Right now we only allow publishers to specify an animate-in-duration and animate-in-delay. The duration allows us to control the speed of the animation but not the position.

Our new proposal is to expose the start/end arguments of the zoom and pan animations:

e.g.

Scales the image from 1x to 3x over 4 seconds:
animate-in="zoom" animate-in-duration="4s" scale-start="1" scale-end="3"

Translates the image -200px horizontally over 4 seconds:
animate-in="pan-left" animate-in-duration="4s" translate-x="200px"