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frame = a view’s location and size using the parent view’s coordinate system (important for placing the view in the parent)
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bounds = a view’s location and size using its own coordinate system (important for placing the view’s content or subviews within itself)
Frame in iOS are like the frames of a picture on the wall. They are relative to the superview. And they don't really change.
Bounds is the coordinate systems within the frame itself. There is a distinction. Because while the frame rarely changes, the bounds inside the view does. This is how UIScrollViews
work as well as animations. They change their bounds but leave their frames.