Files
openlayers/src/ol/browserfeature.js

148 lines
3.0 KiB
JavaScript

goog.provide('ol.BrowserFeature');
goog.require('goog.dom');
goog.require('goog.dom.TagName');
goog.require('ol.webgl');
/**
* @define {boolean} Assume touch.
*/
ol.ASSUME_TOUCH = false;
/**
* @define {boolean} Whether to enable canvas.
*/
ol.ENABLE_CANVAS = true;
/**
* @define {boolean} Whether to enable DOM.
*/
ol.ENABLE_DOM = true;
/**
* @define {boolean} Whether to enable rendering of image layers.
*/
ol.ENABLE_IMAGE = true;
/**
* @define {boolean} Whether to enable rendering of tile layers.
*/
ol.ENABLE_TILE = true;
/**
* @define {boolean} Whether to enable rendering of vector layers.
*/
ol.ENABLE_VECTOR = true;
/**
* @define {boolean} Whether to enable WebGL.
*/
ol.ENABLE_WEBGL = true;
/**
* The ratio between physical pixels and device-independent pixels
* (dips) on the device (`window.devicePixelRatio`).
* @const
* @type {number}
* @todo stability experimental
*/
ol.BrowserFeature.DEVICE_PIXEL_RATIO = goog.global.devicePixelRatio || 1;
/**
* True if browser supports Canvas.
* @const
* @type {boolean}
* @todo stability experimental
*/
ol.BrowserFeature.HAS_CANVAS = ol.ENABLE_CANVAS && (
/**
* @return {boolean} Canvas supported.
*/
function() {
if (!('HTMLCanvasElement' in goog.global)) {
return false;
}
try {
var canvas = /** @type {HTMLCanvasElement} */
(goog.dom.createElement(goog.dom.TagName.CANVAS));
return !goog.isNull(canvas.getContext('2d'));
} catch (e) {
return false;
}
})();
/**
* Indicates if DeviceOrientation is supported in the user's browser.
* @const
* @type {boolean}
* @todo stability experimental
*/
ol.BrowserFeature.HAS_DEVICE_ORIENTATION =
'DeviceOrientationEvent' in goog.global;
/**
* True if browser supports DOM.
* @const
* @type {boolean}
* @todo stability experimental
*/
ol.BrowserFeature.HAS_DOM = ol.ENABLE_DOM;
/**
* Is HTML5 geolocation supported in the current browser?
* @const
* @type {boolean}
* @todo stability experimental
*/
ol.BrowserFeature.HAS_GEOLOCATION = 'geolocation' in goog.global.navigator;
/**
* True if browser supports touch events.
* @const
* @type {boolean}
* @todo stability experimental
*/
ol.BrowserFeature.HAS_TOUCH = ol.ASSUME_TOUCH ||
(goog.global.document &&
'ontouchstart' in goog.global.document.documentElement) ||
!!(goog.global.navigator.msPointerEnabled);
/**
* True if browser supports WebGL.
* @const
* @type {boolean}
* @todo stability experimental
*/
ol.BrowserFeature.HAS_WEBGL = ol.ENABLE_WEBGL && (
/**
* @return {boolean} WebGL supported.
*/
function() {
if (!('WebGLRenderingContext' in goog.global)) {
return false;
}
try {
var canvas = /** @type {HTMLCanvasElement} */
(goog.dom.createElement(goog.dom.TagName.CANVAS));
return !goog.isNull(ol.webgl.getContext(canvas, {
failIfMajorPerformanceCaveat: true
}));
} catch (e) {
return false;
}
})();