Уточнить обработку плотных трендов и восстановление сигналов

python/tests/test_plot.py

@@ -53,6 +53,21 @@ class PlotTests(unittest.TestCase):
         crossed = markers.move(Marker.A, 1900).move(Marker.B, 1100)
         self.assertEqual(-800, self.core.delta(crossed.a, crossed.b))
 
+    def test_deep_x_zoom_preserves_anchor_and_allows_pan_and_zoom_out(self):
+        view = Viewport()
+        for _ in range(65):
+            view = view.transform(self.core, zoom_x=1.25, focus_x=.3)
+            self.assertAlmostEqual(.3, view.x + .3 * view.width)
+        self.assertLess(view.width * 5_000_000, 3)
+        moved = view.transform(self.core, pan_x=.2)
+        self.assertLess(moved.x, view.x)
+        self.assertEqual(view.width, moved.width)
+        expanded = moved.transform(self.core, zoom_x=.8)
+        self.assertGreater(expanded.width, moved.width)
+        limited = view.transform(self.core, zoom_x=1e10)
+        self.assertEqual(1e-7, limited.width)
+        self.assertEqual(limited, limited.transform(self.core, zoom_x=2))
+
     def test_invalid_numeric_inputs_do_not_escape_to_painter(self):
         for value in (math.nan, math.inf, -math.inf):
             self.assertEqual(Viewport(), Viewport().transform(self.core, zoom_x=value))