DataArray

Introduction

vtkDataArray is an abstract superclass for data array objects containing
numeric data.

Methods

computeRange

Compute range of a given array. The array could be composed of tuples and
individual component range could be computed as well as magnitude.

const array = [x0, y0, z0, x1, y1, z1, ..., xn, yn, zn];
const { min: yMin, max: yMax } = computeRange(array, 1, 3);
const { min: minMagnitude, max: maxMagnitude } = computeRange(array, -1, 3);

Argument	Type	Required	Description
values	Array.	Yes	Array to go through to extract the range from
component	Number	No	(default: 0) indice to use inside tuple size
numberOfComponents	Number	No	(default: 1) size of the tuple

createRangeHelper

Create helper object that can be used to gather min, max, count, sum of
a set of values.

extend

Method use to decorate a given object (publicAPI+model) with vtkDataArray characteristics.

Argument	Type	Required	Description
publicAPI		Yes	object on which methods will be bounds (public)
model		Yes	object on which data structure will be bounds (protected)
initialValues	object	No	(default: {})

getComponent

Get the component for a given tupleIdx.

Argument	Type	Required	Description
tupleIdx	Number	Yes
componentIndex	Number	No	(default: 0)

getData

getDataType

Return the name of a typed array

const isFloat32 = ('Float32Array' === getDataType(array));
const clone = new macro.TYPED_ARRAYS[getDataType(array)](array.length);

Argument	Type	Required	Description
typedArray		Yes	to extract its type from

getDataType

getElementComponentSize

Get the size, in bytes, of the lowest-level element of an array.

getMaxNorm

Return the max norm of a given vtkDataArray

Argument	Type	Required	Description
dataArray		Yes	to process

getName

getNumberOfComponents

Get the dimension (n) of the components.

getNumberOfTuples

Get the number of complete tuples (a component group) in the array.

getNumberOfValues

Get the total number of values in the array.

getRange

Get the range of the given component.

Argument	Type	Required	Description
componentIndex	Number	Yes	(default: -1)

getState

getTuple

Argument	Type	Required	Description
idx	Number	Yes
tupleToFill	Array.	No	(default [])

getTupleLocation

Argument	Type	Required	Description
idx	Number	No	(default: 1)

newClone

newInstance

Method use to create a new instance of vtkDataArray

Argument	Type	Required	Description
initialValues	object	No	for pre-setting some of its content

setComponent

Set the component value for a given tupleIdx and componentIndex.

Argument	Type	Required	Description
tupleIdx	Number	Yes
componentIndex	Number	Yes
value	Number	Yes

setData

Argument	Type	Required	Description
typedArray	TypedArray	Yes
numberOfComponents	Number	No

setName

setNumberOfComponents

Set the dimension (n) of the components.

Argument	Type	Required	Description
numberOfComponents	Number	Yes

setRange

Argument	Type	Required	Description
rangeValue	vtkRange	Yes
componentIndex	Number	Yes

setTuple

Argument	Type	Required	Description
idx	Number	Yes
tuple	Array.	Yes

Source

Constants.js

export const DataTypeByteSize = {
  Int8Array: 1,
  Uint8Array: 1,
  Uint8ClampedArray: 1,
  Int16Array: 2,
  Uint16Array: 2,
  Int32Array: 4,
  Uint32Array: 4,
  Float32Array: 4,
  Float64Array: 8,
};

export const VtkDataTypes = {
  VOID: '', // not sure to know what that should be
  CHAR: 'Int8Array',
  SIGNED_CHAR: 'Int8Array',
  UNSIGNED_CHAR: 'Uint8Array',
  SHORT: 'Int16Array',
  UNSIGNED_SHORT: 'Uint16Array',
  INT: 'Int32Array',
  UNSIGNED_INT: 'Uint32Array',
  FLOAT: 'Float32Array',
  DOUBLE: 'Float64Array',
};

export const DefaultDataType = VtkDataTypes.FLOAT;

export default {
  DefaultDataType,
  DataTypeByteSize,
  VtkDataTypes,
};

index.d.ts

/// <reference path='../../../types.ts' />

import { vtkObject, vtkRange } from "vtk.js/Sources/interfaces";

