Files
openlayers/examples/layer-spy.js
Frederic Junod 4a3f70c09b Revert "Simplify import path in examples"
This reverts commit 79c8afdba8.
2018-11-27 16:49:55 +01:00

76 lines
1.9 KiB
JavaScript

import Map from '../src/ol/Map.js';
import View from '../src/ol/View.js';
import TileLayer from '../src/ol/layer/Tile.js';
import {fromLonLat} from '../src/ol/proj.js';
import BingMaps from '../src/ol/source/BingMaps.js';
const key = 'As1HiMj1PvLPlqc_gtM7AqZfBL8ZL3VrjaS3zIb22Uvb9WKhuJObROC-qUpa81U5';
const roads = new TileLayer({
source: new BingMaps({key: key, imagerySet: 'Road'})
});
const imagery = new TileLayer({
source: new BingMaps({key: key, imagerySet: 'Aerial'})
});
const container = document.getElementById('map');
const map = new Map({
layers: [roads, imagery],
target: container,
view: new View({
center: fromLonLat([-109, 46.5]),
zoom: 6
})
});
let radius = 75;
document.addEventListener('keydown', function(evt) {
if (evt.which === 38) {
radius = Math.min(radius + 5, 150);
map.render();
evt.preventDefault();
} else if (evt.which === 40) {
radius = Math.max(radius - 5, 25);
map.render();
evt.preventDefault();
}
});
// get the pixel position with every move
let mousePosition = null;
container.addEventListener('mousemove', function(event) {
mousePosition = map.getEventPixel(event);
map.render();
});
container.addEventListener('mouseout', function() {
mousePosition = null;
map.render();
});
// before rendering the layer, do some clipping
imagery.on('prerender', function(event) {
const ctx = event.context;
const pixelRatio = event.frameState.pixelRatio;
ctx.save();
ctx.beginPath();
if (mousePosition) {
// only show a circle around the mouse
ctx.arc(mousePosition[0] * pixelRatio, mousePosition[1] * pixelRatio,
radius * pixelRatio, 0, 2 * Math.PI);
ctx.lineWidth = 5 * pixelRatio;
ctx.strokeStyle = 'rgba(0,0,0,0.5)';
ctx.stroke();
}
ctx.clip();
});
// after rendering the layer, restore the canvas context
imagery.on('postrender', function(event) {
const ctx = event.context;
ctx.restore();
});