sensehat-screen 0.2.6

//! Frame rotation for the LED Matrix screen
use super::PixelFrame;

/// A counter-clockwise angle, multiple of `90°`, used to create rotated `PixelFrame`s.
#[derive(Copy, Clone)]
pub enum Rotate {
    None,
    Ccw90,
    Ccw180,
    Ccw270,
}

/// Methods enabled by the `rotate` feature.
// TODO: Put this under `Rotate` trait & feature
// brute-force... TODO: optimize to in-place manipulation
impl PixelFrame {
    /// Create a new `PixelFrame` that is rotated by a multiple of `90°`, counter-clockwise.
    pub fn rotate(&self, rotate: Rotate) -> Self {
        match rotate {
            Rotate::None => *self,
            Rotate::Ccw90 => self.rotate_left(),
            Rotate::Ccw180 => self.rotate_180(),
            Rotate::Ccw270 => self.rotate_right(),
        }
    }

    // Rotate the display to the left by 90 degrees. Creates a new `PixelFrame`.
    fn rotate_left(&self) -> Self {
        let mut flip_left = *self;
        flip_left.flip_h();
        flip_left.transpose();
        flip_left
    }

    // Rotate the display by 180 degrees. Creates a new `PixelFrame`.
    fn rotate_180(&self) -> Self {
        let mut flip_180 = *self;
        flip_180.reverse();
        flip_180
    }

    // Rotate the display to the right by 90 degrees. Creates a new `PixelFrame`.
    fn rotate_right(&self) -> Self {
        let mut flip_right = *self;
        flip_right.transpose();
        flip_right.flip_h();
        flip_right
    }
}

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

    const DARK: PixelColor = PixelColor::BLACK;
    const BLUE: PixelColor = PixelColor::BLUE;

    const CHECKER_BASE: [PixelColor; 64] = [
        DARK, DARK, DARK, DARK, BLUE, BLUE, BLUE, BLUE, //
        DARK, DARK, DARK, DARK, BLUE, BLUE, BLUE, BLUE, //
        DARK, DARK, BLUE, DARK, BLUE, DARK, DARK, DARK, //
        DARK, DARK, DARK, DARK, BLUE, DARK, DARK, DARK, //
        DARK, DARK, DARK, DARK, DARK, DARK, DARK, DARK, //
        DARK, DARK, DARK, DARK, DARK, DARK, BLUE, DARK, //
        BLUE, DARK, DARK, DARK, DARK, DARK, BLUE, DARK, //
        BLUE, BLUE, BLUE, DARK, DARK, DARK, DARK, DARK, //
    ];

    const CHECKER_90_CW: [PixelColor; 64] = [
        BLUE, BLUE, DARK, DARK, DARK, DARK, DARK, DARK, //
        BLUE, DARK, DARK, DARK, DARK, DARK, DARK, DARK, //
        BLUE, DARK, DARK, DARK, DARK, BLUE, DARK, DARK, //
        DARK, DARK, DARK, DARK, DARK, DARK, DARK, DARK, //
        DARK, DARK, DARK, DARK, BLUE, BLUE, BLUE, BLUE, //
        DARK, DARK, DARK, DARK, DARK, DARK, BLUE, BLUE, //
        DARK, BLUE, BLUE, DARK, DARK, DARK, BLUE, BLUE, //
        DARK, DARK, DARK, DARK, DARK, DARK, BLUE, BLUE, //
    ];

    const CHECKER_180: [PixelColor; 64] = [
        DARK, DARK, DARK, DARK, DARK, BLUE, BLUE, BLUE, //
        DARK, BLUE, DARK, DARK, DARK, DARK, DARK, BLUE, //
        DARK, BLUE, DARK, DARK, DARK, DARK, DARK, DARK, //
        DARK, DARK, DARK, DARK, DARK, DARK, DARK, DARK, //
        DARK, DARK, DARK, BLUE, DARK, DARK, DARK, DARK, //
        DARK, DARK, DARK, BLUE, DARK, BLUE, DARK, DARK, //
        BLUE, BLUE, BLUE, BLUE, DARK, DARK, DARK, DARK, //
        BLUE, BLUE, BLUE, BLUE, DARK, DARK, DARK, DARK, //
    ];

    const CHECKER_90_CCW: [PixelColor; 64] = [
        BLUE, BLUE, DARK, DARK, DARK, DARK, DARK, DARK, //
        BLUE, BLUE, DARK, DARK, DARK, BLUE, BLUE, DARK, //
        BLUE, BLUE, DARK, DARK, DARK, DARK, DARK, DARK, //
        BLUE, BLUE, BLUE, BLUE, DARK, DARK, DARK, DARK, //
        DARK, DARK, DARK, DARK, DARK, DARK, DARK, DARK, //
        DARK, DARK, BLUE, DARK, DARK, DARK, DARK, BLUE, //
        DARK, DARK, DARK, DARK, DARK, DARK, DARK, BLUE, //
        DARK, DARK, DARK, DARK, DARK, DARK, BLUE, BLUE, //
    ];

    #[test]
    fn pixel_frame_is_rotated_90_degrees_left() {
        let checker_base = PixelFrame(CHECKER_BASE);
        let checker_left = PixelFrame(CHECKER_90_CCW);
        assert_eq!(checker_base.rotate_left(), checker_left);
    }

    #[test]
    fn pixel_frame_is_rotated_by_180_degrees() {
        let checker_base = PixelFrame(CHECKER_BASE);
        let checker_180 = PixelFrame(CHECKER_180);
        assert_eq!(checker_base.rotate_180(), checker_180);
    }

    #[test]
    fn pixel_frame_is_rotated_by_180_degrees_by_two_90_deg_steps() {
        let checker_base = PixelFrame(CHECKER_BASE);
        let checker_180 = PixelFrame(CHECKER_180);
        assert_eq!(checker_base.rotate_left().rotate_left(), checker_180);
    }

    #[test]
    fn pixel_frame_is_rotated_90_degrees_right() {
        let checker_base = PixelFrame(CHECKER_BASE);
        let checker_right = PixelFrame(CHECKER_90_CW);
        assert_eq!(checker_base.rotate_right(), checker_right);
    }
}