Gifsicle manipulates GIF image files. Depending on command line options, it can merge several GIFs into a GIF animation; explode an animation into its component frames; change individual frames in an animation; turn interlacing on and off; add transparency; add delays, disposals, and looping to animations; add and remove comments; flip and rotate; optimize animations for space; change images' colormaps; and other things.
Gifview, a companion program, displays GIF images and animations on an X display. It can display multi-frame GIFs either as slideshows, displaying one frame at a time, or as real-time animations.
Gifdiff, another companion program, checks two GIF files for identical visual appearance. This is probably most useful for testing GIF-manipulating software.
Each of these programs has a manpage, PROGRAMNAME.1.
The Gifsicle package comes with NO WARRANTY, express or implied, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose.
See NEWS.md in this directory for changes in recent versions. The Gifsicle
home page is:
Type ./configure, then make.
If ./configure does not exist (you downloaded from Github), run
autoreconf -i first.
./configure accepts the usual options; see INSTALL for details.
To build without gifview (for example, if you don't have X11), use
./configure --disable-gifview. To build without gifdiff,
use ./configure --disable-gifdiff.
make install will build and install Gifsicle and its manual page
(under /usr/local by default).
To build Gifsicle on Windows using Visual C, change into the src
directory and run
nmake -f Makefile.w32
Gifview will not be built. The makefile is from Emil Mikulic [email protected] with updates by Eddie Kohler and Steven Marthouse [email protected].
To build Gifsicle on Windows using Borland C++, change into the src
directory and run
nmake -f Makefile.bcc
Stephen Schnipsel [email protected] provided Makefile.bcc. You
will need to edit one of these Makefiles to use a different compiler.
You can edit it with any text editor (like Notepad). See the file for
more information.
Please write me if you have trouble building or running Gifsicle, or if you have suggestions or patches.
Eddie Kohler, [email protected] http://www.read.seas.harvard.edu/~kohler/
Patents formerly restricted use of the Lempel-Ziv-Welch compression algorithm used in GIFs. As of October 1, 2006, it is believed (by the Software Freedom Law Center and the Free Software Foundation, among others) that there are no significant patent claims interfering with employment of the GIF format. For that reason, Gifsicle is completely free software.
Nonetheless, Gifsicle can be configured to write run-length-encoded
GIFs, rather than LZW-compressed GIFs, avoiding these obsolete
patents. This idea was first implemented independently by Toshio
Kuratomi [email protected] and Hutchison Avenue Software
Corporation (http://www.hasc.com/, [email protected]). Turn this on by
giving ./configure the --enable-ungif switch. Now that the patents
have expired there is no good reason to turn on this switch, which can
make GIFs a factor of 2 larger or more. If your copy of Gifsicle says
(ungif) when you run gifsicle --version, it is writing
run-length-encoded GIFs.
All source code is Copyright (C) 1997-2017 Eddie Kohler.
IF YOU PLAN TO USE GIFSICLE ONLY TO CREATE OR MODIFY GIF IMAGES, DON'T WORRY ABOUT THE REST OF THIS SECTION. Anyone can use Gifsicle however they wish; the license applies only to those who plan to copy, distribute, or alter its code. If you use Gifsicle for an organizational or commercial Web site, I would appreciate a link to the Gifsicle home page on any 'About This Server' page, but it's not required.
This code is distributed under the GNU General Public License, Version 2 (and only Version 2). The GNU General Public License is available via the Web at http://www.gnu.org/licenses/gpl.html or in the 'COPYING' file in this directory.
The following alternative license may be used at your discretion.
Permission is granted to copy, distribute, or alter Gifsicle, whole or in part, as long as source code copyright notices are kept intact, with the following restriction: Developers or distributors who plan to use Gifsicle code, whole or in part, in a product whose source code will not be made available to the end user -- more precisely, in a context which would violate the GPL -- MUST contact the author and obtain permission before doing so.
Eddie Kohler [email protected] http://www.read.seas.harvard.edu/~kohler/ He wrote it.
Anne Dudfield [email protected] http://www.frii.com/~annied/ She named it.
David Hedbor [email protected] Many bug reports and constructive whining about the optimizer.
Emil Mikulic [email protected] Win32 port help.
Hans Dinsen-Hansen [email protected] http://www.danbbs.dk/~dino/ Adaptive tree method for GIF writing.