/*!
* This program is free software; you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software
* Foundation.
*
* You should have received a copy of the GNU Lesser General Public License along with this
* program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
* or from the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* 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 Lesser General Public License for more details.
*
* Copyright (c) 2002-2013 Pentaho Corporation.. All rights reserved.
*/
package org.pentaho.reporting.libraries.base.util;
import java.awt.Image;
import java.awt.image.ImageObserver;
import java.awt.image.PixelGrabber;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.zip.CRC32;
import java.util.zip.Deflater;
import java.util.zip.DeflaterOutputStream;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.pentaho.reporting.libraries.base.encoder.ImageEncoder;
import org.pentaho.reporting.libraries.base.encoder.UnsupportedEncoderException;
/**
* PngEncoder takes a Java Image object and creates a byte string which can be saved as a PNG file. The Image is
* presumed to use the DirectColorModel.
* <p/>
* <p>Thanks to Jay Denny at KeyPoint Software http://www.keypoint.com/ who let me develop this code on company
* time.</p>
* <p/>
* <p>You may contact me with (probably very-much-needed) improvements, comments, and bug fixes at:</p>
* <p/>
* <p><code>david@catcode.com</code></p>
* <p/>
* <p>This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General
* Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option)
* any later version.</p>
* <p/>
* <p>This library 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 Lesser General Public License for more
* details.</p>
* <p/>
* <p>You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. A copy of the GNU
* LGPL may be found at <code>http://www.gnu.org/copyleft/lesser.html</code></p>
*
* @author J. David Eisenberg
* @version 1.5, 19 Oct 2003
* <p/>
* CHANGES: -------- 19-Nov-2002 : CODING STYLE CHANGES ONLY (by David Gilbert for Object Refinery Limited);
* 19-Sep-2003 : Fix for platforms using EBCDIC (contributed by Paulo Soares); 19-Oct-2003 : Change private
* fields to protected fields so that PngEncoderB can inherit them (JDE) Fixed bug with calculation of nRows
*/
public class PngEncoder implements ImageEncoder
{
/** A logger for debug-messages. */
private static final Log logger = LogFactory.getLog(PngEncoder.class);
/**
* Constant specifying that alpha channel should be encoded.
*/
public static final boolean ENCODE_ALPHA = true;
/**
* Constant specifying that alpha channel should not be encoded.
*/
public static final boolean NO_ALPHA = false;
/**
* Constants for filter (NONE).
*/
public static final int FILTER_NONE = 0;
/**
* Constants for filter (SUB).
*/
public static final int FILTER_SUB = 1;
/**
* Constants for filter (UP).
*/
public static final int FILTER_UP = 2;
/**
* Constants for filter (LAST).
*/
public static final int FILTER_LAST = 2;
/**
* IHDR tag.
*/
private static final byte[] IHDR = {73, 72, 68, 82};
/**
* IDAT tag.
*/
private static final byte[] IDAT = {73, 68, 65, 84};
/**
* IEND tag.
*/
private static final byte[] IEND = {73, 69, 78, 68};
/**
* PHYS tag.
*/
private static final byte[] PHYS = {(byte) 'p', (byte) 'H', (byte) 'Y', (byte) 's'};
/**
* The png bytes.
*/
private byte[] pngBytes;
/**
* The prior row.
*/
private byte[] priorRow;
/**
* The left bytes.
*/
private byte[] leftBytes;
/**
* The image.
*/
private Image image;
/**
* The width.
*/
private int width;
/**
* The height.
*/
private int height;
/**
* The byte position.
*/
private int bytePos;
/**
* The maximum position.
*/
private int maxPos;
/**
* CRC.
*/
private CRC32 crc = new CRC32();
/**
* The CRC value.
*/
private long crcValue;
/**
* A flag indicating whether the alpha channel should also be encoded.
*/
private boolean encodeAlpha;
/**
* The filter type.
*/
private int filter;
/**
* The bytes-per-pixel.
*/
private int bytesPerPixel;
/**
* The physical pixel dimension : number of pixels per inch on the X axis.
*/
private int xDpi;
/**
* The physical pixel dimension : number of pixels per inch on the Y axis.
*/
private int yDpi;
/**
* Used for conversion of DPI to Pixels per Meter.
*/
private static final float INCH_IN_METER_UNIT = 0.0254f;
/**
* The compression level (1 = best speed, 9 = best compression, 0 = no compression).
*/
private int compressionLevel;
/**
* Class constructor.
