Camera: mouse_coordinates_to_world supports scaled window

arcade/experimental/camera.py

@@ -37,14 +37,16 @@ def mouse_coordinates_to_world(self, x, y) -> Tuple[float, float]:
         # Account for black borders in viewport
         vp = self._adjust_viewport_to_aspect_ratio(self.aspect_ratio, self._viewport)
         # Account for projection (including zoom)
-
+        vp_width, vp_height = vp[2], vp[3]
+        proj_width, proj_height = self._projection[1] - self._projection[0], self._projection[3] - self._projection[2]
+        dx, dy = proj_width / vp_width, proj_height / vp_height
+
         return (
-            x + self._scroll_x - vp[0],
-            y + self.scroll_y - vp[1],
+            (x - vp[0]) * dx + self._scroll_x,
+            (y - vp[1]) * dy + self._scroll_y,
         )
 
     # Mouse coordinates to screen (relative)
-    # 
 
     def _adjust_viewport_to_aspect_ratio(self, aspect_ratio: float, viewport: Tuple[int, int, int, int]):
         """
@@ -76,15 +78,6 @@ def aspect_ratio(self) -> float:
         """
         return (self._projection[1] - self._projection[0]) / (self._projection[3] - self._projection[2])
 
-    @property
-    def viewport_size(self) -> Tuple[int, int]:
-        """
-        Get the x and y dimension of the viewport.
-
-        :type: Tuple[int, int]
-        """
-        return self._viewport[2], self._viewport[3]
-
     @property
     def window(self):
         """The window this camera belongs to"""