openseadragon/src/iiiftilesource.js

/*
 * OpenSeadragon - IIIFTileSource
 *
 * Copyright (C) 2009 CodePlex Foundation
 * Copyright (C) 2010-2013 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( $ ){

/**
 * @class IIIFTileSource
 * @classdesc A client implementation of the International Image Interoperability
 * Format: Image API 1.0 - 2.0
 *
 * @memberof OpenSeadragon
 * @extends OpenSeadragon.TileSource
 * @see http://iiif.io/api/image/
 */
$.IIIFTileSource = function( options ){


    $.extend( true, this, options );

    if ( !( this.height && this.width && this['@id'] ) ) {
        throw new Error( 'IIIF required parameters not provided.' );
    }

    options.tileSizePerScaleFactor = {};

    // N.B. 2.0 renamed scale_factors to scaleFactors
    if ( this.tile_width ) {
        options.tileSize = this.tile_width;
    } else if ( this.tile_height ) {
        options.tileSize = this.tile_height;
    } else if ( this.tiles ) {
        // Version 2.0 forwards
        if ( this.tiles.length == 1 ) {
            options.tileSize = this.tiles[0].width;
            this.scale_factors = this.tiles[0].scaleFactors;
        } else {
            // Multiple tile sizes at different levels
            this.scale_factors = [];
            for (var t = 0; t < this.tiles.length; t++ ) {
                for (var sf = 0; sf < this.tiles[t].scaleFactors.length; sf++) {
                    var scaleFactor = this.tiles[t].scaleFactors[sf];
                    this.scale_factors.push(scaleFactor);
                    options.tileSizePerScaleFactor[scaleFactor] = this.tiles[t].width;
                }
            }
        }
    } else {
        // use the largest of tileOptions that is smaller than the short dimension

        var shortDim = Math.min( this.height, this.width ),
            tileOptions = [256,512,1024],
            smallerTiles = [];

        for ( var c = 0; c < tileOptions.length; c++ ) {
            if ( tileOptions[c] <= shortDim ) {
                smallerTiles.push( tileOptions[c] );
            }
        }

        if ( smallerTiles.length > 0 ) {
            options.tileSize = Math.max.apply( null, smallerTiles );
        } else {
            // If we're smaller than 256, just use the short side.
            options.tileSize = shortDim;
        }
        this.tile_width = options.tileSize;  // So that 'full' gets used for
        this.tile_height = options.tileSize; // the region below
    }

    if ( !options.maxLevel ) {
        if ( !this.scale_factors ) {
            options.maxLevel = Number( Math.ceil( Math.log( Math.max( this.width, this.height ), 2 ) ) );
        } else {
            options.maxLevel = Math.floor( Math.pow( Math.max.apply(null, this.scale_factors), 0.5) );
        }
    }

    $.TileSource.apply( this, [ options ] );
};

$.extend( $.IIIFTileSource.prototype, $.TileSource.prototype, /** @lends OpenSeadragon.IIIFTileSource.prototype */{
    /**
     * Determine if the data and/or url imply the image service is supported by
     * this tile source.
     * @function
     * @param {Object|Array} data
     * @param {String} optional - url
     */
     
    supports: function( data, url ) {
        // Version 2.0 and forwards
        if (data.protocol && data.protocol == 'http://iiif.io/api/image') {
            return true;
        // Version 1.1
        } else if ( data['@context'] && (
            data['@context'] == "http://library.stanford.edu/iiif/image-api/1.1/context.json" ||
            data['@context'] == "http://iiif.io/api/image/1/context.json") ) {
            // N.B. the iiif.io context is wrong, but where the representation lives so likely to be used
            return true;

        // Version 1.0
        } else if ( data.profile &&
            data.profile.indexOf("http://library.stanford.edu/iiif/image-api/compliance.html") === 0) {
            return true;
        } else if ( data.identifier && data.width && data.height ) {
            return true;
        } else if ( data.documentElement &&
            "info" == data.documentElement.tagName &&
            "http://library.stanford.edu/iiif/image-api/ns/" ==
                data.documentElement.namespaceURI) {
            return true;

