@edsilv/ami.js/src/widgets/widgets.ruler.js

<p align="center"> <img src="https://user-images.githubusercontent.com/214063/46479857-4cd66e80-c7f0-11e8-9585-5748409c9490.png" width="60%"> </p>

import { widgetsBase } from './widgets.base';
import { widgetsHandle as widgetsHandleFactory } from './widgets.handle';

/**
 * @module widgets/ruler
 */
const widgetsRuler = (three = window.THREE) => {
  if (three === undefined || three.Object3D === undefined) {
    return null;
  }

  const Constructor = widgetsBase(three);
  return class extends Constructor {
    constructor(targetMesh, controls, params = {}) {
      super(targetMesh, controls, params);

      this._widgetType = 'Ruler';

      // incoming parameters (optional: lps2IJK, pixelSpacing, ultrasoundRegions, worldPosition)
      this._calibrationFactor = params.calibrationFactor || null;

      // outgoing values
      this._distance = null;
      this._units = !this._calibrationFactor && !params.pixelSpacing ? 'units' : 'mm';

      this._moving = false;
      this._domHovered = false;

      // mesh stuff
      this._material = null;
      this._geometry = null;
      this._mesh = null;

      // dom stuff
      this._line = null;
      this._label = null;

      // add handles
      this._handles = [];
      const WidgetsHandle = widgetsHandleFactory(three);

      let handle;
      for (let i = 0; i < 2; i++) {
        handle = new WidgetsHandle(targetMesh, controls, params);
        this.add(handle);
        this._handles.push(handle);
      }
      this._handles[1].active = true;
      this._handles[1].tracking = true;

      this._moveHandle = new WidgetsHandle(targetMesh, controls, params);
      this.add(this._moveHandle);
      this._handles.push(this._moveHandle);
      this._moveHandle.hide();

      this.create();

      this.onMove = this.onMove.bind(this);
      this.onHover = this.onHover.bind(this);
      this.addEventListeners();
    }

    addEventListeners() {
      this._container.addEventListener('wheel', this.onMove);

      this._line.addEventListener('mouseenter', this.onHover);
      this._line.addEventListener('mouseleave', this.onHover);
      this._label.addEventListener('mouseenter', this.onHover);
      this._label.addEventListener('mouseleave', this.onHover);
    }

    removeEventListeners() {
      this._container.removeEventListener('wheel', this.onMove);

      this._line.removeEventListener('mouseenter', this.onHover);
      this._line.removeEventListener('mouseleave', this.onHover);
      this._label.removeEventListener('mouseenter', this.onHover);
      this._label.removeEventListener('mouseleave', this.onHover);
    }

    onHover(evt) {
      if (evt) {
        this.hoverDom(evt);
      }

      this.hoverMesh();

      this._hovered = this._handles[0].hovered || this._handles[1].hovered || this._domHovered;
      this._container.style.cursor = this._hovered ? 'pointer' : 'default';
    }

    hoverMesh() {
      // check raycast intersection, do we want to hover on mesh or just css?
    }

    hoverDom(evt) {
      this._domHovered = evt.type === 'mouseenter';
    }

    onStart(evt) {
      this._moveHandle.onMove(evt, true);

      this._handles[0].onStart(evt);
      this._handles[1].onStart(evt);

      this._active = this._handles[0].active || this._handles[1].active || this._domHovered;

      if (this._domHovered && !this._handles[1].tracking) {
        this._moving = true;
        this._controls.enabled = false;
      }

      this.update();
    }

    onMove(evt) {
      if (this._active) {
        const prevPosition = this._moveHandle.worldPosition.clone();

        this._dragged = true;
        this._moveHandle.onMove(evt, true);

        if (this._moving) {
          this._handles.slice(0, -1).forEach(handle => {
            handle.worldPosition.add(this._moveHandle.worldPosition.clone().sub(prevPosition));
          });
        }
      } else {
        this.onHover(null);
      }

      this._handles[0].onMove(evt);
      this._handles[1].onMove(evt);

      this.update();
    }

    onEnd() {
      this._handles[0].onEnd(); // First Handle

      if (
        this._handles[1].tracking &&
        this._handles[0].screenPosition.distanceTo(this._handles[1].screenPosition) < 10
      ) {
        return;
      }

      if (!this._dragged && this._active && !this._handles[1].tracking) {
        this._selected = !this._selected; // change state if there was no dragging
        this._handles[0].selected = this._selected;
      }

      // Second Handle
      if (this._dragged || !this._handles[1].tracking) {
        this._handles[1].tracking = false;
        this._handles[1].onEnd();
      } else {
        this._handles[1].tracking = false;
      }
      this._handles[1].selected = this._selected;

      this._active = this._handles[0].active || this._handles[1].active;
      this._dragged = false;
      this._moving = false;

      this.update();
    }

    create() {
      this.createMesh();
      this.createDOM();
    }

    createMesh() {
      // geometry
      this._geometry = new three.Geometry();
      this._geometry.vertices.push(this._handles[0].worldPosition);
      this._geometry.vertices.push(this._handles[1].worldPosition);

