org.exist.xquery.modules.image.GetWidthFunction Maven / Gradle / Ivy

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/*
 * eXist-db Open Source Native XML Database
 * Copyright (C) 2001 The eXist-db Authors
 *
 * [email protected]
 * http://www.exist-db.org
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */
package org.exist.xquery.modules.image;

import java.awt.Image;
import java.io.IOException;
import java.io.InputStream;
import javax.imageio.ImageIO;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.exist.dom.QName;
import org.exist.xquery.BasicFunction;
import org.exist.xquery.Cardinality;
import org.exist.xquery.FunctionSignature;
import org.exist.xquery.XPathException;
import org.exist.xquery.XQueryContext;
import org.exist.xquery.value.BinaryValue;
import org.exist.xquery.value.FunctionParameterSequenceType;
import org.exist.xquery.value.FunctionReturnSequenceType;
import org.exist.xquery.value.IntegerValue;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.Type;

/**
 * eXist Image Module Extension GetWidthFunction 
 * 
 * Get's the width of an Image
 * 
 * @author Adam Retter
 * @author Loren Cahlander
 * @version 1.2
 *
 * @see org.exist.xquery.BasicFunction#BasicFunction(org.exist.xquery.XQueryContext, org.exist.xquery.FunctionSignature)
 */
public class GetWidthFunction extends BasicFunction {

    private static final Logger logger = LogManager.getLogger(GetWidthFunction.class);
    public final static FunctionSignature signature =
            new FunctionSignature(
            new QName("get-width", ImageModule.NAMESPACE_URI, ImageModule.PREFIX),
            "Gets the width of the image passed in, returning an integer of the images width in pixels or an empty sequence if the image is invalid.",
            new SequenceType[]{
                new FunctionParameterSequenceType("image", Type.BASE64_BINARY, Cardinality.EXACTLY_ONE, "The image data")
            },
            new FunctionReturnSequenceType(Type.INTEGER, Cardinality.ZERO_OR_ONE, "the width in pixels"));

    /**
     * GetWidthFunction Constructor
     *
     * @param context	The Context of the calling XQuery
     */
    public GetWidthFunction(XQueryContext context) {
        super(context, signature);
    }

    /**
     * evaluate the call to the xquery get-width() function,
     * it is really the main entry point of this class
     *
     * @param args		arguments from the get-width() function call
     * @param contextSequence	the Context Sequence to operate on (not used here internally!)
     * @return		A sequence representing the result of the get-width() function call
     *
     * @see org.exist.xquery.BasicFunction#eval(org.exist.xquery.value.Sequence[], org.exist.xquery.value.Sequence)
     */
    @Override
    public Sequence eval(Sequence[] args, Sequence contextSequence) throws XPathException {
        //was an image speficifed
        if (args[0].isEmpty()) {
            return Sequence.EMPTY_SEQUENCE;
        }

        //get the image
        Image image = null;
        BinaryValue imageData = (BinaryValue) args[0].itemAt(0);
        try (InputStream inputStream = imageData.getInputStream()) {
            image = ImageIO.read(inputStream);

        } catch (IOException ioe) {
            logger.error("Unable to read image data!", ioe);
            return Sequence.EMPTY_SEQUENCE;
        }

        if (image == null) {
            logger.error("Unable to read image data!");
            return Sequence.EMPTY_SEQUENCE;
        }

        //Get the width of the image
        int iWidth = image.getWidth(null);

        //did we get the width of the image?
        if (iWidth == -1) {
            //no, log the error
            logger.error("Unable to read image data!");
            return Sequence.EMPTY_SEQUENCE;
        } else {
            //return the width of the image
            return new IntegerValue(iWidth);
        }
    }
}