Function input_sys::libinput_event_gesture_get_angle_delta

pub unsafe extern "C" fn libinput_event_gesture_get_angle_delta(
    event: *mut libinput_event_gesture
) -> f64

@ingroup event_gesture

Return the angle delta in degrees between the last and the current @ref LIBINPUT_EVENT_GESTURE_PINCH_UPDATE event. For gesture events that are not of type @ref LIBINPUT_EVENT_GESTURE_PINCH_UPDATE, this function returns 0.

The angle delta is defined as the change in angle of the line formed by the 2 fingers of a pinch gesture. Clockwise rotation is represented by a positive delta, counter-clockwise by a negative delta. If e.g. the fingers are on the 12 and 6 location of a clock face plate and they move to the 1 resp. 7 location in a single event then the angle delta is 30 degrees.

If more than two fingers are present, the angle represents the rotation around the center of gravity. The calculation of the center of gravity is implementation-dependent.

@return the angle delta since the last event