Factor out ImageTile and ImageTileSource

src/ol/tile.js

@@ -24,10 +24,8 @@ ol.TileState = {
  * @constructor
  * @extends {goog.events.EventTarget}
  * @param {ol.TileCoord} tileCoord Tile coordinate.
- * @param {string} src Image source URI.
- * @param {?string} crossOrigin Cross origin.
  */
-ol.Tile = function(tileCoord, src, crossOrigin) {
+ol.Tile = function(tileCoord) {
 
   goog.base(this);
 
@@ -37,39 +35,10 @@ ol.Tile = function(tileCoord, src, crossOrigin) {
   this.tileCoord = tileCoord;
 
   /**
-   * Image URI
-   *
-   * @private
-   * @type {string}
-   */
-  this.src_ = src;
-
-  /**
-   * @private
+   * @protected
    * @type {ol.TileState}
    */
-  this.state_ = ol.TileState.IDLE;
-
-  /**
-   * @private
-   * @type {Image}
-   */
-  this.image_ = new Image();
-  if (!goog.isNull(crossOrigin)) {
-    this.image_.crossOrigin = crossOrigin;
-  }
-
-  /**
-   * @private
-   * @type {Object.<number, Image>}
-   */
-  this.imageByContext_ = {};
-
-  /**
-   * @private
-   * @type {Array.<number>}
-   */
-  this.imageListenerKeys_ = null;
+  this.state = ol.TileState.IDLE;
 
 };
 goog.inherits(ol.Tile, goog.events.EventTarget);
@@ -85,24 +54,16 @@ ol.Tile.prototype.dispatchChangeEvent = function() {
 
 /**
  * @param {Object=} opt_context Object.
- * @return {Image} Image.
+ * @return {HTMLCanvasElement|HTMLImageElement|HTMLVideoElement} Image.
  */
-ol.Tile.prototype.getImage = function(opt_context) {
-  if (goog.isDef(opt_context)) {
-    var image;
-    var key = goog.getUid(opt_context);
-    if (key in this.imageByContext_) {
-      return this.imageByContext_[key];
-    } else if (goog.object.isEmpty(this.imageByContext_)) {
-      image = this.image_;
-    } else {
-      image = /** @type {Image} */ (this.image_.cloneNode(false));
-    }
-    this.imageByContext_[key] = image;
-    return image;
-  } else {
-    return this.image_;
-  }
+ol.Tile.prototype.getImage = goog.abstractMethod;
+
+
+/**
+ * @return {string} Key.
+ */
+ol.Tile.prototype.getKey = function() {
+  return goog.getUid(this).toString();
 };
 
 
@@ -110,59 +71,10 @@ ol.Tile.prototype.getImage = function(opt_context) {
  * @return {ol.TileState} State.
  */
 ol.Tile.prototype.getState = function() {
-  return this.state_;
+  return this.state;
 };
 
 
 /**
- * Tracks loading or read errors.
- *
- * @private
  */
-ol.Tile.prototype.handleImageError_ = function() {
-  this.state_ = ol.TileState.ERROR;
-  this.unlistenImage_();
-};
-
-
-/**
- * Tracks successful image load.
- *
- * @private
- */
-ol.Tile.prototype.handleImageLoad_ = function() {
-  this.state_ = ol.TileState.LOADED;
-  this.unlistenImage_();
-  this.dispatchChangeEvent();
-};
-
-
-/**
- * Load not yet loaded URI.
- */
-ol.Tile.prototype.load = function() {
-  if (this.state_ == ol.TileState.IDLE) {
-    this.state_ = ol.TileState.LOADING;
-    goog.asserts.assert(goog.isNull(this.imageListenerKeys_));
-    this.imageListenerKeys_ = [
-      goog.events.listenOnce(this.image_, goog.events.EventType.ERROR,
-          this.handleImageError_, false, this),
-      goog.events.listenOnce(this.image_, goog.events.EventType.LOAD,
-          this.handleImageLoad_, false, this)
-    ];
-    this.image_.src = this.src_;
-  }
-};
-
-
-/**
- * Discards event handlers which listen for load completion or errors.
- *
- * @private
- */
-ol.Tile.prototype.unlistenImage_ = function() {
-  goog.asserts.assert(!goog.isNull(this.imageListenerKeys_));
-  goog.array.forEach(this.imageListenerKeys_, goog.events.unlistenByKey);
-  this.imageListenerKeys_ = null;
-};
-
+ol.Tile.prototype.load = goog.abstractMethod;