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/// This module contains the animation related data structures
#[repr(C)]
#[derive(Clone, Copy, Debug)]
pub struct Easing {
    pub x1: f32,
    pub y1: f32,
    pub x2: f32,
    pub y2: f32,
}

// default for Easing
impl Default for Easing {
    fn default() -> Self {
        // Ease out
        Easing {
            x1: 0.42,
            y1: 0.0,
            x2: 0.58,
            y2: 1.0,
        }
    }
}

/// Easing functions are used to interpolate between two values
/// over a period of time. The default easing function is ease out.
/// The easing is calculated using a bezier curve with 2 control points.
///
impl Easing {
    pub fn ease_out() -> Self {
        Easing::default()
    }
    pub fn ease_in() -> Self {
        Easing {
            x1: 0.42,
            y1: 0.0,
            x2: 1.0,
            y2: 1.0,
        }
    }
    pub fn ease_in_out() -> Self {
        Easing {
            x1: 0.42,
            y1: 0.0,
            x2: 0.58,
            y2: 1.0,
        }
    }
    pub fn linear() -> Self {
        Easing {
            x1: 0.0,
            y1: 0.0,
            x2: 1.0,
            y2: 1.0,
        }
    }
    pub fn ease_out_quad() -> Self {
        Easing {
            x1: 0.25,
            y1: 0.46,
            x2: 0.45,
            y2: 0.94,
        }
    }
    pub fn ease_in_quad() -> Self {
        Easing {
            x1: 0.55,
            y1: 0.085,
            x2: 0.68,
            y2: 0.53,
        }
    }
    pub fn ease_in_out_quad() -> Self {
        Easing {
            x1: 0.455,
            y1: 0.03,
            x2: 0.515,
            y2: 0.955,
        }
    }
    pub fn ease_out_cubic() -> Self {
        Easing {
            x1: 0.215,
            y1: 0.61,
            x2: 0.355,
            y2: 1.0,
        }
    }
    pub fn ease_in_cubic() -> Self {
        Easing {
            x1: 0.55,
            y1: 0.055,
            x2: 0.675,
            y2: 0.19,
        }
    }
    pub fn ease_in_out_cubic() -> Self {
        Easing {
            x1: 0.645,
            y1: 0.045,
            x2: 0.355,
            y2: 1.0,
        }
    }
    pub fn ease_out_quart() -> Self {
        Easing {
            x1: 0.165,
            y1: 0.84,
            x2: 0.44,
            y2: 1.0,
        }
    }
    pub fn ease_in_quart() -> Self {
        Easing {
            x1: 0.895,
            y1: 0.03,
            x2: 0.685,
            y2: 0.22,
        }
    }
    pub fn ease_in_out_quart() -> Self {
        Easing {
            x1: 0.77,
            y1: 0.0,
            x2: 0.175,
            y2: 1.0,
        }
    }
    pub fn ease_out_quint() -> Self {
        Easing {
            x1: 0.23,
            y1: 1.0,
            x2: 0.32,
            y2: 1.0,
        }
    }
    pub fn ease_in_quint() -> Self {
        Easing {
            x1: 0.755,
            y1: 0.05,
            x2: 0.855,
            y2: 0.06,
        }
    }
    pub fn ease_in_out_quint() -> Self {
        Easing {
            x1: 0.86,
            y1: 0.0,
            x2: 0.07,
            y2: 1.0,
        }
    }
}