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275 lines
10 KiB
JavaScript
275 lines
10 KiB
JavaScript
/*
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* OpenSeadragon - TileCache
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*
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* Copyright (C) 2009 CodePlex Foundation
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* Copyright (C) 2010-2013 OpenSeadragon contributors
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met:
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*
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* - Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* - Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* - Neither the name of CodePlex Foundation nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
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* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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(function( $ ){
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// private class
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var TileRecord = function( options ) {
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$.console.assert( options, "[TileCache.cacheTile] options is required" );
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$.console.assert( options.tile, "[TileCache.cacheTile] options.tile is required" );
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$.console.assert( options.tiledImage, "[TileCache.cacheTile] options.tiledImage is required" );
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this.tile = options.tile;
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this.tiledImage = options.tiledImage;
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};
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// private class
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var ImageRecord = function(options) {
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$.console.assert( options, "[ImageRecord] options is required" );
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$.console.assert( options.image, "[ImageRecord] options.image is required" );
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this._image = options.image;
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this._tiles = [];
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};
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ImageRecord.prototype = {
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destroy: function() {
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this._image = null;
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this._renderedContext = null;
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this._tiles = null;
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},
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getImage: function() {
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return this._image;
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},
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getRenderedContext: function() {
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if (!this._renderedContext) {
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var canvas = document.createElement( 'canvas' );
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canvas.width = this._image.width;
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canvas.height = this._image.height;
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this._renderedContext = canvas.getContext('2d');
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this._renderedContext.drawImage( this._image, 0, 0 );
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//since we are caching the prerendered image on a canvas
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//allow the image to not be held in memory
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this._image = null;
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}
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return this._renderedContext;
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},
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setRenderedContext: function(renderedContext) {
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$.console.error("ImageRecord.setRenderedContext is deprecated. " +
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"The rendered context should be created by the ImageRecord " +
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"itself when calling ImageRecord.getRenderedContext.");
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this._renderedContext = renderedContext;
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},
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addTile: function(tile) {
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$.console.assert(tile, '[ImageRecord.addTile] tile is required');
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this._tiles.push(tile);
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},
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removeTile: function(tile) {
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for (var i = 0; i < this._tiles.length; i++) {
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if (this._tiles[i] === tile) {
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this._tiles.splice(i, 1);
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return;
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}
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}
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$.console.warn('[ImageRecord.removeTile] trying to remove unknown tile', tile);
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},
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getTileCount: function() {
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return this._tiles.length;
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}
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};
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/**
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* @class TileCache
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* @memberof OpenSeadragon
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* @classdesc Stores all the tiles displayed in a {@link OpenSeadragon.Viewer}.
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* You generally won't have to interact with the TileCache directly.
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* @param {Object} options - Configuration for this TileCache.
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* @param {Number} [options.maxImageCacheCount] - See maxImageCacheCount in
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* {@link OpenSeadragon.Options} for details.
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*/
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$.TileCache = function( options ) {
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options = options || {};
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this._maxImageCacheCount = options.maxImageCacheCount || $.DEFAULT_SETTINGS.maxImageCacheCount;
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this._tilesLoaded = [];
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this._imagesLoaded = [];
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this._imagesLoadedCount = 0;
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};
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/** @lends OpenSeadragon.TileCache.prototype */
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$.TileCache.prototype = {
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/**
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* @returns {Number} The total number of tiles that have been loaded by
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* this TileCache.
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*/
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numTilesLoaded: function() {
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return this._tilesLoaded.length;
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},
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/**
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* Caches the specified tile, removing an old tile if necessary to stay under the
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* maxImageCacheCount specified on construction. Note that if multiple tiles reference
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* the same image, there may be more tiles than maxImageCacheCount; the goal is to keep
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* the number of images below that number. Note, as well, that even the number of images
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* may temporarily surpass that number, but should eventually come back down to the max specified.
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* @param {Object} options - Tile info.
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* @param {OpenSeadragon.Tile} options.tile - The tile to cache.
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* @param {String} options.tile.cacheKey - The unique key used to identify this tile in the cache.
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* @param {Image} options.image - The image of the tile to cache.
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* @param {OpenSeadragon.TiledImage} options.tiledImage - The TiledImage that owns that tile.
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* @param {Number} [options.cutoff=0] - If adding this tile goes over the cache max count, this
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* function will release an old tile. The cutoff option specifies a tile level at or below which
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* tiles will not be released.
