LookupTable

var LookupTable = require('paraviewweb/src/Common/Core/LookupTable'),
    instance = new LookupTable('Temperature');

constructor(name)

Create an instance of a LookupTable while giving it a name.
Usually we use the field name that we want to use
that LookupTable for.

getName() : String

Return the name of the given LookupTable.

getPresets() : [ String… ]

Return the names of the available presets.

setPreset(name)

Use a preset to configure the current instance. This will reset all the
control points and use the one defined inside the preset.

This will trigger the following change event:

{
    change: 'preset',
    lut: lutInstance
}

getScalarRange() : [min, max]

Return the scalar range the LookupTable is using.

setScalarRange(min, max)

Update the scalar range that LookupTable is using.

build(trigger)

This generate a precomputed table for the lookuptable.

If trigger is true, this will trigger the following change event:

{
    change: 'controlPoints',
    lut: lutInstance
}

setNumberOfColors( numberOfColors )

Set the number of colors to be used for the concrete scalar to color mapping.

This will trigger the following change event:

{
    change: 'numberOfColors',
    lut: lutInstance
}

getNumberOfControlPoints() : Number

Return the number of control points used to define the color map.

removeControlPoint(idx) : Boolean

Removes the provided control point index and returns true if the index is
valid and the point was removed, the method will otherwise return false.

getControlPoint(idx) : {x, r, g, b}

Return the control point defined at the provided index.

updateControlPoint(idx, xrgb) : Number

Update the control point defined in the given index by replacing it with the
provided object. The control points will be reset and the table rebuilt.

The method will return the index of the updated control point which could be different if the x value is different.

addControlPoint(xrgb) : Number

Add a new control point and return its corresponding index while rebuilding
the full index map.

A control point should be composed of four fields x, r, g and b with a number between 0 and 1.

var xrgb = {
    x: 0.5,
    r: 1,
    g: 0,
    b: 0.1
};

drawToCanvas(canvas)

Draw the index map into the canvas using a height of 1 pixel and a width corresponding to the number of colors defined.

getColor(scalar) : [r, g, b]

Return the color that should be used for a given scalar value. If the value is outside the scalar range, then the last color defined for that edge will be used.

onChange(callback) : subscription

Helper method used to attach a listener to the topic that is used when the LookupTable change. We rely on Monologue.js for our observer pattern.

destroy()

Remove any listener attached to this LookupTable instance.

