Crosshair bugfix release next (#39598)

### Description of work
This PR handles errors that arises from crosshair functions interacting
with mantid. PR
[39491](#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
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Fixes #39592 .

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### 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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---

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Author: KyleQianliMa

Framework/PythonInterface/mantid/plots/mantidaxes.py

@@ -1325,7 +1325,7 @@ def _remove_matching_curve_from_creation_args(self, workspace_name, workspace_in
         :returns: None
         """
         for index, creation_arg in enumerate(self.creation_args):  # type: int, dict
-            if workspace_name == creation_arg["workspaces"]:
+            if "workspaces" in creation_arg and workspace_name == creation_arg["workspaces"]:
                 if creation_arg.get("wkspIndex", -1) == workspace_index or creation_arg.get("specNum", -1) == spec_num:
                     del self.creation_args[index]
                     return

qt/applications/workbench/workbench/plotting/figureinteraction.py

@@ -874,8 +874,7 @@ def _change_plot_normalization(self, ax):
         for arg_set in ax.creation_args:
             if arg_set["function"] == "contour":
                 continue
-
-            if arg_set["workspaces"] in ax.tracked_workspaces:
+            if "workspaces" in arg_set and arg_set["workspaces"] in ax.tracked_workspaces:
                 workspace = ads.retrieve(arg_set["workspaces"])
                 arg_set["distribution"] = is_normalized
                 if "specNum" not in arg_set:

qt/applications/workbench/workbench/plotting/figuremanager.py

@@ -605,39 +605,49 @@ def _reverse_axis_lines(ax):
             ax.add_line(line)
 
     def crosshair_toggle(self, on):
-        cid = self.canvas.mpl_connect("motion_notify_event", self.crosshair)
-        if not on:
-            self.canvas.mpl_disconnect(cid)
-
-    def crosshair(self, event):
-        axes = self.canvas.figure.gca()
-
-        # create a crosshair made from horizontal and verticle lines.
-        self.horizontal_line = axes.axhline(color="r", lw=1.0, ls="-")
-        self.vertical_line = axes.axvline(color="r", lw=1.0, ls="-")
+        if on:
+            # Create crosshair lines for each axes (except colorbars)
+            self._crosshair_lines = {}
+            for ax in self._axes_that_are_not_colour_bars():
+                ax.set_autoscalex_on(False)
+                ax.set_autoscaley_on(False)
+                hline = ax.axhline(color="r", lw=1.0, ls="-", visible=False)
+                vline = ax.axvline(color="r", lw=1.0, ls="-", visible=False)
+                self._crosshair_lines[ax] = (hline, vline)
+
+            self._crosshair_cid = self.canvas.mpl_connect("motion_notify_event", self.crosshair)
+        else:
+            if hasattr(self, "_crosshair_cid"):
+                self.canvas.mpl_disconnect(self._crosshair_cid)
+                del self._crosshair_cid
 
-        def set_cross_hair_visible(visible):
-            need_redraw = self.horizontal_line.get_visible() != visible
-            self.horizontal_line.set_visible(visible)
-            self.vertical_line.set_visible(visible)
-            return need_redraw
+            if hasattr(self, "_crosshair_lines"):
+                # Remove the crosshair lines
+                for hline, vline in self._crosshair_lines.values():
+                    hline.remove()
+                    vline.remove()
+                del self._crosshair_lines
 
-        # if event is out-of-bound we update
-        if not event.inaxes:
-            need_redraw = set_cross_hair_visible(False)
-            if need_redraw:
-                axes.figure.canvas.draw()
+        self.canvas.draw_idle()
 
+    def crosshair(self, event):
+        if event.inaxes and event.xdata is not None and event.ydata is not None:
+            x = event.xdata
+            y = event.ydata
+
+            # Update all crosshairs to same (x, y)
+            for ax, (hline, vline) in self._crosshair_lines.items():
+                hline.set_ydata([y])
+                vline.set_xdata([x])
+                hline.set_visible(True)
+                vline.set_visible(True)
         else:
-            set_cross_hair_visible(True)
-            x, y = event.xdata, event.ydata
-            self.horizontal_line.set_ydata([y])
-            self.vertical_line.set_xdata([x])
-            self.canvas.draw()
+            # Hide all crosshairs when mouse is out of axes
+            for hline, vline in self._crosshair_lines.values():
+                hline.set_visible(False)
+                vline.set_visible(False)
 
-        # after update we remove
-        self.horizontal_line.remove()
-        self.vertical_line.remove()
+        self.canvas.draw_idle()
 
 
 # -----------------------------------------------------------------------------

qt/applications/workbench/workbench/plotting/test/test_toolbar.py

@@ -132,14 +132,14 @@ def test_button_checked_for_plot_with_no_crosshair(self, mock_qappthread):
         self.assertTrue(self._is_crosshair_button_visible(fig))
 
     @patch("workbench.plotting.figuremanager.QAppThreadCall")
-    def test_button_hiden_for_tiled_plots(self, mock_qappthread):
+    def test_button_for_tiled_plots(self, mock_qappthread):
         mock_qappthread.return_value = mock_qappthread
 
         fig, axes = plt.subplots(2)
         axes[0].plot([-10, 10], [1, 2])
         axes[1].plot([3, 2, 1], [1, 2, 3])
         # crosshair button should be hidden because this is a tiled plot
-        self.assertFalse(self._is_crosshair_button_visible(fig))
+        self.assertTrue(self._is_crosshair_button_visible(fig))
         self.assertFalse(self._is_crosshair_button_checked(fig))
 
     @patch("workbench.plotting.figuremanager.QAppThreadCall")

qt/applications/workbench/workbench/plotting/toolbar.py

@@ -85,7 +85,7 @@ class WorkbenchNavigationToolbar(MantidNavigationToolbar):
         MantidNavigationTool("Fill Area", "Fill area under curves", "mdi.format-color-fill", "waterfall_fill_area", None),
         MantidStandardNavigationTools.SEPARATOR,
         MantidNavigationTool("Help", "Open plotting help documentation", "mdi.help", "launch_plot_help", None),
-        MantidNavigationTool("Crosshair", "Toggle crosshair", "mdi.plus", "toggle_crosshair", False),
+        MantidNavigationTool("Crosshair", "Toggle crosshair", "mdi.target", "toggle_crosshair", False),
         MantidNavigationTool("Hide", "Hide the plot", "mdi.eye", "hide_plot", None),
     )
 
@@ -234,10 +234,8 @@ def set_buttons_visibility(self, fig):
             self.set_fit_enabled(False)
             self.set_superplot_enabled(False)
 
-        # disable crosshair in tiled plots, 3D plots but keep it enabled in color contour plot
-        if (len(fig.get_axes()) > 1 and figure_type(fig) not in [FigureType.Contour]) or (
-            figure_type(fig) in [FigureType.Surface, FigureType.Wireframe, FigureType.Mesh]
-        ):
+        # disable crosshair in 3D plots
+        if figure_type(fig) in [FigureType.Surface, FigureType.Wireframe, FigureType.Mesh]:
             self.set_crosshair_enabled(False)
 
         for ax in fig.get_axes():