We'll look at the compression engine itself shortly, but PNG's performance is not due solely to an improved compression algorithm. PNG also supports a precompression step called filtering.

PNG compression method 0 (the only compression method presently defined for PNG) specifies deflate/inflate compression with a sliding window of at most 32768 bytes.

PNG compression method 0 (the only compression method presently defined for PNG) specifies deflate/inflate compression with a 32K sliding window. Deflate compression is an LZ77 derivative …

Since PNG’s compression filters are not only critical to its efficiency but also one of its more unusual features, we spend some time describing how they work, including several examples.

Compression method is a single-byte integer that indicates the method used to compress the image data. At present, only compression method 0 (deflate/inflate compression with a sliding window of at …

This chapter describes the filter algorithms that can be applied before compression. The purpose of these filters is to prepare the image data for optimum compression.

I'll discuss the details of compression, particularly the lossless variety, at greater length in Chapter 9, "Compression and Filtering". Finally, in describing the advantages of PNG, I will necessarily compare …