Draggable Targets

[Tim Corio <tcorio rochester rr com>]

I have another newbie question.  I'm grateful that this list has been
very indulgent of my recent questions.

I want to let the user place a target (either a cross-hair or a circle)
on an image and then be able to drag it to a new location.  This seems
like common functionality that GTK+ might directly support.  How do I
implement this functionality?

The underlying image is in a Drawing Area which is inside a Scrolled
Window.

My first thought was to place a small image (of the cross-hair) on top
of the image.  I would need to specify the x/y offset of the target
image inside the Scrolled Window, but I don't see how that is supported
in GTK+,

My second thought is to draw the target directly in the Drawing Area,
then redraw then create the drag effect in the motion_event callback by
redrawing the background where the target used to be, and drawing the
target where is now.

Thanks,
Tim