Kelvin color temperature to RGB convertor
npm install color-temperaturecolor-temperature
=================
Converts color temperature in Kelvin to a color in RGB color space -- and vice versa.
The conversion is designed to be fast and usable for image processing. More details on color temperature and the algorithm can be found here.
$ npm install --save color-temperture
``js
var ct = require('color-temperature');
//convert kelvin to RGB
// eg convert typical candlelight (1850K ) to RGB
var rgb = ct.colorTemperature2rgb(1850);
var red = rgb.red;
var green = rgb.green;
var blue = rgb.blue;
`
RGB color is represented in JSON format: An RGB of [0, 128, 255] would be represented as
`js`
{
red : 0,
green : 128,
blue : 255
}Examples
Often, the convertor is deployed as part of an image processing loop. The following example uses streams to generate a PNG similar to that at the top of this README file.
`js
var fs = require('fs');
var png_encoder = require('png-stream');
var ct = require('color-temperature');
var width = 500;
var height = 100;
var kelvinStart = 10;
var kelvinEnd = 40000;
var pixels = new Buffer(width height 3);
for (var w = 0; w < width; w += 1) {
for (var h = 0; h < height; h += 1) {
var i = ((hwidth)+w)3;
kelvin = ((kelvinEnd-kelvinStart)/width)* w + kelvinStart;
var rgb = ct.colorTemperature2rgb(kelvin);
pixels[i] = rgb.red;
pixels[i + 1] = rgb.green;
pixels[i + 2] = rgb.blue;
}
}
var enc = new png_encoder.Encoder(width, height);
enc.pipe(fs.createWriteStream('color-temperature-'+kelvinStart+'-'+kelvinEnd+'.png'));
enc.end(pixels);
`
There are examples in the examples directory.
NOTE The conversions use approximations and are suitable for photo-mainpulation and other non-critical uses.
Accuracy is best between 1000K and 40000K.
`js`
require('color-temperature').colorTemperature2rgb(kelvin);
Convert a color temperature in Kelvin to RGB.
This method uses an approximation based on a curve fit of data from a sparse RGB to
Kelvin mapping.
`js`
require('color-temperature').colorTemperature2rgbUsingTH(kelvin);
A JavaScript port of the original algorithm from Tanner Helland. This method
is mainly here for comparison purposes. Generally, colorTemperature2rgb provides more
accurate results.
`js``
require('color-temperature').rgb2colorTemperature(rgb);
Convert a color in RGB format to a color temperature in Kelvin.
The code is released under an MIT license.
* 0.1.0 Initial release
