cssparser/
color.rs

1/* This Source Code Form is subject to the terms of the Mozilla Public
2 * License, v. 2.0. If a copy of the MPL was not distributed with this
3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
4
5//! General color-parsing utilities, independent on the specific color storage and parsing
6//! implementation.
7//!
8//! For a more complete css-color implementation take a look at cssparser-color crate, or at
9//! Gecko's color module.
10
11// Allow text like <color> in docs.
12#![allow(rustdoc::invalid_html_tags)]
13
14/// The opaque alpha value of 1.0.
15pub const OPAQUE: f32 = 1.0;
16
17use crate::{BasicParseError, Parser, ToCss, Token};
18use std::fmt;
19
20/// Clamp a 0..1 number to a 0..255 range to u8.
21///
22/// Whilst scaling by 256 and flooring would provide
23/// an equal distribution of integers to percentage inputs,
24/// this is not what Gecko does so we instead multiply by 255
25/// and round (adding 0.5 and flooring is equivalent to rounding)
26///
27/// Chrome does something similar for the alpha value, but not
28/// the rgb values.
29///
30/// See <https://bugzilla.mozilla.org/show_bug.cgi?id=1340484>
31///
32/// Clamping to 256 and rounding after would let 1.0 map to 256, and
33/// `256.0_f32 as u8` is undefined behavior:
34///
35/// <https://github.com/rust-lang/rust/issues/10184>
36#[inline]
37pub fn clamp_unit_f32(val: f32) -> u8 {
38    clamp_floor_256_f32(val * 255.)
39}
40
41/// Round and clamp a single number to a u8.
42#[inline]
43pub fn clamp_floor_256_f32(val: f32) -> u8 {
44    val.round().clamp(0., 255.) as u8
45}
46
47/// Serialize the alpha copmonent of a color according to the specification.
48/// <https://drafts.csswg.org/css-color-4/#serializing-alpha-values>
49#[inline]
50pub fn serialize_color_alpha(
51    dest: &mut impl fmt::Write,
52    alpha: Option<f32>,
53    legacy_syntax: bool,
54) -> fmt::Result {
55    let alpha = match alpha {
56        None => return dest.write_str(" / none"),
57        Some(a) => a,
58    };
59
60    // If the alpha component is full opaque, don't emit the alpha value in CSS.
61    if alpha == OPAQUE {
62        return Ok(());
63    }
64
65    dest.write_str(if legacy_syntax { ", " } else { " / " })?;
66
67    // Try first with two decimal places, then with three.
68    let mut rounded_alpha = (alpha * 100.).round() / 100.;
69    if clamp_unit_f32(rounded_alpha) != clamp_unit_f32(alpha) {
70        rounded_alpha = (alpha * 1000.).round() / 1000.;
71    }
72
73    rounded_alpha.to_css(dest)
74}
75
76/// A Predefined color space specified in:
77/// <https://drafts.csswg.org/css-color-4/#predefined>
78#[derive(Clone, Copy, Eq, PartialEq, Debug)]
79#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
80#[cfg_attr(feature = "serde", serde(tag = "type"))]
81pub enum PredefinedColorSpace {
82    /// <https://drafts.csswg.org/css-color-4/#predefined-sRGB>
83    Srgb,
84    /// <https://drafts.csswg.org/css-color-4/#predefined-sRGB-linear>
85    SrgbLinear,
86    /// <https://drafts.csswg.org/css-color-4/#predefined-display-p3>
87    DisplayP3,
88    /// <https://drafts.csswg.org/css-color-4/#predefined-display-p3-linear>
89    DisplayP3Linear,
90    /// <https://drafts.csswg.org/css-color-4/#predefined-a98-rgb>
91    A98Rgb,
92    /// <https://drafts.csswg.org/css-color-4/#predefined-prophoto-rgb>
93    ProphotoRgb,
94    /// <https://drafts.csswg.org/css-color-4/#predefined-rec2020>
95    Rec2020,
96    /// <https://drafts.csswg.org/css-color-4/#predefined-xyz>
97    XyzD50,
98    /// <https://drafts.csswg.org/css-color-4/#predefined-xyz>
99    XyzD65,
100}
101
102impl PredefinedColorSpace {
103    /// Parse a PredefinedColorSpace from the given input.
