point) } : info;
}
function subtractPoint(a, b) {
return { x: a.x - b.x, y: a.y - b.y };
}
function getPanInfo({ point }, history) {
return {
point,
delta: subtractPoint(point, lastDevicePoint(history)),
offset: subtractPoint(point, startDevicePoint(history)),
velocity: getVelocity(history, 0.1),
};
}
function startDevicePoint(history) {
return history[0];
}
function lastDevicePoint(history) {
return history[history.length - 1];
}
function getVelocity(history, timeDelta) {
if (history.length < 2) {
return { x: 0, y: 0 };
}
let i = history.length - 1;
let timestampedPoint = null;
const lastPoint = lastDevicePoint(history);
while (i >= 0) {
timestampedPoint = history[i];
if (lastPoint.timestamp - timestampedPoint.timestamp >
secondsToMilliseconds(timeDelta)) {
break;
}
i--;
}
if (!timestampedPoint) {
return { x: 0, y: 0 };
}
const time = millisecondsToSeconds(lastPoint.timestamp - timestampedPoint.timestamp);
if (time === 0) {
return { x: 0, y: 0 };
}
const currentVelocity = {
x: (lastPoint.x - timestampedPoint.x) / time,
y: (lastPoint.y - timestampedPoint.y) / time,
};
if (currentVelocity.x === Infinity) {
currentVelocity.x = 0;
}
if (currentVelocity.y === Infinity) {
currentVelocity.y = 0;
}
return currentVelocity;
}
export { PanSession };
Zerion Mini Shell 1.0