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Re: Animated gifs

From: David Cary <d.cary@ieee.org>
Date: Sat, 1 Aug 1998 13:24:48 -0500
Message-Id: <l03130303b1e90a9ed012@[192.168.1.40]>
To: Sam Morgan <sam.morgan@global.net.uk>, www-html@w3.org

Earlier versions of IE did this:
when it drew the next frame of the animation, it left the pixels the same
where this frame has transparency.
So my animation of a dog running from left to right left a long streak
behind the dog, because those pixels were drawn on one frame and never
erased or overwritten.

Current versions of IE seem to do this:
when it draws the next frame of the animation, where this frame has
transparency, it reverts those pixels back to the background color/image.
Now my running dog seems to work fine.

I heard about someone saying they compressed their animated gifs much
smaller by only drawing the parts that change (the motion of the eyes and
mouth), and leaving the rest of that frame "transparent" (the trees and
clouds in the background of the 1st frame). I wish I knew how they did
that. Perhaps they were taking advantage of the "feature" in the early
versions of IE, and now that technique doesn't work anymore ?

If there is a way to do this with current versions of IE, I would really
like to know.

>From: Sam Morgan <sam.morgan@global.net.uk>
...
>I use ulead gif animator and others to create lots of transparent animated
>gif's obviously, but sometimes when I view them in IE4 some of the frames
>of the animated gif are not transparent, although this does not happen at
>all with other peoples browsers, I just wondered if anyone had had the
>same experience.
...
>Sam Morgan
...
> URL:http://www.global.net.uk

--
+ David Cary "mailto:d.cary@ieee.org" "http://www.ionet.net/~caryd_osu/david"
| Future Tech, Unknowns, PCMCIA, digital hologram, <*> O-
Received on Saturday, 1 August 1998 16:09:04 GMT

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