WindowBase: Add to_normalized_pos method

kivy/core/window/__init__.py

@@ -1388,6 +1388,19 @@ def to_widget(self, x, y, initial=True, relative=False):
     def to_window(self, x, y, initial=True, relative=False):
         return (x, y)
 
+    def to_normalized_pos(self, x, y):
+        '''Transforms absolute coordinates to normalized (0-1) coordinates
+        using :attr:`system_size`.
+
+        .. versionadded:: 2.1.0
+        '''
+        x_max = self.system_size[0] - 1.0
+        y_max = self.system_size[1] - 1.0
+        return (
+            x / x_max if x_max > 0 else 0.0,
+            y / y_max if y_max > 0 else 0.0
+        )
+
     def _apply_transform(self, m):
         return m
 

kivy/tests/test_window_base.py

@@ -0,0 +1,20 @@
+from itertools import product
+
+from kivy.tests import GraphicUnitTest
+
+
+class WindowBaseTest(GraphicUnitTest):
+
+    def test_to_normalized_pos(self):
+        win = self.Window
+        old_system_size = win.system_size[:]
+        win.system_size = w, h = type(old_system_size)((320, 240))
+        try:
+            for x, y in product([0, 319, 50, 51], [0, 239, 50, 51]):
+                expected_sx = x / (w - 1.0)
+                expected_sy = y / (h - 1.0)
+                result_sx, result_sy = win.to_normalized_pos(x, y)
+                assert result_sx == expected_sx
+                assert result_sy == expected_sy
+        finally:
+            win.system_size = old_system_size