guise/theme/
css.rs

1//! CSS-style color literals: a runtime parser and constructor functions that
2//! produce gpui [`Hsla`] (which carries alpha). Backs the [`color!`] macro.
3//!
4//! Supported notations:
5//! - hex — `#rgb`, `#rgba`, `#rrggbb`, `#rrggbbaa`
6//! - `rgb(r, g, b)` / `rgba(r, g, b, a)` — channels `0..=255` (or `%`), alpha `0..=1` (or `%`)
7//! - `hsl(h, s%, l%)` / `hsla(h, s%, l%, a)` — hue degrees, sat/lum percent
8//! - CSS named colors — `red`, `teal`, `rebeccapurple`, …
9//!
10//! [`color!`]: crate::color
11
12use std::fmt;
13
14use gpui::{Hsla, Rgba};
15
16/// Returned when a CSS color string can't be parsed.
17#[derive(Debug, Clone, PartialEq, Eq)]
18pub struct CssColorError(String);
19
20impl fmt::Display for CssColorError {
21    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
22        write!(f, "guise: invalid CSS color `{}`", self.0)
23    }
24}
25
26impl std::error::Error for CssColorError {}
27
28// --- Constructors (also the macro's expansion targets) ---------------------
29
30fn rgba_f(r: f32, g: f32, b: f32, a: f32) -> Hsla {
31    Rgba {
32        r: (r / 255.0).clamp(0.0, 1.0),
33        g: (g / 255.0).clamp(0.0, 1.0),
34        b: (b / 255.0).clamp(0.0, 1.0),
35        a: a.clamp(0.0, 1.0),
36    }
37    .into()
38}
39
40/// An opaque color from 8-bit channels.
41pub fn rgb(r: u8, g: u8, b: u8) -> Hsla {
42    rgba(r, g, b, 1.0)
43}
44
45/// A color from 8-bit channels plus alpha in `0.0..=1.0`.
46pub fn rgba(r: u8, g: u8, b: u8, a: f32) -> Hsla {
47    rgba_f(r as f32, g as f32, b as f32, a)
48}
49
50/// An opaque color from hue (degrees) and saturation/lightness (`0..=100`).
51pub fn hsl(h: f32, s: f32, l: f32) -> Hsla {
52    hsla(h, s, l, 1.0)
53}
54
55/// A color from hue (degrees), saturation/lightness (`0..=100`), and alpha.
56pub fn hsla(h: f32, s: f32, l: f32, a: f32) -> Hsla {
57    Hsla {
58        h: (h / 360.0).rem_euclid(1.0),
59        s: (s / 100.0).clamp(0.0, 1.0),
60        l: (l / 100.0).clamp(0.0, 1.0),
61        a: a.clamp(0.0, 1.0),
62    }
63}
64
65// --- Parser ----------------------------------------------------------------
66
67/// Parse a CSS color string into an [`Hsla`].
68pub fn css(input: &str) -> Result<Hsla, CssColorError> {
69    let err = || CssColorError(input.to_string());
70    let s = input.trim();
71
72    if let Some(hex) = s.strip_prefix('#') {
73        return parse_hex(hex).ok_or_else(err);
74    }
75    let lower = s.to_ascii_lowercase();
76    if let Some(inner) = wrapped(&lower, "rgba").or_else(|| wrapped(&lower, "rgb")) {
77        return parse_rgb(inner).ok_or_else(err);
78    }
79    if let Some(inner) = wrapped(&lower, "hsla").or_else(|| wrapped(&lower, "hsl")) {
80        return parse_hsl(inner).ok_or_else(err);
81    }
82    named(&lower).map(|(r, g, b)| rgb(r, g, b)).ok_or_else(err)
83}
84
85/// Strip a `name( … )` wrapper, returning the inner argument text.
