#### LineString Arrows

Example of drawing arrows for each line string segment.

Example of drawing arrows for each line string segment.

##### main.js
``````import Draw from 'ol/interaction/Draw.js';
import Map from 'ol/Map.js';
import Point from 'ol/geom/Point.js';
import View from 'ol/View.js';
import {Icon, Stroke, Style} from 'ol/style.js';
import {OSM, Vector as VectorSource} from 'ol/source.js';
import {Tile as TileLayer, Vector as VectorLayer} from 'ol/layer.js';
import {get} from 'ol/proj.js';

const raster = new TileLayer({
source: new OSM(),
});

const source = new VectorSource();

const styleFunction = function (feature) {
const geometry = feature.getGeometry();
const styles = [
// linestring
new Style({
stroke: new Stroke({
color: '#ffcc33',
width: 2,
}),
}),
];

geometry.forEachSegment(function (start, end) {
const dx = end[0] - start[0];
const dy = end[1] - start[1];
const rotation = Math.atan2(dy, dx);
// arrows
styles.push(
new Style({
geometry: new Point(end),
image: new Icon({
src: 'data/arrow.png',
anchor: [0.75, 0.5],
rotateWithView: true,
rotation: -rotation,
}),
}),
);
});

return styles;
};
const vector = new VectorLayer({
source: source,
style: styleFunction,
});

// Limit multi-world panning to one world east and west of the real world.
// Geometry coordinates have to be within that range.
const extent = get('EPSG:3857').getExtent().slice();
extent[0] += extent[0];
extent[2] += extent[2];

const map = new Map({
layers: [raster, vector],
target: 'map',
view: new View({
center: [-11000000, 4600000],
zoom: 4,
extent,
}),
});

map.addInteraction(
new Draw({
source: source,
type: 'LineString',
}),
);
``````
##### index.html
``````<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>LineString Arrows</title>
<link rel="stylesheet" href="node_modules/ol/ol.css">
<style>
.map {
width: 100%;
height: 400px;
}
</style>
</head>
<body>
<div id="map" class="map"></div>

<script type="module" src="main.js"></script>
</body>
</html>``````
##### package.json
``````{
"name": "line-arrows",
"dependencies": {
"ol": "9.2.4"
},
"devDependencies": {
"vite": "^3.2.3"
},
"scripts": {
"start": "vite",
"build": "vite build"
}
}``````