Source

Presets.js

/* eslint-disable no-multi-spaces */
export default {
  lookuptables: {
    spectralflip: {
      controlpoints: [
        {
          x: 0,
          r: 0.3686274509803922,
          g: 0.3098039215686275,
          b: 0.6352941176470588,
        },
        {
          x: 0.1,
          r: 0.196078431372549,
          g: 0.5333333333333333,
          b: 0.7411764705882353,
        },
        { x: 0.2, r: 0.4, g: 0.7607843137254902, b: 0.6470588235294118 },
        {
          x: 0.3,
          r: 0.6705882352941176,
          g: 0.8666666666666667,
          b: 0.6431372549019608,
        },
        {
          x: 0.4,
          r: 0.9019607843137255,
          g: 0.9607843137254902,
          b: 0.596078431372549,
        },
        { x: 0.5, r: 1, g: 1, b: 0.7490196078431373 },
        {
          x: 0.6,
          r: 0.996078431372549,
          g: 0.8784313725490196,
          b: 0.5450980392156862,
        },
        {
          x: 0.7,
          r: 0.9921568627450981,
          g: 0.6823529411764706,
          b: 0.3803921568627451,
        },
        {
          x: 0.8,
          r: 0.9568627450980393,
          g: 0.4274509803921568,
          b: 0.2627450980392157,
        },
        {
          x: 0.9,
          r: 0.8352941176470589,
          g: 0.2431372549019608,
          b: 0.3098039215686275,
        },
        {
          x: 1,
          r: 0.6196078431372549,
          g: 0.00392156862745098,
          b: 0.2588235294117647,
        },
      ],
      range: [0.0, 1.0],
    },
    cold2warm: {
      controlpoints: [
        { x: 0.0, r: 0.23137254902, g: 0.298039215686, b: 0.752941176471 },
        { x: 0.5, r: 0.865, g: 0.865, b: 0.865 },
        { x: 1.0, r: 0.705882352941, g: 0.0156862745098, b: 0.149019607843 },
      ],
      range: [0.0, 1.0],
    },
    rainbow: {
      controlpoints: [
        { x: 0.0, r: 0.0, g: 0.0, b: 1.0 },
        { x: 0.25, r: 0.0, g: 1.0, b: 1.0 },
        { x: 0.5, r: 0.0, g: 1.0, b: 0.0 },
        { x: 0.75, r: 1.0, g: 1.0, b: 0.0 },
        { x: 1.0, r: 1.0, g: 0.0, b: 0.0 },
      ],
      range: [0.0, 1.0],
    },
    'gray scale': {
      controlpoints: [
        { x: 0.0, r: 0.0, g: 0.0, b: 0.0 },
        { x: 1.0, r: 1.0, g: 1.0, b: 1.0 },
      ],
      range: [0.0, 1.0],
    },
    'gray scale flip': {
      controlpoints: [
        { x: 0.0, r: 1.0, g: 1.0, b: 1.0 },
        { x: 1.0, r: 0.0, g: 0.0, b: 0.0 },
      ],
      range: [0.0, 1.0],
    },
    spectral: {
      controlpoints: [
        {
          x: 0,
          r: 0.6196078431372549,
          g: 0.00392156862745098,
          b: 0.2588235294117647,
        },
        {
          x: 0.1,
          r: 0.8352941176470589,
          g: 0.2431372549019608,
          b: 0.3098039215686275,
        },
        {
          x: 0.2,
          r: 0.9568627450980393,
          g: 0.4274509803921568,
          b: 0.2627450980392157,
        },
        {
          x: 0.3,
          r: 0.9921568627450981,
          g: 0.6823529411764706,
          b: 0.3803921568627451,
        },
        {
          x: 0.4,
          r: 0.996078431372549,
          g: 0.8784313725490196,
          b: 0.5450980392156862,
        },
        { x: 0.5, r: 1, g: 1, b: 0.7490196078431373 },
        {
          x: 0.6,
          r: 0.9019607843137255,
          g: 0.9607843137254902,
          b: 0.596078431372549,
        },
        {
          x: 0.7,
          r: 0.6705882352941176,
          g: 0.8666666666666667,
          b: 0.6431372549019608,
        },
        { x: 0.8, r: 0.4, g: 0.7607843137254902, b: 0.6470588235294118 },
        {
          x: 0.9,
          r: 0.196078431372549,
          g: 0.5333333333333333,
          b: 0.7411764705882353,
        },
        {
          x: 1,
          r: 0.3686274509803922,
          g: 0.3098039215686275,
          b: 0.6352941176470588,
        },
      ],
      range: [0.0, 1.0],
    },
    warm: {
      controlpoints: [
        {
          x: 0.0,
          r: 0.4745098039215686,
          g: 0.09019607843137255,
          b: 0.09019607843137255,
        },
        {
          x: 0.2,
          r: 0.7098039215686275,
          g: 0.00392156862745098,
          b: 0.00392156862745098,
        },
        {
          x: 0.4,
          r: 0.9372549019607843,
          g: 0.2784313725490196,
          b: 0.09803921568627451,
        },
        {
          x: 0.6,
          r: 0.9764705882352941,
          g: 0.5137254901960784,
          b: 0.1411764705882353,
        },
        { x: 0.8, r: 1.0, g: 0.7058823529411765, b: 0.0 },
        { x: 1.0, r: 1.0, g: 0.8980392156862745, b: 0.02352941176470588 },
      ],
      range: [0.0, 1.0],
    },
    cool: {
      controlpoints: [
        {
          x: 0,
          r: 0.4588235294117647,
          g: 0.6941176470588235,
          b: 0.00392156862745098,
        },
        {
          x: 0.1666666666666667,
          r: 0.3450980392156863,
          g: 0.5019607843137255,
          b: 0.1607843137254902,
        },
        {
