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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at https://mozilla.org/MPL/2.0/. */
//! Output of parsing a color function, e.g. rgb(..), hsl(..), color(..)
use crate::{color::ColorFlags, values::normalize};
use cssparser::color::{PredefinedColorSpace, OPAQUE};
use super::{
component::ColorComponent,
convert::normalize_hue,
parsing::{NumberOrAngle, NumberOrPercentage},
AbsoluteColor, ColorSpace,
};
/// Represents a specified color function.
#[derive(Debug)]
pub enum ColorFunction {
/// <https://drafts.csswg.org/css-color-4/#rgb-functions>
Rgb(
ColorComponent<u8>, // red
ColorComponent<u8>, // green
ColorComponent<u8>, // blue
ColorComponent<NumberOrPercentage>, // alpha
),
/// <https://drafts.csswg.org/css-color-4/#the-hsl-notation>
Hsl(
ColorComponent<NumberOrAngle>, // hue
ColorComponent<NumberOrPercentage>, // saturation
ColorComponent<NumberOrPercentage>, // lightness
ColorComponent<NumberOrPercentage>, // alpha
bool, // is_legacy_syntax
),
/// <https://drafts.csswg.org/css-color-4/#the-hwb-notation>
Hwb(
ColorComponent<NumberOrAngle>, // hue
ColorComponent<NumberOrPercentage>, // whiteness
ColorComponent<NumberOrPercentage>, // blackness
ColorComponent<NumberOrPercentage>, // alpha
bool, // is_legacy_syntax
),
/// <https://drafts.csswg.org/css-color-4/#specifying-lab-lch>
Lab(
ColorComponent<NumberOrPercentage>, // lightness
ColorComponent<NumberOrPercentage>, // a
ColorComponent<NumberOrPercentage>, // b
ColorComponent<NumberOrPercentage>, // alpha
),
/// <https://drafts.csswg.org/css-color-4/#specifying-lab-lch>
Lch(
ColorComponent<NumberOrPercentage>, // lightness
ColorComponent<NumberOrPercentage>, // chroma
ColorComponent<NumberOrAngle>, // hue
ColorComponent<NumberOrPercentage>, // alpha
),
/// <https://drafts.csswg.org/css-color-4/#specifying-oklab-oklch>
Oklab(
ColorComponent<NumberOrPercentage>, // lightness
ColorComponent<NumberOrPercentage>, // a
ColorComponent<NumberOrPercentage>, // b
ColorComponent<NumberOrPercentage>, // alpha
),
/// <https://drafts.csswg.org/css-color-4/#specifying-oklab-oklch>
Oklch(
ColorComponent<NumberOrPercentage>, // lightness
ColorComponent<NumberOrPercentage>, // chroma
ColorComponent<NumberOrAngle>, // hue
ColorComponent<NumberOrPercentage>, // alpha
),
/// <https://drafts.csswg.org/css-color-4/#color-function>
Color(
PredefinedColorSpace,
ColorComponent<NumberOrPercentage>, // red / x
ColorComponent<NumberOrPercentage>, // green / y
ColorComponent<NumberOrPercentage>, // blue / z
ColorComponent<NumberOrPercentage>, // alpha
),
}
impl ColorFunction {
/// Try to resolve the color function to an [`AbsoluteColor`] that does not
/// contain any variables (currentcolor, color components, etc.).
pub fn resolve_to_absolute(&self) -> AbsoluteColor {
macro_rules! value {
($v:expr) => {{
match $v {
ColorComponent::None => None,
// value should be Copy.