86fn wrapped<'a>(s: &'a str, name: &str) -> Option<&'a str> {
87    let rest = s.strip_prefix(name)?.trim_start();
88    let rest = rest.strip_prefix('(')?;
89    rest.strip_suffix(')')
90}
91
92fn nibble(b: u8) -> Option<u8> {
93    match b {
94        b'0'..=b'9' => Some(b - b'0'),
95        b'a'..=b'f' => Some(b - b'a' + 10),
96        b'A'..=b'F' => Some(b - b'A' + 10),
97        _ => None,
98    }
99}
100
101fn hex2(bytes: &[u8], i: usize) -> Option<f32> {
102    Some((nibble(bytes[i])? * 16 + nibble(bytes[i + 1])?) as f32)
103}
104
105fn parse_hex(hex: &str) -> Option<Hsla> {
106    let b = hex.as_bytes();
107    match b.len() {
108        3 => Some(rgba_f(
109            (nibble(b[0])? * 17) as f32,
110            (nibble(b[1])? * 17) as f32,
111            (nibble(b[2])? * 17) as f32,
112            1.0,
113        )),
114        4 => Some(rgba_f(
115            (nibble(b[0])? * 17) as f32,
116            (nibble(b[1])? * 17) as f32,
117            (nibble(b[2])? * 17) as f32,
118            (nibble(b[3])? * 17) as f32 / 255.0,
119        )),
120        6 => Some(rgba_f(hex2(b, 0)?, hex2(b, 2)?, hex2(b, 4)?, 1.0)),
121        8 => Some(rgba_f(
122            hex2(b, 0)?,
123            hex2(b, 2)?,
124            hex2(b, 4)?,
125            hex2(b, 6)? / 255.0,
126        )),
127        _ => None,
128    }
129}
130
131fn tokens(inner: &str) -> Vec<&str> {
132    inner
133        .split(|c| c == ',' || c == ' ' || c == '/')
134        .filter(|t| !t.is_empty())
135        .collect()
136}
137
138fn num(tok: &str) -> Option<f32> {
139    tok.trim().parse().ok()
140}
141
142/// A color channel: `0..=255` or a percentage of 255.
143fn channel(tok: &str) -> Option<f32> {
144    let t = tok.trim();
145    match t.strip_suffix('%') {
146        Some(p) => Some(num(p)? / 100.0 * 255.0),
147        None => num(t),
148    }
149}
150
151/// An alpha value: `0..=1` or a percentage.
152fn alpha(tok: &str) -> Option<f32> {
153    let t = tok.trim();
154    match t.strip_suffix('%') {
155        Some(p) => Some(num(p)? / 100.0),
156        None => num(t),
157    }
158}
159
160fn parse_rgb(inner: &str) -> Option<Hsla> {
161    let parts = tokens(inner);
162    let a = match parts.len() {
163        3 => 1.0,
164        4 => alpha(parts[3])?,
165        _ => return None,
166    };
167    Some(rgba_f(
168        channel(parts[0])?,
169        channel(parts[1])?,
170        channel(parts[2])?,
171        a,
172    ))
173}
174
175fn parse_hsl(inner: &str) -> Option<Hsla> {
176    let parts = tokens(inner);
177    let a = match parts.len() {
178        3 => 1.0,
179        4 => alpha(parts[3])?,
180        _ => return None,
181    };
182    let h = num(parts[0].trim().trim_end_matches("deg"))?;
183    let s = num(parts[1].trim().trim_end_matches('%'))?;
184    let l = num(parts[2].trim().trim_end_matches('%'))?;
185    Some(hsla(h, s, l, a))
186}
187
188/// The standard CSS named colors.
