adjust the aspect ratio for 2D Mapping scan view

[XuetaoLiu-CLS]

Staff from SXRMB asked about the aspect ratio of the 2D mapping scan view. The aspect ratio of current 2D scan view doesn't match that of the sample. The user expects to have a matched view so that they are able to compare the scan view with the sample more easily.

As mentioned in the meeting, to have matched aspect ratio in the scan view, might make the scan view too small to view. One alternative solution might have a button to switch between the default display ratio and the matched aspect ratio.