Goal is to center the blue circle to the gray box as new boxes appear. Visualize this as an animated "chat" taking place over time. I can successfully set "y" values on the circle for each step based on height of boxes using this.
.to('.chat-rep', {duration:0.25, y: move_chat_icon_distance('.chat1','.chat2',) }, "+=3")
(move_chat_icon_distance does the math, ie; y:+= 1/2 of each box added together + margins, etc) Problem is these are all computed before the animation runs. If the height of a gray box changes while the animation plays things get off track. If I could set the Y value as a .call so I could compute the heights just before I need them this would work. Seems I can't have it both ways? Example Pen https://codepen.io/tpavell/pen/qByMLrg