aura-gui 0.2.2

//! Si la ventana se puede pintar: tapada, minimizada o con tamaño cero no se dibuja nada (cero GPU en reposo).

#[derive(Clone, Copy, Debug)]
pub struct FrameVisibility {
    occluded: bool,
    physical_size: (u32, u32),
}

impl FrameVisibility {
    pub fn new(width: u32, height: u32) -> Self {
        Self { occluded: false, physical_size: (width, height) }
    }

    pub fn resize(&mut self, width: u32, height: u32) {
        self.physical_size = (width, height);
    }

    /// `true` solo en una transición: así las cachés no se purgan una y otra vez.
    pub fn set_occluded(&mut self, occluded: bool) -> bool {
        std::mem::replace(&mut self.occluded, occluded) != occluded
    }

    pub fn is_drawable(&self) -> bool {
        !self.occluded && self.physical_size.0 > 0 && self.physical_size.1 > 0
    }

    pub fn is_occluded(&self) -> bool {
        self.occluded
    }

    pub fn physical_size(&self) -> (u32, u32) {
        self.physical_size
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn occluded_windows_stay_asleep_through_resizes() {
        let mut visibility = FrameVisibility::new(1280, 820);
        assert!(visibility.is_drawable());
        assert!(visibility.set_occluded(true));
        assert!(!visibility.set_occluded(true));
        visibility.resize(1600, 900);
        assert!(!visibility.is_drawable());
        assert!(visibility.set_occluded(false));
        assert!(visibility.is_drawable());
    }

    #[test]
    fn unoccluding_a_zero_sized_window_does_not_make_it_drawable() {
        let mut visibility = FrameVisibility::new(1280, 820);
        visibility.set_occluded(true);
        visibility.resize(0, 820);
        visibility.set_occluded(false);
        assert!(!visibility.is_drawable());
        visibility.resize(1280, 0);
        assert!(!visibility.is_drawable());
        visibility.resize(1280, 820);
        assert!(visibility.is_drawable());
    }
}