Several fixes to scene and remove print from debugging

vpython/vpython.py

@@ -2719,7 +2719,7 @@ def canvas(self, value):
     @property
     def pos(self):
         c = self._canvas
-        return c.center-(norm(c.forward)*(c.range / tan(c.fov/2)))
+        return c.center-(norm(c.axis)*(c.range / tan(c.fov/2)))
     @pos.setter
     def pos(self, value):
         c = self._canvas
@@ -2728,12 +2728,12 @@ def pos(self, value):
     @property
     def axis(self):
         c = self._canvas
-        return norm(c.forward)*( c.range / tan(c.fov/2) )
+        return norm(c._axis)*( c.range / tan(c.fov/2) )
     @axis.setter
     def axis(self, value):
         c = self._canvas
-        c.center = self.pos+value # use current self.pos before it is changed by change in c.forward
-        c.forward = norm(value)
+        c.center = self.pos+value # use current self.pos before it is changed by change in c.axis
+        c.axis = norm(value)
         c.range = mag(value)*tan(c.fov/2)
 
     @property
@@ -2744,14 +2744,17 @@ def up(self, value):
         self._canvas.up = value
 
     def rotate(self, angle=0, axis=None, origin=None):
+        if angle == 0: return
         c = self._canvas
         if axis is None: axis = c.up
-        newaxis = self.axis.rotate(angle=angle, axis=axis)
-        newpos = self.pos
-        if origin is not None:
-            newpos = origin + (self.pos-origin).rotate(angle=angle, axis=axis)
-        c.center = newpos + newaxis
-        c.forward = norm(newaxis)
+        if origin is not None and origin != self.pos:
+            origin = self.pos + (self.pos-origin).rotate(angle=angle, axis=axis)
+        else:
+            origin = self.pos
+        if c._axis.diff_angle(axis) > 1e-6:
+            c.axis = c._axis.rotate(angle=angle, axis=axis)
+        c.up = c._up.rotate(angle=angle, axis=axis)
+        c.center = origin + self.axis
 
 class meta_canvas(object):
     @property
@@ -2794,7 +2797,8 @@ def __init__(self, **args):
 
         # The following determine the view:
         self._range = 1 # user can alter with zoom
-        self._forward = vector(0,0,-1) # user can alter with spin
+        self._axis = vector(0,0,-1) # user can alter with spin
+        self._forward = vector(0,0,-1) # self.axis is primal internally; self._forward is now a synonym
         self._up = vector(0,1,0) # user with touch screen can rotate around z
         self._autoscale = True # set False if user zooms
         self._center = vector(0,0,0) # cannot be altered by user
@@ -2997,11 +3001,20 @@ def center(self,value):
             raise TypeError('center must be a vector')
 
     @property
-    def forward(self):
-        return self._forward
+    def axis(self):
+        return self._axis
+    @axis.setter
+    def axis(self,value):
+        self._axis = self._set_forward = vector(value)
+        if not self._constructing:
+            self.appendcmd({"forward":value.value})
+
+    @property
+    def forward(self): # scene.forward is an external synonym for scene.axis
+        return self._axis
     @forward.setter
     def forward(self,value):
-        self._forward = self._set_forward = vector(value)
+        self._axis = self._set_forward = vector(value)
         if not self._constructing:
             self.appendcmd({"forward":value.value})
 
@@ -3121,7 +3134,6 @@ def handle_event(self, evt):  ## events and scene info updates
             self.mouse.setpick( evt )
             self._waitfor = True # what pick is looking for
         elif ev == '_compound': # compound, text, extrusion
-            print('compound event return')
             obj = self._compound
             p = evt['pos']
             if obj._objName == 'text':