*/
public PngEncoder()
{
this(null, false, PngEncoder.FILTER_NONE, 0);
}
/**
* Class constructor specifying Image to encode, with no alpha channel encoding.
*
* @param image A Java Image object which uses the DirectColorModel
* @see java.awt.Image
*/
public PngEncoder(final Image image)
{
this(image, false, PngEncoder.FILTER_NONE, 0);
}
/**
* Class constructor specifying Image to encode, and whether to encode alpha.
*
* @param image A Java Image object which uses the DirectColorModel
* @param encodeAlpha Encode the alpha channel? false=no; true=yes
* @see java.awt.Image
*/
public PngEncoder(final Image image, final boolean encodeAlpha)
{
this(image, encodeAlpha, PngEncoder.FILTER_NONE, 0);
}
/**
* Class constructor specifying Image to encode, whether to encode alpha, and filter to use.
*
* @param image A Java Image object which uses the DirectColorModel
* @param encodeAlpha Encode the alpha channel? false=no; true=yes
* @param whichFilter 0=none, 1=sub, 2=up
* @see java.awt.Image
*/
public PngEncoder(final Image image, final boolean encodeAlpha, final int whichFilter)
{
this(image, encodeAlpha, whichFilter, 0);
}
/**
* Class constructor specifying Image source to encode, whether to encode alpha, filter to use, and compression
* level.
*
* @param image A Java Image object
* @param encodeAlpha Encode the alpha channel? false=no; true=yes
* @param whichFilter 0=none, 1=sub, 2=up
* @param compLevel 0..9 (1 = best speed, 9 = best compression, 0 = no compression)
* @see java.awt.Image
*/
public PngEncoder(final Image image,
final boolean encodeAlpha,
final int whichFilter,
final int compLevel)
{
this.image = image;
this.encodeAlpha = encodeAlpha;
setFilter(whichFilter);
setCompressionLevel(compLevel);
if (getCompressionLevel() == 0)
{
setCompressionLevel(5);
}
}
/**
* Set the image to be encoded.
*
* @param image A Java Image object which uses the DirectColorModel
* @see java.awt.Image
* @see java.awt.image.DirectColorModel
*/
public void setImage(final Image image)
{
this.image = image;
this.pngBytes = null;
}
/**
* Returns the image to be encoded.
* @return the image to be encoded.
*/
public Image getImage()
{
return image;
}
/**
* Creates an array of bytes that is the PNG equivalent of the current image, specifying whether to encode alpha or
* not.
*
* @param encodeAlpha boolean false=no alpha, true=encode alpha
* @return an array of bytes, or null if there was a problem
* @deprecated Use the other pngEncode method and select the alpha-encoding via the constructor or setter.
*/
public byte[] pngEncode(final boolean encodeAlpha)
{
setEncodeAlpha(encodeAlpha);
return pngEncode();
}
/**
* Creates an array of bytes that is the PNG equivalent of the current image, specifying whether to encode alpha or
* not.
*
* @return an array of bytes, or null if there was a problem
*/
public byte[] pngEncode()
{
final byte[] pngIdBytes = {-119, 80, 78, 71, 13, 10, 26, 10};
if (this.image == null)
{
return null;
}
this.width = this.image.getWidth(null);
this.height = this.image.getHeight(null);
/*
* start with an array that is big enough to hold all the pixels
* (plus filter bytes), and an extra 200 bytes for header info
*/
this.pngBytes = new byte[((this.width + 1) * this.height * 3) + 200];
/*
* keep track of largest byte written to the array
*/
this.maxPos = 0;
this.bytePos = writeBytes(pngIdBytes, 0);
//hdrPos = bytePos;
writeHeader();
writeResolution();
//dataPos = bytePos;
if (writeImageData())
{
writeEnd();
final byte[] pngBytes = resizeByteArray(this.pngBytes, this.maxPos);
this.pngBytes = null;
return pngBytes;
}
else
{
this.pngBytes = null;
return null;
}
}
/**
* Set the alpha encoding on or off.
*
* @param encodeAlpha false=no, true=yes
*/
public void setEncodeAlpha(final boolean encodeAlpha)
{
this.encodeAlpha = encodeAlpha;
}
/**
* Retrieve alpha encoding status.
*
* @return boolean false=no, true=yes
*/
public boolean getEncodeAlpha()
{
return this.encodeAlpha;
}
/**
* Set the filter to use.
