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<TITLE>compress - Image Compression/Decompression Coders</TITLE>
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<!-- INDEX BEGIN -->
<UL>
<LI><A HREF="#NAME">NAME</A>
<LI><A HREF="#SYNOPSIS">SYNOPSIS</A>
<LI><A HREF="#FUNCTION_DESCRIPTIONS">FUNCTION DESCRIPTIONS</A>
<UL>
<LI><A HREF="#ASCII85Encode">ASCII85Encode</A>
<LI><A HREF="#HuffmanDecodeImage">HuffmanDecodeImage</A>
<LI><A HREF="#HuffmanEncodeImage">HuffmanEncodeImage</A>
<LI><A HREF="#Huffman2DEncodeImage">Huffman2DEncodeImage</A>
<LI><A HREF="#LZWEncodeImage">LZWEncodeImage</A>
<LI><A HREF="#PackbitsEncodeImage">PackbitsEncodeImage</A>
<LI><A HREF="#RunlengthDecodeImage">RunlengthDecodeImage</A>
<LI><A HREF="#RunlengthEncodeImage">RunlengthEncodeImage</A>
<LI><A HREF="#SetRunlengthEncoder">SetRunlengthEncoder</A>
<LI><A HREF="#SetRunlengthPackets">SetRunlengthPackets</A>
<LI><A HREF="#ZLIBEncodeImage">ZLIBEncodeImage</A>
</UL>
</UL>
<!-- INDEX END -->
<HR>
<P>
<H1><A NAME="NAME">NAME</A></H1>
<P>
compress - Image Compression/Decompression Coders
<P>
<HR>
<H1><A NAME="SYNOPSIS">SYNOPSIS</A></H1>
<P>
unsigned int <STRONG>Huffman2DEncodeImage</STRONG>(ImageInfo*image_info,Image*image)
<P>
unsigned int <STRONG>HuffmanDecodeImage</STRONG>(Image*image)
<P>
unsigned int <STRONG>HuffmanEncodeImage</STRONG>(constImageInfo*image_info,Image*image)
<P>
unsigned int <STRONG>RunlengthDecodeImage</STRONG>(Image*image)
<P>
unsigned int <STRONG>RunlengthEncodeImage</STRONG>(Image*image)
<P>
<PRE> B<SetRunlengthEncoder>(packet)
</PRE>
<P>
<PRE> B<SetRunlengthPackets>(image,packets)
</PRE>
<P>
<HR>
<H1><A NAME="FUNCTION_DESCRIPTIONS">FUNCTION DESCRIPTIONS</A></H1>
<P>
<HR>
<H2><A NAME="ASCII85Encode">ASCII85Encode</A></H2>
<P>
Method ASCII85Encode encodes data in
<FONT SIZE=-1>ASCII</FONT> base-85 format.
<FONT SIZE=-1>ASCII</FONT> base-85 encoding produces five
<FONT SIZE=-1>ASCII</FONT> printing characters from every four bytes of binary data.
<P>
The format of the ASCII85Encode method is:
<P>
<PRE> void Ascii85Initialize(void)
</PRE>
<P>
<FONT SIZE=-1>A</FONT> description of each parameter follows:
<DL><DL>
<DT><STRONG><A NAME="item_o">code:</A></STRONG><DD>
<P>
a binary unsigned char to encode to
<FONT SIZE=-1>ASCII</FONT> 85.
<DT><STRONG>file:</STRONG><DD>
<P>
write the encoded
<FONT SIZE=-1>ASCII</FONT> character to this file.
</DL></DL>
<P>
<HR>
<H2><A NAME="HuffmanDecodeImage">HuffmanDecodeImage</A></H2>
<P>
Method HuffmanDecodeImage uncompresses an image via Huffman-coding.
<P>
The format of the HuffmanDecodeImage method is:
<blockquote>unsigned int HuffmanDecodeImage (<A HREF="types/Image.html">Image</A> *image) </blockquote>
<P>
<FONT SIZE=-1>A</FONT> description of each parameter follows:
<DL><DL>
<DT><STRONG>status:</STRONG><DD>
<P>
Method HuffmanDecodeImage returns True if all the pixels are compressed
without error, otherwise False.
<DT><STRONG>image:</STRONG><DD>
<P>
The address of a structure of type Image.