        // Not IIIF
        } else {
            return false;
        }
    },

    /**
     *
     * @function
     * @param {Object} data - the raw configuration
     * @example <caption>IIIF 1.1 Info Looks like this</caption>
     * {
     *   "@context" : "http://library.stanford.edu/iiif/image-api/1.1/context.json",
     *   "@id" : "http://iiif.example.com/prefix/1E34750D-38DB-4825-A38A-B60A345E591C",
     *   "width" : 6000,
     *   "height" : 4000,
     *   "scale_factors" : [ 1, 2, 4 ],
     *   "tile_width" : 1024,
     *   "tile_height" : 1024,
     *   "formats" : [ "jpg", "png" ],
     *   "qualities" : [ "native", "grey" ],
     *   "profile" : "http://library.stanford.edu/iiif/image-api/1.1/compliance.html#level0"
     * }
     */
    configure: function( data, url ){
        // Try to deduce our version and fake it upwards if needed
        if ( !$.isPlainObject(data) ) {
            var options = configureFromXml10( data );
            options['@context'] = "http://iiif.io/api/image/1.0/context.json";
            options['@id'] = url.replace('/info.xml', '');
            return options;
        } else if ( !data['@context'] ) {
            data['@context'] = 'http://iiif.io/api/image/1.0/context.json';
            data['@id'] = url.replace('/info.json', '');
            return data;
        } else {
            return data;
        }
    },

    /**
     * Return the tileSize for the given level.
     * @function
     * @param {Number} level
    */
    getTileSize: function( level ){
        var scaleFactor = Math.pow(2, this.maxLevel - level);
        // cache it in case any external code is going to read it directly
        if (this.tileSizePerScaleFactor && this.tileSizePerScaleFactor[scaleFactor]) {
            this.tileSize = this.tileSizePerScaleFactor[scaleFactor];
        }
        return this.tileSize;
    },

    /**
     * Responsible for retreiving the url which will return an image for the
     * region specified by the given x, y, and level components.
     * @function
     * @param {Number} level - z index
     * @param {Number} x
     * @param {Number} y
     * @throws {Error}
     */
    getTileUrl: function( level, x, y ){

        //# constants
        var IIIF_ROTATION = '0',
            //## get the scale (level as a decimal)
            scale = Math.pow( 0.5, this.maxLevel - level ),

            //# image dimensions at this level
            levelWidth = Math.ceil( this.width * scale ),
            levelHeight = Math.ceil( this.height * scale ),

            //## iiif region
            tileSize,
            iiifTileSizeWidth,
            iiifTileSizeHeight,
            iiifRegion,
            iiifTileX,
            iiifTileY,
            iiifTileW,
            iiifTileH,
            iiifSize,
            iiifQuality,
            uri;

        tileSize = this.getTileSize(level);
        iiifTileSizeWidth = Math.ceil( tileSize / scale );
        iiifTileSizeHeight = iiifTileSizeWidth;

        if ( this['@context'].indexOf('/1.0/context.json') > -1 ||
             this['@context'].indexOf('/1.1/context.json') > -1 ||
             this['@context'].indexOf('/1/context.json') > -1 ) {
            iiifQuality = "native.jpg";
        } else {
            iiifQuality = "default.jpg";
        }

        if ( levelWidth < tileSize && levelHeight < tileSize ){
            iiifSize = levelWidth + ",";
            iiifRegion = 'full';
        } else {
            iiifTileX = x * iiifTileSizeWidth;
            iiifTileY = y * iiifTileSizeHeight;
            iiifTileW = Math.min( iiifTileSizeWidth, this.width - iiifTileX );
            iiifTileH = Math.min( iiifTileSizeHeight, this.height - iiifTileY );
            iiifSize = Math.ceil( iiifTileW * scale ) + ",";
            iiifRegion = [ iiifTileX, iiifTileY, iiifTileW, iiifTileH ].join( ',' );
        }
        uri = [ this['@id'], iiifRegion, iiifSize, IIIF_ROTATION, iiifQuality ].join( '/' );

        return uri;
    }

  });


    function configureFromXml10(xmlDoc) {
        //parse the xml
        if ( !xmlDoc || !xmlDoc.documentElement ) {
            throw new Error( $.getString( "Errors.Xml" ) );
        }

        var root            = xmlDoc.documentElement,
            rootName        = root.tagName,
            configuration   = null;

        if ( rootName == "info" ) {
            try {
                configuration = {};
                parseXML10( root, configuration );
                return configuration;

            } catch ( e ) {
                throw (e instanceof Error) ?
                    e :
                    new Error( $.getString("Errors.IIIF") );
            }
        }
        throw new Error( $.getString( "Errors.IIIF" ) );
    }

    function parseXML10( node, configuration, property ) {
        var i,
            value;
        if ( node.nodeType == 3 && property ) {//text node
            value = node.nodeValue.trim();
            if( value.match(/^\d*$/)){
                value = Number( value );
            }
            if( !configuration[ property ] ){
                configuration[ property ] = value;
            }else{
                if( !$.isArray( configuration[ property ] ) ){
                    configuration[ property ] = [ configuration[ property ] ];
                }
                configuration[ property ].push( value );
            }
        } else if( node.nodeType == 1 ){
            for( i = 0; i < node.childNodes.length; i++ ){
                parseXML10( node.childNodes[ i ], configuration, node.nodeName );
            }
        }
    }


}( OpenSeadragon ));