From b63a782ce2653ea0368dfc8c55e825032ac2920b Mon Sep 17 00:00:00 2001
From: LangQi99 <2032771946@qq.com>
Date: Wed, 10 Sep 2025 21:21:15 +0800
Subject: [PATCH 1/3] feat: support x/y-axis zoom

---
 doc/release/next_whats_new/scroll_to_zoom.rst |  3 ++-
 lib/matplotlib/backend_bases.py               | 21 ++++++++++++++-----
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/doc/release/next_whats_new/scroll_to_zoom.rst b/doc/release/next_whats_new/scroll_to_zoom.rst
index bafa312c32a5..1be522b7a255 100644
--- a/doc/release/next_whats_new/scroll_to_zoom.rst
+++ b/doc/release/next_whats_new/scroll_to_zoom.rst
@@ -2,7 +2,8 @@ Zooming using mouse wheel
 ~~~~~~~~~~~~~~~~~~~~~~~~~
 
 ``Ctrl+MouseWheel`` can be used to zoom in the plot windows.
+Additionally, ``x+MouseWheel`` zooms only the x-axis and ``y+MouseWheel`` zooms only the y-axis.
 
-The zoom focusses on the mouse pointer, and keeps the aspect ratio of the axes.
+The zoom focusses on the mouse pointer. With ``Ctrl``, the axes aspect ratio is kept; with ``x`` or ``y``, only the respective axis is scaled.
 
 Zooming is currently only supported on rectilinear Axes.
diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
index 7560db80d2c1..994e41f9fdba 100644
--- a/lib/matplotlib/backend_bases.py
+++ b/lib/matplotlib/backend_bases.py
@@ -2592,7 +2592,7 @@ def scroll_handler(event, canvas=None, toolbar=None):
         # is required for interactive navigation.
         return
 
-    if event.key == "control":  # zoom towards the mouse position
+    if event.key in {"control", "x", "X", "y", "Y"}:  # zoom towards the mouse position
         toolbar.push_current()
 
         xmin, xmax = ax.get_xlim()
@@ -2604,10 +2604,21 @@ def scroll_handler(event, canvas=None, toolbar=None):
         x, y = ax.transScale.transform((event.xdata, event.ydata))
 
         scale_factor = 0.85 ** event.step
-        new_xmin = x - (x - xmin) * scale_factor
-        new_xmax = x + (xmax - x) * scale_factor
-        new_ymin = y - (y - ymin) * scale_factor
-        new_ymax = y + (ymax - y) * scale_factor
+        # Determine which axes to scale based on key
+        zoom_x = event.key in {"control", "x", "X"}
+        zoom_y = event.key in {"control", "y", "Y"}
+
+        if zoom_x:
+            new_xmin = x - (x - xmin) * scale_factor
+            new_xmax = x + (xmax - x) * scale_factor
+        else:
+            new_xmin, new_xmax = xmin, xmax
+
+        if zoom_y:
+            new_ymin = y - (y - ymin) * scale_factor
+            new_ymax = y + (ymax - y) * scale_factor
+        else:
+            new_ymin, new_ymax = ymin, ymax
 
         inv_scale = ax.transScale.inverted()
         (new_xmin, new_ymin), (new_xmax, new_ymax) = inv_scale.transform(

From f8583e08627a98464b21769df681da751dc09055 Mon Sep 17 00:00:00 2001
From: LangQi99 <2032771946@qq.com>
Date: Fri, 12 Sep 2025 11:21:12 +0800
Subject: [PATCH 2/3] Update lib/matplotlib/backend_bases.py

"X" would be generated by "Shift+x"

Co-authored-by: Tim Hoffmann <2836374+timhoffm@users.noreply.github.com>
---
 lib/matplotlib/backend_bases.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
index 994e41f9fdba..7a58717db5a4 100644
--- a/lib/matplotlib/backend_bases.py
+++ b/lib/matplotlib/backend_bases.py
@@ -2592,7 +2592,7 @@ def scroll_handler(event, canvas=None, toolbar=None):
         # is required for interactive navigation.
         return
 
-    if event.key in {"control", "x", "X", "y", "Y"}:  # zoom towards the mouse position
+    if event.key in {"control", "x", "y"}:  # zoom towards the mouse position
         toolbar.push_current()
 
         xmin, xmax = ax.get_xlim()

From 0a744f0ba180dca0a73bf351db89796a9854c7d6 Mon Sep 17 00:00:00 2001
From: LangQi99 <2032771946@qq.com>
Date: Fri, 12 Sep 2025 11:21:26 +0800
Subject: [PATCH 3/3] Update lib/matplotlib/backend_bases.py

"X" would be generated by "Shift+x"

Co-authored-by: Tim Hoffmann <2836374+timhoffm@users.noreply.github.com>
---
 lib/matplotlib/backend_bases.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/matplotlib/backend_bases.py b/lib/matplotlib/backend_bases.py
index 7a58717db5a4..07a48a768de0 100644
--- a/lib/matplotlib/backend_bases.py
+++ b/lib/matplotlib/backend_bases.py
@@ -2605,8 +2605,8 @@ def scroll_handler(event, canvas=None, toolbar=None):
 
         scale_factor = 0.85 ** event.step
         # Determine which axes to scale based on key
-        zoom_x = event.key in {"control", "x", "X"}
-        zoom_y = event.key in {"control", "y", "Y"}
+        zoom_x = event.key in {"control", "x"}
+        zoom_y = event.key in {"control", "y"}
 
         if zoom_x:
             new_xmin = x - (x - xmin) * scale_factor