Ppmtoarbtxt User Manual

ppmtoarbtxt - generate image in arbitrary text format from PPM image

ppmtoarbtxt bodyskl [-hd headskl] [-tl tailskl] [ppmfile]

This program is part of Netpbm(1).

ppmtoarbtxt generates simple text-based graphics formats based on format descriptions given as input. A text-based graphics format is one in which an image is represented by text (like PNM plain format, but unlike PNM raw format).

ppmtoarbtxt reads a PPM image as input. For each pixel in the image, ppmtoarbtxt writes the contents of the skeleton file bodyskl, with certain substitutions based on the value of the pixel, to stdout. The substitutions are as follows:

#(ired format blackref whiteref)

generates an integer in the range blackref to whiteref using format representing the red intensity of the pixel. A red intensity of 0 becomes blackref; a red intensity of maxval becomes whiteref.

#(ired) is equivalent to #(ired %d 0 255).

#(igreen format blackref whiteref)

Same as #(ired..., but for green.

#(iblue format blackref whiteref)

Same as #(ired..., but for blue.

#(ilum format blackref whiteref)

Same as #(ired..., but representing the luminance value (0.299*red + 0.587*green + 0.114*blue) of the pixel.

#(fred format blackref whiteref)

Same as #(ired..., but generates a floating point number instead of an integer.

#(fred) is equivalent to #(fred %f 0.0 1.0).

#(fgreen format blackref whiteref)

Same as #(fred..., but for green.

#(fblue format blackref whiteref)

Same as #(fred..., but for blue.

#(flum format blackref whiteref)

Same as #(fred..., but representing the luminance value (0.299*red + 0.587*green + 0.114*blue) of the pixel.

#(width)

Generates the width in pixels of the image.

#(height)

Generates the height in pixels of the image.

#(posx)

Generates the horizontal position of the pixel, in pixels from the left edge of the image.

#(posy)

Generates the vertical position of the pixel, in pixels from the top edge of the image.

If the skeleton file ends with a LF-character, ppmtoarbtxt ignores it -- it does not include it in the output.

-hd headskl

This option causes ppmtoarbtxt to place the contents of the file named headskl at the beginning of the output, before the first pixel. It does the same substitutions as for bodyskl, except substitutions based on a pixel value are undefined.

-tl tailskl

This option causes ppmtoarbtxt to place the contents of the file named tailskl at the end of the output, after the last pixel. It is analogous to -hd.

gray inversion

Here we generate a PGM plain-format image with gray inversion (like ppmtopgm | pnminvert).

Contents of our head skeleton file:

P2
#(width) #(height)
255

Contents of our body skeleton file:

#(ilum %d 255 0)

povray file

Here we generate a povray file where each pixel is represented by a sphere at location (x,y,z) = (posx,height-posy,luminance). The color of the sphere is the color of the pixel.

Contents of our head skeleton:

#include ’colors.inc’
#include ’textures.inc’
camera {
   location  <#(width) * 0.6, #(height) * 0.7, 80>
   look_at   <#(width) * 0.5, #(height) * 0.5, 0>
}

light_source { <#(width) * 0.5, #(height) * 0.5, 25> color White
}

Contents of our body skeleton:

sphere { <#(posx),#(height)-#(posy),#(ilum %d 0 10)>, 0.5
  texture {
    pigment {
      color rgb <#(fred),#(fgreen),#(fblue)>
    }
    finish {
      phong 1
    }
  }
}

pnmtoplainpnm(1) ppm(1)

ppmtoarbtxt was added to Netpbm in Release 10.14 (March 2003). It existed under the name ppmtotxt since 1995.

Copyright (C) 1995 by Peter Kirchgessner