Change zoom behavior

- use Ctrl+Wheel to zoom
- make this always on - independent of tool state

Author: timhoffm

doc/release/next_whats_new/scroll_to_zoom.rst

@@ -1,11 +1,8 @@
-Scroll-to-zoom in GUIs
-~~~~~~~~~~~~~~~~~~~~~~
+Zooming using mouse wheel
+~~~~~~~~~~~~~~~~~~~~~~~~~
 
-When a plot manipulation tool (pan or zoom tool) in plot windows is enabled,
-a mouse scroll operation results in a zoom focussing on the mouse pointer, keeping the
-aspect ratio of the axes.
+``Ctrl+MouseWheel`` can be used to zoom in the plot windows.
 
-There is no effect if no manipulation tool is selected. This is intentional to
-keep a state in which accidental manipulation of the plot is avoided.
+The zoom focusses on the mouse pointer, and keeps the aspect ratio of the axes.
 
 Zooming is currently only supported on rectilinear Axes.

lib/matplotlib/backend_bases.py

@@ -2582,13 +2582,7 @@ def scroll_handler(event, canvas=None, toolbar=None):
         # zooming is currently only supported on rectilinear axes
         return
 
-    if toolbar is None:
-        toolbar = (canvas or event.canvas).toolbar
-
-    if toolbar is None or toolbar.mode == _Mode.NONE:
-        return
-
-    if event.key is None:  # zoom towards the mouse position
+    if event.key == "control":  # zoom towards the mouse position
         toolbar.push_current()
 
         xmin, xmax = ax.get_xlim()