          x: 0.3333333333333333,
          r: 0.3137254901960784,
          g: 0.8431372549019608,
          b: 0.7490196078431373,
        },
        {
          x: 0.5,
          r: 0.1098039215686274,
          g: 0.5843137254901961,
          b: 0.803921568627451,
        },
        {
          x: 0.6666666666666666,
          r: 0.2313725490196079,
          g: 0.407843137254902,
          b: 0.6705882352941176,
        },
        {
          x: 0.8333333333333334,
          r: 0.6039215686274509,
          g: 0.407843137254902,
          b: 1,
        },
        { x: 1, r: 0.3725490196078431, g: 0.2, b: 0.5019607843137255 },
      ],
      range: [0.0, 1.0],
    },
    blues: {
      controlpoints: [
        {
          x: 0,
          r: 0.2313725490196079,
          g: 0.407843137254902,
          b: 0.6705882352941176,
        },
        {
          x: 0.1666666666666667,
          r: 0.1098039215686274,
          g: 0.5843137254901961,
          b: 0.803921568627451,
        },
        {
          x: 0.3333333333333333,
          r: 0.3058823529411765,
          g: 0.8509803921568627,
          b: 0.9176470588235294,
        },
        {
          x: 0.5,
          r: 0.4509803921568628,
          g: 0.6039215686274509,
          b: 0.8352941176470589,
        },
        {
          x: 0.6666666666666666,
          r: 0.2588235294117647,
          g: 0.2392156862745098,
          b: 0.6627450980392157,
        },
        {
          x: 0.8333333333333334,
          r: 0.3137254901960784,
          g: 0.3294117647058823,
          b: 0.5294117647058824,
        },
        {
          x: 1,
          r: 0.06274509803921569,
          g: 0.1647058823529412,
          b: 0.3215686274509804,
        },
      ],
      range: [0.0, 1.0],
    },
    wildflower: {
      controlpoints: [
        {
          x: 0,
          r: 0.1098039215686274,
          g: 0.5843137254901961,
          b: 0.803921568627451,
        },
        {
          x: 0.1666666666666667,
          r: 0.2313725490196079,
          g: 0.407843137254902,
          b: 0.6705882352941176,
        },
        {
          x: 0.3333333333333333,
          r: 0.4,
          g: 0.2431372549019608,
          b: 0.7176470588235294,
        },
        {
          x: 0.5,
          r: 0.6352941176470588,
          g: 0.3294117647058823,
          b: 0.8117647058823529,
        },
        {
          x: 0.6666666666666666,
          r: 0.8705882352941177,
          g: 0.3803921568627451,
          b: 0.807843137254902,
        },
        {
          x: 0.8333333333333334,
          r: 0.8627450980392157,
          g: 0.3803921568627451,
          b: 0.5843137254901961,
        },
        {
          x: 1,
          r: 0.2392156862745098,
          g: 0.06274509803921569,
          b: 0.3215686274509804,
        },
      ],
      range: [0.0, 1.0],
    },
    citrus: {
      controlpoints: [
        {
          x: 0,
          r: 0.396078431372549,
          g: 0.4862745098039216,
          b: 0.2156862745098039,
        },
        {
          x: 0.2,
          r: 0.4588235294117647,
          g: 0.6941176470588235,
          b: 0.00392156862745098,
        },
        {
          x: 0.4,
          r: 0.6980392156862745,
          g: 0.7294117647058823,
          b: 0.1882352941176471,
        },
        { x: 0.6, r: 1, g: 0.8980392156862745, b: 0.02352941176470588 },
        { x: 0.8, r: 1, g: 0.7058823529411765, b: 0 },
        {
          x: 1,
          r: 0.9764705882352941,
          g: 0.5137254901960784,
          b: 0.1411764705882353,
        },
      ],
      range: [0.0, 1.0],
    },
    organge2purple: {
      controlpoints: [
        {
          x: 0,
          r: 0.4980392156862745,
          g: 0.2313725490196079,
          b: 0.03137254901960784,
        },
        {
          x: 0.1,
          r: 0.7019607843137254,
          g: 0.3450980392156863,
          b: 0.02352941176470588,
        },
        {
          x: 0.2,
          r: 0.8784313725490196,
          g: 0.5098039215686274,
          b: 0.07843137254901961,
        },
        {
          x: 0.3,
          r: 0.9921568627450981,
          g: 0.7215686274509804,
          b: 0.3882352941176471,
        },
        {
          x: 0.4,
          r: 0.996078431372549,
          g: 0.8784313725490196,
          b: 0.7137254901960784,
        },
        {
          x: 0.5,
          r: 0.9686274509803922,
          g: 0.9686274509803922,
          b: 0.9686274509803922,
        },
        {
          x: 0.6,
          r: 0.8470588235294118,
          g: 0.8549019607843137,
          b: 0.9215686274509803,
        },
        {
          x: 0.7,
          r: 0.6980392156862745,
          g: 0.6705882352941176,
          b: 0.8235294117647058,
        },
        {
          x: 0.8,
          r: 0.5019607843137255,
          g: 0.4509803921568628,
          b: 0.6745098039215687,
        },
        {
          x: 0.9,
          r: 0.3294117647058823,
          g: 0.1529411764705882,
          b: 0.5333333333333333,