189fn named(name: &str) -> Option<(u8, u8, u8)> {
190    let rgb = match name {
191        "transparent" => return Some((0, 0, 0)),
192        "aliceblue" => (240, 248, 255),
193        "antiquewhite" => (250, 235, 215),
194        "aqua" | "cyan" => (0, 255, 255),
195        "aquamarine" => (127, 255, 212),
196        "azure" => (240, 255, 255),
197        "beige" => (245, 245, 220),
198        "bisque" => (255, 228, 196),
199        "black" => (0, 0, 0),
200        "blanchedalmond" => (255, 235, 205),
201        "blue" => (0, 0, 255),
202        "blueviolet" => (138, 43, 226),
203        "brown" => (165, 42, 42),
204        "burlywood" => (222, 184, 135),
205        "cadetblue" => (95, 158, 160),
206        "chartreuse" => (127, 255, 0),
207        "chocolate" => (210, 105, 30),
208        "coral" => (255, 127, 80),
209        "cornflowerblue" => (100, 149, 237),
210        "cornsilk" => (255, 248, 220),
211        "crimson" => (220, 20, 60),
212        "darkblue" => (0, 0, 139),
213        "darkcyan" => (0, 139, 139),
214        "darkgoldenrod" => (184, 134, 11),
215        "darkgray" | "darkgrey" => (169, 169, 169),
216        "darkgreen" => (0, 100, 0),
217        "darkkhaki" => (189, 183, 107),
218        "darkmagenta" => (139, 0, 139),
219        "darkolivegreen" => (85, 107, 47),
220        "darkorange" => (255, 140, 0),
221        "darkorchid" => (153, 50, 204),
222        "darkred" => (139, 0, 0),
223        "darksalmon" => (233, 150, 122),
224        "darkseagreen" => (143, 188, 143),
225        "darkslateblue" => (72, 61, 139),
226        "darkslategray" | "darkslategrey" => (47, 79, 79),
227        "darkturquoise" => (0, 206, 209),
228        "darkviolet" => (148, 0, 211),
229        "deeppink" => (255, 20, 147),
230        "deepskyblue" => (0, 191, 255),
231        "dimgray" | "dimgrey" => (105, 105, 105),
232        "dodgerblue" => (30, 144, 255),
233        "firebrick" => (178, 34, 34),
234        "floralwhite" => (255, 250, 240),
235        "forestgreen" => (34, 139, 34),
236        "fuchsia" | "magenta" => (255, 0, 255),
237        "gainsboro" => (220, 220, 220),
238        "ghostwhite" => (248, 248, 255),
239        "gold" => (255, 215, 0),
240        "goldenrod" => (218, 165, 32),
241        "gray" | "grey" => (128, 128, 128),
242        "green" => (0, 128, 0),
243        "greenyellow" => (173, 255, 47),
244        "honeydew" => (240, 255, 240),
245        "hotpink" => (255, 105, 180),
246        "indianred" => (205, 92, 92),
247        "indigo" => (75, 0, 130),
248        "ivory" => (255, 255, 240),
249        "khaki" => (240, 230, 140),
250        "lavender" => (230, 230, 250),
251        "lavenderblush" => (255, 240, 245),
252        "lawngreen" => (124, 252, 0),
253        "lemonchiffon" => (255, 250, 205),
254        "lightblue" => (173, 216, 230),
255        "lightcoral" => (240, 128, 128),
256        "lightcyan" => (224, 255, 255),
257        "lightgoldenrodyellow" => (250, 250, 210),
258        "lightgray" | "lightgrey" => (211, 211, 211),
259        "lightgreen" => (144, 238, 144),
260        "lightpink" => (255, 182, 193),
261        "lightsalmon" => (255, 160, 122),
262        "lightseagreen" => (32, 178, 170),
263        "lightskyblue" => (135, 206, 250),
264        "lightslategray" | "lightslategrey" => (119, 136, 153),
265        "lightsteelblue" => (176, 196, 222),
266        "lightyellow" => (255, 255, 224),
267        "lime" => (0, 255, 0),
268        "limegreen" => (50, 205, 50),
269        "linen" => (250, 240, 230),
270        "maroon" => (128, 0, 0),
271        "mediumaquamarine" => (102, 205, 170),
272        "mediumblue" => (0, 0, 205),
