OpenLayers.Layer.Grid相当于OL3

Question

我们一直在使用Openlayers 2扩展类OpenLayers.Layer.Grid。

现在，我们想升级到OL3。 OL3中OpenLayers.Layer.Grid的等价物是什么？我应该使用哪一堂课？

Openlayers 2扩展课程如下：

OpenLayers.Layer.ABC = OpenLayers.Class(OpenLayers.Layer.Grid, {

  size: null,

  isBaseLayer: true,

  standardTileSize: 256,

  tileOriginCorner: "tl",

  numberOfTiers: 0,

  tileCountUpToTier: null,

  tierSizeInTiles: null,

  tierImageSize: null,

  initialize: function(name, url, size, options) {

    this.initializeZoomify(size);

    OpenLayers.Layer.Grid.prototype.initialize.apply(this, [
      name, url, size, options
    ]);
  },

  initializeZoomify: function( size ) {

    var imageSize = size.clone();
    this.size = size.clone();
    var tiles = new OpenLayers.Size(
      Math.ceil( imageSize.w / this.standardTileSize ),
      Math.ceil( imageSize.h / this.standardTileSize )
    );

    this.tierSizeInTiles = [tiles];
    this.tierImageSize = [imageSize];

    while (imageSize.w > this.standardTileSize ||
    imageSize.h > this.standardTileSize ) {

      imageSize = new OpenLayers.Size(
        Math.floor( imageSize.w / 2 ),
        Math.floor( imageSize.h / 2 )
      );
      tiles = new OpenLayers.Size(
        Math.ceil( imageSize.w / this.standardTileSize ),
        Math.ceil( imageSize.h / this.standardTileSize )
      );
      this.tierSizeInTiles.push( tiles );
      this.tierImageSize.push( imageSize );
    }

    this.tierSizeInTiles.reverse();
    this.tierImageSize.reverse();

    this.numberOfTiers = this.tierSizeInTiles.length;
    var resolutions = [1];
    this.tileCountUpToTier = [0];
    for (var i = 1; i < this.numberOfTiers; i++) {
      resolutions.unshift(Math.pow(2, i));
      this.tileCountUpToTier.push(
        this.tierSizeInTiles[i-1].w * this.tierSizeInTiles[i-1].h +
        this.tileCountUpToTier[i-1]
      );
    }
    if (!this.serverResolutions) {
      this.serverResolutions = resolutions;
    }
  },

  destroy: function() {
    OpenLayers.Layer.Grid.prototype.destroy.apply(this, arguments);

    this.tileCountUpToTier.length = 0;
    this.tierSizeInTiles.length = 0;
    this.tierImageSize.length = 0;

  },

  clone: function (obj) {

    if (obj == null) {
      obj = new OpenLayers.Layer.ABC(this.name,
        this.url,
        this.size,
        this.options);
    }

    obj = OpenLayers.Layer.Grid.prototype.clone.apply(this, [obj]);

    return obj;
  },

  getURL: function (bounds) {
    bounds = this.adjustBounds(bounds);
    var res = this.getServerResolution();
    var x = Math.round((bounds.left - this.tileOrigin.lon) / (res * this.tileSize.w));
    var y = Math.round((this.tileOrigin.lat - bounds.top) / (res * this.tileSize.h));
    var z = this.getZoomForResolution( res );

    var path="";

    var level = this.numberOfTiers - z - 1;
    var sliceStringIndex = this.url.indexOf("&slice");
    var layerTypeIndex = this.url.indexOf("&layerType");
    var stackIndex = this.url.indexOf("&stack");
    var jsonIndex = this.url.indexOf("&json");
    var slice = this.url.substring(sliceStringIndex,layerTypeIndex).replace("&slice=", "");
    var layerType = this.url.substring(layerTypeIndex,stackIndex).replace("&layerType=", "");
    var stack;
      stack = this.url.substring(stackIndex,jsonIndex).replace("&stack=", "");

    var newUrl = this.url.substring(0, sliceStringIndex);


    var prog = ['TILE 0 ' + stack + ' ' + level + ' ' + slice + ' ' + x + ' ' + y + ' none 10 1'];

    var url = newUrl;

     url = this.selectUrl(path, url);
    url += '&prog=' + encodeURIComponent(prog.join('\n'));
    return url;
  },

  getImageSize: function() {
    return this.tileSize;

    if (arguments.length > 0) {
      var bounds = this.adjustBounds(arguments[0]);
      var res = this.getServerResolution();
      var x = Math.round((bounds.left - this.tileOrigin.lon) / (res * this.tileSize.w));
      var y = Math.round((this.tileOrigin.lat - bounds.top) / (res * this.tileSize.h));
      var z = this.getZoomForResolution( res );
      var w = this.standardTileSize;
      var h = this.standardTileSize;

      if (x == this.tierSizeInTiles[z].w -1 ) {
        var w_1 = this.tierImageSize[z].w % this.standardTileSize;
        if(w_1 != 0)
          w = w_1;
      }
      if (y == this.tierSizeInTiles[z].h -1 ) {
        var h_1 = this.tierImageSize[z].h % this.standardTileSize;
        if(h_1 != 0)
          h = h_1;
      }
      return (new OpenLayers.Size(w, h));
    } else {
      return this.tileSize;
    }
  },

  setMap: function(map) {
    OpenLayers.Layer.Grid.prototype.setMap.apply(this, arguments);
    this.tileOrigin = new OpenLayers.LonLat(this.map.maxExtent.left,
      this.map.maxExtent.top);
  },

  CLASS_NAME: "OpenLayers.Layer.ABCLayer"
});