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Forked from tacaswell/simp_zoom.py
Last active June 6, 2023 21:16
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factory for adding zoom callback to matplotlib graphs
from simp_zoom import *
# based on https://gist.github.com/tacaswell/3144287
import matplotlib.pyplot as plt
def zoom_factory(ax=None,base_scale=1.5):
if ax is None: ax = plt.gca()
def zoom_fun(event):
# make this figure the current figure
plt._figure(ax.get_figure().number)
# push the current view to define home if stack is empty
toolbar = ax.get_figure().canvas.toolbar # only set the home state
if toolbar._views.empty():
toolbar.push_current()
# get the current x and y limits
cur_xlim = ax.get_xlim()
cur_ylim = ax.get_ylim()
xdata = event.xdata # get event x location
ydata = event.ydata # get event y location
# hat tip to @giadang
# Get distance from the cursor to the edge of the figure frame
x_left = xdata - cur_xlim[0]
x_right = cur_xlim[1] - xdata
y_top = ydata - cur_ylim[0]
y_bottom = cur_ylim[1] - ydata
if event.button == 'up':
# deal with zoom in
scale_factor = 1/base_scale
elif event.button == 'down':
# deal with zoom out
scale_factor = base_scale
else:
# deal with something that should never happen
scale_factor = 1
print event.button
# set new limits
ax.set_xlim([xdata - x_left*scale_factor,
xdata + x_right*scale_factor])
ax.set_ylim([ydata - y_top*scale_factor,
ydata + y_bottom*scale_factor])
# push the current view limits and position onto the stack
# REVIEW perhaps this should participate in a drag_zoom like
# matplotlib/backend_bases.py:NavigationToolbar2:drag_zoom()
toolbar.push_current()
ax.figure.canvas.draw() # force re-draw
fig = ax.get_figure() # get the figure of interest
# attach the call back
fig.canvas.mpl_connect('scroll_event',zoom_fun)
#return the function
return zoom_fun
# usage: import mpl_zoom
def figure_with_zoom(*args, **kwargs):
# add zooming capabilities to figures
f = plt._figure(*args, **kwargs)
z = zoom_factory()
return f
plt._figure = plt.figure
plt.figure = figure_with_zoom
@ianhi
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ianhi commented May 10, 2020

Also, I think plt._figure has been removed. plt.figure will accomplish the same in matplotlib 3.2 (probably earlier as well but I didn't check)

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