Changing colour based on another layers colour

[Chris Craig]

This is what i thin i need to do, but its not working for me.

color1 = [0.6667, 0.7098, 0.1137, 1];
color2 = [0.6078, 0.0392, 0.3176, 1];
color3 = [0.3137, 0.6392, 0.7294, 1];

n = thisComp.layer(“Controller”).effect(“BG Colour”)(“Color”);
if (n==color1) {
color2
} else if (n==color2) {
color1
} else if (n==color3) {
color2
} else {
0
}

Thanks
Chris

[Dan Ebberts]

To make that work, you’ll have to test each of the r,g,b components of the color array like this:

if (n[0]==color1[0] && n[1]==color1[1] && n[2]==color1[2]) {

… and the numbers will have to match exactly. How do your background colors get decided? It might be simpler to use that same decision to drive both colors.

Dan

[Chris Craig]

Hi Dan

I have a guide layer with a strict colour pallet, that the user will choose with the eye dropper. This effect is on a null, acting as the Master controller, and also on the BG and Text comp layers. The latter is expressed to the master controller Null.

Each BG colour has a correspsonding colour to it, which i wanted to make automatic.

There are about 8-10 different BG colours to choose from.

Thanks once again

Chris

[Dan Ebberts]

I think you’ll need to add a tolerance value to your comparisons, like this:

function colorMatch(a,b){
tolerance = .001;
for (i = 0; i < a.length; i++){ if (Math.abs(a[i] - b[i]) > tolerance) return false;
}
return true;
}

color1 = [0.6667, 0.7098, 0.1137, 1];
color2 = [0.6078, 0.0392, 0.3176, 1];
color3 = [0.3137, 0.6392, 0.7294, 1];

n = thisComp.layer(“Controller”).effect(“BG Colour”)(“Color”).value;
if (colorMatch(n,color1) ){
color2
} else if (colorMatch(n,color2)) {
color1
} else if (colorMatch(n,color3)) {
color2
} else {
[0,0,0,1]
}

Dan

[Chris Craig]

Thank you so much Dan. That is working perfectly.

Can you please tell me what you mean by tolerance though and what it is doing?

Thank you again
Chris

[Dan Ebberts]

Sure. Looking at your color1 value, it was pretty clear that in the Fill effect that color is represented as [170,181,29]. When those values are retreived by an expression, they get normalized so they are between 0.0 and 1.0. So, for example, the 170 becomes 0.66666666…., which is clearly never going to exactly match your comparison value of 0.6667. So I just set up a little routine that says if the value retrieved from the Fill effect is within a tolerance of .001 from the value in your array, that’s close enough and is considered a match.

Dan

[Chris Craig]

ahhh.Thank you very much Dan. Thats perfect.
c.