# FDFAnnotationInk.java

    /*
     * Licensed to the Apache Software Foundation (ASF) under one or more
     * contributor license agreements.  See the NOTICE file distributed with
     * this work for additional information regarding copyright ownership.
     * The ASF licenses this file to You under the Apache License, Version 2.0
     * (the "License"); you may not use this file except in compliance with
     * the License.  You may obtain a copy of the License at
     *
     *      http://www.apache.org/licenses/LICENSE-2.0
     *
     * Unless required by applicable law or agreed to in writing, software
     * distributed under the License is distributed on an "AS IS" BASIS,
     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     * See the License for the specific language governing permissions and
     * limitations under the License.
     */
    package org.apache.pdfbox.pdmodel.fdf;

    import java.io.IOException;
    import java.util.ArrayList;
    import java.util.List;

    import javax.xml.xpath.XPath;
    import javax.xml.xpath.XPathConstants;
    import javax.xml.xpath.XPathExpressionException;
    import javax.xml.xpath.XPathFactory;

    import org.apache.commons.logging.Log;
    import org.apache.commons.logging.LogFactory;
    import org.apache.pdfbox.cos.COSArray;
    import org.apache.pdfbox.cos.COSBase;
    import org.apache.pdfbox.cos.COSDictionary;
    import org.apache.pdfbox.cos.COSName;
    import org.w3c.dom.Element;
    import org.w3c.dom.Node;
    import org.w3c.dom.NodeList;

    /**
     * This represents a Ink FDF annotation.
     *
     * @author Ben Litchfield
     */
    public class FDFAnnotationInk extends FDFAnnotation
    {
        private static final Log LOG = LogFactory.getLog(FDFAnnotationInk.class);
        /**
         * COS Model value for SubType entry.
         */
        public static final String SUBTYPE = "Ink";

        /**
         * Default constructor.
         */
        public FDFAnnotationInk()
        {
            super();
            annot.setName(COSName.SUBTYPE, SUBTYPE);
        }

        /**
         * Constructor.
         *
         * @param a An existing FDF Annotation.
         */
        public FDFAnnotationInk(COSDictionary a)
        {
            super(a);
        }

        /**
         * Constructor.
         *
         * @param element An XFDF element.
         *
         * @throws IOException If there is an error extracting information from the element.
         */
        public FDFAnnotationInk(Element element) throws IOException
        {
            super(element);
            annot.setName(COSName.SUBTYPE, SUBTYPE);

            XPath xpath = XPathFactory.newInstance().newXPath();
            try
            {
                NodeList gestures = (NodeList) xpath.evaluate("inklist/gesture", element,
                        XPathConstants.NODESET);
                if (gestures.getLength() == 0)
                {
                    throw new IOException("Error: missing element 'gesture'");
                }
                List<float[]> inklist = new ArrayList<>();
                for (int i = 0; i < gestures.getLength(); i++)
                {
                    Node node = gestures.item(i);
                    if (node instanceof Element)
                    {
                        String gesture = node.getFirstChild().getNodeValue();
                        String[] gestureValues = gesture.split(",|;");
                        float[] values = new float[gestureValues.length];
                        for (int j = 0; j < gestureValues.length; j++)
                        {
                            values[j] = Float.parseFloat(gestureValues[j]);
                        }
                        inklist.add(values);
                    }
                }
                setInkList(inklist);
            }
            catch (XPathExpressionException e)
            {
                LOG.debug("Error while evaluating XPath expression for inklist gestures", e);
            }
        }

        /**
         * Set the paths making up the freehand "scribble".
         *
         * The ink annotation is made up of one ore more disjoint paths. Each array entry is an array representing a stroked
         * path, being a series of alternating horizontal and vertical coordinates in default user space.
         *
         * @param inklist the List of arrays representing the paths.
         */
        public final void setInkList(List<float[]> inklist)
        {
            COSArray newInklist = new COSArray();
            for (float[] array : inklist)
            {
                COSArray newArray = new COSArray();
                newArray.setFloatArray(array);
                newInklist.add(newArray);
            }
            annot.setItem(COSName.INKLIST, newInklist);
        }

        /**
         * Get the paths making up the freehand "scribble".
         *
         * @see #setInkList(List)
         * @return the List of arrays representing the paths.
         */
        public List<float[]> getInkList()
        {
            COSArray array = annot.getCOSArray(COSName.INKLIST);
            if (array != null)
            {
                List<float[]> retval = new ArrayList<>();
                for (COSBase entry : array)
                {
                    retval.add(((COSArray) entry).toFloatArray());
                }
                return retval;
            }
            else
            {
                return null; // Should never happen as this is a required item
            }
        }
    }