Allow cmap scaling changes when image not ready

hexrdgui/color_map_editor.py

@@ -1,5 +1,6 @@
 import copy
 
+from PySide6.QtCore import QTimer
 from PySide6.QtGui import QColor
 from PySide6.QtWidgets import QColorDialog
 
@@ -24,6 +25,9 @@ def __init__(self, image_object, parent=None):
         # 2. set_norm: a function to set the norm on the image
         # 3. set_scaling: a function to set the scaling on the image
         # 4. scaled_image_data: a property to get the scaled image data
+        # 5. image_ready: an optional boolean property indicating if the image
+        #                 is ready. If not present, the image is assumed to
+        #                 be ready.
 
         self.image_object = image_object
 
@@ -268,4 +272,14 @@ def update_scaling(self):
 
         # Reset the bounds, as the histogram could potentially have moved.
         # This will update the data too.
-        self.update_bounds(self.image_object.scaled_image_data)
+        # Wait until the image is ready to do the update.
+
+        def do_bound_update_if_ready():
+            if not getattr(self.image_object, 'image_ready', True):
+                # If the image is not ready, try again in 250 milliseconds
+                QTimer.singleShot(250, do_bound_update_if_ready)
+                return
+
+            self.update_bounds(self.image_object.scaled_image_data)
+
+        do_bound_update_if_ready()

hexrdgui/image_canvas.py

@@ -412,6 +412,10 @@ def scaled_images(self):
     def scaled_display_images(self):
         return list(self.scaled_display_image_dict.values())
 
+    @property
+    def image_ready(self) -> bool:
+        return self.iviewer is not None
+
     @property
     def blit_artists(self):
         return self.blit_manager.artists
@@ -1692,11 +1696,13 @@ def set_scaling(self, transform):
             image_names = list(self.raw_axes)
             self.load_images(image_names)
         else:
-            for axes_img, img in zip(
-                self.axes_images,
-                self.scaled_display_images,
-            ):
-                axes_img.set_data(img)
+            # If the image is not ready, these will be set later
+            if self.image_ready:
+                for axes_img, img in zip(
+                    self.axes_images,
+                    self.scaled_display_images,
+                ):
+                    axes_img.set_data(img)
 
         self.update_azimuthal_integral_plot()
         self.draw_idle()

hexrdgui/image_tab_widget.py

@@ -323,6 +323,10 @@ def scaled_image_data(self):
         # return the whole image data dict.
         return self.image_canvases[0].scaled_display_image_dict
 
+    @property
+    def image_ready(self) -> bool:
+        return self.image_canvases[0].image_ready
+
     def on_motion_notify_event(self, event):
         # Clear the info if the mouse leaves a plot
         if event.inaxes is None: