public PDPixelMap(PDStream pdStream) 
{
        super(pdStream, "png");
}

Standard constructor. Basically does nothing.

Parameters:

pdStream - The stream that holds the pixel map.

 public COSDictionary getDecodeParams() 
{
        COSBase decodeParms = getCOSStream().getDictionaryObject("DecodeParms");
        if (decodeParms != null)
        {
            if (decodeParms instanceof COSDictionary)
            {
                return (COSDictionary) decodeParms;
            }
            else if (decodeParms instanceof COSArray)
            {
                // not implemented yet, which index should we use?
                return null;//(COSDictionary)((COSArray)decodeParms).get(0);
            }
            else
            {
                return null;
            }
        }
        return null;
}

DecodeParms is an optional parameter for filters. It is provided if any of the filters has nondefault parameters. If there is only one filter it is a dictionary, if there are multiple filters it is an array with an entry for each filter. An array entry can hold a null value if only the default values are used or a dictionary with parameters.

 public int getPredictor() 
{
        COSDictionary decodeParms = getDecodeParams();
        if (decodeParms != null)
        {
            int i = decodeParms.getInt("Predictor");
            if (i != -1)
            {
                return i;
            }
        }
        return 1;
}

A code that selects the predictor algorithm.
• 1 No prediction (the default value)
• 2 TIFF Predictor 2
• 10 PNG prediction (on encoding, PNG None on all rows)
• 11 PNG prediction (on encoding, PNG Sub on all rows)
• 12 PNG prediction (on encoding, PNG Up on all rows)
• 13 PNG prediction (on encoding, PNG Average on all rows)
• 14 PNG prediction (on encoding, PNG Paeth on all rows)
• 15 PNG prediction (on encoding, PNG optimum)
Default value: 1.

 public BufferedImage getRGBImage() throws IOException 
{
        if( image != null )
        {
            return image;
        }
        try
        {
            int width = getWidth();
            int height = getHeight();
            int bpc = getBitsPerComponent();
            int predictor = getPredictor();
            List filters = getPDStream().getFilters();
            ColorModel cm;
            byte[] array = getPDStream().getByteArray();
            // Get the ColorModel right
            PDColorSpace colorspace = getColorSpace();
            if (colorspace == null)
            {
                log.error("getColorSpace() returned NULL.  Predictor = " + getPredictor());
                return null;
            }
            if (bpc == 1)
            {
                byte[] map = new byte[] {(byte)0x00, (byte)0xff};
                cm = new IndexColorModel(1, 2, map, map, map, 1);
            }
            else
            {
                cm = colorspace.createColorModel( bpc );
            }
            log.info("ColorModel: " + cm.toString());
            WritableRaster raster = cm.createCompatibleWritableRaster( width, height );
            DataBufferByte buffer = (DataBufferByte)raster.getDataBuffer();
            byte[] bufferData = buffer.getData();
            /**
             * PDF Spec 1.6 3.3.3 LZW and Flate predictor function
             *
             * Basically if predictor  > 10 and LZW or Flate is being used then the
             * predictor is not used.
             *
             * "For LZWDecode and FlateDecode, a Predictor value greater than or equal to 10
             * merely indicates that a PNG predictor is in use; the specific predictor function
             * used is explicitly encoded in the incoming data. The value of Predictor supplied
             * by the decoding filter need not match the value used when the data was encoded
             * if they are both greater than or equal to 10."
             */
            if( predictor <  10 ||
                filters == null || !(filters.contains( COSName.LZW_DECODE.getName()) ||
                         filters.contains( COSName.FLATE_DECODE.getName()) ) )
            {
                PredictorAlgorithm filter = PredictorAlgorithm.getFilter(predictor);
                filter.setWidth(width);
                filter.setHeight(height);
                filter.setBpp((bpc * 3) / 8);
                filter.decode(array, bufferData);
            }
            else
            {
                System.arraycopy( array, 0,bufferData, 0, 
                        (array.length< bufferData.length?array.length: bufferData.length) );
            }
            image = new BufferedImage(cm, raster, false, null);
            return image;
        } 
        catch (Exception exception)
        {
            log.error(exception, exception);
            //A NULL return is caught in pagedrawer.Invoke.process() so don't re-throw.
            //Returning the NULL falls through to Phlip Koch's TODO section.
            return null;
        }
}

Returns a java.awt.image.BufferedImage of the COSStream set in the constructor or null if the COSStream could not be encoded.

 public  void write2OutputStream(OutputStream out) throws IOException 
{
        getRGBImage();
        if (image!=null)
        {
            ImageIO.write(image, "png", out);
        }
}

Writes the image as .png. {@inheritDoc}