Class RleWriter

Inheritance

System.Object

RleWriter

Namespace: PhotoshopFile

Syntax

public class RleWriter

Constructors

RleWriter(Stream)

Declaration

public RleWriter(Stream stream)

Parameters

Type	Name	Description
System.IO.Stream	stream

Methods

Write(Byte[], Int32, Int32)

Encodes byte data using PackBits RLE compression.

Declaration

public int Write(byte[] data, int offset, int count)

Parameters

Type	Name	Description
System.Byte[]	data	Raw data to be encoded.
System.Int32	offset	Offset at which to begin transferring data.
System.Int32	count	Number of bytes of data to transfer.

Returns

Type	Description
System.Int32	Number of compressed bytes written to the stream.

Remarks

There are multiple ways to encode two-byte runs:

1. Apple PackBits only encodes three-byte runs as repeats.
2. Adobe Photoshop encodes two-byte runs as repeats, unless preceded by literals.
3. TIFF PackBits recommends that two-byte runs be encoded as repeats, unless preceded and followed by literals.

This class adopts the Photoshop behavior, as it has slightly better compression efficiency than Apple PackBits, and is easier to implement than TIFF PackBits.