Checkbox Control using Expressions

[E. Rocka]

Hi all,

I'm trying to control the Mask Layer property in the Colorama plugin to always select the current layer. What I've done is created a Checkbox Control effect on the current layer to dictate that Mask Layer is always set to the current layer's index. If the Checkbox Control is set to off, I would like it to select layer "None". Here's what I've come up with, but since I'm new to expressions, it's not working. What am i doing wrong?

if (effect("Checkbox Control")(1)==true){
effect("Colorama")("Mask Layer")=layer(index);
}else{
effect("Colorama")("Mask Layer")=layer(None);}

Thanks in advance for your expertise!

[Dan Ebberts]

If I understand what you're trying to do, I don't think you can do it with expressions. Colorama's layer control won't accept its own expression (it's not keyframable) and you can't control any property using an expression applied to a different property. Think of expressions as a substitue for keyframes -- if you can't keyframe it, you can't control it with an expression.

Dan

[E. Rocka]

Dan,

So because Colorama's Mask Layer Property isn't animatable (no stopwatch icon next to the property), I cannot affect it using expressions, right?

On the other hand, if I for whatever reason wanted to control Colorama's Masking Mode dropdown list, I could, because it is animatable, correct?

Originally, I wanted to take a text layer that had Colorama applied to it, duplicate it many times, and change each layer's source text. At the same time, I wanted Colorama's Mask Layer property to always choose the current layer (index). So if what you're telling me is true, I would have to manually select the Mask Layer from the dropdown list for each layer, right?

[Dan Ebberts · Accepted solution]

You are correct on all counts. If you have a ton of these to do, you could write a little script that would go through the comp, looking for layers with Colorama applied, and change the Mask layer parameter, but that might be more trouble than it's worth.

Dan

[E. Rocka]

Thanks Dan,

Here, I was under the impression you could do anything with expressions. Thanks for the education!

Eric

[Dan Ebberts]

You may have deduced this, but just to clarify -- the only way to control a property with an expression is by applying an expression to that property. Expressions can't affect anything except the property to which they're applied.

Dan