Delta monkey patch about chroma.js

[gka]

Is this possibly the same as chroma.interpolate, which I totally forgot to mention in the API docs...

chroma.color('red').interpolate(0.5, 'yellow').hex() // "#ff7f00"

// alternative API
chroma.interpolate('red', 'yellow', 0.5);

Works with all color spaces.

[ericvoid]

What I mean by delta is the difference between colors, or the distance of two colors. See the following fiddle:

http://jsfiddle.net/JKYM2/1/

In the "Delta" section I calculated the distance between the green and the orange colors, and then added the distance to the orange, creating the pink color.

So in this way, the interpolation is useful to find colors between two others, and the delta is useful to "advance" given a distance of two colors.

ps: I found a bug on the code above. the add function should be:

chroma.add = function (color, delta) { 
    var c_ = color.hcl(); 
    return chroma.hcl(c_[0] + delta[0], c_[1] + delta[1], c_[2] + delta[2]); 
};

And subtract:

chroma.subtract = function (color, delta) { 
    var c_ = color.hcl(); 
    return chroma.hcl(c_[0] - delta[0], c_[1] - delta[1], c_[2] - delta[2]); 
};

[gka]

So you mean extrapolation. You do the same via:

c.interpolate(2, c1, 'lch');

see this: http://jsfiddle.net/JKYM2/2/

[ericvoid]

Sort of. You can obviously use it for extrapolation.

You could use it to compare two colors, for example to check the distance, create new ones or fix a color.

You could also add arbitrary values, for example I could create a delta of 30 degrees on hue and use it to find the harmonies.

As time libraries has "delta-time" classes to operate on dates and times, I think it would be useful to have "delta-color" on this one.