104    pub fn parse<'i>(input: &mut Parser<'i, '_>) -> Result<Self, BasicParseError<'i>> {
105        let location = input.current_source_location();
106
107        let ident = input.expect_ident()?;
108        Ok(match_ignore_ascii_case! { ident,
109            "srgb" => Self::Srgb,
110            "srgb-linear" => Self::SrgbLinear,
111            "display-p3" => Self::DisplayP3,
112            "display-p3-linear" => Self::DisplayP3Linear,
113            "a98-rgb" => Self::A98Rgb,
114            "prophoto-rgb" => Self::ProphotoRgb,
115            "rec2020" => Self::Rec2020,
116            "xyz-d50" => Self::XyzD50,
117            "xyz" | "xyz-d65" => Self::XyzD65,
118            _ => return Err(location.new_basic_unexpected_token_error(Token::Ident(ident.clone()))),
119        })
120    }
121}
122
123impl ToCss for PredefinedColorSpace {
124    fn to_css<W>(&self, dest: &mut W) -> fmt::Result
125    where
126        W: fmt::Write,
127    {
128        dest.write_str(match self {
129            Self::Srgb => "srgb",
130            Self::SrgbLinear => "srgb-linear",
131            Self::DisplayP3 => "display-p3",
132            Self::DisplayP3Linear => "display-p3-linear",
133            Self::A98Rgb => "a98-rgb",
134            Self::ProphotoRgb => "prophoto-rgb",
135            Self::Rec2020 => "rec2020",
136            Self::XyzD50 => "xyz-d50",
137            Self::XyzD65 => "xyz-d65",
138        })
139    }
140}
141
142/// Parse a color hash, without the leading '#' character.
143#[allow(clippy::result_unit_err)]
144#[inline]
145pub fn parse_hash_color(value: &[u8]) -> Result<(u8, u8, u8, f32), ()> {
146    Ok(match value.len() {
147        8 => (
148            from_hex(value[0])? * 16 + from_hex(value[1])?,
149            from_hex(value[2])? * 16 + from_hex(value[3])?,
150            from_hex(value[4])? * 16 + from_hex(value[5])?,
151            (from_hex(value[6])? * 16 + from_hex(value[7])?) as f32 / 255.0,
152        ),
153        6 => (
154            from_hex(value[0])? * 16 + from_hex(value[1])?,
155            from_hex(value[2])? * 16 + from_hex(value[3])?,
156            from_hex(value[4])? * 16 + from_hex(value[5])?,
157            OPAQUE,
158        ),
159        4 => (
160            from_hex(value[0])? * 17,
161            from_hex(value[1])? * 17,
162            from_hex(value[2])? * 17,
163            (from_hex(value[3])? * 17) as f32 / 255.0,
164        ),
165        3 => (
166            from_hex(value[0])? * 17,
167            from_hex(value[1])? * 17,
168            from_hex(value[2])? * 17,
169            OPAQUE,
170        ),
171        _ => return Err(()),
172    })
173}
174
175ascii_case_insensitive_phf_map! {
176    named_colors -> (u8, u8, u8) = {
177        "black" => (0, 0, 0),
178        "silver" => (192, 192, 192),
179        "gray" => (128, 128, 128),
180        "white" => (255, 255, 255),
181        "maroon" => (128, 0, 0),
182        "red" => (255, 0, 0),
183        "purple" => (128, 0, 128),
184        "fuchsia" => (255, 0, 255),
185        "green" => (0, 128, 0),
186        "lime" => (0, 255, 0),
187        "olive" => (128, 128, 0),
188        "yellow" => (255, 255, 0),
189        "navy" => (0, 0, 128),
190        "blue" => (0, 0, 255),
191        "teal" => (0, 128, 128),
192        "aqua" => (0, 255, 255),
193
194        "aliceblue" => (240, 248, 255),
195        "antiquewhite" => (250, 235, 215),
196        "aquamarine" => (127, 255, 212),
197        "azure" => (240, 255, 255),
198        "beige" => (245, 245, 220),
199        "bisque" => (255, 228, 196),
200        "blanchedalmond" => (255, 235, 205),
201        "blueviolet" => (138, 43, 226),
202        "brown" => (165, 42, 42),
203        "burlywood" => (222, 184, 135),
204        "cadetblue" => (95, 158, 160),
205        "chartreuse" => (127, 255, 0),
206        "chocolate" => (210, 105, 30),
207        "coral" => (255, 127, 80),
208        "cornflowerblue" => (100, 149, 237),
209        "cornsilk" => (255, 248, 220),
210        "crimson" => (220, 20, 60),
211        "cyan" => (0, 255, 255),
212        "darkblue" => (0, 0, 139),
213        "darkcyan" => (0, 139, 139),
214        "darkgoldenrod" => (184, 134, 11),
215        "darkgray" => (169, 169, 169),
216        "darkgreen" => (0, 100, 0),
217        "darkgrey" => (169, 169, 169),
218        "darkkhaki" => (189, 183, 107),
219        "darkmagenta" => (139, 0, 139),
220        "darkolivegreen" => (85, 107, 47),
221        "darkorange" => (255, 140, 0),
222        "darkorchid" => (153, 50, 204),
223        "darkred" => (139, 0, 0),
224        "darksalmon" => (233, 150, 122),
225        "darkseagreen" => (143, 188, 143),
