How to make the edge line connect to the end point?

http://i.imgur.com/syQnv.jpg

i want to connect the upper edge line to the end point. Which function should i use?

Answer 1

[Image Analyst]

Use imline().

[Wei Qing]

is dat using the h = imline(hparent, position) ? but 'hparent' state for? n the 'position' is the end point position that i want the line to reach? how do i get the coordinate of the end point?