NAME

       ppmtoacad - convert PPM to Autocad database or slide

SYNOPSIS

       ppmtoacad

       [-dxb]

       [-poly]

       [-background color]

       [-white]

       [-aspect ratio]

       [-8]

       [ppmfile]

DESCRIPTION

       This program is part of Netpbm(1).

       ppmtoacad reads a PPM image as input and produces an Autocad® slide file or binary database import (.dxb)
       file as output.  If you don't specify ppmfile, ppmtoacad takes the input from Standard Input.

       (Typographical  note:  the  name  of  Autocad  is  often  rendered as AutoCAD.  Netpbm documentation uses
       standard American typography, wherein that is not a valid form of capitalization).

OPTIONS

       In addition to the options common to all programs based on libnetpbm (most notably  -quiet,  see   Common
       Options ), ppmtoacad recognizes the following command line options:

       You may abbreviate any option to its shortest unique prefix.

       -dxb   ppmtoacad writes an Autocad binary database import (.dxb) file.  You read this file with the DXBIN
              command and, once loaded, it becomes part of the Autocad geometrical database, so you can view and
              edit it like any other object.  Each sequence of identical pixels becomes a separate object in the
              database; this can result in very large Autocad drawing files.  However, if you want to trace over
              a bitmap, it lets you zoom and pan around the bitmap as you wish.

       -poly  If  you  don't  specify the -dxb option, ppmtoacad generates an Autocad slide file.  Normally each
              row of pixels is represented by an Autocad line entity.  If you specify -poly,  ppmtoacad  renders
              the pixels as filled polygons.  If you view the slide on a display with higher resolution than the
              source  image, this will cause the pixels to expand instead of appearing as discrete lines against
              the screen background color.  Regrettably, this representation yields  slide  files  which  occupy
              more storage space and take longer to display.

       -background color
              Most  Autocad  display  drivers  can  be  configured  to  use  any  available  color as the screen
              background.  Some users prefer a black screen background,  others  white,  while  splinter  groups
              advocate  burnt  ocher,  tawny  puce,  and shocking gray.  Discarding pixels whose closest Autocad
              color representation is equal to the background color can substantially reduce  the  size  of  the
              Autocad  database  or  slide file needed to represent a bitmap.  If you don't specify -background,
              ppmtoacad assumes the screen background color to be black.  You  may  specify  any  Autocad  color
              number  as  the  screen background; ppmtoacad assumes color numbers to specify the hues defined in
              the standard Autocad 256 color palette.

       -white Since many Autocad users choose a white screen background, this option is provided as a short-cut.
              Specifying -white is identical in effect to -background 7.

       -aspect ratio
              If the source image had non-square pixels (which means it is not standard PPM), specify the  ratio
              of  the  pixel width to pixel height as ratio.  ppmtoacad will correct the resulting slide or .dxb
              file so that pixels on the Autocad screen will be square.  For example, to correct an  image  made
              for a 320x200 VGA/MCGA screen, specify -aspect 0.8333.

       -8     Restricts the colors in the output file to the 8 RGB shades.

RESTRICTIONS

       Autocad has a fixed palette of 256 colors, distributed along the hue, lightness, and saturation axes.  So
       it  may  poorly  render  images  which  contain  many  nearly-identical  colors,  or  colors  not closely
       approximated by Autocad's palette.

       ppmtoacad works best if the system displaying its output can display the full 256 color Autocad  palette.
       Monochrome, 8 color, and 16 color configurations will produce less than optimal results.

       When  creating  a  .dxb  file  or  a  slide file with the -poly option, ppmtoacad finds both vertical and
       horizontal runs of identical pixels and consolidates them into rectangular regions to reduce the size  of
       the  output file.  This is effective for images with large areas of constant color but it's no substitute
       for true raster to vector conversion.  In particular, this process does not optimize thin diagonal  lines
       at all.

       Output files can be huge.

SEE ALSO

       Autocad Reference Manual: Slide File Format and Binary Drawing Interchange (DXB) Files, ppm(1)

AUTHOR

       John Walker
       Autodesk SA
       Avenue des Champs-Montants 14b
       CH-2074 MARIN
       Suisse/Schweiz/Svizzera/Svizra/Switzerland
           Usenet:kelvin@Autodesk.com
           Fax:038/33 88 15
           Voice:038/33 76 33

       Permission  to  use, copy, modify, and distribute this software and its documentation for any purpose and
       without fee is hereby granted, without any conditions or restrictions.  This software is provided "as is"
       without express or implied warranty.

       Autocad and Autodesk are registered trademarks of Autodesk, Inc.

DOCUMENT SOURCE

       This manual page was generated by the Netpbm tool 'makeman' from HTML source.  The  master  documentation
       is at

              http://netpbm.sourceforge.net/doc/ppmtoacad.html

netpbm documentation                             10 October 1991                        Ppmtoacad User Manual(1)