Provided by: fontforge-common_20230101~dfsg-4_all 
NAME
sfddiff - compare two font files
SYNOPSIS
sfddiff [--help] [--ignorehints] [--ignorenames] [--ignoregpos] [--ignoregsub]
[--ignorebitmaps] [--exact] [--warn] [--merge outfile] [--usage] [--version] fontfile1
fontfile2
DESCRIPTION
The program sfddiff compares two font files, which may be in any format that fontforge(1)
can read. It will notice the following differences:
1) Characters are present in one font but not in the other.
2) Characters are present in both fonts but have different sets of outlines or
references. The outlines may be compared so that only exact matches are accepted, or
so that a fuzzier match is used. Similarly references may need to match exactly, or
may be matched after an unlink. This fuzzy comparison is useful when comparing
truetype and postscript fonts, or when comparing a font with references to one
without.
3) The PostScript hints or TrueType instructions are different.
4) The font names (the TrueType 'name' tables) differ.
5) The kerning (and other 'gpos' information) differs.
6) The ligatures (and other 'gsub' information) differ.
7) Any bitmap strikes present in one font but not in the other.
8) Any bitmap characters present in one strike of one font but not in the equivalent
strike of the other.
9) Any bitmap characters which differ.
OPTIONS
--help Provide a description with a list of the available options.
--ignorehints Suppress the reporting of hint/instruction differences.
--ignoregpos Suppress the reporting of kerning (and other 'gpos') differences.
--ignoregsub Suppress the reporting of ligature (and other 'gsub') differences.
--ignorenames Suppress the reporting of name string differences.
--ignorebitmaps Suppress the reporting of bitmap differences.
--exact Require outlines to match exactly.
--warn Warn if the outlines/references are slightly different.
--merge outfile Store a merged version of the two fonts into the specified output file.
The merged data will be based on sfdfile1, any characters present in
sfdfile2 but not in sfdfile1 will be added, and the outlines of sfdfile2
will be placed in the background. Finally, for any characters with
different outlines or references the background of the character will
contain the outlines from sfdfile2 (references will be unlinked into
outlines and those outlines also will be added).
--usage Display the usage description.
--version Display the current version.
SEE ALSO
fontforge(1)
The HTML version of the FontForge manual, available online at:
http://fontforge.sourceforge.net/.
NOTE
FontForge used to be called PfaEdit.
AUTHORS
FontForge is Copyright © 2000–2014 by George Williams, and is currently maintained by the
FontForge development team. See /usr/share/doc/fontforge/AUTHORS for a comprehensive list
of contributors.
LICENSE
The sfddiff program is licensed under GPLv3+: GNU GPL version 3 or later
(http://gnu.org/licenses/gpl.html) with many parts covered by a BSD license
(http://fontforge.org/license.html). Please read the LICENSE file included in the
FontForge distribution for details, or see
https://github.com/fontforge/fontforge/blob/master/LICENSE.
FontForge is available as a whole under the terms of the GNU GPL
(http://www.gnu.org/copyleft/gpl.html), version 3 or any later version. However, almost
all of its parts are available under the "revised BSD license"
(http://www.law.yi.org/~sfllaw/talks/bsd.pdf) because FontForge was mostly written by
George Williams, using that license.
The Revised BSD License is very permissive, and allows for code to be combined with other
code under other licenses.
There are many useful libraries available under copyleft libre licenses, such as the LGPL
and GPL, which FontForge started to use in 2012.
For example, Pango and Cairo are available under the LGPL.
Some features added since 2012 are licensed by their individual developers under the
GPLv3.
BUGS
See the FontForge Github Issue Tracker, at https://github.com/fontforge/fontforge/issues/.
2017 Jun 18 SFDDIFF(1)