In this UIScrollView Tutorial series, we get a sense of how to set the content size for a scroll view as well as how to zoom inside one.
Content Size
In a scroll view, if you do not use auto layout to infer the content size values, you could produce the content size values using an actual content size. Content insets solve the problem of having content that goes underneath other parts of the User Interface and yet still remains reachable using scroll bars. In other words, the purpose of the Content Inset is to make the interaction area smaller than its actual area.
Zooming in a UIScrollView
In zooming a UIScrollView, the important thing to remember is that the zoom happens on a content piece from the scroll view. Content view for zooming should be a subview of the scroll view itself. You have to set the minimum and maximum of zoom.
Summary
Scroll views are among the fundamental views in iPhone/iPad development. They are embedded in most higher-level views such as table views or collections views as well.
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