8000 Merge pull request #24381 from meeseeksmachine/auto-backport-of-pr-24… · matplotlib/matplotlib@3702fd5 · GitHub
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Merge pull request #24381 from meeseeksmachine/auto-backport-of-pr-24366-on-v3.6.x
Backport PR #24366 on branch v3.6.x (DOC: Improve Image Slices Viewer example)
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‎examples/event_handling/image_slices_viewer.py

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"""
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===================
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Image Slices Viewer
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===================
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============
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Scroll event
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============
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Scroll through 2D image slices of a 3D array.
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In this example a scroll wheel event is used to scroll through 2D slices of
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3D data.
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.. note::
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This example exercises the interactive capabilities of Matplotlib, and this
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import matplotlib.pyplot as plt
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# Fixing random state for reproducibility
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np.random.seed(19680801)
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class IndexTracker:
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def __init__(self, ax, X):
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self.ax = ax
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ax.set_title('use scroll wheel to navigate images')
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self.index = 0
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self.X = X
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rows, cols, self.slices = X.shape
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self.ind = self.slices//2
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self.im = ax.imshow(self.X[:, :, self.ind])
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self.ax = ax
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self.im = ax.imshow(self.X[:, :, self.index])
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self.update()
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def on_scroll(self, event):
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print("%s %s" % (event.button, event.step))
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if event.button == 'up':
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self.ind = (self.ind + 1) % self.slices
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else:
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self.ind = (self.ind - 1) % self.slices
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print(event.button, event.step)
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increment = 1 if event.button == 'up' else -1
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max_index = self.X.shape[-1] - 1
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self.index = np.clip(self.index + increment, 0, max_index)
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self.update()
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def update(self):
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self.im.set_data(self.X[:, :, self.ind])
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self.ax.set_ylabel('slice %s' % self.ind)
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self.im.set_data(self.X[:, :, self.index])
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self.ax.set_title(
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f'Use scroll wheel to navigate\nindex {self.index}')
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self.im.axes.figure.canvas.draw()
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fig, ax = plt.subplots(1, 1)
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X = np.random.rand(20, 20, 40)
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x, y, z = np.ogrid[-10:10:100j, -10:10:100j, 1:10:20j]
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X = np.sin(x * y * z) / (x * y * z)
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fig, ax = plt.subplots()
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# create an IndexTracker and make sure it lives during the whole
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# lifetime of the figure by assigning it to a variable
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tracker = IndexTracker(ax, X)
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fig.canvas.mpl_connect('scroll_event', tracker.on_scroll)
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plt.show()

‎lib/matplotlib/backend_bases.py

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be set to the mouse location in data coordinates. See `.KeyEvent`
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and `.MouseEvent` for more info.
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.. note::
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If func is a method, this only stores a weak reference to the
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method. Thus, the figure does not influence the lifetime of
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the associated object. Usually, you want to make sure that the
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object is kept alive throughout the lifetime of the figure by
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holding a reference to it.
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Returns
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-------
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cid

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