openseadragon/src/tilecache.js

299 lines
12 KiB
JavaScript

/*
* OpenSeadragon - TileCache
*
* Copyright (C) 2009 CodePlex Foundation
* Copyright (C) 2010-2023 OpenSeadragon contributors
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* - Neither the name of CodePlex Foundation nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
(function( $ ){
// private class
var TileRecord = function( options ) {
$.console.assert( options, "[TileCache.cacheTile] options is required" );
$.console.assert( options.tile, "[TileCache.cacheTile] options.tile is required" );
$.console.assert( options.tiledImage, "[TileCache.cacheTile] options.tiledImage is required" );
this.tile = options.tile;
this.tiledImage = options.tiledImage;
};
// private class
var ImageRecord = function(options) {
$.console.assert( options, "[ImageRecord] options is required" );
$.console.assert( options.data, "[ImageRecord] options.data is required" );
this._tiles = [];
options.create.apply(null, [this, options.data, options.ownerTile]);
this._destroyImplementation = options.destroy.bind(null, this);
this.getImage = options.getImage.bind(null, this);
this.getData = options.getData.bind(null, this);
this.getRenderedContext = options.getRenderedContext.bind(null, this);
};
ImageRecord.prototype = {
destroy: function() {
this._destroyImplementation();
this._tiles = null;
},
addTile: function(tile) {
$.console.assert(tile, '[ImageRecord.addTile] tile is required');
this._tiles.push(tile);
},
removeTile: function(tile) {
for (var i = 0; i < this._tiles.length; i++) {
if (this._tiles[i] === tile) {
this._tiles.splice(i, 1);
return;
}
}
$.console.warn('[ImageRecord.removeTile] trying to remove unknown tile', tile);
},
getTileCount: function() {
return this._tiles.length;
}
};
/**
* @class TileCache
* @memberof OpenSeadragon
* @classdesc Stores all the tiles displayed in a {@link OpenSeadragon.Viewer}.
* You generally won't have to interact with the TileCache directly.
* @param {Object} options - Configuration for this TileCache.
* @param {Number} [options.maxImageCacheCount] - See maxImageCacheCount in
* {@link OpenSeadragon.Options} for details.
*/
$.TileCache = function( options ) {
options = options || {};
this._maxImageCacheCount = options.maxImageCacheCount || $.DEFAULT_SETTINGS.maxImageCacheCount;
this._tilesLoaded = [];
this._imagesLoaded = [];
this._imagesLoadedCount = 0;
};
/** @lends OpenSeadragon.TileCache.prototype */
$.TileCache.prototype = {
/**
* @returns {Number} The total number of tiles that have been loaded by
* this TileCache.
*/
numTilesLoaded: function() {
return this._tilesLoaded.length;
},
/**
* Caches the specified tile, removing an old tile if necessary to stay under the
* maxImageCacheCount specified on construction. Note that if multiple tiles reference
* the same image, there may be more tiles than maxImageCacheCount; the goal is to keep
* the number of images below that number. Note, as well, that even the number of images
* may temporarily surpass that number, but should eventually come back down to the max specified.
* @param {Object} options - Tile info.
* @param {OpenSeadragon.Tile} options.tile - The tile to cache.
* @param {String} options.tile.cacheKey - The unique key used to identify this tile in the cache.
* @param {Image} options.image - The image of the tile to cache.
* @param {OpenSeadragon.TiledImage} options.tiledImage - The TiledImage that owns that tile.
* @param {Number} [options.cutoff=0] - If adding this tile goes over the cache max count, this
* function will release an old tile. The cutoff option specifies a tile level at or below which
* tiles will not be released.
*/
cacheTile: function( options ) {
$.console.assert( options, "[TileCache.cacheTile] options is required" );
$.console.assert( options.tile, "[TileCache.cacheTile] options.tile is required" );
$.console.assert( options.tile.cacheKey, "[TileCache.cacheTile] options.tile.cacheKey is required" );
$.console.assert( options.tiledImage, "[TileCache.cacheTile] options.tiledImage is required" );
var cutoff = options.cutoff || 0;
var insertionIndex = this._tilesLoaded.length;
var imageRecord = this._imagesLoaded[options.tile.cacheKey];
if (!imageRecord) {
if (!options.data) {
$.console.error("[TileCache.cacheTile] options.image was renamed to options.data. '.image' attribute " +
"has been deprecated and will be removed in the future.");
options.data = options.image;
}
$.console.assert( options.data, "[TileCache.cacheTile] options.data is required to create an ImageRecord" );
imageRecord = this._imagesLoaded[options.tile.cacheKey] = new ImageRecord({
data: options.data,
ownerTile: options.tile,
create: options.tiledImage.source.createTileCache,
destroy: options.tiledImage.source.destroyTileCache,
getImage: options.tiledImage.source.getTileCacheDataAsImage,
getData: options.tiledImage.source.getTileCacheData,
getRenderedContext: options.tiledImage.source.getTileCacheDataAsContext2D,
});
this._imagesLoadedCount++;
}
imageRecord.addTile(options.tile);
options.tile.cacheImageRecord = imageRecord;
// Note that just because we're unloading a tile doesn't necessarily mean
// we're unloading an image. With repeated calls it should sort itself out, though.