*
* @param whichFilter from constant list
*/
public void setFilter(final int whichFilter)
{
this.filter = PngEncoder.FILTER_NONE;
if (whichFilter <= PngEncoder.FILTER_LAST)
{
this.filter = whichFilter;
}
}
/**
* Retrieve filtering scheme.
*
* @return int (see constant list)
*/
public int getFilter()
{
return this.filter;
}
/**
* Set the compression level to use.
*
* @param level the compression level (1 = best speed, 9 = best compression, 0 = no compression)
*/
public void setCompressionLevel(final int level)
{
if (level >= 0 && level <= 9)
{
this.compressionLevel = level;
}
}
/**
* Retrieve compression level.
*
* @return int (1 = best speed, 9 = best compression, 0 = no compression)
*/
public int getCompressionLevel()
{
return this.compressionLevel;
}
/**
* Increase or decrease the length of a byte array.
*
* @param array The original array.
* @param newLength The length you wish the new array to have.
* @return Array of newly desired length. If shorter than the original, the trailing elements are truncated.
*/
protected byte[] resizeByteArray(final byte[] array, final int newLength)
{
final byte[] newArray = new byte[newLength];
final int oldLength = array.length;
System.arraycopy(array, 0, newArray, 0, Math.min(oldLength, newLength));
return newArray;
}
/**
* Write an array of bytes into the pngBytes array. Note: This routine has the side effect of updating maxPos, the
* largest element written in the array. The array is resized by 1000 bytes or the length of the data to be written,
* whichever is larger.
*
* @param data The data to be written into pngBytes.
* @param offset The starting point to write to.
* @return The next place to be written to in the pngBytes array.
*/
protected int writeBytes(final byte[] data, final int offset)
{
this.maxPos = Math.max(this.maxPos, offset + data.length);
if (data.length + offset > this.pngBytes.length)
{
this.pngBytes = resizeByteArray(this.pngBytes, this.pngBytes.length
+ Math.max(1000, data.length));
}
System.arraycopy(data, 0, this.pngBytes, offset, data.length);
return offset + data.length;
}
/**
* Write an array of bytes into the pngBytes array, specifying number of bytes to write. Note: This routine has the
* side effect of updating maxPos, the largest element written in the array. The array is resized by 1000 bytes or
* the length of the data to be written, whichever is larger.
*
* @param data The data to be written into pngBytes.
* @param nBytes The number of bytes to be written.
* @param offset The starting point to write to.
* @return The next place to be written to in the pngBytes array.
*/
protected int writeBytes(final byte[] data, final int nBytes, final int offset)
{
this.maxPos = Math.max(this.maxPos, offset + nBytes);
if (nBytes + offset > this.pngBytes.length)
{
this.pngBytes = resizeByteArray(this.pngBytes, this.pngBytes.length
+ Math.max(1000, nBytes));
}
System.arraycopy(data, 0, this.pngBytes, offset, nBytes);
return offset + nBytes;
}
/**
* Write a two-byte integer into the pngBytes array at a given position.
*
* @param n The integer to be written into pngBytes.
* @param offset The starting point to write to.
* @return The next place to be written to in the pngBytes array.
*/
protected int writeInt2(final int n, final int offset)
{
final byte[] temp = {(byte) ((n >> 8) & 0xff), (byte) (n & 0xff)};
return writeBytes(temp, offset);
}
/**
* Write a four-byte integer into the pngBytes array at a given position.
*
* @param n The integer to be written into pngBytes.
* @param offset The starting point to write to.
* @return The next place to be written to in the pngBytes array.
*/
protected int writeInt4(final int n, final int offset)
{
final byte[] temp = {(byte) ((n >> 24) & 0xff),
(byte) ((n >> 16) & 0xff),
(byte) ((n >> 8) & 0xff),
(byte) (n & 0xff)};
return writeBytes(temp, offset);
}
/**
* Write a single byte into the pngBytes array at a given position.
*
* @param b The integer to be written into pngBytes.
* @param offset The starting point to write to.
* @return The next place to be written to in the pngBytes array.
*/
protected int writeByte(final int b, final int offset)
{
final byte[] temp = {(byte) b};
return writeBytes(temp, offset);
}
/**
* Write a PNG "IHDR" chunk into the pngBytes array.
