src/main/java/org/apache/pdfbox/jbig2/JBIG2ImageMetadata.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.jbig2;

import javax.imageio.metadata.IIOMetadata;
import javax.imageio.metadata.IIOMetadataFormatImpl;
import javax.imageio.metadata.IIOMetadataNode;

import org.w3c.dom.Node;

/**
 * @see IIOMetadata
 */
public class JBIG2ImageMetadata extends IIOMetadata
{

    static final String IMAGE_METADATA_FORMAT_NAME = "jbig2";

    private final JBIG2Page page;

    public JBIG2ImageMetadata(JBIG2Page page)
    {
        super(true, IMAGE_METADATA_FORMAT_NAME, JBIG2ImageMetadataFormat.class.getName(), null,
                null);

        if (page == null)
            throw new IllegalArgumentException("page must not be null");

        this.page = page;
    }

    @Override
    public boolean isReadOnly()
    {
        return true;
    }

    @Override
    public Node getAsTree(String formatName)
    {
        if (formatName.equals(nativeMetadataFormatName))
        {
            return getNativeTree();
        }
        else if (formatName.equals(IIOMetadataFormatImpl.standardMetadataFormatName))
        {
            return getStandardTree();
        }
        else
        {
            throw new IllegalArgumentException("Not a recognized format!");
        }
    }

    private Node getNativeTree()
    {
        IIOMetadataNode root = new IIOMetadataNode(nativeMetadataFormatName);
        root.appendChild(getStandardDimensionNode());
        return root;
    }

    @Override
    public IIOMetadataNode getStandardDimensionNode()
    {
        IIOMetadataNode dimensionNode = new IIOMetadataNode("Dimension");
        IIOMetadataNode node = null; // scratch node

        node = new IIOMetadataNode("PixelAspectRatio");
        node.setAttribute("value", "1.0");
        dimensionNode.appendChild(node);

        node = new IIOMetadataNode("ImageOrientation");
        node.setAttribute("value", "Normal");
        dimensionNode.appendChild(node);

        if (page.getResolutionX() != 0)
        {
            String pixelResolution = Float.toString(25.4f / (page.getResolutionX() / 39.3701f));

            node = new IIOMetadataNode("HorizontalPixelSize");
            node.setAttribute("value", pixelResolution);
            dimensionNode.appendChild(node);
        }

        if (page.getResolutionY() != 0)
        {
            String pixelResolution = Float.toString(25.4f / (page.getResolutionY() / 39.3701f));

            node = new IIOMetadataNode("VerticalPixelSize");
            node.setAttribute("value", pixelResolution);
            dimensionNode.appendChild(node);
        }

        return dimensionNode;
    }

    @Override
    public void mergeTree(String formatName, Node root)
    {
        throw new IllegalStateException("Metadata is read-only!");
    }

    @Override
    public void reset()
    {
        throw new IllegalStateException("Metadata is read-only!");
    }
}