</DL></DL>
<P>
<HR>
<H2><A NAME="HuffmanEncodeImage">HuffmanEncodeImage</A></H2>
<P>
Method HuffmanEncodeImage compresses an image via Huffman-coding.
<P>
The format of the HuffmanEncodeImage method is:
<blockquote>unsigned int HuffmanEncodeImage (const <A HREF="types/ImageInfo.html">ImageInfo</A> *image_info, <A HREF="types/Image.html">Image</A> *image) </blockquote>
<P>
<FONT SIZE=-1>A</FONT> description of each parameter follows:
<DL><DL>
<DT><STRONG>status:</STRONG><DD>
<P>
Method HuffmanEncodeImage returns True if all the pixels are compressed
without error, otherwise False.
<DT><STRONG>image_info:</STRONG><DD>
<P>
Specifies a pointer to an ImageInfo structure.
<DT><STRONG>image:</STRONG><DD>
<P>
The address of a structure of type Image.
</DL></DL>
<P>
<HR>
<H2><A NAME="Huffman2DEncodeImage">Huffman2DEncodeImage</A></H2>
<P>
Method Huffman2DEncodeImage compresses an image via two-dimensional
Huffman-coding.
<P>
The format of the Huffman2DEncodeImage method is:
<blockquote>unsigned int Huffman2DEncodeImage (<A HREF="types/ImageInfo.html">ImageInfo</A> *image_info, <A HREF="types/Image.html">Image</A> *image) </blockquote>
<P>
<FONT SIZE=-1>A</FONT> description of each parameter follows:
<DL><DL>
<DT><STRONG>status:</STRONG><DD>
<P>
Method Huffman2DEncodeImage returns True if all the pixels are compressed
without error, otherwise False.
<DT><STRONG>image_info:</STRONG><DD>
<P>
Specifies a pointer to an ImageInfo structure.
<DT><STRONG>image:</STRONG><DD>
<P>
The address of a structure of type Image.
</DL></DL>
<P>
<HR>
<H2><A NAME="LZWEncodeImage">LZWEncodeImage</A></H2>
<P>
Method LZWEncodeImage compresses an image via LZW-coding specific to Postscript Level
<FONT SIZE=-1>II</FONT> or Portable Document Format. To ensure portability, the binary
<FONT SIZE=-1>LZW</FONT> bytes are encoded as
<FONT SIZE=-1>ASCII</FONT> base-85.
<P>
The format of the LZWEncodeImage method is:
<P>
<PRE> unsigned int LZWEncodeImage(Image *image,
const unsigned int number_pixels,unsigned char *pixels)
</PRE>
<P>
<FONT SIZE=-1>A</FONT> description of each parameter follows:
<DL><DL>
<DT><STRONG>status:</STRONG><DD>
<P>
Method LZWEncodeImage returns True if all the pixels are compressed without
error, otherwise False.
<DT><STRONG>image:</STRONG><DD>
<P>
The address of a structure of type Image.
<DT><STRONG>number_pixels:</STRONG><DD>
<P>
An unsigned interger that specifies the number of pixels to compress.
<DT><STRONG>pixels:</STRONG><DD>
<P>
The address of an unsigned array of characters containing the pixels to
compress.
</DL></DL>
<P>
<HR>
<H2><A NAME="PackbitsEncodeImage">PackbitsEncodeImage</A></H2>
<P>
Method PackbitsEncodeImage compresses an image via Macintosh Packbits encoding specific to Postscript Level
<FONT SIZE=-1>II</FONT> or Portable Document Format. To ensure portability, the binary Packbits bytes are encoded as
<FONT SIZE=-1>ASCII</FONT> Base-85.
<P>
The format of the PackbitsEncodeImage method is:
<P>
<PRE> unsigned int PackbitsEncodeImage(Image *image,
const unsigned int number_pixels,unsigned char *pixels)
</PRE>
<P>
<FONT SIZE=-1>A</FONT> description of each parameter follows:
<DL><DL>
<DT><STRONG>status:</STRONG><DD>
<P>
Method PackbitsEncodeImage returns True if all the pixels are compressed
without error, otherwise False.
<DT><STRONG>image:</STRONG><DD>
<P>
The address of a structure of type Image.
<DT><STRONG>number_pixels:</STRONG><DD>
<P>
An unsigned integer that specifies the number of pixels to compress.
<DT><STRONG>pixels:</STRONG><DD>
<P>
The address of an unsigned array of characters containing the pixels to
compress.