        },
        { x: 1, r: 0.1764705882352941, g: 0, b: 0.2941176470588235 },
      ],
      range: [0.0, 1.0],
    },
    brown2green: {
      controlpoints: [
        {
          x: 0,
          r: 0.3294117647058823,
          g: 0.1882352941176471,
          b: 0.0196078431372549,
        },
        {
          x: 0.1,
          r: 0.5490196078431373,
          g: 0.3176470588235294,
          b: 0.0392156862745098,
        },
        {
          x: 0.2,
          r: 0.7490196078431373,
          g: 0.5058823529411764,
          b: 0.1764705882352941,
        },
        {
          x: 0.3,
          r: 0.8745098039215686,
          g: 0.7607843137254902,
          b: 0.4901960784313725,
        },
        {
          x: 0.4,
          r: 0.9647058823529412,
          g: 0.9098039215686274,
          b: 0.7647058823529411,
        },
        {
          x: 0.5,
          r: 0.9607843137254902,
          g: 0.9607843137254902,
          b: 0.9607843137254902,
        },
        {
          x: 0.6,
          r: 0.7803921568627451,
          g: 0.9176470588235294,
          b: 0.8980392156862745,
        },
        {
          x: 0.7,
          r: 0.5019607843137255,
          g: 0.803921568627451,
          b: 0.7568627450980392,
        },
        {
          x: 0.8,
          r: 0.207843137254902,
          g: 0.592156862745098,
          b: 0.5607843137254902,
        },
        { x: 0.9, r: 0.00392156862745098, g: 0.4, b: 0.3686274509803922 },
        { x: 1, r: 0, g: 0.2352941176470588, b: 0.1882352941176471 },
      ],
      range: [0.0, 1.0],
    },
    blue2green: {
      controlpoints: [
        {
          x: 0,
          r: 0.9686274509803922,
          g: 0.9882352941176471,
          b: 0.9921568627450981,
        },
        {
          x: 0.125,
          r: 0.8980392156862745,
          g: 0.9607843137254902,
          b: 0.9764705882352941,
        },
        { x: 0.25, r: 0.8, g: 0.9254901960784314, b: 0.9019607843137255 },
        { x: 0.375, r: 0.6, g: 0.8470588235294118, b: 0.788235294117647 },
        { x: 0.5, r: 0.4, g: 0.7607843137254902, b: 0.6431372549019608 },
        {
          x: 0.625,
          r: 0.2549019607843137,
          g: 0.6823529411764706,
          b: 0.4627450980392157,
        },
        {
          x: 0.75,
          r: 0.1372549019607843,
          g: 0.5450980392156862,
          b: 0.2705882352941176,
        },
        { x: 0.875, r: 0, g: 0.4274509803921568, b: 0.1725490196078431 },
        { x: 1, r: 0, g: 0.2666666666666667, b: 0.1058823529411765 },
      ],
      range: [0.0, 1.0],
    },
    yellow2brown: {
      controlpoints: [
        { x: 0, r: 1, g: 1, b: 0.8980392156862745 },
        { x: 0.125, r: 1, g: 0.9686274509803922, b: 0.7372549019607844 },
        {
          x: 0.25,
          r: 0.996078431372549,
          g: 0.8901960784313725,
          b: 0.5686274509803921,
        },
        {
          x: 0.375,
          r: 0.996078431372549,
          g: 0.7686274509803922,
          b: 0.3098039215686275,
        },
        { x: 0.5, r: 0.996078431372549, g: 0.6, b: 0.1607843137254902 },
        {
          x: 0.625,
          r: 0.9254901960784314,
          g: 0.4392156862745098,
          b: 0.07843137254901961,
        },
        { x: 0.75, r: 0.8, g: 0.2980392156862745, b: 0.007843137254901961 },
        { x: 0.875, r: 0.6, g: 0.203921568627451, b: 0.01568627450980392 },
        { x: 1, r: 0.4, g: 0.1450980392156863, b: 0.02352941176470588 },
      ],
      range: [0.0, 1.0],
    },
    blue2purple: {
      controlpoints: [
        {
          x: 0,
          r: 0.9686274509803922,
          g: 0.9882352941176471,
          b: 0.9921568627450981,
        },
        {
          x: 0.125,
          r: 0.8784313725490196,
          g: 0.9254901960784314,
          b: 0.9568627450980393,
        },
        {
          x: 0.25,
          r: 0.7490196078431373,
          g: 0.8274509803921568,
          b: 0.9019607843137255,
        },
        {
          x: 0.375,
          r: 0.6196078431372549,
          g: 0.7372549019607844,
          b: 0.8549019607843137,
        },
        {
          x: 0.5,
          r: 0.5490196078431373,
          g: 0.5882352941176471,
          b: 0.7764705882352941,
        },
        {
          x: 0.625,
          r: 0.5490196078431373,
          g: 0.4196078431372549,
          b: 0.6941176470588235,
        },
        {
          x: 0.75,
          r: 0.5333333333333333,
          g: 0.2549019607843137,
          b: 0.615686274509804,
        },
        {
          x: 0.875,
          r: 0.5058823529411764,
          g: 0.05882352941176471,
          b: 0.4862745098039216,
        },
        { x: 1, r: 0.3019607843137255, g: 0, b: 0.2941176470588235 },
      ],
      range: [0.0, 1.0],
    },
    ocean: {
      controlpoints: [
        { x: 0.0, r: 0.039215, g: 0.090195, b: 0.25098 },
        { x: 0.125, r: 0.133333, g: 0.364706, b: 0.521569 },
        { x: 0.25, r: 0.321569, g: 0.760784, b: 0.8 },
