Draw Line in Imageview

A UIImageView is for displaying an existing image.

It is a subclass of UIView.

The most direct way to draw to a view is via the UIView:

UIView has a -layer method that gives you access to the CALayer of the view.

CALayer has a method -drawInContext: that takes a CGContext that gets drawn on the layer.

If you look at the refrence for CGContext [Core Graphics Context], you will find functions for drawing various things.

For drawing lines, you want the functions that deal with defining and filling "paths".