skimage.viewer: incompatibility with Matplotlib 3.5

[grlee77]

Description

The following test fails when run with Matplotlib 3.5.
viewer/tests/test_plugins.py::test_plugin

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> captured stdout >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Crop tool
Select rectangular region and press enter to crop.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> traceback >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

    @pytest.mark.skipif(not has_qt, reason="Qt not installed")
    def test_crop():
        image = data.camera()
        viewer = ImageViewer(image)
        c = Crop()
>       viewer += c

viewer/tests/test_plugins.py:129: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
viewer/viewers/core.py:155: in __add__
    plugin.attach(self)
viewer/plugins/crop.py:21: in attach
    self.rect_tool = RectangleTool(image_viewer,
viewer/canvastools/recttool.py:80: in __init__
    CanvasToolBase.__init__(self, manager, on_move=on_move,
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

self = <skimage.viewer.canvastools.recttool.RectangleTool object at 0x7f8cf89e4f10>, manager = <skimage.viewer.viewers.core.ImageViewer object at 0x7f8cf8a24f70>, on_move = None
on_enter = <bound method Crop.crop of <skimage.viewer.plugins.crop.Crop object at 0x7f8cf89ecaf0>>, on_release = None, useblit = True, ax = None

    def __init__(self, manager, on_move=None, on_enter=None, on_release=None,
                 useblit=True, ax=None):
        self.manager = manager
        self.ax = manager.ax
>       self.artists = []
E       AttributeError: can't set attribute

viewer/canvastools/base.py:33: AttributeError

There are also a number of new deprecation warnings that will become errors in Matplotlib 3.7.

skimage/viewer/qt.py:5: MatplotlibDeprecationWarning: 
  The QT_RC_MAJOR_VERSION attribute was deprecated in Matplotlib 3.5 and will be removed two minor releases later.
    from matplotlib.backends.qt_compat import QtGui, QtCore, QtWidgets, QT_RC_MAJOR_VERSION as _qt_version

skimage/viewer/tests/test_plugins.py::test_crop
skimage/viewer/tests/test_plugins.py::test_color_histogram
  /home/lee8rx/my_git/pyir/scikit-image/skimage/viewer/canvastools/recttool.py:77: MatplotlibDeprecationWarning: The 'rectprops' parameter of __init__() has been renamed 'props' since Matplotlib 3.5; support for the old name will be dropped two minor releases later.
    RectangleSelector.__init__(self, manager.ax, lambda *args: None,

skimage/viewer/tests/test_plugins.py::test_crop
skimage/viewer/tests/test_plugins.py::test_color_histogram
  /home/lee8rx/my_git/pyir/scikit-image/skimage/viewer/canvastools/recttool.py:91: MatplotlibDeprecationWarning: 
  The to_draw attribute was deprecated in Matplotlib 3.5 and will be removed two minor releases later.
    self._rect = self.to_draw

skimage/viewer/tests/test_plugins.py::test_crop
skimage/viewer/tests/test_plugins.py::test_color_histogram
  /home/lee8rx/my_git/pyir/scikit-image/skimage/viewer/canvastools/recttool.py:94: MatplotlibDeprecationWarning: 
  The maxdist attribute was deprecated in Matplotlib 3.5 and will be removed two minor releases later. Use grab_range instead.
    self.maxdist = maxdist

skimage/viewer/tests/test_plugins.py::test_crop
skimage/viewer/tests/test_plugins.py::test_color_histogram
  /home/lee8rx/my_git/pyir/scikit-image/skimage/viewer/canvastools/recttool.py:95: MatplotlibDeprecationWarning: 
  The active_handle attribute was deprecated in Matplotlib 3.5 and will be removed two minor releases later.
    self.active_handle = None

Version information

current v0.19.x branch of scikit-image
Matplotlib 3.5.0

[grlee77]

Currently, users who wish to use skimage.viewer should pin to matplotlib<3.5. In general we encourage moving to another tool such as napari as the viewer module will be removed in the 1.0 release.

[hmaarrfk]

seems like a good plan.

[mkcor]

Currently, users who wish to use skimage.viewer should pin to matplotlib<3.5.

@grlee77 is this documented somewhere?

[grlee77]

@grlee77 is this documented somewhere?

just in this issue (Matplotlib 3.5 is only about a month old). doc PR welcome

[mkcor]

Closing as per #6133 and #6160.