Package com.itextpdf.brotlicompressor

Class BrotliStreamCompressionStrategy

java.lang.Object
com.itextpdf.brotlicompressor.BrotliStreamCompressionStrategy
All Implemented Interfaces:
IStreamCompressionStrategy
public class BrotliStreamCompressionStrategy extends Object implements IStreamCompressionStrategy
Implementation of IStreamCompressionStrategy that uses Brotli compression algorithm.

Brotli is a modern compression algorithm that typically provides better compression ratios than traditional Flate/Deflate compression, especially for text-heavy content. This strategy can be registered with a PDF document to use Brotli compression for all stream objects.

The compression level from iText (0-9) is automatically mapped to Brotli's compression levels (0-11) for compatibility with existing iText compression settings.

Example usage: 

 PdfDocument pdfDoc = new PdfDocument(new PdfWriter(outputStream));
 pdfDoc.getDiContainer().register(IStreamCompressionStrategy.class,
                                   new BrotliStreamCompressionStrategy());
See Also:

  • Constructor Details

  • Method Details

    • getFilterName

      public PdfName getFilterName()
      Returns the PDF filter name for Brotli compression.

      The filter name /BrotliDecode is used in the PDF stream dictionary to indicate that the stream is compressed using Brotli compression.

      Specified by:
      getFilterName in interface IStreamCompressionStrategy
      Returns:
      PdfName.BrotliDecode representing the Brotli filter

    • getDecodeParams

      public PdfObject getDecodeParams()
      Returns the decode parameters for Brotli decompression.

      Brotli compression does not require additional decode parameters, so this method returns null.

      Specified by:
      getDecodeParams in interface IStreamCompressionStrategy
      Returns:
      null as no decode parameters are needed for Brotli

    • createNewOutputStream

      public OutputStream createNewOutputStream (OutputStream original, PdfStream stream)
      Creates a new Brotli output stream that wraps the original stream.

      This method creates a BrotliOutputStream configured with the compression level specified in the PDF stream. The compression level is automatically converted from iText's 0-9 scale to Brotli's 0-11 scale.

      Specified by:
      createNewOutputStream in interface IStreamCompressionStrategy
      Parameters:
      original - the original output stream to wrap
      stream - the PDF stream being compressed (used to get compression level)
      Returns:
      a new BrotliOutputStream that compresses data before writing to the original stream
      Throws:
      PdfException - if an I/O error occurs while creating the Brotli output stream

    • convertCompressionLevel

      protected int convertCompressionLevel (int compressionLevel)
      Converts iText compression levels (0-9) to Brotli compression levels (0-11).

      This method maps the compression level from iText's standard 0-9 range to Brotli's 0-11 range using linear interpolation. If the input level is out of range, it is set to the default level of 6.

      Mapping formula: brotliLevel = round(iTextLevel * (11.0 / 9.0))

      Parameters:
      compressionLevel - the iText compression level (0-9)
      Returns:
      the corresponding Brotli compression level (0-11)