d44

DjVu IW44 wavelet decoder.
Synopsis
        d44 [-verbose] [-chunks n] iw44file [pnmfile]
    

Description --- File "d44.cpp" illustrates the use of classes IWBitmap and IWPixmap for decompressing a color image or a gray level encoded using DjVu IW44 wavelets. Such files are typically created using program c44.

Arguments --- Argument containing IW44 encoded data. These files usually have suffix ".djvu", ".djv", ".iw44" or ".iw4". The output file will be a PPM file for a color image or a PGM file for a gray level image. These formats can be converted into other file formats using the NetPBM package (http://www.arc.umn.edu/GVL/Software/netpbm.html) or the ImageMagick package (http://www.wizards.dupont.com/cristy). Argument pnmfile is the name of the output file. A single dash "-" can be used to represent the standard output. If this argument is omitted, a filename is generated by replacing the suffix of ".ppm".

Options --- The following options are recognized.

-chunks n
Decodes only the first n chunks of the file. This option allows you to render the successive images displayed while downloading this IW44 file into a web browser.
-verbose
Prints a message describing the decompression times and the memory requirements. Decompression is a two stage process. The IW44 data is first decoded and the wavelet coefficients are stored into a memory efficient data structure. This data structure is then used to render the final image.
    % d44 -v lag.djvu - | xv -
    image: color 510 x 684
    times: 421ms (decoding) + 340ms (rendering)
    memory: 678kB (24% active coefficients)
    

Author:
Léon Bottou <leonb@research.att.com>
Version:
$Id: d44.html,v 1.12 2001/02/15 01:12:21 bcr Exp $

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