/* @see loci.formats.IFormatHandler#close() */
 public void close() throws IOException {
   if (out != null) {
     writeFooter();
   }
   super.close();
   numFrames = 0;
   numFramesPointer = 0;
   nextSequenceNumber = 0;
   littleEndian = false;
 }
  /* @see loci.formats.IFormatHandler#setId(String) */
  public void setId(String id) throws FormatException, IOException {
    super.setId(id);

    if (out.length() == 0) {
      MetadataRetrieve r = getMetadataRetrieve();
      int width = r.getPixelsSizeX(series).getValue().intValue();
      int height = r.getPixelsSizeY(series).getValue().intValue();
      int bytesPerPixel = FormatTools.getBytesPerPixel(r.getPixelsType(series).toString());
      int nChannels = getSamplesPerPixel();
      boolean indexed = getColorModel() != null && (getColorModel() instanceof IndexColorModel);
      littleEndian = !r.getPixelsBinDataBigEndian(series, 0);

      // write 8-byte PNG signature
      out.write(PNG_SIG);

      // write IHDR chunk

      out.writeInt(13);
      byte[] b = new byte[17];
      b[0] = 'I';
      b[1] = 'H';
      b[2] = 'D';
      b[3] = 'R';

      DataTools.unpackBytes(width, b, 4, 4, false);
      DataTools.unpackBytes(height, b, 8, 4, false);

      b[12] = (byte) (bytesPerPixel * 8);
      if (indexed) b[13] = (byte) 3;
      else if (nChannels == 1) b[13] = (byte) 0;
      else if (nChannels == 2) b[13] = (byte) 4;
      else if (nChannels == 3) b[13] = (byte) 2;
      else if (nChannels == 4) b[13] = (byte) 6;
      b[14] = (byte) 0;
      b[15] = (byte) 0;
      b[16] = (byte) 0;

      out.write(b);
      out.writeInt(crc(b));

      // write acTL chunk

      out.writeInt(8);
      out.writeBytes("acTL");
      numFramesPointer = out.getFilePointer();
      out.writeInt(0);
      out.writeInt(0);
      out.writeInt(0); // save a place for the CRC
    }
  }