ColorComponent::Value(value) => Some(*value),
}
}};
}
macro_rules! alpha {
($alpha:expr) => {{
value!($alpha).map(|value| normalize(value.to_number(1.0)).clamp(0.0, OPAQUE))
}};
}
match self {
ColorFunction::Rgb(r, g, b, alpha) => {
let r = value!(r).unwrap_or(0);
let g = value!(g).unwrap_or(0);
let b = value!(b).unwrap_or(0);
AbsoluteColor::srgb_legacy(r, g, b, alpha!(alpha).unwrap_or(0.0))
},
ColorFunction::Hsl(h, s, l, alpha, is_legacy_syntax) => {
// Percent reference range for S and L: 0% = 0.0, 100% = 100.0
const LIGHTNESS_RANGE: f32 = 100.0;
const SATURATION_RANGE: f32 = 100.0;
let mut result = AbsoluteColor::new(
ColorSpace::Hsl,
value!(h).map(|angle| normalize_hue(angle.degrees())),
value!(s).map(|s| s.to_number(SATURATION_RANGE).clamp(0.0, SATURATION_RANGE)),
value!(l).map(|l| l.to_number(LIGHTNESS_RANGE).clamp(0.0, LIGHTNESS_RANGE)),
alpha!(alpha),
);
if *is_legacy_syntax {
result.flags.insert(ColorFlags::IS_LEGACY_SRGB);
}
result
},
ColorFunction::Hwb(h, w, b, alpha, is_legacy_syntax) => {
// Percent reference range for W and B: 0% = 0.0, 100% = 100.0
const WHITENESS_RANGE: f32 = 100.0;
const BLACKNESS_RANGE: f32 = 100.0;
let mut result = AbsoluteColor::new(
ColorSpace::Hwb,
value!(h).map(|angle| normalize_hue(angle.degrees())),
value!(w).map(|w| w.to_number(WHITENESS_RANGE).clamp(0.0, WHITENESS_RANGE)),
value!(b).map(|b| b.to_number(BLACKNESS_RANGE).clamp(0.0, BLACKNESS_RANGE)),
alpha!(alpha),
);
if *is_legacy_syntax {
result.flags.insert(ColorFlags::IS_LEGACY_SRGB);
}
result
},
ColorFunction::Lab(l, a, b, alpha) => {
// for L: 0% = 0.0, 100% = 100.0
// for a and b: -100% = -125, 100% = 125
const LIGHTNESS_RANGE: f32 = 100.0;
const A_B_RANGE: f32 = 125.0;
AbsoluteColor::new(
ColorSpace::Lab,
value!(l).map(|l| l.to_number(LIGHTNESS_RANGE)),
value!(a).map(|a| a.to_number(A_B_RANGE)),
value!(b).map(|b| b.to_number(A_B_RANGE)),
alpha!(alpha),
)
},
ColorFunction::Lch(l, c, h, alpha) => {
// for L: 0% = 0.0, 100% = 100.0
// for C: 0% = 0, 100% = 150
const LIGHTNESS_RANGE: f32 = 100.0;
const CHROMA_RANGE: f32 = 150.0;
AbsoluteColor::new(
ColorSpace::Lch,
value!(l).map(|l| l.to_number(LIGHTNESS_RANGE)),
value!(c).map(|c| c.to_number(CHROMA_RANGE)),
value!(h).map(|angle| normalize_hue(angle.degrees())),
alpha!(alpha),
)
},
ColorFunction::Oklab(l, a, b, alpha) => {
// for L: 0% = 0.0, 100% = 1.0
// for a and b: -100% = -0.4, 100% = 0.4
const LIGHTNESS_RANGE: f32 = 1.0;
const A_B_RANGE: f32 = 0.4;
AbsoluteColor::new(
ColorSpace::Oklab,
value!(l).map(|l| l.to_number(LIGHTNESS_RANGE)),
value!(a).map(|a| a.to_number(A_B_RANGE)),
value!(b).map(|b| b.to_number(A_B_RANGE)),
alpha!(alpha),
)
},
ColorFunction::Oklch(l, c, h, alpha) => {
// for L: 0% = 0.0, 100% = 1.0
// for C: 0% = 0.0 100% = 0.4
const LIGHTNESS_RANGE: f32 = 1.0;
const CHROMA_RANGE: f32 = 0.4;
AbsoluteColor::new(
ColorSpace::Oklch,
value!(l).map(|l| l.to_number(LIGHTNESS_RANGE)),
value!(c).map(|c| c.to_number(CHROMA_RANGE)),
value!(h).map(|angle| normalize_hue(angle.degrees())),
alpha!(alpha),
)
},
ColorFunction::Color(color_space, r, g, b, alpha) => AbsoluteColor::new(
(*color_space).into(),
value!(r).map(|c| c.to_number(1.0)),
value!(g).map(|c| c.to_number(1.0)),
value!(b).map(|c| c.to_number(1.0)),
alpha!(alpha),
),
}
}
}
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