/*
* 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.util;
import java.awt.image.BufferedImage;
import java.awt.image.RenderedImage;
import java.io.File;
import java.io.IOException;
import java.util.Iterator;
import javax.imageio.IIOException;
import javax.imageio.IIOImage;
import javax.imageio.ImageIO;
import javax.imageio.ImageTypeSpecifier;
import javax.imageio.ImageWriteParam;
import javax.imageio.ImageWriter;
import javax.imageio.metadata.IIOInvalidTreeException;
import javax.imageio.metadata.IIOMetadata;
import javax.imageio.metadata.IIOMetadataNode;
import javax.imageio.stream.ImageOutputStream;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
/**
* This class handles some ImageIO operations.
*
* @version $Revision$
*
*/
public class ImageIOUtil
{
private ImageIOUtil()
{
// Default constructor
}
/**
* Converts a given page range of a PDF document to bitmap images.
* @param image the image to be written
* @param imageFormat the target format (ex. "png")
* @param filename used to construct the filename for the individual images
* @param imageType the image type (see {@link BufferedImage}.TYPE_*)
* @param resolution the resolution in dpi (dots per inch)
* @return true if the images were produced, false if there was an error
* @throws IOException if an I/O error occurs
*/
public static boolean writeImage(BufferedImage image, String imageFormat, String filename,
int imageType, int resolution)
throws IOException
{
boolean bSuccess = true;
ImageOutputStream output = null;
ImageWriter imageWriter = null;
try
{
String fileName = filename + "." + imageFormat;
output = ImageIO.createImageOutputStream( new File( fileName ) );
boolean foundWriter = false;
Iterator<ImageWriter> writerIter = ImageIO.getImageWritersByFormatName( imageFormat );
while( writerIter.hasNext() && !foundWriter )
{
try
{
imageWriter = (ImageWriter)writerIter.next();
ImageWriteParam writerParams = imageWriter.getDefaultWriteParam();
if( writerParams.canWriteCompressed() )
{
writerParams.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
// reset the compression type if overwritten by setCompressionMode
if (writerParams.getCompressionType() == null)
{
writerParams.setCompressionType(writerParams.getCompressionTypes()[0]);
}
writerParams.setCompressionQuality(1.0f);
}
IIOMetadata meta = createMetadata( image, imageWriter, writerParams, resolution);
imageWriter.setOutput( output );
imageWriter.write( null, new IIOImage( image, null, meta ), writerParams );
foundWriter = true;
}
catch( IIOException io )
{
throw new IOException( io.getMessage() );
}
finally
{
if( imageWriter != null )
{
imageWriter.dispose();
}
}
}
if( !foundWriter )
{
bSuccess = false;
}
}
finally
{
if( output != null )
{
output.flush();
output.close();
}
}
return bSuccess;
}
private static IIOMetadata createMetadata(RenderedImage image, ImageWriter imageWriter,
ImageWriteParam writerParams, int resolution)
{
ImageTypeSpecifier type;
if (writerParams.getDestinationType() != null)
{
type = writerParams.getDestinationType();
}
else
{
type = ImageTypeSpecifier.createFromRenderedImage( image );
}
IIOMetadata meta = imageWriter.getDefaultImageMetadata( type, writerParams );
return (addResolution(meta, resolution) ? meta : null);
}
private static final String STANDARD_METADATA_FORMAT = "javax_imageio_1.0";
private static boolean addResolution(IIOMetadata meta, int resolution)
{
if (!meta.isReadOnly() && meta.isStandardMetadataFormatSupported())
{
IIOMetadataNode root = (IIOMetadataNode)meta.getAsTree(STANDARD_METADATA_FORMAT);
IIOMetadataNode dim = getChildNode(root, "Dimension");
if (dim == null)
{
dim = new IIOMetadataNode("Dimension");
root.appendChild(dim);
}
IIOMetadataNode child;
child = getChildNode(dim, "HorizontalPixelSize");
if (child == null)
{
child = new IIOMetadataNode("HorizontalPixelSize");
dim.appendChild(child);
}
child.setAttribute("value",
Double.toString(resolution / 25.4));
child = getChildNode(dim, "VerticalPixelSize");
if (child == null)
{
child = new IIOMetadataNode("VerticalPixelSize");
dim.appendChild(child);
}
child.setAttribute("value",
Double.toString(resolution / 25.4));
try
{
meta.mergeTree(STANDARD_METADATA_FORMAT, root);
}
catch (IIOInvalidTreeException e)
{
throw new RuntimeException("Cannot update image metadata: "
+ e.getMessage());
}
return true;
}
return false;
}
private static IIOMetadataNode getChildNode(Node n, String name)
{
NodeList nodes = n.getChildNodes();
for (int i = 0; i < nodes.getLength(); i++)
{
Node child = nodes.item(i);
if (name.equals(child.getNodeName()))
{
return (IIOMetadataNode)child;
}
}
return null;
}
}