The position of the child controls in the iOS sub-control are converted to the location of the parent control

cgrect focusframe = [_scrollview convertrect:_joinview. Frame Toview : Self . View ];

Here _scrollview is self. Child controls for view

_joinview is the child control of _scrollview, and here is the calculation of the _joinview in self. the location of the view,

Of course, there are other similar methods.

[View convertpoint:<# (Cgpoint) #> fromview:<# (UIView *) #>]

[View convertpoint:<# (Cgpoint) #> toview:<# (UIView *) #>]

[self. View convertrect:<# (CGRect) #> fromview:<# (UIView *) #>]

[self. View convertrect:<# (CGRect) #> toview:<# (UIView *) #>]