Auto-slide Null to position on marker

[Dan Ebberts]

Once your expression finds the current marker, I think it needs accumulate the heights for all the layers associated with previous markers. It looks like (I apologize if I’m incorrect about this) you’re assuming the the results of the expression’s previous calculations will be available as value[1], which is not the case (expressions have no access to values they previously calculated).

[Hannes Holtermann]

Hey Dan,

I guess your analysis is spot on. I was thinking that there is some sort of state saving. How would you handle this? Create a recurrsive loop to sum up all previous heights? Or is there a more elegant way?

[Dan Ebberts]

Once you have the index of the most recent marker (n), you can use that to loop through all the comps associated with the previous markers and add up the heights + margins for the layers in those comps.

[Hannes Holtermann]

<div>So I’m getting closer but something still seems off as at some markers the calculatioin doesnt seem to fit. Can you spot something I’m missing?</div><div>

day = "DI_";
margin = effect("Margin")("ADBE Slider Control-0001");
m = marker;
transitionTime = .5;
n = 0;

getContentHeight = function(layerID) {
    layerID--; // exclude current layer from calculation by subtracting 1
    if(layerID > 0) {
        if(layerID < 10) {
            layer = day + "0" + layerID;
        } else {
            layer = day + layerID;
        }
        s = eval('comp("' + layer +'").layer("Programm").sourceRectAtTime();');
        return s.height + margin;
    } else {
        return 0;
    }
}
if (m.numKeys > 0){
    n = m.nearestKey(time).index;
    if (time < m.key(n).time) n--;
}
if (n > 0){
    totalOffset = 0;
    for(i=0; i < n; i++) {
        totalOffset += getContentHeight(n);
        i++;
    }

    t = time - m.key(n).time;
    y = ease(time, n, transitionTime, value[1], totalOffset);
    value - [0,y];
} else
    value

</div>

[Dan Ebberts]

It seems like your loop should be more like this:

totalOffset = 0;
for(i=1; i <= n; i++) {
    totalOffset += getContentHeight(i);
}

[Hannes Holtermann]

Hmm, I guess that my marker detection is somewhat off because it’s only sliding up every second marker. Is looking for nearestKey the right thing to do if I want to push the content up as soon as the marker has been passed?

Thanks a lot for your help, Dan!

[Dan Ebberts]

Did you catch the edit I made to my last post? It originally still had the i++ from your loop in there, which would make it skip layers. I changed it, but you may have seen the pre-edit version. I’m hoping that’s the issue.

[Hannes Holtermann]

Oh wow, you’re awesome. Thanks a lot. I forgot to remove it after changing from a while loop.

I’ve also noted that a couple of markers where off by a couple of frames resulting in a wrong calculation by sourceRectAtTime().

One last thing: Do you know why it’s not easing the animation? It’s just a jump cut. I’d love to do a ease out for 1s. But this doesnt work

y = ease(time, n+1, n+2, value[1], totalOffset);
    value - [0,y]

with n being 

if (m.numKeys > 0){
    n = m.nearestKey(time).index;
    if (time < m.key(n).time) n--;
}

Muchas gracias!

[Dan Ebberts]

Ah. If you want it to ease, you need to calculate the offset due to all the prior markers, as well as the offset that includes the most recent marker. Then you need the times for the most recent marker and the one before that and set your ease up to use those times and offsets. Something like that.

[Hannes Holtermann]

Ah, ok. So I’m getting the offsets like this (just for anyone interested)

    currentOffset = 0;
    totalOffset = 0;
    previousOffset = 0;
    
    for(i=1; i < n-1; i++) {
        currentOffset = getContentHeight(i);
        totalOffset += currentOffset;
        if (i < n-2) {
            previousOffset += currentOffset;
        }
    }

And since I want to start the ease just after the current marker time I don’t need the previous marker time.

I’ve got it all working nicely and want to thank you a lot, Dan!