@acransac/vtk.js/Sources/Widgets/Widgets3D/LineWidget/helpers.js

Visualization Toolkit for the Web

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

export function calculateTextPosition(model) {
  const vector = [0, 0, 0];
  const handle1WorldPos = model.widgetState.getHandle1().getOrigin();
  const handle2WorldPos = model.widgetState.getHandle2().getOrigin();
  let statePositionOnLine = model.widgetState
    .getPositionOnLine()
    .getPosOnLine();
  statePositionOnLine = 1 - statePositionOnLine;
  vtkMath.subtract(handle1WorldPos, handle2WorldPos, vector);
  vtkMath.multiplyScalar(vector, statePositionOnLine);
  vtkMath.add(vector, handle2WorldPos, vector);
  return vector;
}

export function updateTextPosition(model) {
  const SVGTextState = model.widgetState.getText();
  SVGTextState.setOrigin(calculateTextPosition(model));
}

export function isHandlePlaced(handleIndex, widgetState) {
  const handle1Origin = widgetState.getHandle1().getOrigin();
  if (handleIndex === 0) {
    return handle1Origin.length > 0;
  }

  const handle2Origin = widgetState.getHandle2().getOrigin();
  return (
    handle1Origin.length > 0 &&
    handle2Origin.length > 0 &&
    !vtkMath.areEquals(handle1Origin, handle2Origin, 0)
  );
}

/**
 * Returns the world position of line extremities (placed or not).
 * Returns null if no extremity exist.
 * @param {number} handleIndex 0 or 1
 * @param {object} widgetState state of line widget
 * @param {bool} moveHandle Get move handle position if moveHandle is true and handle is not placed
 */
export function getPoint(handleIndex, widgetState, moveHandle = true) {
  const handle =
    moveHandle && !isHandlePlaced(handleIndex, widgetState)
      ? widgetState.getMoveHandle()
      : widgetState[`getHandle${handleIndex + 1}`]();
  const origin = handle.getOrigin();
  return origin.length ? origin : null;
}

/**
 * Returns the number of handle placed on the scene by checking
 * handle positions. Returns 2 when the user is still
 * placing 2nd handle
 * */
export function getNumberOfPlacedHandles(widgetState) {
  let numberOfPlacedHandles = 0;
  if (isHandlePlaced(0, widgetState)) {
    numberOfPlacedHandles = 1 + isHandlePlaced(1, widgetState);
  }
  return numberOfPlacedHandles;
}