"poline" is an enigmatic color palette generator, that harnesses the mystical witchcraft of polar coordinates. Its methodology, defying conventional color science, is steeped in the esoteric knowledge of the early 20th century. This magical technology defies explanation, drawing lines between anchors to produce visually striking and otherworldly palettes. It is an indispensable tool for the modern generative sorcerer, and a delight for the eye.

The use of "Poline" begins with the invocation of its command, which can be performed with or without arguments. If called without, the tool will generate a mesmerizing palette featuring two randomly selected anchors. On the other hand, one can choose to provide their own anchor points, represented as a list of hsl values, for a more personal touch. The power to shape and mold the colors lies in your hands."

new Poline({
  anchorColors: [
    [309, 0.72, 0.80],
    [67, 0.32, 0.08],
    //...
  ],
});

The magic of "Poline" is revealed through its technique of drawing lines between anchor points. The richness of the palette is determined by the number of points, with each connection producing a unique color.

Increasing the number of points will yield an even greater array of colors. By default, four points are used, but this can easily be adjusted through the 'numPoints' property on your Poline instance, as demonstrated in the code example.

new Poline({
  numPoints: 6,
});

The resulting palette is a product of points multiplied by the number of anchor pairs. It can be changed after initialization by setting the numPoints property on your "Poline" instance.

At the heart of "Poline" lies the concept of anchors, the fixed points that serve as the foundation for the creation of color palettes. Anchors are represented as a list of hsl values, which consist of three components: hue [0…360], saturation [0…1], and lightness [0…1].

The choice is yours, whether to provide your own anchor points during initialization or to allow "Poline" to generate a random selection for you by omitting the 'anchorColors' argument. The versatility of Poline extends "Poline" its initial setup, as you can also add anchors to your palette at any time using the 'addAnchor' method. This method accepts either a color as HSL array values or an array of X, Y, Z coordinates, further expanding the possibilities of your color creation.

poline.addAnchorPoint({
  color: [100, 0.91, 0.80]
});

// or

poline.addAnchorPoint({
  xyz: [0.43, 0.89, 0.91]
});

With this feature, you have the power to fine-tune your palette and make adjustments as your creative vision evolves. So whether you are looking to make subtle changes or bold alterations, "Poline" is always ready to help you achieve your desired result.

The ability to update existing anchors is made possible through the 'updateAnchorPoint' method. This method accepts the reference to the anchor you wish to modify and either a color in the form of HSL representation or an XYZ position array.

poline.updateAnchorPoint({
  point: poline.anchorPoints[0],
  color: [286, 0.22, 0.22]
});

The position function in "Poline" plays a crucial role in determining the distribution of colors between the anchors. It works similar to easing functions and can be imported from the "Poline" module.

A position function is a mathematical function that maps a value between 0 and 1 to another value between 0 and 1. By definition the same position function for all axes "Poline" will draw a straight line between the anchors. The chosen function will determine the distribution of colors between the anchors.

import {
Poline, positionFunctions
} from 'poline';

new Poline({
  positionFunction: 
    positionFunctions.linearPosition,
});

If none is provided, "Poline" will use the default function, which is a sinusoidal function. The following position functions are available and can be included by importing the positionFunctions object from the "Poline" module:

• linearPosition
• exponentialPosition
• quadraticPosition
• cubicPosition
• quarticPosition
• sinusoidalPosition (default)
• asinusoidalPosition
• arcPosition

By defining different position functions for each axis, you can control the distribution of colors along each axis (positionFunctionX, positionFunctionY, positionFunctionZ). This will draw different arcs and create a diverse range of color palettes.

new Poline({
  positionFunctionX: 
    positionFunctions.sinusoidalPosition,
  positionFunctionY: 
    positionFunctions.quadraticPosition,
  positionFunctionZ: 
    positionFunctions.linearPosition,
});

By default, the palette is not a closed loop. This means that the last color generated is not the same as the first color. If you want the palette to be a closed loop, you can set the closedLoop argument to true.

poline.closedLoop = true;

It is also possible to close the loop after the fact by setting poline.closedLoop = true|false.

With the power of hue shifting, "Poline" provides yet another level of customization. This feature allows you to shift the hue of the colors generated by a certain amount, giving you the ability to animate your palette or create similar color combinations with different hues."

"poline" supports hue shifting. This means that the hue of the colors will be shifted by a certain amount. This can be useful if you want to animate the palette or generate a palette that looks similar to your current palette but using different hues.

poline.shiftHue(1);

The amount is a int or float between -Infinity and Infinity. It will permanently shift the hue of all colors in the palette.

In some situations, you might want to know which anchor is closest to a certain position or color. This method is used in the visualizer to highlight to select the closest anchor on click.

poline.getClosestAnchorPoint(
  {xyz: [x, y, null], maxDistance: .1}
)

The maxDistance argument is optional and will return null if the closest anchor is further away than the maxDistance. Any of the xyz or hsl components can be null. If they are null, they will be ignored.

The 'poline' instance returns all colors as an array of hsl arrays or alternatively as an array of CSS strings.

poline.colors
poline.colorsCSS

To remove an anchor, you can use the removeAnchorPoint method. It either takes an anchor reference or an index as an argument.

poline.removeAnchorPoint({
  point: poline.anchorPoints[
    poline.anchorPoints.length - 1
  ]
});
  // or
poline.removeAnchorPoint({
  index: poline.anchorPoints.length - 1
});

To keep the library as lightweight as possible, "poline" only supports the hsl color model out of the box. However, it is easily possible to use other color models by using a library like culori.

import {Poline} from "poline";
import {formatHex} from "culori";
const poline = new Poline(/** options */);

const OKHslColors = [...poline.colors].map(
  c => formatHex({ 
    mode: 'okhsl', 
    {
      h: c.hsl[0], 
      s: c.hsl[1], 
      l: c.hsl[2]}
  })
);
const LCHColors = [...poline.colors].map(
  c => formatHex({ 
    mode: 'lch', 
    { 
      h: hsl[0],
      c: hsl[1] * 51.484,
      l: hsl[2] * 100,  
    }
  })
);

"poline" is available as an npm package. Alternatively you can clone it on GitHub.

npm install poline

You can also use the unpkg CDN to include the library in your project. I recommend using the mjs version of the library. This will allow you to use the import syntax. But you can also use the umd version if you prefer to use the script tag.

import { 
  Poline 
} from 'https://unpkg.com/poline?module'

And thus, the tome of "poline" has been written. Its mystical powers, steeped in the arcane knowledge of the ancients, now reside within these pages. May this compendium serve you in your quest for the ultimate color palette.

The project is MIT licensed and open source. If you find any bugs or have any suggestions please open an issue on GitHub.

Inspired and created with the blessing of Anatoly Zenkov