What command to be used to make "Return" button as a button to continue an automated tool?

I am doing an automated tool on matlab for an image. Now, I used imellipse and the to convert the selected one to binary image. in the automated tool what command can be used to let the user draw the ellipse and how to make the "return" button continue the operation after the user finishes the ellipse?

Answer 1

[Chad Greene]

Use waitforbuttonpress and key = get(gcf, currentcharacter). If key equals 13, the user hit return.