        { x: 0.375, r: 0.690196, g: 0.960784, b: 0.894118 },
        { x: 0.5, r: 0.552941, g: 0.921569, b: 0.552941 },
        { x: 0.625, r: 0.329412, g: 0.6, b: 0.239216 },
        { x: 0.75, r: 0.211765, g: 0.34902, b: 0.078435 },
        { x: 0.875, r: 0.011765, g: 0.207843, b: 0.023525 },
        { x: 1.0, r: 0.286275, g: 0.294118, b: 0.301961 },
      ],
      range: [0.0, 1.0],
    },
    earth: {
      controlpoints: [
        { x: 0.0, r: 0.392157, g: 0.392157, b: 0.392157 },
        { x: 0.586175, r: 0.392157, g: 0.392157, b: 0.392157 },
        { x: 0.589041, r: 0.141176, g: 0.345098, b: 0.478431 },
        { x: 0.589042, r: 0.501961, g: 0.694118, b: 0.172549 },
        { x: 0.617699, r: 0.74902, g: 0.560784, b: 0.188235 },
        { x: 0.789648, r: 0.752941, g: 0.741176, b: 0.729412 },
        { x: 0.993079, r: 0.796078, g: 0.780392, b: 0.772549 },
        { x: 1.0, r: 0.796078, g: 0.780392, b: 0.772549 },
      ],
      range: [0.0, 1.0],
    },
  },
  swatches: {
    colors: [
      { r: 255, g: 255, b: 255 },
      { r: 204, g: 255, b: 255 },
      { r: 204, g: 204, b: 255 },
      { r: 204, g: 204, b: 255 },
      { r: 204, g: 204, b: 255 },
      { r: 204, g: 204, b: 255 },
      { r: 204, g: 204, b: 255 },
      { r: 204, g: 204, b: 255 },
      { r: 204, g: 204, b: 255 },
      { r: 204, g: 204, b: 255 },
      { r: 204, g: 204, b: 255 },
      { r: 255, g: 204, b: 255 },
      { r: 255, g: 204, b: 204 },
      { r: 255, g: 204, b: 204 },
      { r: 255, g: 204, b: 204 },
      { r: 255, g: 204, b: 204 },
      { r: 255, g: 204, b: 204 },
      { r: 255, g: 204, b: 204 },
      { r: 255, g: 204, b: 204 },
      { r: 255, g: 204, b: 204 },
      { r: 255, g: 204, b: 204 },
      { r: 255, g: 255, b: 204 },
      { r: 204, g: 255, b: 204 },
      { r: 204, g: 255, b: 204 },
      { r: 204, g: 255, b: 204 },
      { r: 204, g: 255, b: 204 },
      { r: 204, g: 255, b: 204 },
      { r: 204, g: 255, b: 204 },
      { r: 204, g: 255, b: 204 },
      { r: 204, g: 255, b: 204 },
      { r: 204, g: 255, b: 204 },
      { r: 204, g: 204, b: 204 },
      { r: 153, g: 255, b: 255 },
      { r: 153, g: 204, b: 255 },
      { r: 153, g: 153, b: 255 },
      { r: 153, g: 153, b: 255 },
      { r: 153, g: 153, b: 255 },
      { r: 153, g: 153, b: 255 },
      { r: 153, g: 153, b: 255 },
      { r: 153, g: 153, b: 255 },
      { r: 153, g: 153, b: 255 },
      { r: 204, g: 153, b: 255 },
      { r: 255, g: 153, b: 255 },
      { r: 255, g: 153, b: 204 },
      { r: 255, g: 153, b: 153 },
      { r: 255, g: 153, b: 153 },
      { r: 255, g: 153, b: 153 },
      { r: 255, g: 153, b: 153 },
      { r: 255, g: 153, b: 153 },
      { r: 255, g: 153, b: 153 },
      { r: 255, g: 153, b: 153 },
      { r: 255, g: 204, b: 153 },
      { r: 255, g: 255, b: 153 },
      { r: 204, g: 255, b: 153 },
      { r: 153, g: 255, b: 153 },
      { r: 153, g: 255, b: 153 },
      { r: 153, g: 255, b: 153 },
      { r: 153, g: 255, b: 153 },
      { r: 153, g: 255, b: 153 },
      { r: 153, g: 255, b: 153 },
      { r: 153, g: 255, b: 153 },
      { r: 153, g: 255, b: 204 },
      { r: 204, g: 204, b: 204 },
      { r: 102, g: 255, b: 255 },
      { r: 102, g: 204, b: 255 },
      { r: 102, g: 153, b: 255 },
      { r: 102, g: 102, b: 255 },
      { r: 102, g: 102, b: 255 },
      { r: 102, g: 102, b: 255 },
      { r: 102, g: 102, b: 255 },
      { r: 102, g: 102, b: 255 },
      { r: 153, g: 102, b: 255 },
      { r: 204, g: 102, b: 255 },
      { r: 255, g: 102, b: 255 },
      { r: 255, g: 102, b: 204 },
      { r: 255, g: 102, b: 153 },
      { r: 255, g: 102, b: 102 },
      { r: 255, g: 102, b: 102 },
      { r: 255, g: 102, b: 102 },
      { r: 255, g: 102, b: 102 },
      { r: 255, g: 102, b: 102 },
      { r: 255, g: 153, b: 102 },
      { r: 255, g: 204, b: 102 },
      { r: 255, g: 255, b: 102 },
      { r: 204, g: 255, b: 102 },
      { r: 153, g: 255, b: 102 },
      { r: 102, g: 255, b: 102 },
      { r: 102, g: 255, b: 102 },
      { r: 102, g: 255, b: 102 },
      { r: 102, g: 255, b: 102 },
      { r: 102, g: 255, b: 102 },
      { r: 102, g: 255, b: 153 },
      { r: 102, g: 255, b: 204 },
      { r: 153, g: 153, b: 153 },
      { r: 51, g: 255, b: 255 },
      { r: 51, g: 204, b: 255 },
      { r: 51, g: 153, b: 255 },
      { r: 51, g: 102, b: 255 },
      { r: 51, g: 51, b: 255 },
      { r: 51, g: 51, b: 255 },
      { r: 51, g: 51, b: 255 },
      { r: 102, g: 51, b: 255 },
      { r: 153, g: 51, b: 255 },
      { r: 204, g: 51, b: 255 },
      { r: 255, g: 51, b: 255 },
      { r: 255, g: 51, b: 204 },
      { r: 255, g: 51, b: 153 },
      { r: 255, g: 51, b: 102 },
      { r: 255, g: 51, b: 51 },
      { r: 255, g: 51, b: 51 },
      { r: 255, g: 51, b: 51 },
      { r: 255, g: 102, b: 51 },
      { r: 255, g: 153, b: 51 },
      { r: 255, g: 204, b: 51 },
      { r: 255, g: 255, b: 51 },
      { r: 204, g: 255, b: 51 },
      { r: 153, g: 255, b: 51 },
      { r: 102, g: 255, b: 51 },
      { r: 51, g: 255, b: 51 },
      { r: 51, g: 255, b: 51 },
