Merge single GIFs into an GIF89a Animation
gifmerge uses GIF89a extensions, as well the recent developed application extensions supported by Netscape-2.0 with n-loops. For details on GIF89a see at the GIF89a Specifications.
An excerpt of the Application Extension defined by Netscape (from Understanding GIF89a):
For more specific infos look at Royal Frazier's GIF Making: Looping.
Netscape Navigator has an Application Extension Block that tells Navigator to loop the entire GIF file. The Netscape block MUST APPEAR IMMEDIATELY AFTER THE GLOBAL COLOR TABLE OF THE LOGICAL SCREEN DESCRIPTOR. Only Navigator 2.0 Beta4 or better will recognize this Extension block. The block is 19 bytes long composed of: (note: hexidecimal equivalent supplied for programmers)byte 1 : 33 (hex 0x21) GIF Extension code byte 2 : 255 (hex 0xFF) Application Extension Label byte 3 : 11 (hex (0x0B) Length of Application Block (eleven bytes of data to follow) bytes 4 to 11 : "NETSCAPE" bytes 12 to 14 : "2.0" byte 15 : 3 (hex 0x03) Length of Data Sub-Block (three bytes of data to follow) byte 16 : 1 (hex 0x01) bytes 17 to 18 : 0 to 65535, an unsigned integer in lo-hi byte format. This indicate the number of iterations the loop should be executed. bytes 19 : 0 (hex 0x00) a Data Sub-block Terminator.As of Beta5, the iteration count is ignored and the loop is infinite (an iteration count of zero indicates infinite). I strongly suggest you code the count to be accurate, so that when iterations begin working your GIF will not need to be modified. Technically that is all that needs to be done with this block. More about looping later in the tutorial.
For general approaches of animations look at Animations.
=== GIFMerge Rev 1.30 (C) 1991,1992 by Mark Podlipec Improvements by Rene K. Mueller 1996 Usage: gifmerge [-<r>,<g>,<b>] [-<delay>] [-l<loops>] *.gif > anim.gif -<r>,<g>,<b> set transparency, ie -192,192,192, default: no transparency -<delay> set delay of between images in 1/100th secs, ie -100 default 50 (0.5secs) -l<loops> set loop counter, ie -l0 (ever) or -l1000, default no loopsYou have two images like this:
gifmerge -192,192,192 -l0 -50 perlredb.gif perlgrey.gif > perlredblink.gifGives you
gifmerge -192,192,192 -l0 -50 perlredb.gif -10 perlgrey.gif > perlredblink2.gifGives you
4 frames, delays: 1x 1.0s and 3x 0.1s
more coming soon ...
more coming soon ...
Let me know if you have programmed some animations with gifmerge. A gallery with GIF89 animations you find at Royal Frazier's Animation Gallery.
Also, Netscape-2.0 seems to shows the animations as busy (comets on the "N" right upper corner of your browser) as well indicates "Reading document ..." on the bottom of your browser, which both are quite distracting for readers.
When you go back to a page (using Back-Button) which has GIF89a animations with loops, Netscape2.0 does show only few pictures as animations, some are freezed.
Beside, if you leave a page with some GIF89a animations (with loops as well), to another page, Netscape-2.0 does not show the page while loading as usual.
And finally, Netscape-2.0 gets problems when two or more windows are open with GIF89a animations, you assume right: it crashs in some cases.
.... is your browser busy? I thought so! ;-)