add geom properties

src/groovylight/geom.py

@@ -86,9 +86,14 @@ class DisplayDimensions:
     height: int
     mux: int = 2  # number of lines driven at once.
 
+    @property
     def addr_bits(self) -> int:
         return ceil(log2(self.height / self.mux))
 
+    @property
+    def size(self) -> int:
+        return self.length * self.height
+
 
 class DisplayRotation(Enum):
     """Display rotation enums. The names indicate the general direction
@@ -162,13 +167,25 @@ class DisplayGeometry:
         self.strict = strict
         pass
 
-    def add_string(self, s: DisplayString):
-        """Add a new string to the display. This new string is located at
-        a specific point, and has a direction, along with dimension that reveal
-        the number of address lines (typically 64, with 1:32 selection so 5 address
-        bits) and the total length of the string which is used to size the line
-        buffers.
+    @property
+    def n_strings(self) -> int:
+        """Returns the number of strings in the display"""
+        return len(self._strings)
 
+    @property
+    def framebuffer_size(self) -> int:
+        """Returns the total size of the display, in pixels.
+
+        NOTE: This currently only works with strict=true.
+        """
+        sum = 0
+        for s in self._strings:
+            sum += s.dimensions.size
+
+        return sum
+
+    def add_string(self, s: DisplayString):
+        """Add a new string to the display. 
         When in strict mode, this method will throw an exception if this new string
         will overlap with an existing string.
         """