On Monday 13 November 2006 12:00 pm, rhubarbpie@poetworld.net wrote:

I've created an animated gif which I want to perform what I think is a reverse loop. In explanation, I'll use a three-layer example. I want the animation to proceed from frame 1 to frame 2 to frame 3, then back to frame 2 to frame 1 and repeat. An analogy would be a ball continually rolling between two hills.

I see only the "loop forever" option when saving the gif. I've gotten around that problem by saving as layers frame 1, frame 2, frame 3, frame 2, and frame 1. Savings those frames with the loop forever option does what I want but is a larger file than I think necessary.

I've done some research and see the "reverse loop" option with gimp-gap. I compiled gimp-gap and used frames 1-3 only once. I used the "move path" option and tried reverse loop and reverse frame loop. However, neither option seems to take. It loops only, no reverse.

Animated gifs and The Gimp are quite new to me. Can the gimp-gap reverse loop do what I want with just three frames?

What you want in Gimp-GAP is ping-pong, but it will still take more than three frames. If you are using animated GIFs you can only give each frame timing information. Each frame will be shown in sequence for the specified time alloted to that frame. After the last frame the sequence will begin again with the first frame. There is some optimization of frames in that redundant information contained in previous frames is not saved in each one if you specify (combine) in the Gimp layer comment. Only the information necessary to show the changes between frames is saved. The default mode is (replace), which completely replaces the content of the previous frame with the content of the frame that follows it. It sounds like this is what you would want for your animation. But you won't get the effect you are after with only three frames. The logic used for displaying gif animations does not allow that kind of optimization.

On Monday 13 November 2006 2:41 pm, rhubarbpie@poetworld.net wrote:

Yes, I basically want Gimp-Gap ping-pong. I was unclear in that three frames was only an example. My animation uses 17 frames. I use the replace option and pause 1 second between frames. Both are fine for my animation but I want "ping-pong."

If I understand your post correctly, the simple answer is that it can't be done with Gimp-Gap. If that's correct, what does the "reverse loop" option do?

It CAN be done with GAP. One of the options in the Step mode drop-down box of the Move Path dialog is Ping Pong. It does exactly what you want.

The reverse loop option plays an animation sequence in reverse and loops over the sequence repeatedly.