Add flat-field_pointer.py

https://matplotlib.org/3.8.4/gallery/event_handling/coords_demo.html

datasets/raise/flat-field_pointer.py

@@ -0,0 +1,19 @@
+import matplotlib.pyplot as plt
+import numpy as np
+from matplotlib.backend_bases import MouseButton
+import matplotlib.image as mpimg
+import os
+
+os.chdir('flat-field/TIF')
+
+def onClick(event):
+    if event.button is MouseButton.LEFT:
+        print(event.x, event.y)
+        plt.close()
+
+for fileName in os.listdir():
+    print(fileName)
+    image = mpimg.imread(fileName)
+    plt.imshow(image)
+    plt.connect('button_press_event', onClick)
+    plt.show(block = True)