use std::fmt;
#[derive(Clone, Copy, PartialEq, Debug)]
pub struct Color {
pub r: f32,
pub g: f32,
pub b: f32,
pub a: f32,
}
impl Color {
pub const WHITE: Color = Color::rgba(1.0, 1.0, 1.0, 1.0);
pub const BLACK: Color = Color::rgba(0.0, 0.0, 0.0, 1.0);
pub const TRANSPARENT: Color = Color::rgba(0.0, 0.0, 0.0, 0.0);
pub const fn rgba(r: f32, g: f32, b: f32, a: f32) -> Color {
Color { r, g, b, a }
}
pub const fn rgb(r: f32, g: f32, b: f32) -> Color {
Color { r, g, b, a: 1.0 }
}
pub fn hex(hex: &str) -> Option<Color> {
let digits = hex.strip_prefix('#')?;
if !digits.is_ascii() {
return None;
}
let nibble = |i: usize| u8::from_str_radix(&digits[i..=i], 16).ok();
let byte = |i: usize| u8::from_str_radix(&digits[i..i + 2], 16).ok();
let [r, g, b, a] = match digits.len() {
3 | 4 => {
let channel = |i: usize| nibble(i).map(|v| v * 17);
[channel(0)?, channel(1)?, channel(2)?, if digits.len() == 4 { channel(3)? } else { 255 }]
}
6 | 8 => [byte(0)?, byte(2)?, byte(4)?, if digits.len() == 8 { byte(6)? } else { 255 }],
_ => return None,
};
Some(Color::from_bytes([r, g, b, a]))
}
pub fn css(css: &str) -> Option<Color> {
let css = css.trim();
if css.starts_with('#') {
return Color::hex(css);
}
let lower = css.to_ascii_lowercase();
if let Some(args) = lower.strip_prefix("rgba(").or_else(|| lower.strip_prefix("rgb(")) {
let parts: Vec<&str> = args.strip_suffix(')')?.split([',', '/', ' ']).filter(|p| !p.is_empty()).collect();
if !(3..=4).contains(&parts.len()) {
return None;
}
let channel = |p: &str| match p.strip_suffix('%') {
Some(percent) => percent.parse::<f32>().ok().map(|v| v / 100.0),
None => p.parse::<f32>().ok().map(|v| v / 255.0),
};
let alpha = |p: &str| match p.strip_suffix('%') {
Some(percent) => percent.parse::<f32>().ok().map(|v| v / 100.0),
None => p.parse::<f32>().ok(),
};
let a = parts.get(3).map_or(Some(1.0), |p| alpha(p))?;
return Some(Color::rgba(channel(parts[0])?, channel(parts[1])?, channel(parts[2])?, a).clamped());
}
if lower == "transparent" {
return Some(Color::TRANSPARENT);
}
let i = NAMED.binary_search_by(|(name, _)| name.cmp(&lower.as_str())).ok()?;
let [r, g, b] = NAMED[i].1.to_be_bytes()[1..].try_into().ok()?;
Some(Color::from_bytes([r, g, b, 255]))
}
#[must_use]
pub fn alpha(self, a: f32) -> Color {
Color { a, ..self }
}
pub(crate) fn from_bytes(bytes: [u8; 4]) -> Color {
let [red, green, blue, alpha] = bytes.map(|byte| f32::from(byte) / 255.0);
Color::rgba(red, green, blue, alpha)
}
pub fn to_rgba8(self) -> [u8; 4] {
let q = |v: f32| (v.clamp(0.0, 1.0) * 255.0).round() as u8;
[q(self.r), q(self.g), q(self.b), q(self.a)]
}
pub(crate) fn packed(self) -> u32 {
u32::from_le_bytes(self.to_rgba8())
}
pub(crate) fn to_array(self) -> [f32; 4] {
[self.r, self.g, self.b, self.a]
}
fn clamped(self) -> Color {
let c = |v: f32| v.clamp(0.0, 1.0);
Color::rgba(c(self.r), c(self.g), c(self.b), c(self.a))
}
}
impl fmt::Display for Color {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let [red, green, blue, alpha] = self.to_rgba8();
write!(f, "#{red:02x}{green:02x}{blue:02x}")?;
if alpha == 255 { Ok(()) } else { write!(f, "{alpha:02x}") }
}
}
#[allow(clippy::unreadable_literal)]
static NAMED: &[(&str, u32)] = &[
("aliceblue", 0xf0f8ff),
("antiquewhite", 0xfaebd7),
("aqua", 0x00ffff),
("aquamarine", 0x7fffd4),
("azure", 0xf0ffff),
("beige", 0xf5f5dc),
("bisque", 0xffe4c4),
("black", 0x000000),
("blanchedalmond", 0xffebcd),
("blue", 0x0000ff),
("blueviolet", 0x8a2be2),
("brown", 0xa52a2a),
("burlywood", 0xdeb887),
("cadetblue", 0x5f9ea0),
("chartreuse", 0x7fff00),
("chocolate", 0xd2691e),
("coral", 0xff7f50),
("cornflowerblue", 0x6495ed),
("cornsilk", 0xfff8dc),
("crimson", 0xdc143c),
("cyan", 0x00ffff),
("darkblue", 0x00008b),
("darkcyan", 0x008b8b),
("darkgoldenrod", 0xb8860b),
("darkgray", 0xa9a9a9),