273        "mediumorchid" => (186, 85, 211),
274        "mediumpurple" => (147, 112, 219),
275        "mediumseagreen" => (60, 179, 113),
276        "mediumslateblue" => (123, 104, 238),
277        "mediumspringgreen" => (0, 250, 154),
278        "mediumturquoise" => (72, 209, 204),
279        "mediumvioletred" => (199, 21, 133),
280        "midnightblue" => (25, 25, 112),
281        "mintcream" => (245, 255, 250),
282        "mistyrose" => (255, 228, 225),
283        "moccasin" => (255, 228, 181),
284        "navajowhite" => (255, 222, 173),
285        "navy" => (0, 0, 128),
286        "oldlace" => (253, 245, 230),
287        "olive" => (128, 128, 0),
288        "olivedrab" => (107, 142, 35),
289        "orange" => (255, 165, 0),
290        "orangered" => (255, 69, 0),
291        "orchid" => (218, 112, 214),
292        "palegoldenrod" => (238, 232, 170),
293        "palegreen" => (152, 251, 152),
294        "paleturquoise" => (175, 238, 238),
295        "palevioletred" => (219, 112, 147),
296        "papayawhip" => (255, 239, 213),
297        "peachpuff" => (255, 218, 185),
298        "peru" => (205, 133, 63),
299        "pink" => (255, 192, 203),
300        "plum" => (221, 160, 221),
301        "powderblue" => (176, 224, 230),
302        "purple" => (128, 0, 128),
303        "rebeccapurple" => (102, 51, 153),
304        "red" => (255, 0, 0),
305        "rosybrown" => (188, 143, 143),
306        "royalblue" => (65, 105, 225),
307        "saddlebrown" => (139, 69, 19),
308        "salmon" => (250, 128, 114),
309        "sandybrown" => (244, 164, 96),
310        "seagreen" => (46, 139, 87),
311        "seashell" => (255, 245, 238),
312        "sienna" => (160, 82, 45),
313        "silver" => (192, 192, 192),
314        "skyblue" => (135, 206, 235),
315        "slateblue" => (106, 90, 205),
316        "slategray" | "slategrey" => (112, 128, 144),
317        "snow" => (255, 250, 250),
318        "springgreen" => (0, 255, 127),
319        "steelblue" => (70, 130, 180),
320        "tan" => (210, 180, 140),
321        "teal" => (0, 128, 128),
322        "thistle" => (216, 191, 216),
323        "tomato" => (255, 99, 71),
324        "turquoise" => (64, 224, 208),
325        "violet" => (238, 130, 238),
326        "wheat" => (245, 222, 179),
327        "white" => (255, 255, 255),
328        "whitesmoke" => (245, 245, 245),
329        "yellow" => (255, 255, 0),
330        "yellowgreen" => (154, 205, 50),
331        _ => return None,
332    };
333    Some(rgb)
334}
335
336#[cfg(test)]
337mod tests {
338    use super::*;
339
340    #[test]
341    fn hex_forms() {
342        assert_eq!(css("#228be6").unwrap(), rgb(0x22, 0x8b, 0xe6));
343        assert_eq!(css("228be6").is_err(), true); // needs the leading '#'
344        assert_eq!(css("#fff").unwrap(), rgb(255, 255, 255));
345        assert_eq!(
346            css("#ff000080").unwrap(),
347            rgba(255, 0, 0, 0x80 as f32 / 255.0)
348        );
349    }
350
351    #[test]
352    fn functional_forms() {
353        assert_eq!(css("rgb(34, 139, 230)").unwrap(), rgb(34, 139, 230));
354        assert_eq!(css("rgba(0,0,0,0.5)").unwrap(), rgba(0, 0, 0, 0.5));
355        assert_eq!(css("hsl(210, 80%, 52%)").unwrap(), hsl(210.0, 80.0, 52.0));
356        assert_eq!(
357            css("hsla(210,80%,52%,0.5)").unwrap(),
358            hsla(210.0, 80.0, 52.0, 0.5)
359        );
360    }
361
362    #[test]
363    fn named_colors() {
364        assert_eq!(css("teal").unwrap(), rgb(0, 128, 128));
365        assert_eq!(css("RebeccaPurple").unwrap(), rgb(102, 51, 153));
366        assert!(css("notacolor").is_err());
367    }
368}
guise/theme/css.rs

guise/theme/
css.rs
