DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Mercurial (c68fe15a81fc)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242
//! Color managemement.
//!
//! # Example
//!
//! ```rust
//! use termion::color;
//!
//! fn main() {
//!     println!("{}Red", color::Fg(color::Red));
//!     println!("{}Blue", color::Fg(color::Blue));
//!     println!("{}Back again", color::Fg(color::Reset));
//! }
//! ```

use std::fmt;
use raw::CONTROL_SEQUENCE_TIMEOUT;
use std::io::{self, Write, Read};
use std::time::{SystemTime, Duration};
use async::async_stdin;
use std::env;

/// A terminal color.
pub trait Color {
    /// Write the foreground version of this color.
    fn write_fg(&self, f: &mut fmt::Formatter) -> fmt::Result;
    /// Write the background version of this color.
    fn write_bg(&self, f: &mut fmt::Formatter) -> fmt::Result;
}

macro_rules! derive_color {
    ($doc:expr, $name:ident, $value:expr) => {
        #[doc = $doc]
        #[derive(Copy, Clone, Debug)]
        pub struct $name;

        impl Color for $name {
            #[inline]
            fn write_fg(&self, f: &mut fmt::Formatter) -> fmt::Result {
                write!(f, csi!("38;5;", $value, "m"))
            }

            #[inline]
            fn write_bg(&self, f: &mut fmt::Formatter) -> fmt::Result {
                write!(f, csi!("48;5;", $value, "m"))
            }
        }
    };
}

derive_color!("Black.", Black, "0");
derive_color!("Red.", Red, "1");
derive_color!("Green.", Green, "2");
derive_color!("Yellow.", Yellow, "3");
derive_color!("Blue.", Blue, "4");
derive_color!("Magenta.", Magenta, "5");
derive_color!("Cyan.", Cyan, "6");
derive_color!("White.", White, "7");
derive_color!("High-intensity light black.", LightBlack, "8");
derive_color!("High-intensity light red.", LightRed, "9");
derive_color!("High-intensity light green.", LightGreen, "10");
derive_color!("High-intensity light yellow.", LightYellow, "11");
derive_color!("High-intensity light blue.", LightBlue, "12");
derive_color!("High-intensity light magenta.", LightMagenta, "13");
derive_color!("High-intensity light cyan.", LightCyan, "14");
derive_color!("High-intensity light white.", LightWhite, "15");

impl<'a> Color for &'a Color {
    #[inline]
    fn write_fg(&self, f: &mut fmt::Formatter) -> fmt::Result {
        (*self).write_fg(f)
    }

    #[inline]
    fn write_bg(&self, f: &mut fmt::Formatter) -> fmt::Result {
        (*self).write_bg(f)
    }
}

/// An arbitrary ANSI color value.
#[derive(Clone, Copy, Debug)]
pub struct AnsiValue(pub u8);

impl AnsiValue {
    /// 216-color (r, g, b ≤ 5) RGB.
    pub fn rgb(r: u8, g: u8, b: u8) -> AnsiValue {
        debug_assert!(r <= 5,
                      "Red color fragment (r = {}) is out of bound. Make sure r ≤ 5.",
                      r);
        debug_assert!(g <= 5,
                      "Green color fragment (g = {}) is out of bound. Make sure g ≤ 5.",
                      g);
        debug_assert!(b <= 5,
                      "Blue color fragment (b = {}) is out of bound. Make sure b ≤ 5.",
                      b);

        AnsiValue(16 + 36 * r + 6 * g + b)
    }

    /// Grayscale color.
    ///
    /// There are 24 shades of gray.
    pub fn grayscale(shade: u8) -> AnsiValue {
        // Unfortunately, there are a little less than fifty shades.
        debug_assert!(shade < 24,
                      "Grayscale out of bound (shade = {}). There are only 24 shades of \
                      gray.",
                      shade);

        AnsiValue(0xE8 + shade)
    }
}

impl Color for AnsiValue {
    #[inline]
    fn write_fg(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, csi!("38;5;{}m"), self.0)
    }

    #[inline]
    fn write_bg(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, csi!("48;5;{}m"), self.0)
    }
}

/// A truecolor RGB.
#[derive(Debug, Clone, Copy, PartialEq)]
pub struct Rgb(pub u8, pub u8, pub u8);

impl Color for Rgb {
    #[inline]
    fn write_fg(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, csi!("38;2;{};{};{}m"), self.0, self.1, self.2)
    }

    #[inline]
    fn write_bg(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, csi!("48;2;{};{};{}m"), self.0, self.1, self.2)
    }
}

/// Reset colors to defaults.
#[derive(Debug, Clone, Copy)]
pub struct Reset;

impl Color for Reset {
    #[inline]
    fn write_fg(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, csi!("39m"))
    }

    #[inline]
    fn write_bg(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, csi!("49m"))
    }
}

/// A foreground color.
#[derive(Debug, Clone, Copy)]
pub struct Fg<C: Color>(pub C);

impl<C: Color> fmt::Display for Fg<C> {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        self.0.write_fg(f)
    }
}

/// A background color.
#[derive(Debug, Clone, Copy)]
pub struct Bg<C: Color>(pub C);

impl<C: Color> fmt::Display for Bg<C> {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        self.0.write_bg(f)
    }
}

/// Types that allow detection of the colors they support.
pub trait DetectColors {
    /// How many ANSI colors are supported (from 8 to 256)?
    ///
    /// Beware: the information given isn't authoritative, it's infered through escape codes or the
    /// value of `TERM`, more colors may be available.
    fn available_colors(&mut self) -> io::Result<u16>;
}

impl<W: Write> DetectColors for W {
    fn available_colors(&mut self) -> io::Result<u16> {
        let mut stdin = async_stdin();

        if detect_color(self, &mut stdin, 0)? {
            // OSC 4 is supported, detect how many colors there are.
            // Do a binary search of the last supported color.
            let mut min = 8;
            let mut max = 256;
            let mut i;
            while min + 1 < max {
                i = (min + max) / 2;
                if detect_color(self, &mut stdin, i)? {
                    min = i
                } else {
                    max = i
                }
            }
            Ok(max)
        } else {
            // OSC 4 is not supported, trust TERM contents.
            Ok(match env::var_os("TERM") {
                   Some(val) => {
                       if val.to_str().unwrap_or("").contains("256color") {
                           256
                       } else {
                           8
                       }
                   }
                   None => 8,
               })
        }
    }
}

/// Detect a color using OSC 4.
fn detect_color(stdout: &mut Write, stdin: &mut Read, color: u16) -> io::Result<bool> {
    // Is the color available?
    // Use `ESC ] 4 ; color ; ? BEL`.
    write!(stdout, "\x1B]4;{};?\x07", color)?;
    stdout.flush()?;

    let mut buf: [u8; 1] = [0];
    let mut total_read = 0;

    let timeout = Duration::from_millis(CONTROL_SEQUENCE_TIMEOUT);
    let now = SystemTime::now();
    let bell = 7u8;

    // Either consume all data up to bell or wait for a timeout.
    while buf[0] != bell && now.elapsed().unwrap() < timeout {
        total_read += stdin.read(&mut buf)?;
    }

    // If there was a response, the color is supported.
    Ok(total_read > 0)
}