("darkgreen", 0x006400),
("darkgrey", 0xa9a9a9),
("darkkhaki", 0xbdb76b),
("darkmagenta", 0x8b008b),
("darkolivegreen", 0x556b2f),
("darkorange", 0xff8c00),
("darkorchid", 0x9932cc),
("darkred", 0x8b0000),
("darksalmon", 0xe9967a),
("darkseagreen", 0x8fbc8f),
("darkslateblue", 0x483d8b),
("darkslategray", 0x2f4f4f),
("darkslategrey", 0x2f4f4f),
("darkturquoise", 0x00ced1),
("darkviolet", 0x9400d3),
("deeppink", 0xff1493),
("deepskyblue", 0x00bfff),
("dimgray", 0x696969),
("dimgrey", 0x696969),
("dodgerblue", 0x1e90ff),
("firebrick", 0xb22222),
("floralwhite", 0xfffaf0),
("forestgreen", 0x228b22),
("fuchsia", 0xff00ff),
("gainsboro", 0xdcdcdc),
("ghostwhite", 0xf8f8ff),
("gold", 0xffd700),
("goldenrod", 0xdaa520),
("gray", 0x808080),
("green", 0x008000),
("greenyellow", 0xadff2f),
("grey", 0x808080),
("honeydew", 0xf0fff0),
("hotpink", 0xff69b4),
("indianred", 0xcd5c5c),
("indigo", 0x4b0082),
("ivory", 0xfffff0),
("khaki", 0xf0e68c),
("lavender", 0xe6e6fa),
("lavenderblush", 0xfff0f5),
("lawngreen", 0x7cfc00),
("lemonchiffon", 0xfffacd),
("lightblue", 0xadd8e6),
("lightcoral", 0xf08080),
("lightcyan", 0xe0ffff),
("lightgoldenrodyellow", 0xfafad2),
("lightgray", 0xd3d3d3),
("lightgreen", 0x90ee90),
("lightgrey", 0xd3d3d3),
("lightpink", 0xffb6c1),
("lightsalmon", 0xffa07a),
("lightseagreen", 0x20b2aa),
("lightskyblue", 0x87cefa),
("lightslategray", 0x778899),
("lightslategrey", 0x778899),
("lightsteelblue", 0xb0c4de),
("lightyellow", 0xffffe0),
("lime", 0x00ff00),
("limegreen", 0x32cd32),
("linen", 0xfaf0e6),
("magenta", 0xff00ff),
("maroon", 0x800000),
("mediumaquamarine", 0x66cdaa),
("mediumblue", 0x0000cd),
("mediumorchid", 0xba55d3),
("mediumpurple", 0x9370db),
("mediumseagreen", 0x3cb371),
("mediumslateblue", 0x7b68ee),
("mediumspringgreen", 0x00fa9a),
("mediumturquoise", 0x48d1cc),
("mediumvioletred", 0xc71585),
("midnightblue", 0x191970),
("mintcream", 0xf5fffa),
("mistyrose", 0xffe4e1),
("moccasin", 0xffe4b5),
("navajowhite", 0xffdead),
("navy", 0x000080),
("oldlace", 0xfdf5e6),
("olive", 0x808000),
("olivedrab", 0x6b8e23),
("orange", 0xffa500),
("orangered", 0xff4500),
("orchid", 0xda70d6),
("palegoldenrod", 0xeee8aa),
("palegreen", 0x98fb98),
("paleturquoise", 0xafeeee),
("palevioletred", 0xdb7093),
("papayawhip", 0xffefd5),
("peachpuff", 0xffdab9),
("peru", 0xcd853f),
("pink", 0xffc0cb),
("plum", 0xdda0dd),
("powderblue", 0xb0e0e6),
("purple", 0x800080),
("rebeccapurple", 0x663399),
("red", 0xff0000),
("rosybrown", 0xbc8f8f),
("royalblue", 0x4169e1),
("saddlebrown", 0x8b4513),
("salmon", 0xfa8072),
("sandybrown", 0xf4a460),
("seagreen", 0x2e8b57),
("seashell", 0xfff5ee),
("sienna", 0xa0522d),
("silver", 0xc0c0c0),
("skyblue", 0x87ceeb),
("slateblue", 0x6a5acd),
("slategray", 0x708090),
("slategrey", 0x708090),
("snow", 0xfffafa),
("springgreen", 0x00ff7f),
("steelblue", 0x4682b4),
("tan", 0xd2b48c),
("teal", 0x008080),
("thistle", 0xd8bfd8),
("tomato", 0xff6347),
("turquoise", 0x40e0d0),
("violet", 0xee82ee),
("wheat", 0xf5deb3),
("white", 0xffffff),
("whitesmoke", 0xf5f5f5),
("yellow", 0xffff00),
("yellowgreen", 0x9acd32),
];
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn parses_css() {
assert_eq!(Color::hex("#ff8000"), Some(Color::from_bytes([255, 128, 0, 255])));
assert_eq!(Color::hex("#f80c"), Some(Color::from_bytes([255, 136, 0, 204])));
assert_eq!(Color::css("rgb(255, 0, 0)"), Some(Color::rgb(1.0, 0.0, 0.0)));
assert_eq!(Color::css("rgba(0 0 255 / 50%)"), Some(Color::rgba(0.0, 0.0, 1.0, 0.5)));
assert_eq!(Color::css("RebeccaPurple"), Color::hex("#663399"));
assert_eq!(Color::css("nope"), None);
assert!(NAMED.windows(2).all(|w| w[0].0 < w[1].0), "sorted for binary search");
assert_eq!(Color::hex("#336699").unwrap().to_string(), "#336699");
assert_eq!(Color::hex("#336699").unwrap().packed(), 0xff99_6633);
}
}