</DL></DL>
<P>
<HR>
<H2><A NAME="RunlengthDecodeImage">RunlengthDecodeImage</A></H2>
<P>
Method RunlengthDecodeImage unpacks the packed image pixels into
runlength-encoded pixel packets. The packed image pixel memory is then
freed.
<P>
The format of the RunlengthDecodeImage method is:
<blockquote>unsigned int RunlengthDecodeImage (<A HREF="types/Image.html">Image</A> *image) </blockquote>
<P>
<FONT SIZE=-1>A</FONT> description of each parameter follows:
<DL><DL>
<DT><STRONG>status:</STRONG><DD>
<P>
Method RunlengthDecodeImage return True if the image is decoded. False is
returned if there is an error occurs.
<DT><STRONG>image:</STRONG><DD>
<P>
The address of a structure of type Image.
</DL></DL>
<P>
<HR>
<H2><A NAME="RunlengthEncodeImage">RunlengthEncodeImage</A></H2>
<P>
Method RunlengthEncodeImage packs the runlength-encoded pixel packets into
the minimum number of bytes.
<P>
The format of the RunlengthEncodeImage method is:
<blockquote>unsigned int RunlengthEncodeImage (<A HREF="types/Image.html">Image</A> *image) </blockquote>
<P>
<FONT SIZE=-1>A</FONT> description of each parameter follows:
<DL><DL>
<DT><STRONG>status:</STRONG><DD>
<P>
Method RunlengthEncodeImage return the number of bytes the image consumes.
Zero is returned if an error occurs.
<DT><STRONG>image:</STRONG><DD>
<P>
The address of a structure of type Image.
</DL></DL>
<P>
<HR>
<H2><A NAME="SetRunlengthEncoder">SetRunlengthEncoder</A></H2>
<P>
Method SetRunlengthEncoder initializes the runlength encoder.
<P>
The format of the SetRunlengthEncoder function is:
<blockquote>SetRunlengthEncoder (packet) </blockquote>
<P>
<FONT SIZE=-1>A</FONT> description of each parameter follows:
<DL><DL>
<DT><STRONG>packet:</STRONG><DD>
<P>
Specifies a RunlengthPacket type.
</DL></DL>
<P>
<HR>
<H2><A NAME="SetRunlengthPackets">SetRunlengthPackets</A></H2>
<P>
Method SetRunlengthPackets initializes the runlength encoder.
<P>
The format of the SetRunlengthPackets function is:
<blockquote>SetRunlengthPackets (image, packets) </blockquote>
<P>
<FONT SIZE=-1>A</FONT> description of each parameter follows:
<DL><DL>
<DT><STRONG>image:</STRONG><DD>
<P>
The address of a structure of type Image.
<DT><STRONG>packets:</STRONG><DD>
<P>
The number of runlength packets.
</DL></DL>
<P>
<HR>
<H2><A NAME="ZLIBEncodeImage">ZLIBEncodeImage</A></H2>
<P>
Method ZLIBEncodeImage compresses an image via ZLIB-coding specific to Postscript Level
<FONT SIZE=-1>II</FONT> or Portable Document Format. To ensure portability, the binary
<FONT SIZE=-1>ZLIB</FONT> bytes are encoded as
<FONT SIZE=-1>ASCII</FONT> base-85.
<P>
The format of the ZLIBEncodeImage method is:
<P>
<PRE> unsigned int ZLIBEncodeImage(Image *image,
const unsigned long number_pixels,const unsigned int quality,
unsigned char *pixels)
</PRE>
<P>
<FONT SIZE=-1>A</FONT> description of each parameter follows:
<DL><DL>
<DT><STRONG>status:</STRONG><DD>
<P>
Method ZLIBEncodeImage returns True if all the pixels are compressed
without error, otherwise False.
<DT><STRONG>file:</STRONG><DD>
<P>
The address of a structure of type
<FONT SIZE=-1>FILE.</FONT>
<FONT SIZE=-1>ZLIB</FONT> encoded pixels are written to this file.
<DT><STRONG>number_pixels:</STRONG><DD>
<P>
An unsigned integer that specifies the number of pixels to compress.
<DT><STRONG>quality:</STRONG><DD>
<P>
the compression level (0-100).
<DT><STRONG>pixels:</STRONG><DD>
<P>
The address of an unsigned array of characters containing the pixels to
compress.
</DL></DL>
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