      { r: 51, g: 255, b: 51 },
      { r: 51, g: 255, b: 102 },
      { r: 51, g: 255, b: 153 },
      { r: 51, g: 255, b: 204 },
      { r: 153, g: 153, b: 153 },
      { r: 0, g: 255, b: 255 },
      { r: 0, g: 204, b: 255 },
      { r: 0, g: 153, b: 255 },
      { r: 0, g: 102, b: 255 },
      { r: 0, g: 51, b: 255 },
      { r: 0, g: 0, b: 255 },
      { r: 51, g: 0, b: 255 },
      { r: 102, g: 0, b: 255 },
      { r: 153, g: 0, b: 255 },
      { r: 204, g: 0, b: 255 },
      { r: 255, g: 0, b: 255 },
      { r: 255, g: 0, b: 204 },
      { r: 255, g: 0, b: 153 },
      { r: 255, g: 0, b: 102 },
      { r: 255, g: 0, b: 51 },
      { r: 255, g: 0, b: 0 },
      { r: 255, g: 51, b: 0 },
      { r: 255, g: 102, b: 0 },
      { r: 255, g: 153, b: 0 },
      { r: 255, g: 204, b: 0 },
      { r: 255, g: 255, b: 0 },
      { r: 204, g: 255, b: 0 },
      { r: 153, g: 255, b: 0 },
      { r: 102, g: 255, b: 0 },
      { r: 51, g: 255, b: 0 },
      { r: 0, g: 255, b: 0 },
      { r: 0, g: 255, b: 51 },
      { r: 0, g: 255, b: 102 },
      { r: 0, g: 255, b: 153 },
      { r: 0, g: 255, b: 204 },
      { r: 102, g: 102, b: 102 },
      { r: 0, g: 204, b: 204 },
      { r: 0, g: 204, b: 204 },
      { r: 0, g: 153, b: 204 },
      { r: 0, g: 102, b: 204 },
      { r: 0, g: 51, b: 204 },
      { r: 0, g: 0, b: 204 },
      { r: 51, g: 0, b: 204 },
      { r: 102, g: 0, b: 204 },
      { r: 153, g: 0, b: 204 },
      { r: 204, g: 0, b: 204 },
      { r: 204, g: 0, b: 204 },
      { r: 204, g: 0, b: 204 },
      { r: 204, g: 0, b: 153 },
      { r: 204, g: 0, b: 102 },
      { r: 204, g: 0, b: 51 },
      { r: 204, g: 0, b: 0 },
      { r: 204, g: 51, b: 0 },
      { r: 204, g: 102, b: 0 },
      { r: 204, g: 153, b: 0 },
      { r: 204, g: 204, b: 0 },
      { r: 204, g: 204, b: 0 },
      { r: 204, g: 204, b: 0 },
      { r: 153, g: 204, b: 0 },
      { r: 102, g: 204, b: 0 },
      { r: 51, g: 204, b: 0 },
      { r: 0, g: 204, b: 0 },
      { r: 0, g: 204, b: 51 },
      { r: 0, g: 204, b: 102 },
      { r: 0, g: 204, b: 153 },
      { r: 0, g: 204, b: 204 },
      { r: 102, g: 102, b: 102 },
      { r: 0, g: 153, b: 153 },
      { r: 0, g: 153, b: 153 },
      { r: 0, g: 153, b: 153 },
      { r: 0, g: 102, b: 153 },
      { r: 0, g: 51, b: 153 },
      { r: 0, g: 0, b: 153 },
      { r: 51, g: 0, b: 153 },
      { r: 102, g: 0, b: 153 },
      { r: 153, g: 0, b: 153 },
      { r: 153, g: 0, b: 153 },
      { r: 153, g: 0, b: 153 },
      { r: 153, g: 0, b: 153 },
      { r: 153, g: 0, b: 153 },
      { r: 153, g: 0, b: 102 },
      { r: 153, g: 0, b: 51 },
      { r: 153, g: 0, b: 0 },
      { r: 153, g: 51, b: 0 },
      { r: 153, g: 102, b: 0 },
      { r: 153, g: 153, b: 0 },
      { r: 153, g: 153, b: 0 },
      { r: 153, g: 153, b: 0 },
      { r: 153, g: 153, b: 0 },
      { r: 153, g: 153, b: 0 },
      { r: 102, g: 153, b: 0 },
      { r: 51, g: 153, b: 0 },
      { r: 0, g: 153, b: 0 },
      { r: 0, g: 153, b: 51 },
      { r: 0, g: 153, b: 102 },
      { r: 0, g: 153, b: 153 },
      { r: 0, g: 153, b: 153 },
      { r: 51, g: 51, b: 51 },
      { r: 0, g: 102, b: 102 },
      { r: 0, g: 102, b: 102 },
      { r: 0, g: 102, b: 102 },
      { r: 0, g: 102, b: 102 },
      { r: 0, g: 51, b: 102 },
      { r: 0, g: 0, b: 102 },
      { r: 51, g: 0, b: 102 },
      { r: 102, g: 0, b: 102 },
      { r: 102, g: 0, b: 102 },
      { r: 102, g: 0, b: 102 },
      { r: 102, g: 0, b: 102 },
      { r: 102, g: 0, b: 102 },
      { r: 102, g: 0, b: 102 },
      { r: 102, g: 0, b: 102 },
      { r: 102, g: 0, b: 51 },
      { r: 102, g: 0, b: 0 },
      { r: 102, g: 51, b: 0 },
      { r: 102, g: 102, b: 0 },
      { r: 102, g: 102, b: 0 },
      { r: 102, g: 102, b: 0 },
      { r: 102, g: 102, b: 0 },
      { r: 102, g: 102, b: 0 },
      { r: 102, g: 102, b: 0 },
      { r: 102, g: 102, b: 0 },
      { r: 51, g: 102, b: 0 },
      { r: 0, g: 102, b: 0 },
      { r: 0, g: 102, b: 51 },
      { r: 0, g: 102, b: 102 },
      { r: 0, g: 102, b: 102 },
      { r: 0, g: 102, b: 102 },
      { r: 0, g: 0, b: 0 },
      { r: 0, g: 51, b: 51 },
      { r: 0, g: 51, b: 51 },
      { r: 0, g: 51, b: 51 },
      { r: 0, g: 51, b: 51 },
      { r: 0, g: 51, b: 51 },
      { r: 0, g: 0, b: 51 },
      { r: 51, g: 0, b: 51 },
      { r: 51, g: 0, b: 51 },
      { r: 51, g: 0, b: 51 },
      { r: 51, g: 0, b: 51 },
      { r: 51, g: 0, b: 51 },
      { r: 51, g: 0, b: 51 },
      { r: 51, g: 0, b: 51 },
      { r: 51, g: 0, b: 51 },
      { r: 51, g: 0, b: 51 },
      { r: 51, g: 0, b: 0 },
      { r: 51, g: 51, b: 0 },
      { r: 51, g: 51, b: 0 },
      { r: 51, g: 51, b: 0 },
      { r: 51, g: 51, b: 0 },
      { r: 51, g: 51, b: 0 },
      { r: 51, g: 51, b: 0 },
      { r: 51, g: 51, b: 0 },
      { r: 51, g: 51, b: 0 },
      { r: 0, g: 51, b: 0 },
      { r: 0, g: 51, b: 51 },
      { r: 0, g: 51, b: 51 },
      { r: 0, g: 51, b: 51 },
      { r: 0, g: 51, b: 51 },
      { r: 51, g: 51, b: 51 },
    ],
    columns: 31,
    rows: 9,
  },
};

