FM / geometry

/opt/canhelp/node_modules/leaflet/src/geometry/

/opt/canhelp/node_modules/leaflet/src/geometry

Name	Size	Mode	Actions
Bounds.js	6197	0644	edit dl rm
index.js	306	0644	edit dl rm
LineUtil.js	8784	0644	edit dl rm
Point.js	6142	0644	edit dl rm
PolyUtil.js	4079	0644	edit dl rm
Transformation.js	2487	0644	edit dl rm

Edit: /opt/canhelp/node_modules/leaflet/src/geometry/LineUtil.js (8784B)

import {Point, toPoint} from './Point';
import * as Util from '../core/Util';
import {toLatLng} from '../geo/LatLng';
import {centroid} from './PolyUtil';
import {toLatLngBounds} from '../geo/LatLngBounds';

/*
 * @namespace LineUtil
 *
 * Various utility functions for polyline points processing, used by Leaflet internally to make polylines lightning-fast.
 */

// Simplify polyline with vertex reduction and Douglas-Peucker simplification.
// Improves rendering performance dramatically by lessening the number of points to draw.

// @function simplify(points: Point[], tolerance: Number): Point[]
// Dramatically reduces the number of points in a polyline while retaining
// its shape and returns a new array of simplified points, using the
// [Ramer-Douglas-Peucker algorithm](https://en.wikipedia.org/wiki/Ramer-Douglas-Peucker_algorithm).
// Used for a huge performance boost when processing/displaying Leaflet polylines for
// each zoom level and also reducing visual noise. tolerance affects the amount of
// simplification (lesser value means higher quality but slower and with more points).
// Also released as a separated micro-library [Simplify.js](https://mourner.github.io/simplify-js/).
export function simplify(points, tolerance) {
	if (!tolerance || !points.length) {
		return points.slice();
	}

var sqTolerance = tolerance * tolerance;

// stage 1: vertex reduction
	    points = _reducePoints(points, sqTolerance);

// stage 2: Douglas-Peucker simplification
	    points = _simplifyDP(points, sqTolerance);

return points;
}

// @function pointToSegmentDistance(p: Point, p1: Point, p2: Point): Number
// Returns the distance between point `p` and segment `p1` to `p2`.
export function pointToSegmentDistance(p, p1, p2) {
	return Math.sqrt(_sqClosestPointOnSegment(p, p1, p2, true));
}

// @function closestPointOnSegment(p: Point, p1: Point, p2: Point): Number
// Returns the closest point from a point `p` on a segment `p1` to `p2`.
export function closestPointOnSegment(p, p1, p2) {
	return _sqClosestPointOnSegment(p, p1, p2);
}

// Ramer-Douglas-Peucker simplification, see https://en.wikipedia.org/wiki/Ramer-Douglas-Peucker_algorithm
function _simplifyDP(points, sqTolerance) {

var len = points.length,
	    ArrayConstructor = typeof Uint8Array !== undefined + '' ? Uint8Array : Array,
	    markers = new ArrayConstructor(len);

markers[0] = markers[len - 1] = 1;

_simplifyDPStep(points, markers, sqTolerance, 0, len - 1);

var i,
	    newPoints = [];

for (i = 0; i < len; i++) {
		if (markers[i]) {
			newPoints.push(points[i]);
		}
	}

return newPoints;
}

function _simplifyDPStep(points, markers, sqTolerance, first, last) {

var maxSqDist = 0,
	index, i, sqDist;

for (i = first + 1; i <= last - 1; i++) {
		sqDist = _sqClosestPointOnSegment(points[i], points[first], points[last], true);

if (sqDist > maxSqDist) {
			index = i;
			maxSqDist = sqDist;
		}
	}

if (maxSqDist > sqTolerance) {
		markers[index] = 1;

_simplifyDPStep(points, markers, sqTolerance, first, index);
		_simplifyDPStep(points, markers, sqTolerance, index, last);
	}
}

// reduce points that are too close to each other to a single point
function _reducePoints(points, sqTolerance) {
	var reducedPoints = [points[0]];

for (var i = 1, prev = 0, len = points.length; i < len; i++) {
		if (_sqDist(points[i], points[prev]) > sqTolerance) {
			reducedPoints.push(points[i]);
			prev = i;
		}
	}
	if (prev < len - 1) {
		reducedPoints.push(points[len - 1]);
	}
	return reducedPoints;
}

var _lastCode;

// @function clipSegment(a: Point, b: Point, bounds: Bounds, useLastCode?: Boolean, round?: Boolean): Point[]|Boolean
// Clips the segment a to b by rectangular bounds with the
// [Cohen-Sutherland algorithm](https://en.wikipedia.org/wiki/Cohen%E2%80%93Sutherland_algorithm)
// (modifying the segment points directly!). Used by Leaflet to only show polyline
// points that are on the screen or near, increasing performance.
export function clipSegment(a, b, bounds, useLastCode, round) {
	var codeA = useLastCode ? _lastCode : _getBitCode(a, bounds),
	    codeB = _getBitCode(b, bounds),

codeOut, p, newCode;

// save 2nd code to avoid calculating it on the next segment
	    _lastCode = codeB;

while (true) {
		// if a,b is inside the clip window (trivial accept)
		if (!(codeA | codeB)) {
			return [a, b];
		}

