Differences between contentsize, contentinset, and contentoffset

Contentsize:The size of the content view. in fact, it is the area where scrollview can scroll. For example, frame = (0, 0,320,480) contentsize = (320,960) indicates that your scrollview can scroll up or down, and the rolling area is twice the frame size.

Contentoffset:The point at which the origin of the content view is offset from the origin of the scroll view. it is the offset of the vertex in the current display area of scrollview relative to the frame vertex. For example, if you pull to the bottom of the last example, contentoffset is (0,480), that is, y offset is 480.

Contentinset:The distance that the content view is inset from the enclosing scroll view. it is the position of the contentview vertex of the scrollview relative to the scrollview. For example, if your contentinset = (0,100), your contentview is displayed starting from the scrollview (0,100 ).