index.js

import Monologue from 'monologue.js';
import Presets from 'paraviewweb/src/Common/Core/LookupTable/Presets';

const CHANGE_TOPIC = 'LookupTable.change';

// Global helper methods ------------------------------------------------------

function applyRatio(a, b, ratio) {
  return (b - a) * ratio + a;
}

function interpolateColor(pointA, pointB, scalar) {
  const ratio = (scalar - pointA[0]) / (pointB[0] - pointA[0]);
  return [
    applyRatio(pointA[1], pointB[1], ratio),
    applyRatio(pointA[2], pointB[2], ratio),
    applyRatio(pointA[3], pointB[3], ratio),
    255,
  ];
}

function extractPoint(controlPoints, idx) {
  return [
    controlPoints[idx].x,
    controlPoints[idx].r,
    controlPoints[idx].g,
    controlPoints[idx].b,
  ];
}

function xrgbCompare(a, b) {
  return a.x - b.x;
}

// ----------------------------------------------------------------------------

export default class LookupTable {
  constructor(name, discrete = false) {
    this.name = name;
    this.scalarRange = [0, 1];
    this.delta = 1;
    this.controlPoints = null;
    this.colorTableSize = 256;
    this.colorTable = null;
    this.colorNaN = [0, 0, 0, 0];
    this.setPreset('spectralflip');
    this.discrete = discrete;
    this.scale = 1;

    // Auto rebuild
    this.build();
  }

  getName() {
    return this.name;
  }

  /* eslint-disable class-methods-use-this */
  getPresets() {
    return Object.keys(Presets.lookuptables);
  }

  setPreset(name) {
    this.colorTable = null;
    this.controlPoints = [];

    const colors = Presets.lookuptables[name].controlpoints;
    const count = colors.length;

    for (let i = 0; i < count; i++) {
      this.controlPoints.push({
        x: colors[i].x,
        r: colors[i].r,
        g: colors[i].g,
        b: colors[i].b,
      });
    }

