NAME
     GxYat - Yet Another GrADS Metafile Translator

SYNOPSIS
     gxyat [OPTIONS] metafile_name[.gx]

DESCRIPTION
     GxYat is a GrADS metafile translator based on the Cairo Vector
     Graphics library. On input, the file extension is assumed to be '.gm',
     if omitted. One can use '-' to indicate that the metafile is
     coming from standard input. The output format is determined from
     the output file name extension; the default is PNG.

     GxYat is capable of producing PNG, Postscript, PDF and Scalable
     Vector Graphics (SVG) output. When producing PNG images, the translator
     uses antialiasing for rendering line drawing but not for polygon fills,
     resulting in nicer fonts, but no artificial horizontal lines in the 
     shaded contours. 

     The input metafile may contain more than one frame; multipage PS and
     PDF output will result in such cases. However, PNG and SVG output
     require one image per file. By using %d or other printf variant
     format such as %02d in the output file name it is possible to have
     the resulting files numbered in sequence. See EXAMPLES below.

     The GxYat output can be displayed by a variety of viewers. On Linux, 
     I particularly like evince, a document viewer that is capable of 
     displaying all the formats produced by GxYat: be sure to check out
     its presentation mode.  Firefox 2 has native support for PNG and SVG;
     Acrobad Reader, as well as Ghostscript and frontends can read the PS/
     PDF output. The ImageMagick utilities can handle all GxYat output
     formats except for SVG which it does not render properly. On Linux, 
     the Inkscape SVG Vector Illustrator is a nice SVG editor for annotating
     GrADS plots (since it is SVG, the output is scalable). Adobe 
     Illustrator also has native suppoprt for SVG.

OPTIONS
     +a           turns anti-aliasing OFF (default is ON)
     -h           prints this manual page
     -i fname     input file name; '-' means standard input;   
     -o fname     output file name; the file name extension determines
                  the desired format:
                     png     Portable Network Graphics        
                     ps      Postscript
                     pdf     Portable Document Format (PDF)
                     svg     Scalable Vector Graphics
                  Both PS and PDF allow multiple pages per file; PNG and
                  SVG require one image per file; in such cases, specify %d
                  in the file name for the image number in the sequence 
                  - see EXAMPLES below.
                  Default:  same base name as input file, 'png' extension
     -r           Black background (default is white)
     -v           Verbose.
     -x m         For images, the number of horizontal pixels (default=800);
                  For PS/PDF output, the horizontal size of the images 
                  in points (1 point = 1/72 inches); default is 792 points
                  (11 inches)
     -y n         For images, the number of vertical pixels (default=600);
                  For PS/PDF output, the horizontal size of the images 
                  in points (1 point = 1/72 inches); default is 612 points
                  (8.5 inches)

EXAMPLES
     1) Producing a PNG image file with the default 800x600 size:
        $ gxyat model.gx
     2) Producing a PDF file with the default 792x612 size (11x8.5 inches):
        $ gxyat -o model.pdf model.gx
     3) Producing a PNG image file of size 1024x758 with a black
        background:
        $ gxyat -x 1024 -y 758 -r model.gx 
     4) Producing a SVG file to be rendered with size 1600x1200:
        $ gxyat -o model.svg -x 1600 -y 1200 model.gx
     5) Producing multiple image files from a metafile with multiple frames:
        $ gxyat -o frame-%d.png frames.gx
        $ gxyat -o frame-%02d.svg frames.gx
     6) The following DOES NOT work:
        $ gxyat -o frame-%d.ps  frames.gx
        $ gxyat -o frame-%d.pdf frames.gx

BUGS
     Only PNG images do not have artificial horizontal lines in shaded
     contours; the other formats still do, at least when rendered to the
     screen with antialising on. This is a feature of the Cairo Vector
     Graphics Library and/or the particular viewers. Since the SVG standard
     makes provision for selective antialiasing during rendering, it is 
     possible that Cairo will support this feature at some point.
     The PS output still needs some tuning; the bounding box seem to be
     correct, though.

TO DO
     Allow for compressed SVG and PS output through zlib.
     Allow for output to STDOUT and/or to pipes.
     Allow for images to be rendered directly on the screen.

VERSION
     GxYat Version 1.0.0 built with Cairo Version 1.4.2

AUTHOR
     Arlindo da Silva <dasilva@alum.mit.edu> based on gxpng
     by Matthias Muennich. 

COPYRIGHT
     Copyright (c) 2007 Arlindo da Silva
     This is free software released under the GNU General Public
     License; see the source for copying conditions.
     There is NO  warranty;  not even for MERCHANTABILITY or FITNESS 
     FOR A PARTICULAR PURPOSE.

SEE ALSO
     Other GrADS metafile translators: gxeps, gxps, gxtran, gxpng, gximg
     GrADS Home Page: http://grads.iges.org/grads 
     Cairo Vector Graphics Library: http://cairographics.org/