1Ppmtoacad User Manual(0)                              Ppmtoacad User Manual(0)
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NAME

6       ppmtoacad - convert PPM to Autocad database or slide
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SYNOPSIS

10       ppmtoacad
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12       [-dxb]
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14       [-poly]
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16       [-background color]
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18       [-white]
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20       [-aspect ratio]
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22       [-8]
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24       [ppmfile]
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DESCRIPTION

28       This program is part of Netpbm(1).
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30       ppmtoacad  reads  a  PPM  image as input and produces an Autocad® slide
31       file or binary database import (.dxb) file as  output.   If  you  don't
32       specify ppmfile, ppmtoacad takes the input from Standard Input.
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34       (Typographical  note: the name of Autocad is often rendered as AutoCAD.
35       Netpbm documentation uses standard American typography, wherein that is
36       not a valid form of capitalization).
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OPTIONS

40       In  addition  to  the options common to all programs based on libnetpbm
41       (most notably -quiet, see
42        Common Options ⟨index.html#commonoptions⟩ ), ppmtoacad recognizes  the
43       following command line options:
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45       You may abbreviate any option to its shortest unique prefix.
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49       -dxb   ppmtoacad  writes an Autocad binary database import (.dxb) file.
50              You read this file with the DXBIN command and, once  loaded,  it
51              becomes  part  of  the  Autocad geometrical database, so you can
52              view and edit it like any other object.  Each sequence of  iden‐
53              tical pixels becomes a separate object in the database; this can
54              result in very large Autocad drawing  files.   However,  if  you
55              want to trace over a bitmap, it lets you zoom and pan around the
56              bitmap as you wish.
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59       -poly  If you don't specify the -dxb option, ppmtoacad generates an Au‐
60              tocad slide file.  Normally each row of pixels is represented by
61              an Autocad line entity.  If you specify -poly, ppmtoacad renders
62              the  pixels as filled polygons.  If you view the slide on a dis‐
63              play with higher resolution than the  source  image,  this  will
64              cause  the  pixels  to  expand  instead of appearing as discrete
65              lines against the screen background  color.   Regrettably,  this
66              representation  yields  slide  files  which  occupy more storage
67              space and take longer to display.
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70       -background color
71              Most Autocad display drivers can be configured to use any avail‐
72              able  color as the screen background.  Some users prefer a black
73              screen background, others white, while splinter groups  advocate
74              burnt  ocher,  tawny puce, and shocking gray.  Discarding pixels
75              whose closest Autocad color representation is equal to the back‐
76              ground  color  can  substantially reduce the size of the Autocad
77              database or slide file needed to represent  a  bitmap.   If  you
78              don't  specify  -background,  ppmtoacad assumes the screen back‐
79              ground color to be black.  You may  specify  any  Autocad  color
80              number as the screen background; ppmtoacad assumes color numbers
81              to specify the hues defined in the standard  Autocad  256  color
82              palette.
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85       -white Since  many Autocad users choose a white screen background, this
86              option is provided as a short-cut.  Specifying -white is identi‐
87              cal in effect to -background 7.
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90       -aspect ratio
91              If the source image had non-square pixels (which means it is not
92              standard PPM), specify the ratio of the  pixel  width  to  pixel
93              height  as ratio.  ppmtoacad will correct the resulting slide or
94              .dxb file so that pixels on the Autocad screen will  be  square.
95              For  example,  to  correct  an image made for a 320x200 VGA/MCGA
96              screen, specify -aspect 0.8333.
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99       -8     Restricts the colors in the output file to the 8 RGB shades.
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RESTRICTIONS

104       Autocad has a fixed palette of 256 colors, distributed along  the  hue,
105       lightness,  and  saturation axes.  So it may poorly render images which
106       contain many nearly-identical colors, or colors  not  closely  approxi‐
107       mated by Autocad's palette.
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109       ppmtoacad  works  best  if the system displaying its output can display
110       the full 256 color Autocad palette.  Monochrome, 8 color, and 16  color
111       configurations will produce less than optimal results.
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113       When  creating  a .dxb file or a slide file with the -poly option, ppm‐
114       toacad finds both vertical and horizontal runs of identical pixels  and
115       consolidates  them  into  rectangular regions to reduce the size of the
116       output file.  This is effective for images with large areas of constant
117       color  but it's no substitute for true raster to vector conversion.  In
118       particular, this process does not optimize thin diagonal lines at all.
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120       Output files can be huge.
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SEE ALSO

124       Autocad Reference Manual: Slide File Format and Binary  Drawing  Inter‐
125       change (DXB) Files, ppm(1)
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AUTHOR

129       John Walker
130       Autodesk SA
131       Avenue des Champs-Montants 14b
132       CH-2074 MARIN
133       Suisse/Schweiz/Svizzera/Svizra/Switzerland
134           Usenet:kelvin@Autodesk.com
135           Fax:038/33 88 15
136           Voice:038/33 76 33
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139       Permission  to  use, copy, modify, and distribute this software and its
140       documentation for any purpose and without fee is hereby granted,  with‐
141       out  any conditions or restrictions.  This software is provided "as is"
142       without express or implied warranty.
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144       Autocad and Autodesk are registered trademarks of Autodesk, Inc.
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DOCUMENT SOURCE

147       This manual page was generated by the Netpbm tool 'makeman'  from  HTML
148       source.  The master documentation is at
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150              http://netpbm.sourceforge.net/doc/ppmtoacad.html
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152netpbm documentation            10 October 1991       Ppmtoacad User Manual(0)
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