132 lines
2.6 KiB
JavaScript
132 lines
2.6 KiB
JavaScript
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import {
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every
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} from 'min-dash';
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/**
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* @typedef {import('../util/Types').Axis} Axis
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* @typedef {import('../util/Types').Point} Point
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* @typedef {import('../util/Types').Rect} Rect
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*/
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/**
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* Computes the distance between two points.
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*
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* @param {Point} p
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* @param {Point} q
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*
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* @return {number} The distance between the two points.
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*/
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export function pointDistance(a, b) {
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if (!a || !b) {
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return -1;
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}
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return Math.sqrt(
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Math.pow(a.x - b.x, 2) +
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Math.pow(a.y - b.y, 2)
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);
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}
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/**
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* Returns true if the point r is on the line between p and q.
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*
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* @param {Point} p
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* @param {Point} q
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* @param {Point} r
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* @param {number} [accuracy=5] The accuracy with which to check (lower is better).
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*
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* @return {boolean}
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*/
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export function pointsOnLine(p, q, r, accuracy) {
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if (typeof accuracy === 'undefined') {
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accuracy = 5;
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}
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if (!p || !q || !r) {
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return false;
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}
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var val = (q.x - p.x) * (r.y - p.y) - (q.y - p.y) * (r.x - p.x),
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dist = pointDistance(p, q);
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// @see http://stackoverflow.com/a/907491/412190
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return Math.abs(val / dist) <= accuracy;
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}
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var ALIGNED_THRESHOLD = 2;
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/**
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* Check whether two points are horizontally or vertically aligned.
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*
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* @param {Point[]|Point} a
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* @param {Point} [b]
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*
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* @return {string|boolean} If and how the two points are aligned ('h', 'v' or `false`).
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*/
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export function pointsAligned(a, b) {
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var points = Array.from(arguments).flat();
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const axisMap = {
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'x': 'v',
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'y': 'h'
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};
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for (const [ axis, orientation ] of Object.entries(axisMap)) {
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if (pointsAlignedOnAxis(axis, points)) {
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return orientation;
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}
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}
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return false;
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}
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/**
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* @param {Axis} axis
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* @param {Point[]} points
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*
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* @return {boolean}
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*/
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export function pointsAlignedOnAxis(axis, points) {
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const referencePoint = points[0];
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return every(points, function(point) {
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return Math.abs(referencePoint[axis] - point[axis]) <= ALIGNED_THRESHOLD;
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});
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}
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/**
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* Returns true if the point p is inside the rectangle rect
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*
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* @param {Point} p
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* @param {Rect} rect
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* @param {number} tolerance
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*
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* @return {boolean}
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*/
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export function pointInRect(p, rect, tolerance) {
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tolerance = tolerance || 0;
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return p.x > rect.x - tolerance &&
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p.y > rect.y - tolerance &&
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p.x < rect.x + rect.width + tolerance &&
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p.y < rect.y + rect.height + tolerance;
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}
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/**
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* Returns a point in the middle of points p and q
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*
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* @param {Point} p
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* @param {Point} q
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*
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* @return {Point} The mid point between the two points.
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*/
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export function getMidPoint(p, q) {
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return {
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x: Math.round(p.x + ((q.x - p.x) / 2.0)),
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y: Math.round(p.y + ((q.y - p.y) / 2.0))
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};
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}
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