@cquiroz/aladin-lite/lib/js/Tile.js

AladinLite module

// Copyright 2013 - UDS/CNRS
// The Aladin Lite program is distributed under the terms
// of the GNU General Public License version 3.
//
// This file is part of Aladin Lite.
//
//    Aladin Lite is free software: you can redistribute it and/or modify
//    it under the terms of the GNU General Public License as published by
//    the Free Software Foundation, version 3 of the License.
//
//    Aladin Lite is distributed in the hope that it will be useful,
//    but WITHOUT ANY WARRANTY; without even the implied warranty of
//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//    GNU General Public License for more details.
//
//    The GNU General Public License is available in COPYING file
//    along with Aladin Lite.
//

/******************************************************************************
 * Aladin Lite project
 *
 * File Tile
 *
 * Author: Thomas Boch[CDS]
 *
 *****************************************************************************/
var Tile = function () {
  // constructor
  function Tile(img, url) {
    this.img = img;
    this.url = url;
  } // check whether the image corresponding to the tile is loaded and ready to be displayed
  //
  // source : http://www.sajithmr.me/javascript-check-an-image-is-loaded-or-not


  Tile.isImageOk = function (img) {
    if (img.allSkyTexture) {
      return true;
    }

    if (!img.src) {
      return false;
    } // During the onload event, IE correctly identifies any images that
    // weren’t downloaded as not complete. Others should too. Gecko-based
    // browsers act like NS4 in that they report this incorrectly.


    if (!img.complete) {
      return false;
    } // However, they do have two very useful properties: naturalWidth and
    // naturalHeight. These give the true size of the image. If it failed
    // to load, either of these should be zero.


    if (typeof img.naturalWidth != "undefined" && img.naturalWidth === 0) {
      return false;
    } // No other way of checking: assume it’s ok.


    return true;
  };

  return Tile;
}();

export default Tile;