/**
 * Output of the rangeHelper instance
 */
interface VtkStatisticInformation {
	min: number;
	max: number;
	count: number;
	sum: number;
	mean: number;
}

/**
 * Helper class used to compute data range of a set of numbers
 */
interface vtkRangeHelper {
	add(value: number): void;
	get(): VtkStatisticInformation;
	getRange(): vtkRange;
}

export interface vtkDataArray extends vtkObject {

	/**
	 * Get the size, in bytes, of the lowest-level element of an array.
	 */
	getElementComponentSize(): number;

	/**
	 * Get the component for a given tupleIdx.
	 * @param {Number} tupleIdx 
	 * @param {Number} [componentIndex] (default: 0)
	 */
	getComponent(tupleIdx: number, componentIndex?: number): number;

	/**
	 * Set the component value for a given tupleIdx and componentIndex.
	 * @param {Number} tupleIdx 
	 * @param {Number} componentIndex 
	 * @param {Number} value 
	 */
	setComponent(tupleIdx: number, componentIndex: number, value: number): void;

	/**
	 * 
	 */
	getData(): TypedArray;

	/**
	 * Get the range of the given component.
	 *
	 * @param {Number} componentIndex (default: -1)
	 */
	getRange(componentIndex?: number): vtkRange;

	/**
	 * 
	 * @param {vtkRange} rangeValue 
	 * @param {Number} componentIndex 
	 */
	setRange(rangeValue: vtkRange, componentIndex: number): [number, number];

	/**
	 * 
	 * @param {Number} idx 
	 * @param {Number[]} tuple 
	 */
	setTuple(idx: number, tuple: number[]): void;

	/**
	 *
	 * @param {Number} idx 
	 * @param {Number[]} [tupleToFill] (default [])
	 */
	getTuple(idx: number, tupleToFill?: number[]): number[];

	/**
	 *
	 * @param {Number} [idx] (default: 1)
	 */
	getTupleLocation(idx?: number): number;

	/**
	 * Get the dimension (n) of the components.
	 */
	getNumberOfComponents(): number;

	/**
	 * Get the total number of values in the array.
	 */
	getNumberOfValues(): number;

	/**
	 * Get the number of complete tuples (a component group) in the array.
	 */
	getNumberOfTuples(): number;

	/**
	 * 
	 */
	getDataType(): string;

	/**
	 * 
	 */
	newClone(): vtkDataArray;

	/**
	 * 
	 */
	getName(): string;

	/**
	 * 
	 * @param {TypedArray} typedArray 
	 * @param {Number} [numberOfComponents] 
	 */
	setData(typedArray: TypedArray, numberOfComponents?: number): void;

	/**
	 * 
	 */
	getState(): object;

	// --- via macro --

	/**
	 * 
	 */
	setName(name: string): boolean;

	/**
	 * Set the dimension (n) of the components.
	 * @param {Number} numberOfComponents 
	 */
	setNumberOfComponents(numberOfComponents: number): boolean;
}

// ----------------------------------------------------------------------------
// Static API
// ----------------------------------------------------------------------------

/**
 * Compute range of a given array. The array could be composed of tuples and
 * individual component range could be computed as well as magnitude.
 *
 * ```js
 * const array = [x0, y0, z0, x1, y1, z1, ..., xn, yn, zn];
 * const { min: yMin, max: yMax } = computeRange(array, 1, 3);
 * const { min: minMagnitude, max: maxMagnitude } = computeRange(array, -1, 3);
 * ```
 *
 * @param {Number[]} values Array to go through to extract the range from
 * @param {Number} [component] (default: 0) indice to use inside tuple size
 * @param {Number} [numberOfComponents] (default: 1) size of the tuple
 */
export function computeRange(values: number[], component?: number, numberOfComponents?: number): vtkRange;