*/
protected void writeHeader()
{
this.bytePos = writeInt4(13, this.bytePos);
final int startPos = bytePos;
this.bytePos = writeBytes(PngEncoder.IHDR, this.bytePos);
this.width = this.image.getWidth(null);
this.height = this.image.getHeight(null);
this.bytePos = writeInt4(this.width, this.bytePos);
this.bytePos = writeInt4(this.height, this.bytePos);
this.bytePos = writeByte(8, this.bytePos); // bit depth
this.bytePos = writeByte((this.encodeAlpha) ? 6 : 2, this.bytePos);
// direct model
this.bytePos = writeByte(0, this.bytePos); // compression method
this.bytePos = writeByte(0, this.bytePos); // filter method
this.bytePos = writeByte(0, this.bytePos); // no interlace
this.crc.reset();
this.crc.update(this.pngBytes, startPos, this.bytePos - startPos);
this.crcValue = this.crc.getValue();
this.bytePos = writeInt4((int) this.crcValue, this.bytePos);
}
/**
* Perform "sub" filtering on the given row. Uses temporary array leftBytes to store the original values of the
* previous pixels. The array is 16 bytes long, which will easily hold two-byte samples plus two-byte alpha.
*
* @param pixels The array holding the scan lines being built
* @param startPos Starting position within pixels of bytes to be filtered.
* @param width Width of a scanline in pixels.
*/
protected void filterSub(final byte[] pixels, final int startPos, final int width)
{
final int offset = this.bytesPerPixel;
final int actualStart = startPos + offset;
final int nBytes = width * this.bytesPerPixel;
int leftInsert = offset;
int leftExtract = 0;
for (int i = actualStart; i < startPos + nBytes; i++)
{
this.leftBytes[leftInsert] = pixels[i];
pixels[i] = (byte) ((pixels[i] - this.leftBytes[leftExtract]) % 256);
leftInsert = (leftInsert + 1) % 0x0f;
leftExtract = (leftExtract + 1) % 0x0f;
}
}
/**
* Perform "up" filtering on the given row. Side effect: refills the prior row with current row
*
* @param pixels The array holding the scan lines being built
* @param startPos Starting position within pixels of bytes to be filtered.
* @param width Width of a scanline in pixels.
*/
protected void filterUp(final byte[] pixels, final int startPos, final int width)
{
final int nBytes = width * this.bytesPerPixel;
for (int i = 0; i < nBytes; i++)
{
final byte currentByte = pixels[startPos + i];
pixels[startPos + i] = (byte) ((pixels[startPos + i] - this.priorRow[i]) % 256);
this.priorRow[i] = currentByte;
}
}
/**
* Write the image data into the pngBytes array. This will write one or more PNG "IDAT" chunks. In order to conserve
* memory, this method grabs as many rows as will fit into 32K bytes, or the whole image; whichever is less.
*
* @return true if no errors; false if error grabbing pixels
*/
protected boolean writeImageData()
{
this.bytesPerPixel = (this.encodeAlpha) ? 4 : 3;
final Deflater scrunch = new Deflater(this.compressionLevel);
final ByteArrayOutputStream outBytes = new ByteArrayOutputStream(1024);
final DeflaterOutputStream compBytes = new DeflaterOutputStream(outBytes, scrunch);
try
{
int startRow = 0; // starting row to process this time through
//noinspection SuspiciousNameCombination
int rowsLeft = this.height; // number of rows remaining to write
while (rowsLeft > 0)
{
final int nRows = Math.max(Math.min(32767 / (this.width * (this.bytesPerPixel + 1)), rowsLeft), 1);
final int[] pixels = new int[this.width * nRows];
final PixelGrabber pg = new PixelGrabber(this.image, 0, startRow,
this.width, nRows, pixels, 0, this.width);
try
{
pg.grabPixels();
}
catch (Exception e)
{
logger.error("interrupted waiting for pixels!", e);
return false;
}
if ((pg.getStatus() & ImageObserver.ABORT) != 0)
{
logger.error("image fetch aborted or errored");
return false;
}
/*
* Create a data chunk. scanLines adds "nRows" for
* the filter bytes.
