The scripts are coherent between themselves, to make an animation in Gimp where the bottom layer is the first to play. My mirror-layers script will copy in reverse order your layers, to make the animation run backwards (so that initial layers plus copied layers make a whole cycle of "swing"), so you can use that and discard the extra layers.
The jagged edges are not due to Gimp but to the GIF format. Smooth edges are obtained with semi-transparent pixels but GIF only does dully opaque or fully transparent pixels. So the image becomes jagged when you export. If your image is color-indexed in Gimp, then transparency works like in a GIF and the edges are jagged from the start. The WebP format I mentioned earlier has no such limitation.
Another explanation is that unlike vectors, bitmaps are not easily scalable. With CGI such as this depending on interpolation algorithm you either get blurry edges (Linear/Cubic/NoHalo/LowHalo) or jagged edge (None). When you zoom in (not exactly the same thing as scaling) Gimp doesn't interpolate.
AFAIK there is no widely supported animated vector format. It could be possible to make a vector animation with SVG files and some JavaScript but this could slow down the client workstation.
The jagged edges are not due to Gimp but to the GIF format. Smooth edges are obtained with semi-transparent pixels but GIF only does dully opaque or fully transparent pixels. So the image becomes jagged when you export. If your image is color-indexed in Gimp, then transparency works like in a GIF and the edges are jagged from the start. The WebP format I mentioned earlier has no such limitation.
Another explanation is that unlike vectors, bitmaps are not easily scalable. With CGI such as this depending on interpolation algorithm you either get blurry edges (Linear/Cubic/NoHalo/LowHalo) or jagged edge (None). When you zoom in (not exactly the same thing as scaling) Gimp doesn't interpolate.
AFAIK there is no widely supported animated vector format. It could be possible to make a vector animation with SVG files and some JavaScript but this could slow down the client workstation.