Example of brightness/contrast control on the client (WebGL only).
This example shows how to control brightness/contrast on the client, the example is limited to WebGL.
<!DOCTYPE html>
<html>
<head>
<title>Brightness/contrast example</title>
<script src="https://code.jquery.com/jquery-1.11.2.min.js"></script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css">
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="http://openlayers.org/en/v3.9.0/css/ol.css" type="text/css">
<script src="http://openlayers.org/en/v3.9.0/build/ol.js"></script>
<style>
#reset-brightness {
min-width: 138px;
}
#reset-contrast {
min-width: 120px;
}
</style>
</head>
<body>
<div class="container-fluid">
<div class="row-fluid">
<div class="span12">
<div id="map" class="map"></div>
<div id="no-webgl" class="alert alert-danger" style="display: none">
This example requires a browser that supports <a href="http://get.webgl.org/">WebGL</a>.
</div>
<div class="btn-group">
<button id="increase-brightness"><i class="fa fa-plus"></i></button>
<button id="reset-brightness">Brightness</button>
<button id="decrease-brightness"><i class="fa fa-minus"></i></button>
</div>
<div class="btn-group">
<button id="increase-contrast"><i class="fa fa-plus"></i></button>
<button id="reset-contrast">Contrast</button>
<button id="decrease-contrast"><i class="fa fa-minus"></i></button>
</div>
</div>
</div>
</div>
<script>
function setResetBrightnessButtonHTML() {
resetBrightness.innerHTML = 'Brightness (' +
layer.getBrightness().toFixed(3) + ')';
}
function setResetContrastButtonHTML() {
resetContrast.innerHTML = 'Contrast (' + layer.getContrast().toFixed(3) + ')';
}
if (!ol.has.WEBGL) {
var info = document.getElementById('no-webgl');
/**
* display error message
*/
info.style.display = '';
} else {
var layer = new ol.layer.Tile({
source: new ol.source.MapQuest({layer: 'sat'})
});
var map = new ol.Map({
layers: [layer],
renderer: 'webgl',
target: 'map',
view: new ol.View({
center: [0, 0],
zoom: 2
})
});
var increaseBrightness = document.getElementById('increase-brightness');
var resetBrightness = document.getElementById('reset-brightness');
var decreaseBrightness = document.getElementById('decrease-brightness');
setResetBrightnessButtonHTML();
increaseBrightness.addEventListener('click', function() {
layer.setBrightness(Math.min(layer.getBrightness() + 0.125, 1));
setResetBrightnessButtonHTML();
}, false);
resetBrightness.addEventListener('click', function() {
layer.setBrightness(0);
setResetBrightnessButtonHTML();
}, false);
decreaseBrightness.addEventListener('click', function() {
layer.setBrightness(Math.max(layer.getBrightness() - 0.125, -1));
setResetBrightnessButtonHTML();
}, false);
var increaseContrast = document.getElementById('increase-contrast');
var resetContrast = document.getElementById('reset-contrast');
var decreaseContrast = document.getElementById('decrease-contrast');
setResetContrastButtonHTML();
increaseContrast.addEventListener('click', function() {
layer.setContrast(layer.getContrast() + 0.125);
setResetContrastButtonHTML();
}, false);
resetContrast.addEventListener('click', function() {
layer.setContrast(1);
setResetContrastButtonHTML();
}, false);
decreaseContrast.addEventListener('click', function() {
layer.setContrast(Math.max(layer.getContrast() - 0.125, 0));
setResetContrastButtonHTML();
}, false);
}
</script>
</body>
</html>