launchy 0.4.1

Low-level bindings and high-level abstractions for the Novation Launchpad MIDI devices
Documentation 
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/// A 2-bit color, with only red and green components
#[derive(Debug, Copy, Clone, Eq, PartialEq, Default, Hash)]
pub struct Color {
    red: u8,
    green: u8,
}

impl Color {
    // Standard colors
    pub const OFF: Color = Color { red: 0, green: 0 };
    pub const RED: Color = Color { red: 3, green: 0 };
    pub const GREEN: Color = Color { red: 0, green: 3 };
    pub const AMBER: Color = Color { red: 3, green: 3 };

    // Extended colors
    pub const DIM_GREEN: Color = Color { red: 0, green: 1 };
    pub const DIM_RED: Color = Color { red: 1, green: 0 };
    pub const ORANGE: Color = Color { red: 3, green: 2 };
    pub const YELLOW: Color = Color { red: 2, green: 3 };

    // Alias colors
    pub const BLACK: Color = Color::OFF;

    /// Create a new color from the given red and green components.
    ///
    /// Both values must be less than 4 (they are 2-bit values)
    pub fn new(red: u8, green: u8) -> Color {
        assert!(red < 4);
        assert!(green < 4);

        Color { red, green }
    }

    pub fn red(&self) -> u8 {
        self.red
    }
    pub fn green(&self) -> u8 {
        self.green
    }
    pub fn set_red(&mut self, red: u8) {
        assert!(red < 4);
        self.red = red
    }
    pub fn set_green(&mut self, green: u8) {
        assert!(green < 4);
        self.green = green
    }
}

#[derive(Debug, Ord, PartialOrd, Eq, PartialEq, Hash, Copy, Clone)]
pub enum Brightness {
    Off,
    Low,
    Medium,
    Full,
}

#[derive(Debug, Eq, PartialEq, Hash, Copy, Clone)]
#[repr(u8)]
pub enum Buffer {
    A = 0,
    B = 1,
}

/// This enum specifies how a light state change should affect the other buffer, if at all
#[derive(Debug, Hash, Eq, PartialEq, Copy, Clone)]
pub enum DoubleBufferingBehavior {
    /// Only write to the currently edited buffer
    None,
    /// Clear the other buffer's copy of this LED
    Clear,
    /// Write this LED data to both buffers
    Copy,
}

/// Specifies a double buffering mode change
#[derive(Debug, Eq, PartialEq, Hash, Clone)]
pub struct DoubleBuffering {
    // If true, copy the contents from the new "displayed" buffer to the new "edited" buffer
    pub copy: bool,
    // If true, continually flip "displayed" buffers to make a flashing effect
    pub flash: bool,
    // The buffer that is being edited
    pub edited_buffer: Buffer,
    // The buffer that is being displayed
    pub displayed_buffer: Buffer,
}

pub(crate) fn make_color_code(color: Color, dbb: DoubleBufferingBehavior) -> u8 {
    // Bit 6 - Must be 0
    // Bit 5..4 - Green LED brightness
    // Bit 3 - Clear - If 1: clear the other buffer’s copy of this LED.
    // Bit 2 - Copy - If 1: write this LED data to both buffers.
    // Bit 1..0 - Red LED brightness
    let double_buffering_code = match dbb {
        DoubleBufferingBehavior::None => 0b00,
        DoubleBufferingBehavior::Copy => 0b01,
        DoubleBufferingBehavior::Clear => 0b10,
    };
    (color.green << 4) | (double_buffering_code << 2) | color.red
}

pub(crate) fn make_color_code_loopable(color: Color, should_loop: bool) -> u8 {
    // Bit 6 - Loop - If 1: loop the text
    // Bit 5..4 - Green LED brightness
    // Bit 3..2 - Clear/Copy (as seen in make_color_code), which don't apply for text
    // Bit 1..0 - Red LED brightness

    ((should_loop as u8) << 6) | (color.green() << 4) | color.red()
}