event-start

event-start is a compiled Lisp function in `subr.el'.

(event-start EVENT)

Return the starting position of EVENT.
EVENT should be a mouse click, drag, or key press event. If
EVENT is nil, the value of `posn-at-point' is used instead.

The following accessor functions are used to access the elements
of the position:

`posn-window': The window the event is in.
`posn-area': A symbol identifying the area the event occurred in,
or nil if the event occurred in the text area.
`posn-point': The buffer position of the event.
`posn-x-y': The pixel-based coordinates of the event.
`posn-col-row': The estimated column and row corresponding to the
position of the event.
`posn-actual-col-row': The actual column and row corresponding to the
position of the event.
`posn-string': The string object of the event, which is either
nil or (STRING . POSITION)'.
`posn-image': The image object of the event, if any.
`posn-object': The image or string object of the event, if any.
`posn-timestamp': The time the event occurred, in milliseconds.

For more information, see Info node `(elisp)Click Events'.