[Oleg Pirogov]

I’ve just noticed this comparison:
valueAtTime(tempsDebut-thisComp.frameDuration) < valueAtTime(tempsDebut)
It is not THE problem, cause with rebond = false; it’s not evaluated, but it hints that the expression was meant for 1D properties and in general should not be applied for 2D-properties like Position in your example (cause for 2D properties this becomes “<” vector comparison which doesn’t make any sense).

[Oleg Pirogov]

So, have you tried it with Legacy ExtendScript (File -> Project Settings)?
This expression won’t work for default AE CC 2019 expression engine.

[Oleg Pirogov]

Which version of AE is it?

[Oleg Pirogov]

Oh wait.
T.sourceRectAtTime(time-T.inPoint,true) – you evaluate sourceRectAtTime at time-T.inPoint.
So at 9;22 it takes the size of the text’s rectangle at 9;22-7;28=1;24 which is zero, I suppose;

Change it to T.sourceRectAtTime(time,true) everywhere, that should work.

[Oleg Pirogov]

What are shape’s Size and Position values when it disappears?

[Oleg Pirogov]

Not exactly sure how all things work in your project, but:
1) Skew is the other angle, so multiplying by tan, not dividing
2) Default rectangle shape is skewed with respect to its center: the top and the bottom both move by the same amount in the opposite directions. I.e. the total shift should be divided by 2.

So try:
x = a*Math.tan(degreesToRadians(SVal))/2;// Tan value of 44
I assume it’s an expression for the yellow shape’s position and it’s aligned with green at zero skew.

[Oleg Pirogov]

On the first glance: I would expect myEditText assignment to be in onClick event:

Button.onClick = function(){
var myEditText = myText.text;
main('Bouncing_texts.ffx', myEditText); // FINAL FUNCTION!!!
};

or actually:
Button.onClick = function(){
main('Bouncing_texts.ffx', myText.text); // FINAL FUNCTION!!!
};

[Oleg Pirogov]

This error means that the expression is evaluated to be a number (dimension 1) and not a vector like [0,0] (dimension 2) which the Position property in 2D space should be.

The given expression works fine for me as it is.

The code is incompatible with the new AE 2019 JavaScript Engine and should raise an error (though I’m not sure which one exactly). Make sure you are not using this in AE 2019 without Legacy Engine turned on.

[Oleg Pirogov]

>origin is always marked as Source Rectanlge’s top-left corner
This is not “always”. In case of masks applied, for instance. And “fixed/variable source rectangles” are loose terms invented by me.

[Oleg Pirogov]

Does the value varies with time?
Cause expressions are evaluated at their respective comps’ times and times on the left and on the right sides are different.