Re: animate incredibly slow compared to 21.3

[Richard Stallman]

    To make scrolling (even of images or lines of widely different height)
    reliable, compute-motion would need to pay attention to every display
    element and parameter, including things like frame-local face properties.

    So either it re-implements the redisplay or it reuses the redisplay.

The display mechanism at C level is already designed to facilitate
this.  It's just a matter of adapting the higher levels to use it.

If this was already done for vertical-motion, it can surely be done
for compute-motion.

    > IMO, compute-motion is too cumbersome to use.

The facility is essential.  The idea of eliminating it makes no sense.
I don't know of a way to make it simpler to use, but I would be glad
if it were.

(The C-level mechanism has similar complexities in its interface.
They are simply necessary.)