Manual: 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 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  poly‐
	      gons.   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 ef‐
       fective 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	 im‐
       plied 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)