@cquiroz/aladin-lite/lib/js/TileBuffer.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 TileBuffer
 *
 * Author: Thomas Boch[CDS]
 *
 *****************************************************************************/
import Tile from './Tile';

var TileBuffer = function () {
  var NB_MAX_TILES = 800; // buffer size
  // constructor

  function TileBuffer() {
    this.pointer = 0;
    this.tilesMap = {};
    this.tilesArray = new Array(NB_MAX_TILES);

    for (var i = 0; i < NB_MAX_TILES; i++) {
      this.tilesArray[i] = new Tile(new Image(), null);
    }
  }

  TileBuffer.prototype.addTile = function (url) {
    // return null if already in buffer
    if (this.getTile(url)) {
      return null;
    } // delete existing tile


    var curTile = this.tilesArray[this.pointer];

    if (curTile.url != null) {
      curTile.img.src = null;
      delete this.tilesMap[curTile.url];
    }

    this.tilesArray[this.pointer].url = url;
    this.tilesMap[url] = this.tilesArray[this.pointer];
    this.pointer++;

    if (this.pointer >= NB_MAX_TILES) {
      this.pointer = 0;
    }

    return this.tilesMap[url];
  };

  TileBuffer.prototype.getTile = function (url) {
    return this.tilesMap[url];
  };

  return TileBuffer;
}();

export default TileBuffer;