NAME

dvirle - convert dvi version 2 files, produced by TeX82, to RLE images

SYNOPSIS

dvirle [ -m number ] [ -h ] [ -s ] [ -d number ] [ -x xfilter ] [ -y yfilter ] infile.dvi

DESCRIPTION

Dvirle converts .dvi files produced by TeX(1) to RLE(5) format. The basic process involves two passes. In the first pass, the .dvi file is converted into a list of characters. The second pass takes this list and converts it to RLE. The image is filtered to produce gray-scale letters. 300dpi fonts are used, producing an unfiltered page size of approximately 2500×3500 pixels. The default is to average this by 5 pixels in the X direction and 5 in the Y, producing a 510×708 image. The filtering parameters can be altered with the -x and -y flags.

The -m number option is used to change the device magnification (which is in addition to any magnification defined in the TeX source file). Number should be replaced by an integer which is 1000 times the magnification you want. for example, -m 1315 would produce output magnified to 131.5% of true size. The default is no magnification (1000). Note, however, that a site will only support particular magnifications. If you get error messages indicating that fonts are missing when using this option, you probably have picked an unsupported magnification.

The -h flag, when supplied, causes the image to be converted "on its side" (rotated by 90 degrees).

Normally the first pass prints the page numbers from the .dvi file. The -s flag suppresses these.

The default maxdrift parameter is 2 pixels (1/100th of an inch); the -d option may be used to alter this. The maxdrift parameter determines just how much font spacing is allowed to influence character positioning. The default value 2 allows a small amount of variation within words without allowing any letters to become too far out of position.

The output file contains a number of separate RLE images concatenated, one for each page in the input. These can be separated with rlesplit(1). The output images have a single image channel and an identical "alpha" channel. For compositing with a colored background, it will be necessary to use rleswap(1) to expand it to 3 color channels.

The shell script topcrop will crop off the top 384 lines of the output image (assuming the default LaTeX page size and dvirle filtering parameters), making it suitable for viewing on a (384×512) frame buffer.

    topcrop <file.rle >cropfile.rle

A better solution is to use something like the following LaTeX macros to set the page size so that, with the default filter parameters, the output images will be 510×384.

\newcommand{\maxpage}{	%% Make page as large as possible
	\setlength{\topmargin}{0in}
	\setlength{\oddsidemargin}{0pt}
	\setlength{\evensidemargin}{0pt}
	\setlength{\marginparwidth}{0pt}
	\setlength{\marginparsep}{0pt}
	\setlength{\headheight}{0pt}
	\setlength{\headsep}{0pt}
	\setlength{\textwidth}{6.5in}}
\newcommand{\plainpage}{	%% Page with space for headers
	\pagestyle{plain}
	\setlength{\textheight}{4.0667in}
	\setlength{\footheight}{12pt}
	\setlength{\footskip}{24pt}
	\maxpage}
			
\newcommand{\headingspage}{	%% Page with headers
	\pagestyle{headings}
	\setlength{\textheight}{4.0667in}
	\setlength{\footheight}{12pt}
	\setlength{\footskip}{24pt}
	\maxpage}
\newcommand{\emptypage}{	%% Page with no headers
	\pagestyle{empty}
	\setlength{\textheight}{4.4in}
	\setlength{\footheight}{0pt}
	\setlength{\footskip}{0pt}
	\maxpage}

FILES

dvirle1 first pass
dvirle2 second pass

AUTHOR

The original (Versatec) version was written by Janet Incerpi of Brown University. Richard Furuta and Carl Binding of the University of Washington modified the programs for DVI version 2 files. Chris Torek of the University of Maryland rewrote both passes in order to make them run at reasonable speeds. Spencer W. Thomas of the University of Utah converted it to produce RLE images as output.

BUGS

The -h option doesn't work properly. Use rleflip(1) instead.

Truncates pages wider than 2550 pixels (8.5 inches).

Doesn't handle missing fonts gracefully.