      // material
      this._material = new three.LineBasicMaterial();

      this.updateMeshColor();

      // mesh
      this._mesh = new three.Line(this._geometry, this._material);
      this._mesh.visible = true;

      this.add(this._mesh);
    }

    createDOM() {
      this._line = document.createElement('div');
      this._line.className = 'widgets-line';
      this._container.appendChild(this._line);

      this._label = document.createElement('div');
      this._label.className = 'widgets-label';
      this._container.appendChild(this._label);

      this.updateDOMColor();
    }

    hideDOM() {
      this._line.style.display = 'none';
      this._label.style.display = 'none';
      this._handles.forEach(elem => elem.hideDOM());
    }

    showDOM() {
      this._line.style.display = '';
      this._label.style.display = '';
      this._handles[0].showDOM();
      this._handles[1].showDOM();
    }

    update() {
      this.updateColor();

      this._handles[0].update();
      this._handles[1].update();

      // calculate values
      const distanceData = this.getDistanceData(
        this._handles[0].worldPosition,
        this._handles[1].worldPosition,
        this._calibrationFactor
      );

      this._distance = distanceData.distance;
      if (distanceData.units) {
        this._units = distanceData.units;
      }

      this.updateMeshColor();
      this.updateMeshPosition();

      this.updateDOM();
    }

    updateMeshColor() {
      if (this._material) {
        this._material.color.set(this._color);
      }
    }

    updateMeshPosition() {
      if (this._geometry) {
        this._geometry.verticesNeedUpdate = true;
      }
    }

    updateDOM() {
      this.updateDOMColor();

      // update line
      const lineData = this.getLineData(
        this._handles[0].screenPosition,
        this._handles[1].screenPosition
      );

      this._line.style.transform = `translate3D(${lineData.transformX}px, ${
        lineData.transformY
      }px, 0)
      rotate(${lineData.transformAngle}rad)`;
      this._line.style.width = lineData.length + 'px';

      // update label
      if (this._units === 'units' && !this._label.hasAttribute('title')) {
        this._label.setAttribute('title', 'Calibration is required to display the distance in mm');
        this._label.style.color = this._colors.error;
      } else if (this._units !== 'units' && this._label.hasAttribute('title')) {
        this._label.removeAttribute('title');
        this._label.style.color = this._colors.text;
      }
      this._label.innerHTML = `${this._distance.toFixed(2)} ${this._units}`;

      let angle = Math.abs(lineData.transformAngle);
      if (angle > Math.PI / 2) {
        angle = Math.PI - angle;
      }

      const labelPadding =
        Math.tan(angle) < this._label.offsetHeight / this._label.offsetWidth
          ? this._label.offsetWidth / 2 / Math.cos(angle) + 15 // 5px for each handle + padding
          : this._label.offsetHeight / 2 / Math.cos(Math.PI / 2 - angle) + 15;
      const paddingVector = lineData.line.normalize().multiplyScalar(labelPadding);
      const paddingPoint =
        lineData.length > labelPadding * 2
          ? this._handles[1].screenPosition.clone().sub(paddingVector)
          : this._handles[1].screenPosition.clone().add(paddingVector);
      const transform = this.adjustLabelTransform(this._label, paddingPoint);

      this._label.style.transform = `translate3D(${transform.x}px, ${transform.y}px, 0)`;
    }

    updateDOMColor() {
      this._line.style.backgroundColor = this._color;
      this._label.style.borderColor = this._color;
    }

    free() {
      this.removeEventListeners();

      this._handles.forEach(h => {
        this.remove(h);
        h.free();
      });
      this._handles = [];

      this._container.removeChild(this._line);
      this._container.removeChild(this._label);

      // mesh, geometry, material
      this.remove(this._mesh);
      this._mesh.geometry.dispose();
      this._mesh.geometry = null;
      this._mesh.material.dispose();
      this._mesh.material = null;
      this._mesh = null;
      this._geometry.dispose();
      this._geometry = null;
      this._material.vertexShader = null;
      this._material.fragmentShader = null;
      this._material.uniforms = null;
      this._material.dispose();
      this._material = null;

      super.free();
    }

    getMeasurements() {
      return {
        distance: this._distance,
        units: this._units,
      };
    }

    get targetMesh() {
      return this._targetMesh;
    }

    set targetMesh(targetMesh) {
      this._targetMesh = targetMesh;
      this._handles.forEach(elem => (elem.targetMesh = targetMesh));
      this.update();
    }

    get worldPosition() {
      return this._worldPosition;
    }

    set worldPosition(worldPosition) {
      this._handles[0].worldPosition.copy(worldPosition);
      this._handles[1].worldPosition.copy(worldPosition);
      this._worldPosition.copy(worldPosition);
      this.update();
    }

    get calibrationFactor() {
      return this._calibrationFactor;
    }

    set calibrationFactor(calibrationFactor) {
      this._calibrationFactor = calibrationFactor;
      this._units = 'mm';
      this.update();
    }
  };
};

export { widgetsRuler };
export default widgetsRuler();