allow locking of all objects

masque/label.py

@@ -3,7 +3,7 @@ import copy
 import numpy
 from numpy import pi
 
-from . import PatternError
+from .error import PatternError, PatternLockedError
 from .utils import is_scalar, vector2, rotation_matrix_2d
 
 
@@ -12,9 +12,9 @@ __author__ = 'Jan Petykiewicz'
 
 class Label:
     """
-    A circle, which has a position and radius.
+    A text annotation with a position and layer (but no size; it is not drawn)
     """
-    __slots__ = ('_offset', '_layer', '_string', 'identifier')
+    __slots__ = ('_offset', '_layer', '_string', 'identifier', 'locked')
     # [x_offset, y_offset]
     _offset: numpy.ndarray
 
@@ -27,6 +27,13 @@ class Label:
     # Arbitrary identifier tuple
     identifier: Tuple
 
+    locked: bool                # If True, any changes to the label will raise a PatternLockedError
+
+    def __setattr__(self, name, value):
+        if self.locked and name != 'locked':
+            raise PatternLockedError()
+        object.__setattr__(self, name, value)
+
     # ---- Properties
     # offset property
     @property
@@ -78,11 +85,20 @@ class Label:
     def __init__(self,
                  string: str,
                  offset: vector2=(0.0, 0.0),
-                 layer: int=0):
+                 layer: int=0,
+                 locked: bool = False):
+        self.unlock()
         self.identifier = ()
         self.string = string
         self.offset = numpy.array(offset, dtype=float)
         self.layer = layer
+        self.locked = locked
+
+    def __copy__(self) -> 'Label':
+        return Label(string=self.string,
+                     offset=self.offset.copy(),
+                     layer=self.layer,
+                     locked=self.locked)
 
     def  __deepcopy__(self, memo: Dict = None) -> 'Label':
         memo = {} if memo is None else memo
@@ -134,4 +150,20 @@ class Label:
         """
         return numpy.array([self.offset, self.offset])
 
+    def lock(self) -> 'Label':
+        """
+        Lock the Label
 
+        :return: self
+        """
+        object.__setattr__(self, 'locked', True)
+        return self
+
+    def unlock(self) -> 'Label':
+        """
+        Unlock the Label
+
+        :return: self
+        """
+        object.__setattr__(self, 'locked', False)
+        return self