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The Apache PDFBox library is an open source Java tool for working with PDF documents.
/*
* Copyright 2014 The Apache Software Foundation.
*
* Licensed 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.pdmodel.graphics.image;
import java.awt.Color;
import java.awt.Transparency;
import java.awt.image.BufferedImage;
import java.awt.image.WritableRaster;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import javax.imageio.stream.MemoryCacheImageOutputStream;
import org.apache.pdfbox.cos.COSDictionary;
import org.apache.pdfbox.cos.COSName;
import org.apache.pdfbox.filter.Filter;
import org.apache.pdfbox.filter.FilterFactory;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.graphics.color.PDColorSpace;
import org.apache.pdfbox.pdmodel.graphics.color.PDDeviceColorSpace;
import org.apache.pdfbox.pdmodel.graphics.color.PDDeviceGray;
import org.apache.pdfbox.pdmodel.graphics.color.PDDeviceRGB;
/**
* Factory for creating a PDImageXObject containing a lossless compressed image.
*
* @author Tilman Hausherr
*/
public final class LosslessFactory
{
private LosslessFactory()
{
}
/**
* Creates a new lossless encoded Image XObject from a Buffered Image.
*
* @param document the document where the image will be created
* @param image the buffered image to embed
* @return a new Image XObject
* @throws IOException if something goes wrong
*/
public static PDImageXObject createFromImage(PDDocument document, BufferedImage image)
throws IOException
{
int bpc;
PDDeviceColorSpace deviceColorSpace;
ByteArrayOutputStream bos = new ByteArrayOutputStream();
int height = image.getHeight();
int width = image.getWidth();
if ((image.getType() == BufferedImage.TYPE_BYTE_GRAY && image.getColorModel().getPixelSize() <= 8)
|| (image.getType() == BufferedImage.TYPE_BYTE_BINARY && image.getColorModel().getPixelSize() == 1))
{
MemoryCacheImageOutputStream mcios = new MemoryCacheImageOutputStream(bos);
// grayscale images need one color per sample
bpc = image.getColorModel().getPixelSize();
deviceColorSpace = PDDeviceGray.INSTANCE;
for (int y = 0; y < height; ++y)
{
for (int x = 0; x < width; ++x)
{
mcios.writeBits(image.getRGB(x, y) & 0xFF, bpc);
}
while (mcios.getBitOffset() != 0)
{
mcios.writeBit(0);
}
}
mcios.flush();
mcios.close();
}
else
{
// RGB
bpc = 8;
deviceColorSpace = PDDeviceRGB.INSTANCE;
for (int y = 0; y < height; ++y)
{
for (int x = 0; x < width; ++x)
{
Color color = new Color(image.getRGB(x, y));
bos.write(color.getRed());
bos.write(color.getGreen());
bos.write(color.getBlue());
}
}
}
PDImageXObject pdImage = prepareImageXObject(document, bos.toByteArray(),
image.getWidth(), image.getHeight(), bpc, deviceColorSpace);
// alpha -> soft mask
PDImage xAlpha = createAlphaFromARGBImage(document, image);
if (xAlpha != null)
{
pdImage.getCOSObject().setItem(COSName.SMASK, xAlpha);
}
return pdImage;
}
/**
* Creates a grayscale Flate encoded PDImageXObject from the alpha channel
* of an image.
*
* @param document the document where the image will be created.
* @param image an ARGB image.
*
* @return the alpha channel of an image as a grayscale image.
*
* @throws IOException if something goes wrong
*/
private static PDImageXObject createAlphaFromARGBImage(PDDocument document, BufferedImage image)
throws IOException
{
// this implementation makes the assumption that the raster values can be used 1:1 for
// the stream.
// Sadly the type of the databuffer is usually TYPE_INT and not TYPE_BYTE so we can't just
// save it directly
if (!image.getColorModel().hasAlpha())
{
return null;
}
// extract the alpha information
WritableRaster alphaRaster = image.getAlphaRaster();
if (alphaRaster == null)
{
// happens sometimes (PDFBOX-2654) despite colormodel claiming to have alpha
return createAlphaFromARGBImage2(document, image);
}
int[] pixels = alphaRaster.getPixels(0, 0,
alphaRaster.getWidth(),
alphaRaster.getHeight(),
(int[]) null);
ByteArrayOutputStream bos = new ByteArrayOutputStream();
int bpc;
if (image.getTransparency() == Transparency.BITMASK)
{
bpc = 1;
MemoryCacheImageOutputStream mcios = new MemoryCacheImageOutputStream(bos);
int width = alphaRaster.getWidth();
int p = 0;
for (int pixel : pixels)
{
mcios.writeBit(pixel);
++p;
if (p % width == 0)
{
while (mcios.getBitOffset() != 0)
{
mcios.writeBit(0);
}
}
}
mcios.flush();
mcios.close();
}
else
{
bpc = 8;
for (int pixel : pixels)
{
bos.write(pixel);
}
}
PDImageXObject pdImage = prepareImageXObject(document, bos.toByteArray(),
image.getWidth(), image.getHeight(), bpc, PDDeviceGray.INSTANCE);
return pdImage;
}
// create alpha image the hard way: get the alpha through getRGB()
private static PDImageXObject createAlphaFromARGBImage2(PDDocument document, BufferedImage bi)
throws IOException
{
ByteArrayOutputStream bos = new ByteArrayOutputStream();
int bpc;
if (bi.getTransparency() == Transparency.BITMASK)
{
bpc = 1;
MemoryCacheImageOutputStream mcios = new MemoryCacheImageOutputStream(bos);
for (int y = 0, h = bi.getHeight(); y < h; ++y)
{
for (int x = 0, w = bi.getWidth(); x < w; ++x)
{
int alpha = bi.getRGB(x, y) >>> 24;
mcios.writeBit(alpha);
}
while (mcios.getBitOffset() != 0)
{
mcios.writeBit(0);
}
}
mcios.flush();
mcios.close();
}
else
{
bpc = 8;
for (int y = 0, h = bi.getHeight(); y < h; ++y)
{
for (int x = 0, w = bi.getWidth(); x < w; ++x)
{
int alpha = bi.getRGB(x, y) >>> 24;
bos.write(alpha);
}
}
}
PDImageXObject pdImage = prepareImageXObject(document, bos.toByteArray(),
bi.getWidth(), bi.getHeight(), bpc, PDDeviceGray.INSTANCE);
return pdImage;
}
/**
* Create a PDImageXObject while making a decision whether not to
* compress, use Flate filter only, or Flate and LZW filters.
*
* @param document The document.
* @param byteArray array with data.
* @param width the image width
* @param height the image height
* @param bitsPerComponent the bits per component
* @param initColorSpace the color space
* @return the newly created PDImageXObject with the data compressed.
* @throws IOException
*/
private static PDImageXObject prepareImageXObject(PDDocument document,
byte [] byteArray, int width, int height, int bitsPerComponent,
PDColorSpace initColorSpace) throws IOException
{
ByteArrayOutputStream baos = new ByteArrayOutputStream();
Filter filter = FilterFactory.INSTANCE.getFilter(COSName.FLATE_DECODE);
filter.encode(new ByteArrayInputStream(byteArray), baos, new COSDictionary(), 0);
ByteArrayInputStream encodedByteStream = new ByteArrayInputStream(baos.toByteArray());
return new PDImageXObject(document, encodedByteStream, COSName.FLATE_DECODE,
width, height, bitsPerComponent, initColorSpace);
}
}