*/
final byte[] scanLines = new byte[this.width * nRows * this.bytesPerPixel + nRows];
if (this.filter == PngEncoder.FILTER_SUB)
{
this.leftBytes = new byte[16];
}
if (this.filter == PngEncoder.FILTER_UP)
{
this.priorRow = new byte[this.width * this.bytesPerPixel];
}
int scanPos = 0;
int startPos = 1;
for (int i = 0; i < this.width * nRows; i++)
{
if (i % this.width == 0)
{
scanLines[scanPos++] = (byte) this.filter;
startPos = scanPos;
}
scanLines[scanPos++] = (byte) ((pixels[i] >> 16) & 0xff);
scanLines[scanPos++] = (byte) ((pixels[i] >> 8) & 0xff);
scanLines[scanPos++] = (byte) ((pixels[i]) & 0xff);
if (this.encodeAlpha)
{
scanLines[scanPos++] = (byte) ((pixels[i] >> 24)
& 0xff);
}
if ((i % this.width == this.width - 1)
&& (this.filter != PngEncoder.FILTER_NONE))
{
if (this.filter == PngEncoder.FILTER_SUB)
{
filterSub(scanLines, startPos, this.width);
}
if (this.filter == PngEncoder.FILTER_UP)
{
filterUp(scanLines, startPos, this.width);
}
}
}
/*
* Write these lines to the output area
*/
compBytes.write(scanLines, 0, scanPos);
startRow += nRows;
rowsLeft -= nRows;
}
compBytes.close();
/*
* Write the compressed bytes
*/
final byte[] compressedLines = outBytes.toByteArray();
final int nCompressed = compressedLines.length;
this.crc.reset();
this.bytePos = writeInt4(nCompressed, this.bytePos);
this.bytePos = writeBytes(PngEncoder.IDAT, this.bytePos);
this.crc.update(PngEncoder.IDAT);
this.bytePos = writeBytes(compressedLines, nCompressed,
this.bytePos);
this.crc.update(compressedLines, 0, nCompressed);
this.crcValue = this.crc.getValue();
this.bytePos = writeInt4((int) this.crcValue, this.bytePos);
return true;
}
catch (IOException e)
{
logger.error("Failed to write PNG Data", e);
return false;
}
finally
{
scrunch.finish();
scrunch.end();
}
}
/**
* Write a PNG "IEND" chunk into the pngBytes array.
*/
protected void writeEnd()
{
this.bytePos = writeInt4(0, this.bytePos);
this.bytePos = writeBytes(PngEncoder.IEND, this.bytePos);
this.crc.reset();
this.crc.update(PngEncoder.IEND);
this.crcValue = this.crc.getValue();
this.bytePos = writeInt4((int) this.crcValue, this.bytePos);
}
/**
* Set the DPI for the X axis.
*
* @param xDpi The number of dots per inch
*/
public void setXDpi(final int xDpi)
{
this.xDpi = Math.round(xDpi / PngEncoder.INCH_IN_METER_UNIT);
}
/**
* Get the DPI for the X axis.
*
* @return The number of dots per inch
*/
public int getXDpi()
{
return Math.round(xDpi * PngEncoder.INCH_IN_METER_UNIT);
}
/**
* Set the DPI for the Y axis.
*
* @param yDpi The number of dots per inch
*/
public void setYDpi(final int yDpi)
{
this.yDpi = Math.round(yDpi / PngEncoder.INCH_IN_METER_UNIT);
}
/**
* Get the DPI for the Y axis.
*
* @return The number of dots per inch
*/
public int getYDpi()
{
return Math.round(yDpi * PngEncoder.INCH_IN_METER_UNIT);
}
/**
* Set the DPI resolution.
*
* @param xDpi The number of dots per inch for the X axis.
* @param yDpi The number of dots per inch for the Y axis.
*/
public void setDpi(final int xDpi, final int yDpi)
{
this.xDpi = Math.round(xDpi / PngEncoder.INCH_IN_METER_UNIT);
this.yDpi = Math.round(yDpi / PngEncoder.INCH_IN_METER_UNIT);
}
/**
* Write a PNG "pHYs" chunk into the pngBytes array.
*/
protected void writeResolution()
{
if (xDpi > 0 && yDpi > 0)
{
bytePos = writeInt4(9, bytePos);
final int startPos = bytePos;
bytePos = writeBytes(PngEncoder.PHYS, bytePos);
bytePos = writeInt4(xDpi, bytePos);
bytePos = writeInt4(yDpi, bytePos);
bytePos = writeByte(1, bytePos); // unit is the meter.
crc.reset();
crc.update(pngBytes, startPos, bytePos - startPos);
crcValue = crc.getValue();
bytePos = writeInt4((int) crcValue, bytePos);
}
}
public void encodeImage(final Image image,
final OutputStream outputStream,
final float quality,
final boolean encodeAlpha) throws IOException, UnsupportedEncoderException
{
setCompressionLevel(Math.min (9, Math.max(0, (int)(quality * 10))));
setImage(image);
setEncodeAlpha(encodeAlpha);
final byte[] bytes = this.pngEncode();
outputStream.write(bytes);
}
public String getMimeType()
{
return "image/png";
}
}