1Ppmtoacad User Manual(0) Ppmtoacad User Manual(0)
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6 ppmtoacad - convert PPM to Autocad database or slide
7
10 ppmtoacad
11 [-dxb]
13 [-poly]
15 [-background color]
17 [-white]
19 [-aspect ratio]
21 [-8]
23 [ppmfile]
25
28 This program is part of Netpbm(1).
29 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.
33 (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).
37
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:
44 You may abbreviate any option to its shortest unique prefix.
46 -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.
57 -poly If you don't specify the -dxb option, ppmtoacad generates an
60 Autocad slide file. Normally each row of pixels is represented
61 by an Autocad line entity. If you specify -poly, ppmtoacad ren‐
62 ders the pixels as filled polygons. If you view the slide on a
63 display 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.
68 -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.
83 -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.
88 -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.
97 -8 Restricts the colors in the output file to the 8 RGB shades.
100
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.
108 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.
112 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.
119 Output files can be huge.
121
124 Autocad Reference Manual: Slide File Format and Binary Drawing Inter‐
125 change (DXB) Files, ppm(1)
126
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
137 Permission to use, copy, modify, and distribute this software and its
139 documentation for any purpose and without fee is hereby granted, with‐
140 out any conditions or restrictions. This software is provided "as is"
141 without express or implied warranty.
142 Autocad and Autodesk are registered trademarks of Autodesk, Inc.
144
146 This manual page was generated by the Netpbm tool 'makeman' from HTML
147 source. The master documentation is at
148 http://netpbm.sourceforge.net/doc/ppmtoacad.html
150netpbm documentation 10 October 1991 Ppmtoacad User Manual(0)