Use appium to generate navigation diagram

hi all, all of you know about mobile test are hard to verify UI especially iOS / Android version upgrade of the impact to app. i create this sample to capture all screen and combine it together as logical flow so that everyone can easy to understand:

here is the screenshot of iOS 12.1

and here iOS 11.4 (similar)

finally i diff both image so i can easy to know the different of mobile app upgrade test:

here is the source code:

the concept not only apply to mobile app, web page as well.