ExPng.Chunks.Header (ExPng v0.2.0)
Stores the data collected from a PNG's header data chunk. This chunk enodes information about
- the image's width and height
- the bit_depth of encoded pixel data
- the color mode the image pixel data is stored in
- whether the image data has been interlaced using the Adam7 interlacing algorithm
- the filter method applied to the image. This is different than the
filter type used by each line of the image (see
ExPng.Image.Line), and the only current valid value for this field is
- the compression method applied to the image data. Like the filter
0is the only allowed value for this field. PNG uses the DEFLATE compression algorithm, and
ExPnguses Erlang's implementation of zlib.
The data contained in this struct is read from a PNG when decoding, and generated
automatically for an image when encoding, so
ExPng users should never have to
manipulate this data manually.