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| import Layer from 'ol/layer/Layer.js';
import Map from 'ol/Map.js';
import Source from 'ol/source/Source.js';
import View from 'ol/View.js';
import stringify from 'json-stringify-safe';
import {FullScreen} from 'ol/control.js';
import {
compose,
create,
toString as toTransformString,
} from 'ol/transform.js';
import {createXYZ} from 'ol/tilegrid.js';
const worker = new Worker('./worker.js', {type: 'module'});
let container,
transformContainer,
canvas,
rendering,
workerFrameState,
mainThreadFrameState;
function updateContainerTransform() {
if (workerFrameState) {
const viewState = mainThreadFrameState.viewState;
const renderedViewState = workerFrameState.viewState;
const center = viewState.center;
const resolution = viewState.resolution;
const rotation = viewState.rotation;
const renderedCenter = renderedViewState.center;
const renderedResolution = renderedViewState.resolution;
const renderedRotation = renderedViewState.rotation;
const transform = create();
if (!rotation) {
compose(
transform,
(renderedCenter[0] - center[0]) / resolution,
(center[1] - renderedCenter[1]) / resolution,
renderedResolution / resolution,
renderedResolution / resolution,
rotation - renderedRotation,
0,
0
);
}
transformContainer.style.transform = toTransformString(transform);
}
}
const map = new Map({
layers: [
new Layer({
render: function (frameState) {
if (!container) {
container = document.createElement('div');
container.style.position = 'absolute';
container.style.width = '100%';
container.style.height = '100%';
transformContainer = document.createElement('div');
transformContainer.style.position = 'absolute';
transformContainer.style.width = '100%';
transformContainer.style.height = '100%';
container.appendChild(transformContainer);
canvas = document.createElement('canvas');
canvas.style.position = 'absolute';
canvas.style.left = '0';
canvas.style.transformOrigin = 'top left';
transformContainer.appendChild(canvas);
}
mainThreadFrameState = frameState;
updateContainerTransform();
if (!rendering) {
rendering = true;
worker.postMessage({
action: 'render',
frameState: JSON.parse(stringify(frameState)),
});
} else {
frameState.animate = true;
}
return container;
},
source: new Source({
attributions: [
'<a href="https://www.maptiler.com/copyright/" target="_blank">© MapTiler</a>',
'<a href="https://www.openstreetmap.org/copyright" target="_blank">© OpenStreetMap contributors</a>',
],
}),
}),
],
target: 'map',
view: new View({
resolutions: createXYZ({tileSize: 512}).getResolutions(),
center: [0, 0],
zoom: 2,
}),
});
map.addControl(new FullScreen());
map.on('pointermove', function (evt) {
if (evt.dragging) {
return;
}
const pixel = map.getEventPixel(evt.originalEvent);
worker.postMessage({
action: 'requestFeatures',
pixel: pixel,
});
});
worker.addEventListener('message', (message) => {
if (message.data.action === 'loadImage') {
const image = new Image();
image.crossOrigin = 'anonymous';
image.addEventListener('load', function () {
createImageBitmap(image, 0, 0, image.width, image.height).then(
(imageBitmap) => {
worker.postMessage(
{
action: 'imageLoaded',
image: imageBitmap,
src: message.data.src,
},
[imageBitmap]
);
}
);
});
image.src = message.data.src;
} else if (message.data.action === 'getFeatures') {
showInfo(message.data.features);
} else if (message.data.action === 'requestRender') {
map.render();
} else if (canvas && message.data.action === 'rendered') {
requestAnimationFrame(function () {
const imageData = message.data.imageData;
canvas.width = imageData.width;
canvas.height = imageData.height;
canvas.getContext('2d').drawImage(imageData, 0, 0);
canvas.style.transform = message.data.transform;
workerFrameState = message.data.frameState;
updateContainerTransform();
});
rendering = false;
}
});
const info = document.getElementById('info');
function showInfo(propertiesFromFeatures) {
if (propertiesFromFeatures.length == 0) {
info.innerText = '';
info.style.opacity = 0;
return;
}
const properties = propertiesFromFeatures.map((e) =>
Object.keys(e)
.filter((key) => !key.includes(':'))
.reduce((newObj, currKey) => ((newObj[currKey] = e[currKey]), newObj), {})
);
info.innerText = JSON.stringify(properties, null, 2);
info.style.opacity = 1;
}
|
)
