From 532aa3176062a39a4ee9de692df34d65fdc03bdb Mon Sep 17 00:00:00 2001
From: Nick Leaf <nleaf@nvidia.com>
Date: Thu, 18 Jun 2020 13:48:01 -0700
Subject: [PATCH] Fixed camera zoom in Firefox by using event.deltaY instead of
 event.wheelDelta (which only worked in Chrome, I guess). While I was at it, I
 moved more of the zoom calculation to the python side, added a
 user-accessible zoomScale member to the PVDisplay class, and changed the
 calculation to make the step size the same for both zoom in and zoom out.

Signed-off-by: Nick Leaf <nleaf@nvidia.com>
---
 ipyparaview/widgets.py | 4 +++-
 js/lib/widgets.js      | 8 ++------
 2 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/ipyparaview/widgets.py b/ipyparaview/widgets.py
index cfd5760..2683510 100644
--- a/ipyparaview/widgets.py
+++ b/ipyparaview/widgets.py
@@ -48,6 +48,7 @@ class PVDisplay(widgets.DOMWidget):
     # class variables
     instances = dict()
     rotateScale = 5.0
+    zoomScale = 0.05
 
     @classmethod
     def GetOrCreate(cls, ren, runAsync=True, **kwargs):
@@ -223,6 +224,7 @@ def __panCam(self, mouseDelta):
     def __zoomCam(self, mouseDelta):
         #zooms by scaling the distance between camera and focus
         rlim = 0.00001 #minimum allowable radius
+        d = (1.0+self.zoomScale)**mouseDelta
         if self.mode == 'Dask':
             from dask.distributed import wait
             wait([r.zoomCam(mouseDelta,rlim) for r in self.renderers])
@@ -230,7 +232,7 @@ def __zoomCam(self, mouseDelta):
             (self.renv.CameraPosition,
              self.renv.CameraFocalPoint,
              self.renv.CameraViewUp) = zoomCameraTurntable(
-                     mouseDelta,
+                     d,
                      self.renv.CameraPosition,
                      self.renv.CameraFocalPoint,
                      self.renv.CameraViewUp,
diff --git a/js/lib/widgets.js b/js/lib/widgets.js
index 64804e1..36d4eca 100644
--- a/js/lib/widgets.js
+++ b/js/lib/widgets.js
@@ -115,18 +115,14 @@ var PVDisplayView = widgets.DOMWidgetView.extend({
             };
 
             function handleScroll(e){
-                const wheelScl = 1.0/40.0;
-                const dScl = 0.05;
-
                 e.preventDefault();
                 e.stopPropagation();
-                let d = e.wheelDelta ? e.wheelDelta*wheelScl : e.detail ? -e.detail : 0;
-                wheelAccum += d;
+                wheelAccum += Math.sign(e.deltaY);
 
                 t = Date.now();
                 if(t - lastMouseT > 1000.0/model.get('maxEventRate')){
                     if(wheelAccum){
-                        view.send({event: 'zoom', 'data': 1.0-dScl*wheelAccum});
+                        view.send({event: 'zoom', 'data': wheelAccum});
                     }
                     wheelAccum = 0.0;
                     lastMouseT = t;