Source: core/drawing/engine/engine.js

  1. /**
  2.  * @fileoverview Namespace for the rendering engine. Also a
  3.  * static class providing constants and static functions.
  4.  */
  6. goog.provide('xrx.engine');
  10. goog.require('goog.userAgent');
  14. /**
  15.  * Engine base class.
  16.  * @constructor
  17.  * @namespace xrx.engine
  18.  * @memberof xrx
  19.  */
  20. xrx.engine = function() {};
  24. /**
  25.  * <a href="http://www.w3.org/TR/2014/CR-2dcontext-20140821/">The 2D Canvas rendering engine.</a>
  26.  * @type {string}
  27.  * @const
  28.  */
  29. xrx.engine.CANVAS = 'canvas';
  33. /**
  34.  * <a href="http://www.w3.org/TR/SVG/">The SVG rendering engine.</a>
  35.  * @type {string}
  36.  * @const
  37.  */
  38. xrx.engine.SVG = 'svg';
  42. /**
  43.  * <a href="http://www.w3.org/TR/NOTE-VML">The VML rendering engine.</a>
  44.  * @type {string}
  45.  * @const
  46.  */
  47. xrx.engine.VML = 'vml';
  51. /**
  52.  * Whether an eninge uses a DOM representation.
  53.  * @param {(xrx.engine.CANVAS|xrx.engine.SVG|xrx.engine.VML)} engine The engine to test.
  54.  * @return {boolean} Whether the engine uses a DOM representation.
  55.  */
  56. xrx.engine.hasDom = function(engine) {
  57.   return engine === xrx.engine.SVG || engine === xrx.engine.VML;
  58. };
  62. /**
  63.  * Whether an engine is supported by the current browser.
  64.  * @param {(xrx.engine.CANVAS|xrx.engine.SVG|xrx.engine.VML)} engine The engine to test.
  65.  */
  66. xrx.engine.isSupported = function(engine) {
  67.   if (engine === xrx.engine.CANVAS) {
  68.     return !!document.createElement('canvas').getContext;
  69.   } else if (engine === xrx.engine.SVG) {
  70.     return !!document.createElementNS &&
  71.       !!document.createElementNS(xrx.svg.Namespace['svg'], 'svg').createSVGRect;
  72.   } else if (engine === xrx.engine.VML) {
  73.     return !!document.namespaces;
  74.   } else {
  75.     throw Error('Unknown engine.');
  76.   }
  77. };