    // Auto rebuild
    this.build();

    this.emit(CHANGE_TOPIC, { change: 'preset', lut: this });
  }

  updateControlPoints(controlPoints) {
    this.colorTable = null;
    this.controlPoints = [];

    const count = controlPoints.length;

    for (let i = 0; i < count; i++) {
      this.controlPoints.push({
        x: controlPoints[i].x,
        r: controlPoints[i].r,
        g: controlPoints[i].g,
        b: controlPoints[i].b,
      });
    }

    // Auto rebuild
    this.build();

    this.emit(CHANGE_TOPIC, { change: 'controlPoints', lut: this });
  }

  setColorForNaN(r = 0, g = 0, b = 0, a = 0) {
    this.colorNaN = [r, g, b, a];
  }

  getColorForNaN() {
    return this.colorNaN;
  }

  getScalarRange() {
    return [Number(this.scalarRange[0]), Number(this.scalarRange[1])];
  }

  setScalarRange(min, max) {
    this.scalarRange = [min, max];
    this.delta = max - min;

    this.emit(CHANGE_TOPIC, { change: 'scalarRange', lut: this });
  }

  build(trigger) {
    let currentControlIdx = 0;

    if (this.colorTable) {
      return;
    }

    this.colorTable = [];
    if (this.discrete) {
      this.colorTableSize = this.controlPoints.length;
      this.scale = 50;
      for (let idx = 0; idx < this.colorTableSize; idx++) {
        const color = this.controlPoints[idx];
        this.colorTable.push([color.r, color.g, color.b, 255]);
      }
    } else {
      this.scale = 1;
      for (let idx = 0; idx < this.colorTableSize; idx++) {
        const value = idx / (this.colorTableSize - 1);
        let pointA = extractPoint(this.controlPoints, currentControlIdx);
        let pointB = extractPoint(this.controlPoints, currentControlIdx + 1);

        if (value > pointB[0]) {
          currentControlIdx += 1;
          pointA = extractPoint(this.controlPoints, currentControlIdx);
          pointB = extractPoint(this.controlPoints, currentControlIdx + 1);
        }

        this.colorTable.push(interpolateColor(pointA, pointB, value));
      }
    }

    if (trigger) {
      this.emit(CHANGE_TOPIC, { change: 'controlPoints', lut: this });
    }
  }

  setNumberOfColors(nbColors) {
    this.colorTableSize = nbColors;
    this.colorTable = null;

    // Auto rebuild
    this.build();

    this.emit(CHANGE_TOPIC, { change: 'numberOfColors', lut: this });
  }

  getNumberOfControlPoints() {
    return this.controlPoints ? this.controlPoints.length : 0;
  }

  removeControlPoint(idx) {
    if (idx > 0 && idx < this.controlPoints.length - 1) {
      this.controlPoints.splice(idx, 1);

      // Auto rebuild and trigger change
      this.colorTable = null;
      this.build(true);

      return true;
    }
    return false;
  }

  getControlPoint(idx) {
    return this.controlPoints[idx];
  }

  updateControlPoint(idx, xrgb) {
    this.controlPoints[idx] = xrgb;
    const xValue = xrgb.x;

    // Ensure order
    this.controlPoints.sort(xrgbCompare);

    // Auto rebuild and trigger change
    this.colorTable = null;
    this.build(true);

    // Return the modified index of current control point
    for (let i = 0; i < this.controlPoints.length; i++) {
      if (this.controlPoints[i].x === xValue) {
        return i;
      }
    }
    return 0;
  }

  addControlPoint(xrgb) {
    this.controlPoints.push(xrgb);
    const xValue = xrgb.x;

    // Ensure order
    this.controlPoints.sort(xrgbCompare);

    // Auto rebuild and trigger change
    this.colorTable = null;
    this.build(true);

    // Return the modified index of current control point
    for (let i = 0; i < this.controlPoints.length; i++) {
      if (this.controlPoints[i].x === xValue) {
        return i;
      }
    }
    return -1;
  }

  drawToCanvas(canvas) {
    const colors = this.colorTable;
    const length = this.scale * colors.length;
    const ctx = canvas.getContext('2d');
    const canvasData = ctx.getImageData(0, 0, length, 1);

    for (let i = 0; i < length; i++) {
      const colorIdx = Math.floor(i / this.scale);
      canvasData.data[i * 4 + 0] = Math.floor(255 * colors[colorIdx][0]);
      canvasData.data[i * 4 + 1] = Math.floor(255 * colors[colorIdx][1]);
      canvasData.data[i * 4 + 2] = Math.floor(255 * colors[colorIdx][2]);
      canvasData.data[i * 4 + 3] = 255;
    }
    ctx.putImageData(canvasData, 0, 0);
  }

  getColor(scalar) {
    if (Number.isNaN(scalar)) {
      return this.colorNaN;
    }
    const idxValue = Math.floor(
      (this.colorTableSize * (scalar - this.scalarRange[0])) / this.delta
    );
    if (idxValue < 0) {
      return this.colorTable[0];
    }
    if (idxValue >= this.colorTableSize) {
      return this.colorTable[this.colorTable.length - 1];
    }
    return this.colorTable[idxValue];
  }

  destroy() {
    this.off();
  }

  onChange(callback) {
    return this.on(CHANGE_TOPIC, callback);
  }
}

// Add Observer pattern using Monologue.js
Monologue.mixInto(LookupTable);