Make zooming work in qt-embedding example.

anntzer · anntzer · commit 65497d317cf8 · 2020-05-07T18:22:22.000+02:00
Calling set_ylim everytime in _update_canvas breaks interactive zoom.
diff --git a/examples/user_interfaces/embedding_in_qt_sgskip.py b/examples/user_interfaces/embedding_in_qt_sgskip.py
@@ -45,19 +45,18 @@ def __init__(self):
         self._static_ax.plot(t, np.tan(t), ".")
 
         self._dynamic_ax = dynamic_canvas.figure.subplots()
+        t = np.linspace(0, 10, 101)
+        # Set up a Line2D.
+        self._line, = self._dynamic_ax.plot(t, np.sin(t + time.time()))
         self._timer = dynamic_canvas.new_timer(50)
         self._timer.add_callback(self._update_canvas)
         self._timer.start()
 
     def _update_canvas(self):
-        self._dynamic_ax.clear()
         t = np.linspace(0, 10, 101)
-        # Use fixed vertical limits to prevent autoscaling changing the scale
-        # of the axis.
-        self._dynamic_ax.set_ylim(-1.1, 1.1)
         # Shift the sinusoid as a function of time.
-        self._dynamic_ax.plot(t, np.sin(t + time.time()))
-        self._dynamic_ax.figure.canvas.draw()
+        self._line.set_data(t, np.sin(t + time.time()))
+        self._line.figure.canvas.draw()
 
 
 if __name__ == "__main__":
