Add gradient feature.

[aurium]

Methods for two color models: gradientRGB and gradientHSL.
The gradientHSL supports clokwise and counterclokwise hue rotations.

[Qix-]

What's the point of this? Why not use .mix()? seems like this is gold plating.

[aurium]

To do a gradient, mix is more computationally costly.

[aurium]

The Travis errors are not related to my patch... Node 0.12 still a valid target?

[Qix-]

Note that some of the above below (github keeps changing) comments apply to both functions.

---

I did a benchmark and the gradient function is indeed faster for steps >= 4.

const Color = require('./color');
const benchmark = require('benchmark');

const srcColor = new Color('#FF0000');
const destColor = new Color('#00FF00');

new benchmark.Suite()
	.add('mix3', function () {
		const gradient = [
			srcColor,
			srcColor.mix(destColor, 0.5),
			destColor
		];
	})
	.add('grad3', function () {
		const gradient = srcColor.gradientRGB(destColor, 3);
	})
	.on('cycle', function(event) {
		console.log(String(event.target));
	})
	.on('complete', function() {
		console.log('Fastest is ' + this.filter('fastest').map('name'));
	})
	.run({ 'async': true });


new benchmark.Suite()
	.add('mix4', function () {
		const gradient = [
			srcColor,
			srcColor.mix(destColor, 0.33),
			srcColor.mix(destColor, 0.66),
			destColor
		];
	})
	.add('grad4', function () {
		const gradient = srcColor.gradientRGB(destColor, 4);
	})
	.on('cycle', function(event) {
		console.log(String(event.target));
	})
	.on('complete', function() {
		console.log('Fastest is ' + this.filter('fastest').map('name'));
	})
	.run({ 'async': true });


new benchmark.Suite()
	.add('mix5', function () {
		const gradient = [
			srcColor,
			srcColor.mix(destColor, 0.25),
			srcColor.mix(destColor, 0.5),
			srcColor.mix(destColor, 0.75),
			destColor
		];
	})
	.add('grad5', function () {
		const gradient = srcColor.gradientRGB(destColor, 5);
	})
	.on('cycle', function(event) {
		console.log(String(event.target));
	})
	.on('complete', function() {
		console.log('Fastest is ' + this.filter('fastest').map('name'));
	})
	.run({ 'async': true });

[Qix-]

The Travis errors are not related to my patch... Node 0.12 still a valid target?

No, don't worry about CI. I'll let you know if there are any actionable items. This package needs to be refreshed sometime soon anyway - 0.12 will be removed, but not before this PR is merged unfortunately.

[aurium]

Hi @Qix-, is this ok? Do you need any help with this repo?

[Qix-]

See https://github.com/Qix-/color/pull/158#issuecomment-558352861 on why changes take forever for me to merge.

[aurium]

There is a channel where you share your thoughts about this? A page at @Qix-/color/wiki maybe?
Do you use Telegram? You can find me with this same @name there.