if ( this._imagesLoadedCount > this._maxImageCacheCount ) {
var worstTile = null;
var worstTileIndex = -1;
var worstTileRecord = null;
var prevTile, worstTime, worstLevel, prevTime, prevLevel, prevTileRecord;
for ( var i = this._tilesLoaded.length - 1; i >= 0; i-- ) {
prevTileRecord = this._tilesLoaded[ i ];
prevTile = prevTileRecord.tile;
if ( prevTile.level <= cutoff || prevTile.beingDrawn ) {
continue;
} else if ( !worstTile ) {
worstTile = prevTile;
worstTileIndex = i;
worstTileRecord = prevTileRecord;
continue;
}
prevTime = prevTile.lastTouchTime;
worstTime = worstTile.lastTouchTime;
prevLevel = prevTile.level;
worstLevel = worstTile.level;
if ( prevTime < worstTime ||
( prevTime === worstTime && prevLevel > worstLevel ) ) {
worstTile = prevTile;
worstTileIndex = i;
worstTileRecord = prevTileRecord;
}
}
if ( worstTile && worstTileIndex >= 0 ) {
this._unloadTile(worstTileRecord);
insertionIndex = worstTileIndex;
}
}
this._tilesLoaded[ insertionIndex ] = new TileRecord({
tile: options.tile,
tiledImage: options.tiledImage
});
},
/**
* Clears all tiles associated with the specified tiledImage.
* @param {OpenSeadragon.TiledImage} tiledImage
*/
clearTilesFor: function( tiledImage ) {
$.console.assert(tiledImage, '[TileCache.clearTilesFor] tiledImage is required');
var tileRecord;
for ( var i = 0; i < this._tilesLoaded.length; ++i ) {
tileRecord = this._tilesLoaded[ i ];
if ( tileRecord.tiledImage === tiledImage ) {
this._unloadTile(tileRecord);
this._tilesLoaded.splice( i, 1 );
i--;
}
}
},
// private
getImageRecord: function(cacheKey) {
$.console.assert(cacheKey, '[TileCache.getImageRecord] cacheKey is required');
return this._imagesLoaded[cacheKey];
},
// private
_unloadTile: function(tileRecord) {
$.console.assert(tileRecord, '[TileCache._unloadTile] tileRecord is required');
var tile = tileRecord.tile;
var tiledImage = tileRecord.tiledImage;
// tile.getCanvasContext should always exist in normal usage (with $.Tile)
// but the tile cache test passes in a dummy object
let context2D = tile.getCanvasContext && tile.getCanvasContext();
tile.unload();
tile.cacheImageRecord = null;
var imageRecord = this._imagesLoaded[tile.cacheKey];
if(!imageRecord){
return;
}
imageRecord.removeTile(tile);
if (!imageRecord.getTileCount()) {
imageRecord.destroy();
delete this._imagesLoaded[tile.cacheKey];
this._imagesLoadedCount--;
if(context2D){
/**
* Free up canvas memory
* (iOS 12 or higher on 2GB RAM device has only 224MB canvas memory,
* and Safari keeps canvas until its height and width will be set to 0).
*/
context2D.canvas.width = 0;
context2D.canvas.height = 0;
/**
* Triggered when an image has just been unloaded
*
* @event image-unloaded
* @memberof OpenSeadragon.Viewer
* @type {object}
* @property {CanvasRenderingContext2D} context2D - The context that is being unloaded
*/
tiledImage.viewer.raiseEvent("image-unloaded", {
context2D: context2D
});
}
}
/**
* Triggered when a tile has just been unloaded from the cache.
*
* @event tile-unloaded
* @memberof OpenSeadragon.Viewer
* @type {object}
* @property {OpenSeadragon.TiledImage} tiledImage - The tiled image of the unloaded tile.
* @property {OpenSeadragon.Tile} tile - The tile which has been unloaded.
*/
tiledImage.viewer.raiseEvent("tile-unloaded", {
tile: tile,
tiledImage: tiledImage
});
}
};
}( OpenSeadragon ));