From 8b75b77aac14e4351636060e446eca8725bdcf40 Mon Sep 17 00:00:00 2001
From: francis-wong <francis.wong@utexas.edu>
Date: Sun, 11 Jun 2023 15:17:24 +0800
Subject: [PATCH] use RectangleSelector for callbacks and use getter functions
 for axes

---
 galleries/examples/event_handling/viewlims.py | 59 +++++++++++--------
 1 file changed, 33 insertions(+), 26 deletions(-)

diff --git a/galleries/examples/event_handling/viewlims.py b/galleries/examples/event_handling/viewlims.py
index b47e3b5b0801..391447c132fa 100644
--- a/galleries/examples/event_handling/viewlims.py
+++ b/galleries/examples/event_handling/viewlims.py
@@ -3,7 +3,7 @@
 Viewlims
 ========
 
-Creates two identical panels.  Zooming in on the right panel will show
+Creates two identical panels.  Zooming in on the left panel will show
 a rectangle in the first panel, denoting the zoomed region.
 
 .. note::
@@ -17,21 +17,13 @@
 import matplotlib.pyplot as plt
 import numpy as np
 
-from matplotlib.patches import Rectangle
-
-
-# We just subclass Rectangle so that it can be called with an Axes
-# instance, causing the rectangle to update its shape to match the
-# bounds of the Axes
-class UpdatingRect(Rectangle):
-    def __call__(self, ax):
-        self.set_bounds(*ax.viewLim.bounds)
-        ax.figure.canvas.draw_idle()
-
+from matplotlib.widgets import RectangleSelector
 
 # A class that will regenerate a fractal set as we zoom in, so that you
 # can actually see the increasing detail.  A box in the left panel will show
 # the area to which we are zoomed.
+
+
 class MandelbrotDisplay:
     def __init__(self, h=500, w=500, niter=50, radius=2., power=2):
         self.height = h
@@ -59,8 +51,12 @@ def ax_update(self, ax):
         self.width, self.height = \
             np.round(ax.patch.get_window_extent().size).astype(int)
         # Get the range for the new area
-        vl = ax.viewLim
-        extent = vl.x0, vl.x1, vl.y0, vl.y1
+        x0, x1 = ax.get_xlim()
+        y0, y1 = ax.get_ylim()
+        extent = x0, x1, y0, y1
+        x0, x1 = ax.get_xlim()
+        y0, y1 = ax.get_ylim()
+        extent = x0, x1, y0, y1
         # Update the image object with our new data and extent
         im = ax.images[-1]
         im.set_data(self.compute_image(*extent))
@@ -68,6 +64,20 @@ def ax_update(self, ax):
         ax.figure.canvas.draw_idle()
 
 
+def select_callback(eclick, erelease):
+    extent = rect_selector.extents
+
+    ax2.set_autoscale_on(False)
+    # Zoom the selected part
+    # Set xlim, ylim range for plot
+    # of rectangle selector box.
+    ax2.set_xlim(extent[0], extent[1])
+    ax2.set_ylim(extent[2], extent[3])
+
+    # update the right subplot
+    md.ax_update(ax2)
+    ax2.figure.canvas.draw_idle()
+
 md = MandelbrotDisplay()
 Z = md.compute_image(-2., 0.5, -1.25, 1.25)
 
@@ -77,17 +87,14 @@ def ax_update(self, ax):
 ax2.imshow(Z, origin='lower',
            extent=(md.x.min(), md.x.max(), md.y.min(), md.y.max()))
 
-rect = UpdatingRect(
-    [0, 0], 0, 0, facecolor='none', edgecolor='black', linewidth=1.0)
-rect.set_bounds(*ax2.viewLim.bounds)
-ax1.add_patch(rect)
-
-# Connect for changing the view limits
-ax2.callbacks.connect('xlim_changed', rect)
-ax2.callbacks.connect('ylim_changed', rect)
-
-ax2.callbacks.connect('xlim_changed', md.ax_update)
-ax2.callbacks.connect('ylim_changed', md.ax_update)
-ax2.set_title("Zoom here")
+rect_selector = RectangleSelector(
+        ax1, select_callback,
+        useblit=True,
+        button=[1],
+        interactive=True,
+        minspanx=5,
+        minspany=5,
+        spancoords='pixels')
 
+ax1.set_title("Zoom here")
 plt.show()