/*
* $Id: PngWriter.java 4784 2011-03-15 08:33:00Z blowagie $
*
* This file is part of the iText (R) project.
* Copyright (c) 1998-2011 1T3XT BVBA
* Authors: Bruno Lowagie, Paulo Soares, et al.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License version 3
* as published by the Free Software Foundation with the addition of the
* following permission added to Section 15 as permitted in Section 7(a):
* FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY 1T3XT,
* 1T3XT DISCLAIMS THE WARRANTY OF NON INFRINGEMENT OF THIRD PARTY RIGHTS.
*
* This program 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 Affero General Public License for more details.
* You should have received a copy of the GNU Affero General Public License
* along with this program; if not, see http://www.gnu.org/licenses or write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA, 02110-1301 USA, or download the license from the following URL:
* http://itextpdf.com/terms-of-use/
*
* The interactive user interfaces in modified source and object code versions
* of this program must display Appropriate Legal Notices, as required under
* Section 5 of the GNU Affero General Public License.
*
* In accordance with Section 7(b) of the GNU Affero General Public License,
* a covered work must retain the producer line in every PDF that is created
* or manipulated using iText.
*
* You can be released from the requirements of the license by purchasing
* a commercial license. Buying such a license is mandatory as soon as you
* develop commercial activities involving the iText software without
* disclosing the source code of your own applications.
* These activities include: offering paid services to customers as an ASP,
* serving PDFs on the fly in a web application, shipping iText with a closed
* source product.
*
* For more information, please contact iText Software Corp. at this
* address: [email protected]
*/
package com.itextpdf.text.pdf.codec;
import com.itextpdf.text.DocWriter;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.zip.DeflaterOutputStream;
/**
* Writes a PNG image.
*
* @author Paulo Soares
* @since 5.0.3
*/
public class PngWriter {
private static final byte[] PNG_SIGNTURE = {(byte)137, 80, 78, 71, 13, 10, 26, 10};
private static final byte[] IHDR = DocWriter.getISOBytes("IHDR");
private static final byte[] PLTE = DocWriter.getISOBytes("PLTE");
private static final byte[] IDAT = DocWriter.getISOBytes("IDAT");
private static final byte[] IEND = DocWriter.getISOBytes("IEND");
private static final byte[] iCCP = DocWriter.getISOBytes("iCCP");
private static long[] crc_table;
private OutputStream outp;
public PngWriter(OutputStream outp) throws IOException {
this.outp = outp;
outp.write(PNG_SIGNTURE);
}
public void writeHeader(int width, int height, int bitDepth, int colorType) throws IOException {
ByteArrayOutputStream ms = new ByteArrayOutputStream();
outputInt(width, ms);
outputInt(height, ms);
ms.write(bitDepth);
ms.write(colorType);
ms.write(0);
ms.write(0);
ms.write(0);
writeChunk(IHDR, ms.toByteArray());
}
public void writeEnd() throws IOException {
writeChunk(IEND, new byte[0]);
}
public void writeData(byte[] data, int stride) throws IOException {
ByteArrayOutputStream stream = new ByteArrayOutputStream();
DeflaterOutputStream zip = new DeflaterOutputStream(stream);
for (int k = 0; k < data.length; k += stride) {
zip.write(0);
zip.write(data, k, stride);
}
zip.finish();
writeChunk(IDAT, stream.toByteArray());
}
public void writePalette(byte[] data) throws IOException {
writeChunk(PLTE, data);
}
public void writeIccProfile(byte[] data) throws IOException {
ByteArrayOutputStream stream = new ByteArrayOutputStream();
stream.write((byte)'I');
stream.write((byte)'C');
stream.write((byte)'C');
stream.write(0);
stream.write(0);
DeflaterOutputStream zip = new DeflaterOutputStream(stream);
zip.write(data);
zip.finish();
writeChunk(iCCP, stream.toByteArray());
}
private static void make_crc_table() {
if (crc_table != null)
return;
long[] crc2 = new long[256];
for (int n = 0; n < 256; n++) {
long c = n;
for (int k = 0; k < 8; k++) {
if ((c & 1) != 0)
c = 0xedb88320L ^ (c >> 1);
else
c = c >> 1;
}
crc2[n] = c;
}
crc_table = crc2;
}
private static long update_crc(long crc, byte[] buf, int offset, int len) {
long c = crc;
if (crc_table == null)
make_crc_table();
for (int n = 0; n < len; n++) {
c = crc_table[(int)((c ^ buf[n + offset]) & 0xff)] ^ (c >> 8);
}
return c;
}
private static long crc(byte[] buf, int offset, int len) {
return update_crc(0xffffffffL, buf, offset, len) ^ 0xffffffffL;
}
private static long crc(byte[] buf) {
return update_crc(0xffffffffL, buf, 0, buf.length) ^ 0xffffffffL;
}
public void outputInt(int n) throws IOException {
outputInt(n, outp);
}
public static void outputInt(int n, OutputStream s) throws IOException {
s.write((byte)(n >> 24));
s.write((byte)(n >> 16));
s.write((byte)(n >> 8));
s.write((byte)n);
}
public void writeChunk(byte[] chunkType, byte[] data) throws IOException {
outputInt(data.length);
outp.write(chunkType, 0, 4);
outp.write(data);
long c = update_crc(0xffffffffL, chunkType, 0, chunkType.length);
c = update_crc(c, data, 0, data.length) ^ 0xffffffffL;
outputInt((int)c);
}
}
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