Think about when you walk into your apartment. Siri chirps in and says, this room is 16 feet by 30 feet. Then you walk into the bathroom and Siri says, this room is 6 feet wide and 10 feet long. As you move from room to room Siri tells you the dimensions of the room you are in.
GeometryReader works on the same principle. It can tell you a number of values for its containing view. Awesome!
You have Geometry reader in the MissionView, yes? You also have a mission badge photo in the MissionView. But it stays the same size when you scroll to the bottom to see the astronauts, yes?
What if you could determine how far down the MissionView you are? Say you were 50% down the view, maybe you could update a State variable and apply a percentage to the size of the Mission Badge? When you reach 80% down the view, the State variable is automatically updated, and so is the MissionBadge's size. When you get to the bottom of the view the MissionBadge is reduced to half its normal size. There is some math involved here.
But what you need to find out is HOW do you determine HOW FAR down the view you are.
@twostraws has a nice video Scroll View Using Geometry Reader
This video has some hints for you! Review this a few times. Think how you might apply these techniques. Try a few things, then come back and tell us about your success!
