Conference auss::decfax_vms

959.0. "Some notes on Conversions" by AUSS::GARSON (DECcharity Program Office) Tue Apr 15 1997 13:07

For the sake of simplicity it will be assumed that DECfax Mail V1.2 is
installed and that it is configured to "convert all outgoing messages to image
within the converter".

All CDA conversions use the DECfax Mail CDA options file, DFX$COM:
DFX$CONVERT.CDA$OPTIONS.

Except where noted all temporary files go into DFX$WORK and are named
TMPxxxxxxxxxxxxxxxx.* where x...x is used to guarantee uniqueness.

Each bodypart is converted separately but the final output image is
appended into DFX$OUT:MSGnnnnnnn.DDIF which is created initially as a temporary
file in DFX$OUT and renamed to its final name when complete.

Before converting any PostScript file with HostPS it is standardized. This
involves appending DFX$LLV:DFX$PROLOGUE.PS, removing the first character if it
is a CTRL/D and removing the last character if it is a CTRL/D. (This is mostly
necessary for non-standard PostScript files produced on PCs but the prologue
file is a useful hook anyway e.g. for emboldening the Digital supplied Courier
font.)


Data type TEXT
==============

Use CDA to convert from TEXT to PostScript. The style file is CDA$LIBRARY:
DEFSTYLE.DDIF if the longest line does not exceed 80 characters and
DFX$LLV:DEFSTYLE.DDIF otherwise.

Use HostPS to convert from PostScript to an image.


Data type WPSMAIL
=================

{A WPSMAIL file results from sending a WPS-PLUS document via Message Router
i.e. the sender converts the WPS-PLUS document to WPSMAIL before encoding it
for sending via Message Router and the receiver (DECfax Mail) is expected to
convert it back to WPS-PLUS.}

Convert WPSMAIL back to WPS-PLUS (not a CDA conversion, non-standard temporary
file naming) and then convert as for WPS-PLUS.


Data type WPS-PLUS
==================

Use CDA to convert from WPS-PLUS to PostScript, then HostPS to convert to an
image. The CDA options file identifies the style file,
DFX$LLV:DFX$DX_COUR.DOC_STYLE by default.


User Defined Data type
======================

Generally speaking a user defined data type will be converted to PostScript by
the user supplied or user customised converter and then converted as for
PostScript. Details of the conversion are obviously controlled by the provider
of the customised converter.


Data type PostScript
====================

HostPS is used to convert from PostScript to an image.


Coverpage
=========

An included PostScript file is converted to an image using HostPS. The
resulting image is "cropped" using the %%BoundingBox specified in the
PostScript file.

Text after tag substitution is converted to an image using DFX$FONT_FILE (not
CDA).

An included DDIF file (which must be bitonal) is included directly in the
resulting image.