Crosshair bugfix release next

[KyleQianliMa]

Description of work

This PR handles errors that arises from crosshair functions interacting with mantid. PR 39491

The issue is when changing normalisation and error bars, the figure object is treated as mantid object such as mantidaxes with key word arg such as "workspaces". The crosshair, at the moment, is implemented purely as matplotlib object and would cause error and crash the plot. A quick fix is to catch these errors.

In the long term, we will integrate the crosshair as a mantid specific object for handling mantid data.

Summary of work

Fixes #39592 .

Further detail of work

To test:

Run the instructions in the smoking tests, specifically focusing on changing normalisation and error bars while crosshair is open.

This script can be used to quickly open the plot pannel for testing:

# import mantid algorithms, numpy and matplotlib
from mantid.simpleapi import *
import matplotlib.pyplot as plt
from mantid.plots.utility import MantidAxType

MAR11060 = Load('MAR11060')

fig, axes = plt.subplots(edgecolor='#ffffff', ncols=2, nrows=2, num='MAR11060-1', subplot_kw={'projection': 'mantid'})
axes[0][0].plot(MAR11060, color='#1f77b4', label='MAR11060: spec 1', wkspIndex=0)
axes[0][0].set_xlabel('Time-of-flight ($\\mu s$)')
axes[0][0].set_ylabel('Counts ($\\mu s$)$^{-1}$')
legend = axes[0][0].legend(fontsize=8.0) #.set_draggable(True).legend # uncomment to set the legend draggable

axes[0][1].plot(MAR11060, color='#1f77b4', label='MAR11060: spec 2', wkspIndex=1)
axes[0][1].set_xlabel('Time-of-flight ($\\mu s$)')
axes[0][1].set_ylabel('Counts ($\\mu s$)$^{-1}$')
legend = axes[0][1].legend(fontsize=8.0) #.set_draggable(True).legend # uncomment to set the legend draggable

axes[1][0].plot(MAR11060, color='#1f77b4', label='MAR11060: spec 3', wkspIndex=2)
axes[1][0].set_xlabel('Time-of-flight ($\\mu s$)')
axes[1][0].set_ylabel('Counts ($\\mu s$)$^{-1}$')
legend = axes[1][0].legend(fontsize=8.0) #.set_draggable(True).legend # uncomment to set the legend draggable

axes[1][1].plot(MAR11060, color='#1f77b4', label='MAR11060: spec 4', wkspIndex=3)
axes[1][1].set_xlabel('Time-of-flight ($\\mu s$)')
axes[1][1].set_ylabel('Counts ($\\mu s$)$^{-1}$')
legend = axes[1][1].legend(fontsize=8.0) #.set_draggable(True).legend # uncomment to set the legend draggable

fig.show()

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[peterfpeterson]

This does indeed work as advertised. I tried with normal line plots.

[jhaigh0]

Thanks for fixing those bugs we found with the plot crosshair, I don't envy you adding anything to the plotting interface, it's a minefield.
Unfortunately we found something else this morning, when you double-click with the crosshair toggled on, the curve settings open. In the list of curves are two curves called child_<number> which are the vertical and horizontal components of the crosshair. If you try and change any settings for one of the crosshair curves, when you click apply you get an error. If you 'continue working' you end up with just half a crosshair (attempting to toggle it off in this state also gives an error).
I think probably as a workaround you want to just filter that list of curves in the plot options so that the user can't mess around with them (I think that would be done here). Similar problems happen if you open them, remove one of crosshair curves, and try to toggle them on.