DVGT351.README (BETA) - 18:18 GMT +10:00 Wed 25 August 1993. ------------------------------------------------------------ This is a brief overview of dvgt 3.51 beta. WHAT IS dvgt 3.5? ----------------- dvgt 3.5 (version 3 mod 5) is an enhancement (with permission) of Andrew Trevorrow's `dvitovdu', a public domain TeX dvi file previewer familiar to some Vax/VMS users. Specifically, dvgt is based on Andrew's unix version 3.0 of dvitovdu. dvitovdu was written in Modula-2. dvgt, however, is in ANSI C (but old-style C is used if the compiler does not define __STDC__); it has been massaged for Sun/OS on a Sun 4, Solaris 2.1 on a Sparc 10, and for AIX on an IBM Risc/6000. Like dvitovdu, dvgt has Terse, Box and Full preview modes. Terse mode uses the text mode of the VDU, and is insensitive to zoom. Box mode shows the bounding boxes of characters. Full mode gives a graphically rendered preview. On non-graphic terminals at low screen magnifications, Terse mode is the most useful, but as one zooms in, Box and Full modes become more and more accurate. dvgt issues a help page to new users, and 3.5 gives more information when it exits. dvgt 3.5 tries to open a log file, `dvgt.vlg', to catch messages that occur before option parsing is complete. If a DVI file named `document.dvi' is to be viewed, dvgt will soon try to open a second log file named `document.vlg'; if that fails, `dvgt.vlg' continues to be used. If `dvgt.vlg' cannot be opened, then no logfile is written. Version 3.5 allows the search of multiple directories when seeking TFM or PK fonts. Since both AIX and Sun/OS are forms of unix, alternative directories are separated by a colon `:' character. Much larger PK bitmaps can now be handled, as the former fixed-size bitmap data structure has been replaced by a call to malloc. A side-effect is that small bitmaps are automatically stored efficiently. dvgt now has an enlarged set of environment variables, all prefixed with "DV_". For example, DV_TERM can be set independently of the normal TERM variable. (A user of 3.4 requested that.) In version 3.5, many of the commands were altered. See the "help" file in the "help" directory for the specifics. A new command, control-L, refreshes the screen, though only after the whole command line has been parsed. This behavior is typical of dvgt commands, and was present in dvitovdu, perhaps for the benefit of slow connections. dvgt's font search strategy is now to seek a PK font first; in Full mode this gives a passably accurate representation of the text. If that fails, and the font has a `PostScript prefix' (as per the "-p" option), then the TFM is tried and outlines displayed (like Box mode); next try is the dummy PK font, then the correct TFM, then the dummy TFM. If all else fails, dvgt writes ascii text (as in Terse mode); this uses cmr encoding, so it's likely to misidentify characters from other fonts. Earlier versions of dvgt have been used in the USA for English text, and in Japan to display text using Japanese fonts. Osaka University was recently (April 93) porting it to a DECStation under Ultrix. The author uses dvgt to preview dvi files remotely, using NCSA Telnet or MS-Kermit. Communication protocols are complex - and in Telnet's case, incomplete - systems, and use of dvgt may require some experimentation to give good results for graphic preview. For NCSA Telnet, the "ncsatel" vdu driver appears to give satisfactory results, thanks to input from Vijay (vijay@ncst.ernet.in). WHAT IS dvgt 3.51? ------------------ Version 3.51 is revision 1 of 3.5, containing bug fixes for non-ANSI compilers, and for mixed systems containing an ANSI compiler and a non-ANSI library. There are now separate Makefiles for gcc and Sun's cc. The PK font environment variable TEXPKS, used by dvips, is now used; it takes precedence over the more common PKFONTS. A Bourne shell script, "sane", is provided, in case dvgt leaves the screen messed up. This may be modified, if and as required for the local installation. NOTE: strings are limited to eighty (80) characters; if paths, for example, are longer than this, then you may increase the value of the constant "maxstring" #defined in the file "src/globals.h". As the TODO now records, I wish to use dynamic strings for paths in a future release. Geoffrey Tobin