1 files changed, 145 insertions, 0 deletions
diff --git a/doc/imgrotate.texi b/doc/imgrotate.texi
new file mode 100644
index 0000000..f4f044d
--- /dev/null
+++ b/doc/imgrotate.texi
@@ -0,0 +1,145 @@
+@c Copyright (C) 1992 Free Software Foundation.
+@c This is part of the GNU font utilities manual.
+@c For copying conditions, see the file fontutil.texi.
+
+@node IMGrotate, Fontconvert, Imageto, Top
+@chapter IMGrotate
+
+@pindex imgrotate
+@cindex rotation, of images
+@cindex image rotation
+
+IMGrotate rotates an IMG file, either 90 or 180 degrees clockwise.  We
+call the latter---somewhat inaccurately---a ``flip''.  (We haven't
+needed other rotation angles, so we haven't implemented them.)
+
+The IMG format is an image format output by a few programs, including the
+one that drives the scanner we have.  (Again, we haven't needed other
+image formats, so we haven't implemented them.)
+
+Both the input and output are IMG files.
+
+The current implementation of IMGrotate uses an extremely slow and
+stupid algorithm, because it was a quick hack.  It would be useful to
+replace it with a better algorithm.  @xref{Program features}, for a
+reference.
+
+@menu
+* IMGrotate usage::             Doing the image rotation.
+* Invoking IMGrotate::          Command-line options.
+@end menu
+
+
+@node IMGrotate usage, Invoking IMGrotate,  , IMGrotate
+@section IMGrotate usage
+
+@cindex IMGrotate usage
+@cindex usage of IMGrotate
+
+The physical construction of a source to be scanned may make it hard
+or impossible to end up with an upright image.  But the task of
+extracting characters from an image is complicated by allowing for a
+rotated image.  Hence this program to turn rotated images upright.
+
+@flindex x @r{prefix}
+By default, the name of the output file is the same as the input file;
+both are extended with @file{.img} if necessary.  If this would result
+in the output overwriting the input, @samp{x} is prepended to the output
+name.
+
+@menu
+* Clockwise rotation::          Rotating clockwise.
+* Flip rotation::               FLipping end-for-end.
+@end menu
+
+
+@node Clockwise rotation, Flip rotation,  , IMGrotate usage
+@subsection Clockwise rotation
+
+@cindex clockwise rotation
+@cindex rotation, clockwise
+@opindex -rotate-clockwise
+
+You specify clockwise rotation of an image with the option
+@samp{-rotate-clockwise}.  This rotates the input 90 degrees clockwise.
+For example, the following (an @samp{h} on its side):
+
+@example
+      *****
+     *
+     *
+***********
+@end example
+
+@noindent turns upright.
+
+
+@node Flip rotation,  , Clockwise rotation, IMGrotate usage
+@subsection Flip rotation
+
+@cindex flip rotation
+@cindex rotation, flip
+
+You specify ``flip'' rotation of an image with the option @samp{-flip}.
+This flips the input end for end and reverses left and right, i.e., does
+a 180 degree rotation.  For example, the following (an @samp{h} upside
+down and backwards):
+
+@example
+  *  *
+  *  *
+  *  *
+   ***
+     *
+     *
+     *
+@end example
+
+@noindent turns upright.
+
+
+@node Invoking IMGrotate,  , IMGrotate usage, IMGrotate
+@section Invoking IMGrotate
+
+@cindex IMGrotate options
+@cindex invocation of IMGrotate
+@cindex options for IMGrotate
+
+This section describes the options that IMGrotate accepts.
+@xref{Command-line options}, for general option syntax.
+
+The name of the main input file (@pxref{Main input file}) is called
+@var{image-name} below.
+
+@table @samp
+
+@opindex -flip
+@item -flip
+Rotate the input 180 degrees, i.e., flip it end for end and left to
+right.  @xref{Flip rotation}.
+
+@opindex -help
+@item -help
+Print a usage message.  @xref{Common options}.
+
+@opindex -output-file
+@cindex output file, naming
+@item -output-file @var{filename}
+Write to @var{filename} if @var{filename} has a suffix.  If it doesn't,
+write to @file{@var{filename}.img}, unless that would overwrite the
+input, in which case write to @file{x@var{filename}.img}.  By default,
+use @var{image-name} for @var{filename}.
+
+@opindex -rotate-clockwise
+@item -rotate-clockwise
+Rotate the input 90 degrees clockwise.  @xref{Clockwise rotation}.
+
+@opindex -verbose
+@item -verbose
+Output progress reports.  @xref{Common options}.
+
+@opindex -version
+@item -version
+Print the version number.  @xref{Common options}.
+
+@end table