cross-gesture/lib/cjs/utils.js

Gesture lib for the modern browsers

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.getCrossPoint = exports.getDirectionAndSpeed = exports.getRotateDeg = exports.pinchTimes = exports.vectorDot = exports.vectorAbs = void 0;
var types_1 = require("./types");
function vectorAbs(v) {
    return Math.sqrt(v.x * v.x + v.y * v.y);
}
exports.vectorAbs = vectorAbs;
function vectorDot(f, t) {
    return f.x * t.x + f.y * t.y;
}
exports.vectorDot = vectorDot;
// 返回缩放的倍数
function pinchTimes(from, to) {
    var fromLen = Math.sqrt(Math.pow(Math.abs(from[0].x - from[1].x), 2) + Math.pow(Math.abs(from[0].y - from[1].y), 2));
    var toLen = Math.sqrt(Math.pow(Math.abs(to[0].x - to[1].x), 2) + Math.pow(Math.abs(to[0].y - to[1].y), 2));
    return toLen / fromLen;
}
exports.pinchTimes = pinchTimes;
// 返回旋转的角度
// 顺时针为正数
function getRotateDeg(from, to) {
    var fromVector = { x: from[1].x - from[0].x, y: from[1].y - from[0].y };
    var toVector = { x: to[1].x - to[0].x, y: to[1].y - to[0].y };
    // direction: https://blog.csdn.net/qq_42778110/article/details/81567954
    var direction = fromVector.x * toVector.y - fromVector.y * toVector.x;
    if (direction === 0) {
        return 0;
    }
    // a * b = |a|*|b|*cos(deg)
    // cos(deg) = (a * b) / (|a| * |b|)
    var cosDeg = vectorDot(fromVector, toVector) / (vectorAbs(fromVector) * vectorAbs(toVector));
    return (direction > 0 ? 1 : -1) * Math.acos(cosDeg);
}
exports.getRotateDeg = getRotateDeg;
// 返回滑动反向和速度
function getDirectionAndSpeed(from, to, duration) {
    var distanceX = to.x - from.x;
    var distanceY = to.y - from.y;
    return {
        vDirection: distanceX > 0 ? types_1.SwipeDirection.right : types_1.SwipeDirection.left,
        vSpeed: distanceX / duration,
        hDirection: distanceY > 0 ? types_1.SwipeDirection.bottom : types_1.SwipeDirection.top,
        hSpeed: distanceY / duration,
    };
}
exports.getDirectionAndSpeed = getDirectionAndSpeed;
function getCrossPoint(from, to) {
    // k = (y2 - y1) / (x2 - x1)
    // b = y1 - k * x1
    var k1 = (from[1].y - from[0].y) / (from[1].x - from[0].x);
    var b1 = from[0].y - k1 * from[0].x;
    var k2 = (to[1].y - to[0].y) / (to[1].x - to[0].x);
    var b2 = to[0].y - k2 * to[0].x;
    // x = (b1 - b2) / (k2 - k1)
    // y = k1x + b1
    var x = (b1 - b2) / (k2 - k1);
    return {
        x: x,
        y: k1 * x + b1,
    };
}
exports.getCrossPoint = getCrossPoint;
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