prepare for callbacks on modification of ctrlpts and weights arrays

Author: cshorler

geomdl/NURBS.py

@@ -127,8 +127,8 @@ def ctrlpts(self):
         # Populate the cache, if necessary
         if not self._cache['ctrlpts']:
             c, w = compatibility.separate_ctrlpts_weights(self._control_points)
-            self._cache['ctrlpts'] = [crd for crd in c]
-            self._cache['weights'] = w
+            self._cache['ctrlpts'] = self._array_type(iter(c))
+            self._cache['weights'] = self._array_type(iter(w))
         return self._cache['ctrlpts']
 
     @ctrlpts.setter
@@ -159,8 +159,8 @@ def weights(self):
         # Populate the cache, if necessary
         if not self._cache['weights']:
             c, w = compatibility.separate_ctrlpts_weights(self._control_points)
-            self._cache['ctrlpts'] = [crd for crd in c]
-            self._cache['weights'] = w
+            self._cache['ctrlpts'] = self._array_type(iter(c))
+            self._cache['weights'] = self._array_type(iter(w))
         return self._cache['weights']
 
     @weights.setter
@@ -192,6 +192,7 @@ def reset(self, **kwargs):
         if reset_ctrlpts:
             # Delete the caches
             self._cache['ctrlpts'] = self._init_array()
+            # TODO: why is this reset differently from the initialisation?
             self._cache['weights'][:] = self._init_array()
 
 
@@ -330,8 +331,8 @@ def ctrlpts(self):
         """
         if not self._cache['ctrlpts']:
             c, w = compatibility.separate_ctrlpts_weights(self._control_points)
-            self._cache['ctrlpts'] = [crd for crd in c]
-            self._cache['weights'] = w
+            self._cache['ctrlpts'] = self._array_type(iter(c))
+            self._cache['weights'] = self._array_type(iter(w))
         return self._cache['ctrlpts']
 
     @ctrlpts.setter
@@ -361,8 +362,8 @@ def weights(self):
         """
         if not self._cache['weights']:
             c, w = compatibility.separate_ctrlpts_weights(self._control_points)
-            self._cache['ctrlpts'] = [crd for crd in c]
-            self._cache['weights'] = w
+            self._cache['ctrlpts'] = self._array_type(iter(c))
+            self._cache['weights'] = self._array_type(iter(w))
         return self._cache['weights']
 
     @weights.setter
@@ -518,8 +519,8 @@ def ctrlpts(self):
         """
         if not self._cache['ctrlpts']:
             c, w = compatibility.separate_ctrlpts_weights(self._control_points)
-            self._cache['ctrlpts'] = [crd for crd in c]
-            self._cache['weights'] = w
+            self._cache['ctrlpts'] = self._array_type(iter(c))
+            self._cache['weights'] = self._array_type(iter(w))
         return self._cache['ctrlpts']
 
     @ctrlpts.setter
@@ -549,8 +550,8 @@ def weights(self):
         """
         if not self._cache['weights']:
             c, w = compatibility.separate_ctrlpts_weights(self._control_points)
-            self._cache['ctrlpts'] = [crd for crd in c]
-            self._cache['weights'] = w
+            self._cache['ctrlpts'] = self._array_type(iter(c))
+            self._cache['weights'] = self._array_type(iter(w))
         return self._cache['weights']
 
     @weights.setter

geomdl/_collections.py

@@ -0,0 +1,55 @@
+# callback handlers for list modification
+# https://stackoverflow.com/a/13259435/1162349
+
+import sys
+
+_pyversion = sys.version_info[0]
+
+def callback_method(func):
+    def notify(self,*args,**kwargs):
+        for _,callback in self._callbacks:
+            callback()
+        return func(self,*args,**kwargs)
+    return notify
+
+class NotifyList(list):
+    extend = callback_method(list.extend)
+    append = callback_method(list.append)
+    remove = callback_method(list.remove)
+    pop = callback_method(list.pop)
+    __delitem__ = callback_method(list.__delitem__)
+    __setitem__ = callback_method(list.__setitem__)
+    __iadd__ = callback_method(list.__iadd__)
+    __imul__ = callback_method(list.__imul__)
+
+    #Take care to return a new NotifyList if we slice it.
+    if _pyversion < 3:
+        __setslice__ = callback_method(list.__setslice__)
+        __delslice__ = callback_method(list.__delslice__)
+        def __getslice__(self,*args):
+            return self.__class__(list.__getslice__(self,*args))
+
+    def __getitem__(self,item):
+        if isinstance(item,slice):
+            return self.__class__(list.__getitem__(self,item))
+        else:
+            return list.__getitem__(self,item)
+
+    def __init__(self,*args):
+        list.__init__(self,*args)
+        self._callbacks = []
+        self._callback_cntr = 0
+
+    def register_callback(self,cb):
+        self._callbacks.append((self._callback_cntr,cb))
+        self._callback_cntr += 1
+        return self._callback_cntr - 1
+
+    def unregister_callback(self,cbid):
+        for idx,(i,cb) in enumerate(self._callbacks):
+            if i == cbid:
+                self._callbacks.pop(idx)
+                return cb
+        else:
+            return None
+

geomdl/abstract.py

@@ -11,6 +11,7 @@
 from .six import add_metaclass
 from . import vis, helpers, knotvector, voxelize, utilities, tessellate
 from .base import GeomdlBase, GeomdlEvaluator, GeomdlError, GeomdlWarning, GeomdlTypeSequence
+from ._collections import NotifyList
 
 
 @add_metaclass(abc.ABCMeta)
@@ -34,9 +35,9 @@ class Geometry(GeomdlBase):
     # __slots__ = ('_iter_index', '_array_type', '_eval_points')
 
     def __init__(self, *args, **kwargs):
-        self._geometry_type = "default" if not hasattr(self, '_geometry_type') else self._geometry_type  # geometry type
         super(Geometry, self).__init__(*args, **kwargs)
-        self._array_type = list if not hasattr(self, '_array_type') else self._array_type  # array storage type
+        self._geometry_type = getattr(self, '_geometry_type', 'default') # geometry type
+        self._array_type = getattr(self, '_array_type', NotifyList) # array storage type
         self._eval_points = self._init_array()  # evaluated points
 
     def __iter__(self):