man > ppmtoacad

Ppmtoacad User Manual(1)               General Commands Manual              Ppmtoacad User Manual(1)

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 identi‐
              cal  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.  Nor‐
              mally  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  pix‐
              els  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  repre‐
              sent  a  bitmap.  If you don't specify -background, ppmtoacad assumes the screen back‐
              ground 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 stan‐
              dard 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), spec‐
              ify 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 satura‐
       tion 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 Auto‐
       cad 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 verti‐
       cal 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  con‐
       stant 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 AT 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)