From cc102d79493d766e503c4424e1e2e389756a828c Mon Sep 17 00:00:00 2001
From: Sebastien Jourdain <sebastien.jourdain@kitware.com>
Date: Sat, 9 Dec 2017 12:32:44 -0700
Subject: [PATCH 1/2] fix(TrackballPan): Fix parallel projection issue

---
 Sources/Interaction/Manipulators/TrackballPan/index.js | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/Sources/Interaction/Manipulators/TrackballPan/index.js b/Sources/Interaction/Manipulators/TrackballPan/index.js
index 3741c055d97..099c02d3074 100644
--- a/Sources/Interaction/Manipulators/TrackballPan/index.js
+++ b/Sources/Interaction/Manipulators/TrackballPan/index.js
@@ -34,9 +34,9 @@ function vtkTrackballPan(publicAPI, model) {
       vtkMath.cross(vpn, up, right);
 
       // These are different because y is flipped.
-      const size = interactor.getView().getSize();
-      let dx = (pos.x - lastPos.x) / size[1];
-      let dy = (lastPos.y - pos.y) / size[1];
+      const height = interactor.getView().getSize()[1];
+      let dx = (pos.x - lastPos.x) / height;
+      let dy = (lastPos.y - pos.y) / height;
 
       const scale = camera.getParallelScale();
       dx *= scale * 2.0;
@@ -51,8 +51,8 @@ function vtkTrackballPan(publicAPI, model) {
       tmp = (right[2] * dx) + (up[2] * dy);
       camPos[2] += tmp;
       fp[2] += tmp;
-      camera.setPosition(camPos);
-      camera.setFocalPoint(fp);
+      camera.setPosition(camPos[0], camPos[1], camPos[2]);
+      camera.setFocalPoint(fp[0], fp[1], fp[2]);
     } else {
       const center = model.center;
       const style = interactor.getInteractorStyle();

From 195417eab4c7ec41757354eeea4f896f825f79ec Mon Sep 17 00:00:00 2001
From: Sebastien Jourdain <sebastien.jourdain@kitware.com>
Date: Sat, 9 Dec 2017 12:33:20 -0700
Subject: [PATCH 2/2] fix(TrackballZoom): Ensure renderer to be found

---
 Sources/Interaction/Manipulators/TrackballZoom/index.js | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/Sources/Interaction/Manipulators/TrackballZoom/index.js b/Sources/Interaction/Manipulators/TrackballZoom/index.js
index 7f036afccc0..e207d77b595 100644
--- a/Sources/Interaction/Manipulators/TrackballZoom/index.js
+++ b/Sources/Interaction/Manipulators/TrackballZoom/index.js
@@ -2,6 +2,7 @@ import macro                from 'vtk.js/Sources/macro';
 import vtkCameraManipulator from 'vtk.js/Sources/Interaction/Manipulators/CameraManipulator';
 
 const { vtkWarningMacro } = macro;
+const DEFAULT_POSITION = { x: 0, y: 0 };
 
 // ----------------------------------------------------------------------------
 // vtkTrackballZoom methods
@@ -15,7 +16,10 @@ function vtkTrackballZoom(publicAPI, model) {
     const size = interactor.getView().getSize();
 
     try {
-      const camera = interactor.getInteractorStyle().getCurrentRenderer().getActiveCamera();
+      const { x, y } = interactor.getAnimationEventPosition(interactor.getPointerIndex()) || DEFAULT_POSITION;
+      const interactorStyle = interactor.getInteractorStyle();
+      const renderer = interactorStyle.getCurrentRenderer() || interactor.findPokedRenderer(x, y);
+      const camera = renderer.getActiveCamera();
       if (camera.getParallelProjection()) {
         model.zoomScale = 1.5 / size[1];
       } else {