glissade 0.2.10

Rust library that provides various utilities for animations and transitions
Documentation 
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use crate::{Keyframes, Time};
use std::fmt::Debug;
use std::marker::PhantomData;

/// An animation that repeats keyframes indefinitely.
pub struct RepeatKeyframes<T, X: Time, S: Keyframes<T, X>> {
    keyframes: S,
    phantom: PhantomData<(T, X)>,
}

impl<T, X: Time, S: Keyframes<T, X> + Debug> Debug for RepeatKeyframes<T, X, S>
where
    X::Duration: Debug,
{
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.debug_struct("RepeatKeyframes")
            .field("keyframes", &self.keyframes)
            .finish()
    }
}

impl<T, X: Time, S: Keyframes<T, X> + PartialEq> PartialEq for RepeatKeyframes<T, X, S> {
    fn eq(&self, other: &Self) -> bool {
        self.keyframes == other.keyframes
    }
}

impl<T, X: Time, S: Keyframes<T, X>> RepeatKeyframes<T, X, S> {
    pub fn new(keyframes: S) -> Self {
        Self {
            keyframes,
            phantom: Default::default(),
        }
    }
}

impl<T, X: Time, S: Keyframes<T, X>> Keyframes<T, X> for RepeatKeyframes<T, X, S> {
    fn get(&self, offset: X::Duration) -> T {
        if !self.keyframes.is_finite() {
            return self.keyframes.get(offset);
        }

        let n = X::duration_as_f32(offset) / X::duration_as_f32(self.keyframes.duration());
        let step_offset = X::duration_scale(self.keyframes.duration(), n.floor());

        let offset = if step_offset < offset {
            X::duration_diff(offset, step_offset)
        } else {
            Default::default()
        };
        self.keyframes.get(offset)
    }

    fn duration(&self) -> X::Duration {
        panic!("RepeatKeyframes has infinite duration");
    }

    fn is_finite(&self) -> bool {
        false
    }

    fn end_value(&self) -> T {
        panic!("RepeatKeyframes has no end value");
    }
}

impl<T, X: Time, S: Keyframes<T, X> + Clone> Clone for RepeatKeyframes<T, X, S> {
    fn clone(&self) -> Self {
        Self {
            keyframes: self.keyframes.clone(),
            phantom: Default::default(),
        }
    }
}

impl<T, X: Time, S: Keyframes<T, X> + Copy> Copy for RepeatKeyframes<T, X, S> {}

#[cfg(test)]
mod tests {
    use crate::{keyframes, Keyframes};

    #[test]
    fn test_repeat_keyframes() {
        let keyframes = keyframes::from::<f64, f64>(0.0).go_to(8.0, 1.0).repeat();
        assert_eq!(keyframes.get(0.0), 0.0);
        assert_eq!(keyframes.get(0.5), 4.0);
        assert_eq!(keyframes.get(0.75), 6.0);
        assert_eq!(keyframes.get(1.5), 4.0);
        assert_eq!(keyframes.get(2.25), 2.0);
        assert_eq!(keyframes.get(2.5), 4.0);
        assert_eq!(keyframes.get(8.25), 2.0);
    }
}