/**
 * Create helper object that can be used to gather min, max, count, sum of
 * a set of values.
 */
export function createRangeHelper(): vtkRangeHelper

/**
 * Return the name of a typed array
 *
 * ```js
 * const isFloat32 = ('Float32Array' === getDataType(array));
 * const clone = new macro.TYPED_ARRAYS[getDataType(array)](array.length);
 * ```
 *
 * @param typedArray to extract its type from
 */
export function getDataType(typedArray: TypedArray): string

/**
 * Return the max norm of a given vtkDataArray
 *
 * @param dataArray to process
 */
export function getMaxNorm(dataArray: vtkDataArray): number

/**
 * Method use to decorate a given object (publicAPI+model) with vtkDataArray characteristics.
 *
 * @param publicAPI object on which methods will be bounds (public)
 * @param model object on which data structure will be bounds (protected)
 * @param {object} [initialValues] (default: {})
 */
export function extend(publicAPI: object, model: object, initialValues?: object): void;

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

/**
 * Method use to create a new instance of vtkDataArray
 * @param {object} [initialValues] for pre-setting some of its content
 */
export function newInstance(initialValues?: object): vtkDataArray;

/**
 * Constants capturing the number of bytes per element based on its data type.
 */
export enum DataTypeByteSize {
	Int8Array,
	Uint8Array,
	Uint8ClampedArray,
	Int16Array,
	Uint16Array,
	Int32Array,
	Uint32Array,
	Float32Array,
	Float64Array,
}

/**
 * Constants capturing the various VTK data types.
 */
export enum VtkDataTypes {
	VOID,
	CHAR,
	SIGNED_CHAR,
	UNSIGNED_CHAR,
	SHORT,
	UNSIGNED_SHORT,
	INT,
	UNSIGNED_INT,
	FLOAT,
	DOUBLE,
}

/**
 * vtkDataArray is an abstract superclass for data array objects containing
 * numeric data.
 */
export declare const vtkDataArray: {
	newInstance: typeof newInstance,
	extend: typeof extend,
	// static
	computeRange: typeof computeRange,
	createRangeHelper: typeof createRangeHelper,
	getDataType: typeof getDataType,
	getMaxNorm: typeof getMaxNorm,
	// constants
	DataTypeByteSize: typeof DataTypeByteSize,
	VtkDataTypes: typeof VtkDataTypes,
	DefaultDataType: VtkDataTypes,
};

export default vtkDataArray;

index.js

import Constants from 'vtk.js/Sources/Common/Core/DataArray/Constants';
import * as macro from 'vtk.js/Sources/macro';
import * as vtkMath from 'vtk.js/Sources/Common/Core/Math';

const { DefaultDataType } = Constants;
const TUPLE_HOLDER = [];

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

function createRangeHelper() {
  let min = Number.MAX_VALUE;
  let max = -Number.MAX_VALUE;
  let count = 0;
  let sum = 0;

  return {
    add(value) {
      if (min > value) {
        min = value;
      }
      if (max < value) {
        max = value;
      }
      count++;
      sum += value;
    },
    get() {
      return { min, max, count, sum, mean: sum / count };
    },
    getRange() {
      return { min, max };
    },
  };
}

function computeRange(values, component = 0, numberOfComponents = 1) {
  const helper = createRangeHelper();
  const size = values.length;
  let value = 0;

  if (component < 0 && numberOfComponents > 1) {
    // Compute magnitude
    for (let i = 0; i < size; i += numberOfComponents) {
      value = 0;
      for (let j = 0; j < numberOfComponents; j++) {
        value += values[i + j] * values[i + j];
      }
      value **= 0.5;
      helper.add(value);
    }
    return helper.getRange();
  }

  const offset = component < 0 ? 0 : component;
  for (let i = offset; i < size; i += numberOfComponents) {
    helper.add(values[i]);
  }

  return helper.getRange();
}

function ensureRangeSize(rangeArray, size = 0) {
  const ranges = rangeArray || [];
  // Pad ranges with null value to get the
  while (ranges.length <= size) {
    ranges.push(null);
  }
  return ranges;
}

function getDataType(typedArray) {
  // Expects toString() to return "[object ...Array]"
  return Object.prototype.toString.call(typedArray).slice(8, -1);
}

function getMaxNorm(normArray) {
  const numComps = normArray.getNumberOfComponents();
  let maxNorm = 0.0;
  for (let i = 0; i < normArray.getNumberOfTuples(); ++i) {
    const norm = vtkMath.norm(normArray.getTuple(i), numComps);
    if (norm > maxNorm) {
      maxNorm = norm;
    }
  }
  return maxNorm;
}

