XmObjectAtPoint — A toolkit function that determines which child
intersects or comes closest to a specified point "XmObjectAtPoint"
XmObjectAtPoint searches the child list of the specified manager widget
and returns the child most closely associated with the specified x,y
For the typical Motif manager widget, XmObjectAtPoint uses the
following rules to determine the returned object:
· If one child intersects x,y, XmObjectAtPoint returns the widget
ID of that child.
· If more than one child intersects x,y, XmObjectAtPoint returns
the widget ID of the visible child.
· If no child intersects x,y, XmObjectAtPoint returns NULL.
The preceding rules are only general. In fact, each manager widget is
free to define "most closely associated" as it desires. For example,
if no child intersects x,y, a manager might return the child closest to
widget Specifies a manager widget.
x Specifies the x-coordinate about which you are seeking child
information. The x-coordinate must be specified in pixels,
relative to the left side of manager.
y Specifies the y-coordinate about which you are seeking child
information. The y-coordinate must be specified in pixels,
relative to the top side of manager.
Returns the child of manager most closely associated with x,y. If none
of its children are sufficiently associated with x,y, returns NULL.