Files
openlayers/examples/image-load-events.js
2018-01-10 09:35:42 -07:00

107 lines
2.0 KiB
JavaScript

import Map from '../src/ol/Map.js';
import View from '../src/ol/View.js';
import _ol_layer_Image_ from '../src/ol/layer/Image.js';
import _ol_source_ImageWMS_ from '../src/ol/source/ImageWMS.js';
/**
* Renders a progress bar.
* @param {Element} el The target element.
* @constructor
*/
function Progress(el) {
this.el = el;
this.loading = 0;
this.loaded = 0;
}
/**
* Increment the count of loading tiles.
*/
Progress.prototype.addLoading = function() {
if (this.loading === 0) {
this.show();
}
++this.loading;
this.update();
};
/**
* Increment the count of loaded tiles.
*/
Progress.prototype.addLoaded = function() {
var this_ = this;
setTimeout(function() {
++this_.loaded;
this_.update();
}, 100);
};
/**
* Update the progress bar.
*/
Progress.prototype.update = function() {
var width = (this.loaded / this.loading * 100).toFixed(1) + '%';
this.el.style.width = width;
if (this.loading === this.loaded) {
this.loading = 0;
this.loaded = 0;
var this_ = this;
setTimeout(function() {
this_.hide();
}, 500);
}
};
/**
* Show the progress bar.
*/
Progress.prototype.show = function() {
this.el.style.visibility = 'visible';
};
/**
* Hide the progress bar.
*/
Progress.prototype.hide = function() {
if (this.loading === this.loaded) {
this.el.style.visibility = 'hidden';
this.el.style.width = 0;
}
};
var progress = new Progress(document.getElementById('progress'));
var source = new _ol_source_ImageWMS_({
url: 'https://ahocevar.com/geoserver/wms',
params: {'LAYERS': 'topp:states'},
serverType: 'geoserver'
});
source.on('imageloadstart', function() {
progress.addLoading();
});
source.on('imageloadend', function() {
progress.addLoaded();
});
source.on('imageloaderror', function() {
progress.addLoaded();
});
var map = new Map({
layers: [
new _ol_layer_Image_({source: source})
],
target: 'map',
view: new View({
center: [-10997148, 4569099],
zoom: 4
})
});