// ----------------------------------------------------------------------------
// Static API
// ----------------------------------------------------------------------------

export const STATIC = {
  computeRange,
  createRangeHelper,
  getDataType,
  getMaxNorm,
};

// ----------------------------------------------------------------------------
// vtkDataArray methods
// ----------------------------------------------------------------------------

function vtkDataArray(publicAPI, model) {
  // Set our className
  model.classHierarchy.push('vtkDataArray');

  function dataChange() {
    model.ranges = null;
    publicAPI.modified();
  }

  publicAPI.getElementComponentSize = () => model.values.BYTES_PER_ELEMENT;

  // Description:
  // Return the data component at the location specified by tupleIdx and
  // compIdx.
  publicAPI.getComponent = (tupleIdx, compIdx = 0) =>
    model.values[tupleIdx * model.numberOfComponents + compIdx];

  // Description:
  // Set the data component at the location specified by tupleIdx and compIdx
  // to value.
  // Note that i is less than NumberOfTuples and j is less than
  //  NumberOfComponents. Make sure enough memory has been allocated
  // (use SetNumberOfTuples() and SetNumberOfComponents()).
  publicAPI.setComponent = (tupleIdx, compIdx, value) => {
    if (value !== model.values[tupleIdx * model.numberOfComponents + compIdx]) {
      model.values[tupleIdx * model.numberOfComponents + compIdx] = value;
      dataChange();
    }
  };

  publicAPI.getData = () => model.values;

  publicAPI.getRange = (componentIndex = -1) => {
    const rangeIdx =
      componentIndex < 0 ? model.numberOfComponents : componentIndex;
    let range = null;

    if (!model.ranges) {
      model.ranges = ensureRangeSize(model.ranges, model.numberOfComponents);
    }
    range = model.ranges[rangeIdx];

    if (range) {
      model.rangeTuple[0] = range.min;
      model.rangeTuple[1] = range.max;
      return model.rangeTuple;
    }

    // Need to compute ranges...
    range = computeRange(
      model.values,
      componentIndex,
      model.numberOfComponents
    );
    model.ranges[rangeIdx] = range;
    model.rangeTuple[0] = range.min;
    model.rangeTuple[1] = range.max;
    return model.rangeTuple;
  };

  publicAPI.setRange = (rangeValue, componentIndex) => {
    if (!model.ranges) {
      model.ranges = ensureRangeSize(model.ranges, model.numberOfComponents);
    }
    const range = { min: rangeValue.min, max: rangeValue.max };

    model.ranges[componentIndex] = range;
    model.rangeTuple[0] = range.min;
    model.rangeTuple[1] = range.max;

    return model.rangeTuple;
  };

  publicAPI.setTuple = (idx, tuple) => {
    const offset = idx * model.numberOfComponents;
    for (let i = 0; i < model.numberOfComponents; i++) {
      model.values[offset + i] = tuple[i];
    }
  };

