Mapping JSON data to color ramp

[aoifem79461480]

Hi all! I'm trying to map values stored in a JSON file to a colour ramp in AE. Something like:

linear(myData.value, value_min, value_max, #FFFFFF, #000081)

...in the fill colour property, if the linear expression could be used in this way. So taking a value from my dataset, figuring out where it sits along the colour gradient and applying that fill colour to the shape.

Is there a way to do this with expressions in AE?

[Mylenium]

No such thing. Controls contained in sub-dialogs and custom controls cannot be accessed with expressions and in many cases not even with scripts when the "data blob" formatting isn't known. That's the iron rule of AE. whatever you have in mind will require a different approach like using the Ramp or Tint effects to colorize your artwork.

Mylenium

[Mathias Moehl]

In expressions, colors are arrays [red,green,blue,alpha] with values between 0 and 1. Linear can work with those. The only thing you need to do is to convert your #FFFFFF to the corresponding array [0,0,0,1].

My free tool mamoworldJSON has this conversion build-in and supports (i.e. converts) color values of the form #FFFFFF to the required arrays out of the box.
If you don't want to use mamoworldJSON and rather implement it yourself - this is how it works:

function hexStringToColorArray(val){
var colorString = /([0-9a-fA-F]{6})/.exec(val)[1];
var color = [];
color[0] = parseInt(colorString.substr(0,2),16)/255;
color[1] = parseInt(colorString.substr(2,2),16)/255;
color[2] = parseInt(colorString.substr(4,2),16)/255;
color[3] = 1;
return color;
}
linear(myData.value,value_min,value_max,hexStringToColorArray("#FFFFFF"),hexStringToColorArray("#000081"))

[aoifem79461480 · Accepted solution]

Just an update – I managed to make this work using the hexToRgb() expression!

linear(myData.value, value_min, value_max, hexToRgb("FFFFFF"), hexToRgb("000081"))

[Mathias Moehl]

Oh, yes, expressions has its own implementation to convert hex to RGB! So my solution is unnecessarily complicated.