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Add a d3 example

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Éric Lemoine
2013-09-22 09:58:26 +01:00
parent 5af738593e
commit 2633d8784c
3 changed files with 155 additions and 0 deletions
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<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="chrome=1">
<meta name="viewport" content="initial-scale=1.0, user-scalable=no, width=device-width">
<link rel="stylesheet" href="../css/ol.css" type="text/css">
<link rel="stylesheet" href="../resources/bootstrap/css/bootstrap.min.css" type="text/css">
<link rel="stylesheet" href="../resources/layout.css" type="text/css">
<link rel="stylesheet" href="../resources/bootstrap/css/bootstrap-responsive.min.css" type="text/css">
<title>d3 integration example</title>
</head>
<body>
<div class="navbar navbar-inverse navbar-fixed-top">
<div class="navbar-inner">
<div class="container">
<a class="brand" href="./">OpenLayers 3 Examples</a>
<ul class="nav pull-right">
<li><iframe class="github-watch-button" src="http://ghbtns.com/github-btn.html?user=openlayers&repo=ol3&type=watch&count=true"
allowtransparency="true" frameborder="0" scrolling="0" height="20" width="90"></iframe></li>
<li><a href="https://twitter.com/share" class="twitter-share-button" data-count="none" data-hashtags="openlayers">&nbsp;</a></li>
<li><div class="g-plusone-wrapper"><div class="g-plusone" data-size="medium" data-annotation="none"></div></div></li>
</ul>
</div>
</div>
</div>
<div class="container-fluid">
<div class="row-fluid">
<div class="span12">
<div id="map" class="map"></div>
</div>
</div>
<div class="row-fluid">
<div class="span12">
<h4 id="title">d3 integration example</h4>
<p id="shortdesc">Example of using ol3 and d3 together.</p>
<div id="docs">
<p>The example loads TopoJSON geometries and uses d3 (<code>d3.geo.path</code>) to render these geometries to a canvas element that is then used as the image of an ol3 image layer.</p>
<p>See the <a href="d3.js" target="_blank">d3.js source</a> to see how this is done.</p>
</div>
<div id="tags">d3</div>
</div>
</div>
</div>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script src="http://d3js.org/topojson.v1.min.js"></script>
<script src="loader.js?id=d3" type="text/javascript"></script>
<script src="../resources/social-links.js" type="text/javascript"></script>
</body>
</html>

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// NOCOMPILE
// this example uses d3 for which we don't have an externs file.
goog.require('ol');
goog.require('ol.Map');
goog.require('ol.View2D');
goog.require('ol.extent');
goog.require('ol.layer.Image');
goog.require('ol.layer.Tile');
goog.require('ol.proj');
goog.require('ol.source.ImageCanvas');
goog.require('ol.source.Stamen');
var map = new ol.Map({
layers: [
new ol.layer.Tile({
source: new ol.source.Stamen({
layer: 'watercolor'
})
})
],
renderers: ['canvas'],
target: 'map',
view: new ol.View2D({
center: ol.proj.transform([-97, 38], 'EPSG:4326', 'EPSG:3857'),
zoom: 4
})
});
/**
* Load the topojson data and create an ol.layer.Image for that data.
*/
d3.json('data/us.json', function(error, us) {
var features = topojson.feature(us, us.objects.counties);
/**
* This function uses d3 to render the topojson features to a canvas.
* @param {ol.Extent} extent Extent.
* @param {number} resolution Resolution.
* @param {ol.Size} size Size.
* @param {ol.proj.Projection} projection Projection.
* @return {HTMLCanvasElement}
*/
var canvasFunction = function(extent, resolution, size, projection) {
var canvasWidth = size[0];
var canvasHeight = size[1];
var canvas = d3.select(document.createElement('canvas'));
canvas.attr('width', canvasWidth).attr('height', canvasHeight);
var context = canvas.node().getContext('2d');
var d3Projection = d3.geo.mercator().scale(1).translate([0, 0]);
var d3Path = d3.geo.path().projection(d3Projection);
var pixelBounds = d3Path.bounds(features);
var pixelBoundsWidth = pixelBounds[1][0] - pixelBounds[0][0];
var pixelBoundsHeight = pixelBounds[1][1] - pixelBounds[0][1];
var geoBounds = d3.geo.bounds(features);
var geoBoundsLeftBottom = ol.proj.transform(
geoBounds[0], 'EPSG:4326', projection);
var geoBoundsRightTop = ol.proj.transform(
geoBounds[1], 'EPSG:4326', projection);
var geoBoundsWidth = geoBoundsRightTop[0] - geoBoundsLeftBottom[0];
if (geoBoundsWidth < 0) {
geoBoundsWidth += ol.extent.getWidth(projection.getExtent());
}
var geoBoundsHeight = geoBoundsRightTop[1] - geoBoundsLeftBottom[1];
var widthResolution = geoBoundsWidth / pixelBoundsWidth;
var heightResolution = geoBoundsHeight / pixelBoundsHeight;
var r = Math.max(widthResolution, heightResolution);
var scale = r / (resolution / pixelRatio);
var center = ol.proj.transform(ol.extent.getCenter(extent),
projection, 'EPSG:4326');
d3Projection.scale(scale).center(center)
.translate([canvasWidth / 2, canvasHeight / 2]);
d3Path = d3Path.projection(d3Projection).context(context);
d3Path(features);
context.stroke();
return canvas[0][0];
};
var layer = new ol.layer.Image({
source: new ol.source.ImageCanvas({
canvasFunction: canvasFunction,
projection: 'EPSG:3857'
})
});
map.addLayer(layer);
});

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