Press QWERTY to rotate 10 deg on x/y axis on each view 
  Press ASDFGH to increase MIP thickness 10 px on x/y axis on each view 
  + shift to decrease rotation / thickness
  Press any other key to reset

  

    
    Level
  
    
    Crosshair

    
    Pan

    
    Zoom
  
          
  // =====================
  // Define viewports ====
  // =====================
  
  const targetElements = {
    top: {
      element: document.getElementById("viewer-1"),
      key: "top"
    },
    left: {
      element: document.getElementById("viewer-2"),
      key: "left"
    },
      front: {
        element: document.getElementById("viewer-3"),
        key: "front"
      }
  };
  
  // =============================
  // Build volume and load mpr ===
  // =============================

  /**
  * Header must be in the form:
  * {
  *   volume: {
  *            rows: number,
  *            cols: number.
  *            imageIds: [],
  *            imagePosition: [number, number, number],
  *            sliceThickness: number
  *           }
  * }
  *
  * Data is a TypedArray
  */
  
  // build vtk volume with larvitar
  const image = diglettk.buildVtkVolume(header, data);
  // run mpr
  mpr = new diglettk.MPRManager(targetElements);
  // get initial state obj
  state = mpr.getInitialState();
  console.log("state", state);
  // set image
  mpr.setImage(state, image);
  // set active tool ("level" or "crosshair")
  mpr.setTool("level", state);
  // add keyoboard events to interact with mpr
  addEvents(mpr, state);