A touch_point is the event<-detail
of the events of a finger on a touch screen. The first finger that
touches the screen acts as the left mouse button: it generates
ms_left_down, ms_left_drag and ms_left_up, so applications that only use
the mouse also work with a touch screen. While it is down, other fingers
generate touch_down, touch_motion, touch_up and touch_cancel. These are
delivered to the window of the first finger. If the first finger is
lifted while others are still down, no finger acts as the mouse until
all fingers are lifted. If the system cancels the first finger, e.g.,
because it recognised a gesture, it generates ms_left_up.
The event<-device
of these events is the input_device of the touch screen, whose input_device<-kind
is touch. As the event delegates to its detail, the values
below are normally requested from the event:
get(Ev, finger, Finger)