tests_dicom_dicomGenerator.js

import {getTypedArray} from '../../src/dicom/dicomParser.js';
import {getPixelDataTag} from '../../src/dicom/dicomTag.js';

import {
  BinaryPixGenerator
} from './binaryPixGenerator.js';
import {
  FilePixGenerator,
  fileCheckTags
} from './filePixGenerator.js';
import {
  GradSquarePixGenerator
} from './gradSquarePixGenerator.js';
import {
  MPRPixGenerator,
  mprCheckTags
} from './mprPixGenerator.js';
import {
  SquarePixGenerator
} from './squarePixGenerator.js';

// List of pixel generators
export const _pixelGenerators = {
  binary: {generator: BinaryPixGenerator},
  file: {generator: FilePixGenerator, checkTags: fileCheckTags},
  gradSquare: {generator: GradSquarePixGenerator},
  mpr: {generator: MPRPixGenerator, checkTags: mprCheckTags},
  square: {generator: SquarePixGenerator}
};

// List of required tags for generating pixel data
const _requiredPixelTags = [
  'TransferSyntaxUID',
  'Rows',
  'Columns',
  'BitsAllocated',
  'PixelRepresentation',
  'SamplesPerPixel',
  'PhotometricInterpretation'
];

/**
 * Check a list of input tags against a required list.
 *
 * @param {object} tags The tags to check.
 * @param {Array} requiredTags Array of tag names.
 * @param {boolean} withLog Flag to log errors or not.
 * @returns {boolean} True if all required tags are present in the input.
 */
export function checkTags(tags, requiredTags, withLog) {
  if (typeof withLog === 'undefined') {
    withLog = false;
  }
  let check = true;
  for (let i = 0; i < requiredTags.length; ++i) {
    if (typeof tags[requiredTags[i]] === 'undefined') {
      if (withLog) {
        console.log('Missing ' +
          requiredTags[i] + ' for pixel generation.');
      }
      check = false;
      break;
    }
  }
  return check;
}

/**
 * Get the DICOM pixel data from a DICOM tags object.
 *
 * @param {object} tags The DICOM tags object.
 * @param {string} pixGeneratorName The name of a pixel generator.
 * @param {number} sliceNumber The slice number.
 * @param {Array} images The images to pass to the generator.
 * @param {number} numberOfSlices The result number of slices.
 * @returns {object} The DICOM pixel data element.
 */
export function generatePixelDataFromJSONTags(
  tags, pixGeneratorName, sliceNumber, images, numberOfSlices) {

  // default
  if (typeof pixGeneratorName === 'undefined') {
    pixGeneratorName = 'gradSquare';
  }
  if (typeof sliceNumber === 'undefined') {
    sliceNumber = 0;
  }
  if (typeof numberOfSlices === 'undefined') {
    numberOfSlices = 1;
  }

  // check tags
  if (!checkTags(tags, _requiredPixelTags, true)) {
    throw new Error('Missing meta data for dicom creation.');
  }

  // extract info from tags
  const numberOfRows = tags.Rows;
  const numberOfColumns = tags.Columns;
  const numberOfFrames = tags.NumberOfFrames;
  const bitsAllocated = tags.BitsAllocated;
  const pixelRepresentation = tags.PixelRepresentation;
  const samplesPerPixel = tags.SamplesPerPixel;
  // trim in case config contains padding
  const photometricInterpretation = tags.PhotometricInterpretation.trim();

  const sliceLength = numberOfRows * numberOfColumns;
  const dataLength = sliceLength * samplesPerPixel;

  // check values
  if (samplesPerPixel !== 1 && samplesPerPixel !== 3) {
    throw new Error(
      'Unsupported SamplesPerPixel for pixel generation: ' +
      samplesPerPixel);
  }
  if ((samplesPerPixel === 1 && !(photometricInterpretation === 'MONOCHROME1' ||
        photometricInterpretation === 'MONOCHROME2')) ||
        (samplesPerPixel === 3 && photometricInterpretation !== 'RGB')) {
    throw new Error(
      'Unsupported PhotometricInterpretation for pixel generation: ' +
      photometricInterpretation + ' with SamplesPerPixel: ' + samplesPerPixel);
  }

  let numberOfSamples = 1;
  let numberOfColourPlanes = 1;
  if (samplesPerPixel === 3) {
    if (typeof tags.PlanarConfiguration === 'undefined') {
      throw new Error('Missing PlanarConfiguration for pixel generation.');
    }
    const planarConfiguration = tags.PlanarConfiguration;
    if (planarConfiguration !== 0 && planarConfiguration !== 1) {
      throw new Error(
        'Unsupported PlanarConfiguration for pixel generation: ' +
        planarConfiguration);
    }
    if (planarConfiguration === 0) {
      numberOfSamples = 3;
    } else {
      numberOfColourPlanes = 3;
    }
  }

  // create pixel array
  const pixels = getTypedArray(
    bitsAllocated, pixelRepresentation, dataLength);

  // pixels generator
  if (typeof _pixelGenerators[pixGeneratorName] === 'undefined') {
    throw new Error('Unknown PixelData generator: ' + pixGeneratorName);
  }
  const GeneratorClass = _pixelGenerators[pixGeneratorName].generator;
  const generator = new GeneratorClass({
    numberOfColumns: numberOfColumns,
    numberOfRows: numberOfRows,
    numberOfSlices: numberOfSlices,
    numberOfFrames: numberOfFrames,
    numberOfSamples: numberOfSamples,
    numberOfColourPlanes: numberOfColourPlanes,
    photometricInterpretation: photometricInterpretation,
    imageOrientationPatient: tags.ImageOrientationPatient
  });
  if (typeof generator.setImages !== 'undefined') {
    generator.setImages(images);
  }
  if (typeof generator.setNumberOfSlices !== 'undefined') {
    generator.setNumberOfSlices(numberOfSlices);
  }
  generator.generate(pixels, sliceNumber);

  // create and return the DICOM element
  let vr = 'OW';
  if (bitsAllocated === 8) {
    vr = 'OB';
  }
  const pixVL = pixels.BYTES_PER_ELEMENT * dataLength;
  return {
    tag: getPixelDataTag(),
    vr: vr,
    vl: pixVL,
    value: pixels
  };
};

/**
 * Extract the image data from an image.
 *
 * @param {Image} image The image to get the data from.
 * @returns {object} The image data buffer.
 */
export function getImageDataData(image) {
  // draw the image in the canvas in order to get its data
  const canvas = document.createElement('canvas');
  canvas.width = image.width;
  canvas.height = image.height;
  const ctx = canvas.getContext('2d');
  ctx.drawImage(image, 0, 0);
  // get the image data
  const imageData = ctx.getImageData(0, 0, image.width, image.height);
  // data.data
  return imageData.data;
};