// if a,b is outside the clip window (trivial reject)
		if (codeA & codeB) {
			return false;
		}

// other cases
		codeOut = codeA || codeB;
		p = _getEdgeIntersection(a, b, codeOut, bounds, round);
		newCode = _getBitCode(p, bounds);

if (codeOut === codeA) {
			a = p;
			codeA = newCode;
		} else {
			b = p;
			codeB = newCode;
		}
	}
}

export function _getEdgeIntersection(a, b, code, bounds, round) {
	var dx = b.x - a.x,
	    dy = b.y - a.y,
	    min = bounds.min,
	    max = bounds.max,
	    x, y;

if (code & 8) { // top
		x = a.x + dx * (max.y - a.y) / dy;
		y = max.y;

} else if (code & 4) { // bottom
		x = a.x + dx * (min.y - a.y) / dy;
		y = min.y;

} else if (code & 2) { // right
		x = max.x;
		y = a.y + dy * (max.x - a.x) / dx;

} else if (code & 1) { // left
		x = min.x;
		y = a.y + dy * (min.x - a.x) / dx;
	}

return new Point(x, y, round);
}

export function _getBitCode(p, bounds) {
	var code = 0;

if (p.x < bounds.min.x) { // left
		code |= 1;
	} else if (p.x > bounds.max.x) { // right
		code |= 2;
	}

if (p.y < bounds.min.y) { // bottom
		code |= 4;
	} else if (p.y > bounds.max.y) { // top
		code |= 8;
	}

return code;
}

// square distance (to avoid unnecessary Math.sqrt calls)
function _sqDist(p1, p2) {
	var dx = p2.x - p1.x,
	    dy = p2.y - p1.y;
	return dx * dx + dy * dy;
}

// return closest point on segment or distance to that point
export function _sqClosestPointOnSegment(p, p1, p2, sqDist) {
	var x = p1.x,
	    y = p1.y,
	    dx = p2.x - x,
	    dy = p2.y - y,
	    dot = dx * dx + dy * dy,
	    t;

if (dot > 0) {
		t = ((p.x - x) * dx + (p.y - y) * dy) / dot;

if (t > 1) {
			x = p2.x;
			y = p2.y;
		} else if (t > 0) {
			x += dx * t;
			y += dy * t;
		}
	}

dx = p.x - x;
	dy = p.y - y;

return sqDist ? dx * dx + dy * dy : new Point(x, y);
}

// @function isFlat(latlngs: LatLng[]): Boolean
// Returns true if `latlngs` is a flat array, false is nested.
export function isFlat(latlngs) {
	return !Util.isArray(latlngs[0]) || (typeof latlngs[0][0] !== 'object' && typeof latlngs[0][0] !== 'undefined');
}

export function _flat(latlngs) {
	console.warn('Deprecated use of _flat, please use L.LineUtil.isFlat instead.');
	return isFlat(latlngs);
}

/* @function polylineCenter(latlngs: LatLng[], crs: CRS): LatLng
 * Returns the center ([centroid](http://en.wikipedia.org/wiki/Centroid)) of the passed LatLngs (first ring) from a polyline.
 */
export function polylineCenter(latlngs, crs) {
	var i, halfDist, segDist, dist, p1, p2, ratio, center;

if (!latlngs || latlngs.length === 0) {
		throw new Error('latlngs not passed');
	}

if (!isFlat(latlngs)) {
		console.warn('latlngs are not flat! Only the first ring will be used');
		latlngs = latlngs[0];
	}

var centroidLatLng = toLatLng([0, 0]);

var bounds = toLatLngBounds(latlngs);
	var areaBounds = bounds.getNorthWest().distanceTo(bounds.getSouthWest()) * bounds.getNorthEast().distanceTo(bounds.getNorthWest());
	// tests showed that below 1700 rounding errors are happening
	if (areaBounds < 1700) {
		// getting a inexact center, to move the latlngs near to [0, 0] to prevent rounding errors
		centroidLatLng = centroid(latlngs);
	}

var len = latlngs.length;
	var points = [];
	for (i = 0; i < len; i++) {
		var latlng = toLatLng(latlngs[i]);
		points.push(crs.project(toLatLng([latlng.lat - centroidLatLng.lat, latlng.lng - centroidLatLng.lng])));
	}

for (i = 0, halfDist = 0; i < len - 1; i++) {
		halfDist += points[i].distanceTo(points[i + 1]) / 2;
	}

// The line is so small in the current view that all points are on the same pixel.
	if (halfDist === 0) {
		center = points[0];
	} else {
		for (i = 0, dist = 0; i < len - 1; i++) {
			p1 = points[i];
			p2 = points[i + 1];
			segDist = p1.distanceTo(p2);
			dist += segDist;

if (dist > halfDist) {
				ratio = (dist - halfDist) / segDist;
				center = [
					p2.x - ratio * (p2.x - p1.x),
					p2.y - ratio * (p2.y - p1.y)
				];
				break;
			}
		}
	}

var latlngCenter = crs.unproject(toPoint(center));
	return toLatLng([latlngCenter.lat + centroidLatLng.lat, latlngCenter.lng + centroidLatLng.lng]);
}

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