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*/
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cacheTile: function( options ) {
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$.console.assert( options, "[TileCache.cacheTile] options is required" );
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$.console.assert( options.tile, "[TileCache.cacheTile] options.tile is required" );
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$.console.assert( options.tile.cacheKey, "[TileCache.cacheTile] options.tile.cacheKey is required" );
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$.console.assert( options.tiledImage, "[TileCache.cacheTile] options.tiledImage is required" );
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var cutoff = options.cutoff || 0;
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var insertionIndex = this._tilesLoaded.length;
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var imageRecord = this._imagesLoaded[options.tile.cacheKey];
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if (!imageRecord) {
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$.console.assert( options.image, "[TileCache.cacheTile] options.image is required to create an ImageRecord" );
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imageRecord = this._imagesLoaded[options.tile.cacheKey] = new ImageRecord({
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image: options.image
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});
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this._imagesLoadedCount++;
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}
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imageRecord.addTile(options.tile);
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options.tile.cacheImageRecord = imageRecord;
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// Note that just because we're unloading a tile doesn't necessarily mean
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// we're unloading an image. With repeated calls it should sort itself out, though.
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if ( this._imagesLoadedCount > this._maxImageCacheCount ) {
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var worstTile = null;
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var worstTileIndex = -1;
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var worstTileRecord = null;
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var prevTile, worstTime, worstLevel, prevTime, prevLevel, prevTileRecord;
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for ( var i = this._tilesLoaded.length - 1; i >= 0; i-- ) {
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prevTileRecord = this._tilesLoaded[ i ];
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prevTile = prevTileRecord.tile;
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if ( prevTile.level <= cutoff || prevTile.beingDrawn ) {
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continue;
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} else if ( !worstTile ) {
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worstTile = prevTile;
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worstTileIndex = i;
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worstTileRecord = prevTileRecord;
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continue;
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}
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prevTime = prevTile.lastTouchTime;
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worstTime = worstTile.lastTouchTime;
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prevLevel = prevTile.level;
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worstLevel = worstTile.level;
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if ( prevTime < worstTime ||
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( prevTime === worstTime && prevLevel > worstLevel ) ) {
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worstTile = prevTile;
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worstTileIndex = i;
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worstTileRecord = prevTileRecord;
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}
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}
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if ( worstTile && worstTileIndex >= 0 ) {
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this._unloadTile(worstTileRecord);
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insertionIndex = worstTileIndex;
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}
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}
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this._tilesLoaded[ insertionIndex ] = new TileRecord({
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tile: options.tile,
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tiledImage: options.tiledImage
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});
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},
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/**
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* Clears all tiles associated with the specified tiledImage.
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* @param {OpenSeadragon.TiledImage} tiledImage
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*/
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clearTilesFor: function( tiledImage ) {
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$.console.assert(tiledImage, '[TileCache.clearTilesFor] tiledImage is required');
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var tileRecord;
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for ( var i = 0; i < this._tilesLoaded.length; ++i ) {
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tileRecord = this._tilesLoaded[ i ];
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if ( tileRecord.tiledImage === tiledImage ) {
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this._unloadTile(tileRecord);
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this._tilesLoaded.splice( i, 1 );
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i--;
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}
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}
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},
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// private
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getImageRecord: function(cacheKey) {
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$.console.assert(cacheKey, '[TileCache.getImageRecord] cacheKey is required');
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return this._imagesLoaded[cacheKey];
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},
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// private
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_unloadTile: function(tileRecord) {
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$.console.assert(tileRecord, '[TileCache._unloadTile] tileRecord is required');
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var tile = tileRecord.tile;
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var tiledImage = tileRecord.tiledImage;
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tile.unload();
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tile.cacheImageRecord = null;
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var imageRecord = this._imagesLoaded[tile.cacheKey];
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imageRecord.removeTile(tile);
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if (!imageRecord.getTileCount()) {
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imageRecord.destroy();
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delete this._imagesLoaded[tile.cacheKey];
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this._imagesLoadedCount--;
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}
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/**
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* Triggered when a tile has just been unloaded from memory.
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*
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* @event tile-unloaded
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* @memberof OpenSeadragon.Viewer
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* @type {object}
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* @property {OpenSeadragon.TiledImage} tiledImage - The tiled image of the unloaded tile.
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* @property {OpenSeadragon.Tile} tile - The tile which has been unloaded.
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*/
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tiledImage.viewer.raiseEvent("tile-unloaded", {
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tile: tile,
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tiledImage: tiledImage
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});
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}
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};
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}( OpenSeadragon ));
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