Struct trackball::Touch

pub struct Touch<F: Ord, N: RealField> { /* fields omitted */ }

Touch gestures inducing slide, orbit, scale, and focus.

Implements Default and can be created with Scene::default().

Both its methods must be invoked on matching events fired by your 3D graphics library of choice.

Implementations

impl<F: Ord, N: RealField> Touch<F, N>

pub fn compute(
    &mut self,
    fid: F,
    pos: &Point2<N>,
    mvs: usize
) -> Option<(usize, Point2<N>, N, N)>

Computes centroid position, roll angle, and scale ratio from finger gestures.

Parameters are:

• fid as generic finger ID like Some(id) for touch and None for mouse events,
• pos as current cursor/finger position in screen space,
• mvs as number of finger moves for debouncing potential finger tap gesture with zero resulting in no delay of non-tap gestures while tap gesture can still be recognized. Use zero unless tap gestures are hardly recognized.

Returns number of fingers, centroid position, roll angle, and scale ratio in screen space in the order mentioned or None when debouncing tap gesture with non-vanishing mvs. See Self::discard() for tap gesture result.

pub fn discard(&mut self, fid: F) -> Option<(usize, Point2<N>)>

Removes finger position and returns number of fingers and centroid position of tap gesture.

Returns None as long as there are finger positions or no tap gesture has been recognized.

Panics if generic finger ID fid is unknown.

Trait Implementations

impl<F: Clone + Ord, N: Clone + RealField> Clone for Touch<F, N>

fn clone(&self) -> Touch<F, N>

Returns a copy of the value.

pub fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<F: Debug + Ord, N: Debug + RealField> Debug for Touch<F, N>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<F: Default + Ord, N: Default + RealField> Default for Touch<F, N>

fn default() -> Touch<F, N>

Returns the “default value” for a type.