  publicAPI.getTuple = (idx, tupleToFill = TUPLE_HOLDER) => {
    const numberOfComponents = model.numberOfComponents || 1;
    if (tupleToFill.length !== numberOfComponents) {
      tupleToFill.length = numberOfComponents;
    }
    const offset = idx * numberOfComponents;
    // Check most common component sizes first
    // to avoid doing a for loop if possible
    if (numberOfComponents === 1) {
      tupleToFill[0] = model.values[offset];
    } else if (numberOfComponents === 2) {
      tupleToFill[0] = model.values[offset];
      tupleToFill[1] = model.values[offset + 1];
    } else if (numberOfComponents === 3) {
      tupleToFill[0] = model.values[offset];
      tupleToFill[1] = model.values[offset + 1];
      tupleToFill[2] = model.values[offset + 2];
    } else if (numberOfComponents === 4) {
      tupleToFill[0] = model.values[offset];
      tupleToFill[1] = model.values[offset + 1];
      tupleToFill[2] = model.values[offset + 2];
      tupleToFill[3] = model.values[offset + 3];
    } else {
      for (let i = 0; i < numberOfComponents; i++) {
        tupleToFill[i] = model.values[offset + i];
      }
    }
    return tupleToFill;
  };

  publicAPI.getTupleLocation = (idx = 1) => idx * model.numberOfComponents;
  publicAPI.getNumberOfComponents = () => model.numberOfComponents;
  publicAPI.getNumberOfValues = () => model.values.length;
  publicAPI.getNumberOfTuples = () =>
    model.values.length / model.numberOfComponents;
  publicAPI.getDataType = () => model.dataType;
  /* eslint-disable no-use-before-define */
  publicAPI.newClone = () =>
    newInstance({
      empty: true,
      name: model.name,
      dataType: model.dataType,
      numberOfComponents: model.numberOfComponents,
    });
  /* eslint-enable no-use-before-define */

  publicAPI.getName = () => {
    if (!model.name) {
      publicAPI.modified();
      model.name = `vtkDataArray${publicAPI.getMTime()}`;
    }
    return model.name;
  };

  publicAPI.setData = (typedArray, numberOfComponents) => {
    model.values = typedArray;
    model.size = typedArray.length;
    model.dataType = getDataType(typedArray);
    if (numberOfComponents) {
      model.numberOfComponents = numberOfComponents;
    }
    if (model.size % model.numberOfComponents !== 0) {
      model.numberOfComponents = 1;
    }
    dataChange();
  };

  // Override serialization support
  publicAPI.getState = () => {
    const jsonArchive = { ...model, vtkClass: publicAPI.getClassName() };

    // Convert typed array to regular array
    jsonArchive.values = Array.from(jsonArchive.values);
    delete jsonArchive.buffer;

    // Clean any empty data
    Object.keys(jsonArchive).forEach((keyName) => {
      if (!jsonArchive[keyName]) {
        delete jsonArchive[keyName];
      }
    });

    // Sort resulting object by key name
    const sortedObj = {};
    Object.keys(jsonArchive)
      .sort()
      .forEach((name) => {
        sortedObj[name] = jsonArchive[name];
      });

    // Remove mtime
    if (sortedObj.mtime) {
      delete sortedObj.mtime;
    }

    return sortedObj;
  };
}

// ----------------------------------------------------------------------------
// Object factory
// ----------------------------------------------------------------------------

const DEFAULT_VALUES = {
  name: '',
  numberOfComponents: 1,
  size: 0,
  dataType: DefaultDataType,
  rangeTuple: [0, 0],
  // values: null,
  // ranges: null,
};

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

export function extend(publicAPI, model, initialValues = {}) {
  Object.assign(model, DEFAULT_VALUES, initialValues);

  if (!model.empty && !model.values && !model.size) {
    throw new TypeError(
      'Cannot create vtkDataArray object without: size > 0, values'
    );
  }

  if (!model.values) {
    model.values = macro.newTypedArray(model.dataType, model.size);
  } else if (Array.isArray(model.values)) {
    model.values = macro.newTypedArrayFrom(model.dataType, model.values);
  }

  if (model.values) {
    model.size = model.values.length;
    model.dataType = getDataType(model.values);
  }

  // Object methods
  macro.obj(publicAPI, model);
  macro.set(publicAPI, model, ['name', 'numberOfComponents']);

  // Object specific methods
  vtkDataArray(publicAPI, model);
}

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

export const newInstance = macro.newInstance(extend, 'vtkDataArray');

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

export default { newInstance, extend, ...STATIC, ...Constants };