Draw a rectangle on top of an image using RGtk2?

Dear all,

I use gtkImageFromFile to display an image. Then I want to do some
gsignal to handle mouse event. I click the mouse and move a another
position and release. I can get the position of the firs click and the
release position,  then I would to draw a rectangle to display the
region I have selected. I need some hints on what functions should I
look for. I tried to google but don't know how.

Thanks.

HUANG Ronggui, Wincent
PhD Candidate
Dept of Public and Social Administration
City University of Hong Kong
Home page: http://asrr.r-forge.r-project.org/rghuang.html