/*
* 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.
*/
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import org.apache.pdfbox.cos.COSBase;
import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.cos.COSObject;
import org.apache.pdfbox.cos.COSStream;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.common.PDStream;
/**
* A simple command line utility for reducing the size of the ref-guide PDF.
* <p>
* Currently this script focuses on using {@link COSName#FLATE_DECODE} to compress the (decoded) Objects
* in the source PDF, but other improvements may be possible in the future.
* </p>
* <p>
* This code is originally based on the <code>WriteDecodedDoc</code> example provided with <a href="https://pdfbox.apache.org/">Apache PDFBox</a>.
* </p>
* <p>
* <b>NOTE:</b> This class should <em>NOT</em> be considered a general purpose tool for reducing the size of
* <em>any</em> PDF.
* Decisions made in this code can and will be focused explicitly on serving the purpose of reducing the size of the
* Solr Reference Guide PDF, as originally produced by asciidoctor, and may not be generally useful for all PDFs
* "in the wild".
* </p>
*/
public class ReducePDFSize {
public static void main(String[] args) throws IOException {
if (2 != args.length) {
throw new RuntimeException("arg0 must be input file, org1 must be output file");
}
String in = args[0];
String out = args[1];
PDDocument doc = null;
try {
doc = PDDocument.load(new File(in));
doc.setAllSecurityToBeRemoved(true);
for (COSObject cosObject : doc.getDocument().getObjects()) {
COSBase base = cosObject.getObject();
// if it's a stream: decode it, then re-write it using FLATE_DECODE
if (base instanceof COSStream) {
COSStream stream = (COSStream) base;
byte[] bytes;
try {
bytes = new PDStream(stream).toByteArray();
} catch (IOException ex) {
// NOTE: original example code from PDFBox just logged & "continue;"d here, 'skipping' this stream.
// If this type of failure ever happens, we can (perhaps) consider (re)ignoring this type of failure?
//
// IIUC then that will leave the original (non-decoded / non-flated) stream in place?
throw new RuntimeException("can't serialize byte[] from: " +
cosObject.getObjectNumber() + " " +
cosObject.getGenerationNumber() + " obj: " +
ex.getMessage(), ex);
}
stream.removeItem(COSName.FILTER);
OutputStream streamOut = stream.createOutputStream(COSName.FLATE_DECODE);
streamOut.write(bytes);
streamOut.close();
}
}
doc.getDocumentCatalog();
doc.save( out );
} finally {
if ( doc != null ) {
doc.close();
}
}
}
}