226        "darkslateblue" => (72, 61, 139),
227        "darkslategray" => (47, 79, 79),
228        "darkslategrey" => (47, 79, 79),
229        "darkturquoise" => (0, 206, 209),
230        "darkviolet" => (148, 0, 211),
231        "deeppink" => (255, 20, 147),
232        "deepskyblue" => (0, 191, 255),
233        "dimgray" => (105, 105, 105),
234        "dimgrey" => (105, 105, 105),
235        "dodgerblue" => (30, 144, 255),
236        "firebrick" => (178, 34, 34),
237        "floralwhite" => (255, 250, 240),
238        "forestgreen" => (34, 139, 34),
239        "gainsboro" => (220, 220, 220),
240        "ghostwhite" => (248, 248, 255),
241        "gold" => (255, 215, 0),
242        "goldenrod" => (218, 165, 32),
243        "greenyellow" => (173, 255, 47),
244        "grey" => (128, 128, 128),
245        "honeydew" => (240, 255, 240),
246        "hotpink" => (255, 105, 180),
247        "indianred" => (205, 92, 92),
248        "indigo" => (75, 0, 130),
249        "ivory" => (255, 255, 240),
250        "khaki" => (240, 230, 140),
251        "lavender" => (230, 230, 250),
252        "lavenderblush" => (255, 240, 245),
253        "lawngreen" => (124, 252, 0),
254        "lemonchiffon" => (255, 250, 205),
255        "lightblue" => (173, 216, 230),
256        "lightcoral" => (240, 128, 128),
257        "lightcyan" => (224, 255, 255),
258        "lightgoldenrodyellow" => (250, 250, 210),
259        "lightgray" => (211, 211, 211),
260        "lightgreen" => (144, 238, 144),
261        "lightgrey" => (211, 211, 211),
262        "lightpink" => (255, 182, 193),
263        "lightsalmon" => (255, 160, 122),
264        "lightseagreen" => (32, 178, 170),
265        "lightskyblue" => (135, 206, 250),
266        "lightslategray" => (119, 136, 153),
267        "lightslategrey" => (119, 136, 153),
268        "lightsteelblue" => (176, 196, 222),
269        "lightyellow" => (255, 255, 224),
270        "limegreen" => (50, 205, 50),
271        "linen" => (250, 240, 230),
272        "magenta" => (255, 0, 255),
273        "mediumaquamarine" => (102, 205, 170),
274        "mediumblue" => (0, 0, 205),
275        "mediumorchid" => (186, 85, 211),
276        "mediumpurple" => (147, 112, 219),
277        "mediumseagreen" => (60, 179, 113),
278        "mediumslateblue" => (123, 104, 238),
279        "mediumspringgreen" => (0, 250, 154),
280        "mediumturquoise" => (72, 209, 204),
281        "mediumvioletred" => (199, 21, 133),
282        "midnightblue" => (25, 25, 112),
283        "mintcream" => (245, 255, 250),
284        "mistyrose" => (255, 228, 225),
285        "moccasin" => (255, 228, 181),
286        "navajowhite" => (255, 222, 173),
287        "oldlace" => (253, 245, 230),
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        "rebeccapurple" => (102, 51, 153),
303        "rosybrown" => (188, 143, 143),
304        "royalblue" => (65, 105, 225),
305        "saddlebrown" => (139, 69, 19),
306        "salmon" => (250, 128, 114),
307        "sandybrown" => (244, 164, 96),
308        "seagreen" => (46, 139, 87),
309        "seashell" => (255, 245, 238),
310        "sienna" => (160, 82, 45),
311        "skyblue" => (135, 206, 235),
312        "slateblue" => (106, 90, 205),
313        "slategray" => (112, 128, 144),
314        "slategrey" => (112, 128, 144),
315        "snow" => (255, 250, 250),
316        "springgreen" => (0, 255, 127),
317        "steelblue" => (70, 130, 180),
318        "tan" => (210, 180, 140),
319        "thistle" => (216, 191, 216),
320        "tomato" => (255, 99, 71),
321        "turquoise" => (64, 224, 208),
322        "violet" => (238, 130, 238),
323        "wheat" => (245, 222, 179),
324        "whitesmoke" => (245, 245, 245),
325        "yellowgreen" => (154, 205, 50),
326    }
327}
328
329/// Returns the named color with the given name.
330/// <https://drafts.csswg.org/css-color-4/#typedef-named-color>
331#[allow(clippy::result_unit_err)]
332#[inline]
333pub fn parse_named_color(ident: &str) -> Result<(u8, u8, u8), ()> {
334    named_colors::get(ident).copied().ok_or(())
335}
336
337/// Returns an iterator over all named CSS colors.
338/// <https://drafts.csswg.org/css-color-4/#typedef-named-color>
339#[inline]
340pub fn all_named_colors() -> impl Iterator<Item = (&'static str, (u8, u8, u8))> {
341    named_colors::entries().map(|(k, v)| (*k, *v))
342}
343
344#[inline]
345fn from_hex(c: u8) -> Result<u8, ()> {
346    match c {
347        b'0'..=b'9' => Ok(c - b'0'),
348        b'a'..=b'f' => Ok(c - b'a' + 10),
349        b'A'..=b'F' => Ok(c - b'A' + 10),
350        _ => Err(()),
351    }
352}
cssparser/color.rs

cssparser/
color.rs
