arcade-physics/lib/geom/line/Extend.js

Use Arcade Physics without Phaser.

"use strict";
/**
 * @author       Richard Davey <rich@photonstorm.com>
 * @copyright    2020 Photon Storm Ltd.
 * @license      {@link https://opensource.org/licenses/MIT|MIT License}
 */
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
Object.defineProperty(exports, "__esModule", { value: true });
const Length_1 = __importDefault(require("./Length"));
/**
 * Extends the start and end points of a Line by the given amounts.
 *
 * The amounts can be positive or negative. Positive points will increase the length of the line,
 * while negative ones will decrease it.
 *
 * If no `right` value is provided it will extend the length of the line equally in both directions.
 *
 * Pass a value of zero to leave the start or end point unchanged.
 *
 * @function Phaser.Geom.Line.Extend
 * @since 3.16.0
 *
 * @param {Phaser.Geom.Line} line - The line instance to extend.
 * @param {number} left - The amount to extend the start of the line by.
 * @param {number} [right] - The amount to extend the end of the line by. If not given it will be set to the `left` value.
 *
 * @return {Phaser.Geom.Line} The modified Line instance.
 */
const Extend = (line, left, right) => {
    if (right === undefined) {
        right = left;
    }
    const length = (0, Length_1.default)(line);
    const slopX = line.x2 - line.x1;
    const slopY = line.y2 - line.y1;
    if (left) {
        line.x1 = line.x1 - (slopX / length) * left;
        line.y1 = line.y1 - (slopY / length) * left;
    }
    if (right) {
        line.x2 = line.x2 + (slopX / length) * right;
        line.y2 = line.y2 + (slopY / length) * right;
    }
    return line;
};
exports.default = Extend;
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