typst_library/layout/
ratio.rs

1use std::fmt::{self, Debug, Formatter};
2use std::ops::{Add, Div, Mul, Neg};
3
4use ecow::EcoString;
5use typst_utils::{Numeric, Scalar};
6
7use crate::foundations::{Repr, repr, ty};
8
9/// A ratio of a whole.
10///
11/// A ratio is written as a number, followed by a percent sign. Ratios most
12/// often appear as part of a [relative length]($relative), to specify the size
13/// of some layout element relative to the page or some container.
14///
15/// ```example
16/// #rect(width: 25%)
17/// ```
18///
19/// However, they can also describe any other property that is relative to some
20/// base, e.g. an amount of [horizontal scaling]($scale.x) or the
21/// [height of parentheses]($math.lr.size) relative to the height of the content
22/// they enclose.
23///
24/// # Scripting
25/// Within your own code, you can use ratios as you like. You can multiply them
26/// with various other types as shown below:
27///
28/// |  Multiply by    |  Example                | Result          |
29/// |-----------------|-------------------------|-----------------|
30/// | [`ratio`]       | `{27% * 10%}`           | `{2.7%}`        |
31/// | [`length`]      | `{27% * 100pt}`         | `{27pt}`        |
32/// | [`relative`]    | `{27% * (10% + 100pt)}` | `{2.7% + 27pt}` |
33/// | [`angle`]       | `{27% * 100deg}`        | `{27deg}`       |
34/// | [`int`]         | `{27% * 2}`             | `{54%}`         |
35/// | [`float`]       | `{27% * 0.37037}`       | `{10%}`         |
36/// | [`fraction`]    | `{27% * 3fr}`           | `{0.81fr}`      |
37///
38/// When ratios are [displayed]($repr) in the document, they are rounded to two
39/// significant digits for readability.
40#[ty(cast)]
41#[derive(Default, Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
42pub struct Ratio(Scalar);
43
44impl Ratio {
45    /// A ratio of `0%` represented as `0.0`.
46    pub const fn zero() -> Self {
47        Self(Scalar::ZERO)
48    }
49
50    /// A ratio of `100%` represented as `1.0`.
51    pub const fn one() -> Self {
52        Self(Scalar::ONE)
53    }
54
55    /// Create a new ratio from a value, where `1.0` means `100%`.
56    pub const fn new(ratio: f64) -> Self {
57        Self(Scalar::new(ratio))
58    }
59
60    /// Get the underlying ratio.
61    pub const fn get(self) -> f64 {
62        (self.0).get()
63    }
64
65    /// Whether the ratio is zero.
66    pub fn is_zero(self) -> bool {
67        self.0 == 0.0
68    }
69
70    /// Whether the ratio is one.
71    pub fn is_one(self) -> bool {
72        self.0 == 1.0
73    }
74
75    /// The absolute value of this ratio.
76    pub fn abs(self) -> Self {
77        Self::new(self.get().abs())
78    }
79
80    /// Return the ratio of the given `whole`.
81    pub fn of<T: Numeric>(self, whole: T) -> T {
82        let resolved = whole * self.get();
83        if resolved.is_finite() { resolved } else { T::zero() }
84    }
85}
86
87impl Debug for Ratio {
88    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
89        write!(f, "{:?}%", self.get() * 100.0)
90    }
91}
92
93impl Repr for Ratio {
94    fn repr(&self) -> EcoString {
95        repr::format_float_with_unit(self.get() * 100.0, "%")
96    }
97}
98
99impl Neg for Ratio {
100    type Output = Self;
101
102    fn neg(self) -> Self {
103        Self(-self.0)
104    }
105}
106
107impl Add for Ratio {
108    type Output = Self;
109
110    fn add(self, other: Self) -> Self {
111        Self(self.0 + other.0)
112    }
113}
114
115typst_utils::sub_impl!(Ratio - Ratio -> Ratio);
116
117impl Mul for Ratio {
118    type Output = Self;
119
120    fn mul(self, other: Self) -> Self {
121        Self(self.0 * other.0)
122    }
123}
124
125impl Mul<f64> for Ratio {
126    type Output = Self;
127
128    fn mul(self, other: f64) -> Self {
129        Self(self.0 * other)
130    }
131}
132
133impl Mul<Ratio> for f64 {
134    type Output = Ratio;
135
136    fn mul(self, other: Ratio) -> Ratio {
137        other * self
138    }
139}
140
141impl Div for Ratio {
142    type Output = f64;
143
144    fn div(self, other: Self) -> f64 {
145        self.get() / other.get()
146    }
147}
148
149impl Div<f64> for Ratio {
150    type Output = Self;
151
152    fn div(self, other: f64) -> Self {
153        Self(self.0 / other)
154    }
155}
156
157impl Div<Ratio> for f64 {
158    type Output = Self;
159
160    fn div(self, other: Ratio) -> Self {
161        self / other.get()
162    }
163}
164
165typst_utils::assign_impl!(Ratio += Ratio);
166typst_utils::assign_impl!(Ratio -= Ratio);
167typst_utils::assign_impl!(Ratio *= Ratio);
168typst_utils::assign_impl!(Ratio *= f64);
169typst_utils::assign_impl!(Ratio /= f64);
typst_library/layout/ratio.rs

typst_library/layout/
ratio.rs
