Package com.itextpdf.kernel.pdf

Class ASCII85CompressionStrategy

java.lang.Object

com.itextpdf.kernel.pdf.ASCII85CompressionStrategy

All Implemented Interfaces:

IStreamCompressionStrategy

       public class ASCII85CompressionStrategy extends Object implements IStreamCompressionStrategy
      

A compression strategy that uses the ASCII85Decode filter for PDF streams.

This strategy implements the IStreamCompressionStrategy interface and provides ASCII85Decode encoding.

The strategy ensures, that streams are saved using just 7-bit ASCII characters, but it typically increases sizes of streams by 25% compared to just saving them as-is. So calling this a "compression strategy" is a misnomer.

Constructor Summary

Constructors

Constructor	Description
ASCII85CompressionStrategy()	Constructs a new ASCII85CompressionStrategy instance.

Method Summary

Modifier and Type	Method	Description
OutputStream	createNewOutputStream(OutputStream original, PdfStream stream)	Creates a new output stream with ASCII85 compression applied.
PdfObject	getDecodeParams()	Returns the decode parameters for the ASCII85Decode filter.
PdfName	getFilterName()	Returns the name of the compression filter.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

ASCII85CompressionStrategy

             public ASCII85CompressionStrategy()
            

Constructs a new ASCII85CompressionStrategy instance.

Method Details

getFilterName

             public PdfName getFilterName()
            

Returns the name of the compression filter.

Specified by:

getFilterName in interface IStreamCompressionStrategy

Returns:

PdfName.ASCII85Decode representing the ASCII85Decode filter

getDecodeParams

             public PdfObject getDecodeParams()
            

Returns the decode parameters for the ASCII85Decode filter.

This implementation returns null as no special decode parameters are required for standard ASCII85 compression.

Specified by:

getDecodeParams in interface IStreamCompressionStrategy

Returns:

null as no decode parameters are needed

createNewOutputStream

             public OutputStream createNewOutputStream
             (OutputStream original, PdfStream stream)
            

Creates a new output stream with ASCII85 compression applied.

This method wraps the original output stream in a ASCII85OutputStream that applies ASCII85 compression.

Specified by:

createNewOutputStream in interface IStreamCompressionStrategy

Parameters:

original - the original output stream to wrap

stream - the PDF stream containing compression configuration

Returns:

a new ASCII85OutputStream that compresses data using the ASCII85 algorithm