Fix ratio computation.

Author: ebezzam

scripts/measure/prep_display_image.py

@@ -127,12 +127,12 @@ def display(
             # rescale according to non-negative value
             if image_res[0] < 0:
                 new_height = image_res[1]
-                ratio = new_height / float(image_width)
+                ratio = new_height / float(image_height)
                 image_res = (int(ratio * image_width), new_height)
 
             elif image_res[1] < 0:
                 new_width = image_res[0]
-                ratio = new_width / float(image_height)
+                ratio = new_width / float(image_width)
                 image_res = (new_width, int(ratio * image_height))
 
         # set image within screen