Ubuntu Manpage: asciitopgm - convert ASCII graphics into a PGM

NAME

       asciitopgm - convert ASCII graphics into a PGM

SYNOPSIS

       asciitopgm [-d divisor] height width [asciifile]

DESCRIPTION

This program is part of Netpbm(1).

asciitopgm reads ASCII data as input and produces a PGM image with pixel values which are an
approximation of the "brightness" of the ASCII characters, assuming black-on-white printing. In other
words, a capital M is very dark, a period is very light, and a space is white.

Obviously, asciitopgm assumes a certain font in assigning a brightness value to a character.

asciitopgm considers ASCII control characters to be all white. For a lower case character, It assigns a
special brightnesses which has nothing to do with what it looks like printed. asciitopgm takes the ASCII
character code from the lower 7 bits of each input byte. But it warns you if the most significant bit of
any input byte is not zero.

The output image is height pixels high by width pixels wide, truncating and padding with white on the
right and bottom as necessary.

The divisor value is an integer (decimal) by which the blackness of an input character is divided. You
can use this to adjust the brightness of the output: for example, if the image is too bright, increase
the divisor.

In a sort of reminiscence of Fortran line printer carriage control, where a line starts with + (plus),
asciitopgm combines it with the previous row of output instead of generating a new row. This allows a
larger range of gray values. (In Fortran carriage control, the first character of every line sent to the
printer tells how much to advance the paper, with + meaning not at all, so that the rest of the
characters on the line overstrike the ones already on the paper. What asciitopgm does is rather
different in that asciitopgm does not reserve the first character of every line that way. If the first
character is anything but +, asciitopgm considers it just to be first character of the image.

If you're looking for something that creates an image of text, with that text specified in ASCII, that is
something quite different. Use pbmtext for that.

OPTIONS

       In addition to the options common to all programs based on libnetpbm (most notably  -quiet,  see   Common
       Options ), asciitopgm recognizes the following command line option:

       -d divisor
              Specify  the  value  by  which the blackness of an input character is divided.  This is an integer
              value.  Default value is 1.  Larger values produce darker output images.

AUTHOR

       Wilson H. Bent. Jr. (whb@usc.edu)

DOCUMENT SOURCE