typst_library/layout/
sides.rs

1use std::fmt::{self, Debug, Formatter};
2use std::ops::Add;
3
4use typst_utils::Get;
5
6use crate::diag::{bail, HintedStrResult};
7use crate::foundations::{
8    cast, AlternativeFold, CastInfo, Dict, Fold, FromValue, IntoValue, Reflect, Resolve,
9    StyleChain, Value,
10};
11use crate::layout::{Abs, Alignment, Axes, Axis, Corner, Rel, Size};
12
13/// A container with left, top, right and bottom components.
14#[derive(Default, Copy, Clone, Eq, PartialEq, Hash)]
15pub struct Sides<T> {
16    /// The value for the left side.
17    pub left: T,
18    /// The value for the top side.
19    pub top: T,
20    /// The value for the right side.
21    pub right: T,
22    /// The value for the bottom side.
23    pub bottom: T,
24}
25
26impl<T> Sides<T> {
27    /// Create a new instance from the four components.
28    pub const fn new(left: T, top: T, right: T, bottom: T) -> Self {
29        Self { left, top, right, bottom }
30    }
31
32    /// Create an instance with four equal components.
33    pub fn splat(value: T) -> Self
34    where
35        T: Clone,
36    {
37        Self {
38            left: value.clone(),
39            top: value.clone(),
40            right: value.clone(),
41            bottom: value,
42        }
43    }
44
45    /// Map the individual fields with `f`.
46    pub fn map<F, U>(self, mut f: F) -> Sides<U>
47    where
48        F: FnMut(T) -> U,
49    {
50        Sides {
51            left: f(self.left),
52            top: f(self.top),
53            right: f(self.right),
54            bottom: f(self.bottom),
55        }
56    }
57
58    /// Convert from `&Sides<T>` to `Sides<&T>`.
59    pub fn as_ref(&self) -> Sides<&T> {
60        Sides {
61            left: &self.left,
62            top: &self.top,
63            right: &self.right,
64            bottom: &self.bottom,
65        }
66    }
67
68    /// Zip two instances into one.
69    pub fn zip<U>(self, other: Sides<U>) -> Sides<(T, U)> {
70        Sides {
71            left: (self.left, other.left),
72            top: (self.top, other.top),
73            right: (self.right, other.right),
74            bottom: (self.bottom, other.bottom),
75        }
76    }
77
78    /// An iterator over the sides, starting with the left side, clockwise.
79    pub fn iter(&self) -> impl Iterator<Item = &T> {
80        [&self.left, &self.top, &self.right, &self.bottom].into_iter()
81    }
82
83    /// Whether all sides are equal.
84    pub fn is_uniform(&self) -> bool
85    where
86        T: PartialEq,
87    {
88        self.left == self.top && self.top == self.right && self.right == self.bottom
89    }
90}
91
92impl<T: Add> Sides<T> {
93    /// Sums up `left` and `right` into `x`, and `top` and `bottom` into `y`.
94    pub fn sum_by_axis(self) -> Axes<T::Output> {
95        Axes::new(self.left + self.right, self.top + self.bottom)
96    }
97}
98
99impl<T> Sides<Option<T>> {
100    /// Unwrap-or-default the individual sides.
101    pub fn unwrap_or_default(self) -> Sides<T>
102    where
103        T: Default,
104    {
105        self.map(Option::unwrap_or_default)
106    }
107}
108
109impl Sides<Rel<Abs>> {
110    /// Evaluate the sides relative to the given `size`.
111    pub fn relative_to(&self, size: Size) -> Sides<Abs> {
112        Sides {
113            left: self.left.relative_to(size.x),
114            top: self.top.relative_to(size.y),
115            right: self.right.relative_to(size.x),
116            bottom: self.bottom.relative_to(size.y),
117        }
118    }
119
120    /// Whether all sides are zero.
121    pub fn is_zero(&self) -> bool {
122        self.left.is_zero()
123            && self.top.is_zero()
124            && self.right.is_zero()
125            && self.bottom.is_zero()
126    }
127}
128
129impl<T> Get<Side> for Sides<T> {
130    type Component = T;
131
132    fn get_ref(&self, side: Side) -> &T {
133        match side {
134            Side::Left => &self.left,
135            Side::Top => &self.top,
136            Side::Right => &self.right,
137            Side::Bottom => &self.bottom,
138        }
139    }
140
141    fn get_mut(&mut self, side: Side) -> &mut T {
142        match side {
143            Side::Left => &mut self.left,
144            Side::Top => &mut self.top,
145            Side::Right => &mut self.right,
146            Side::Bottom => &mut self.bottom,
147        }
148    }
149}
150
151impl<T: Debug + PartialEq> Debug for Sides<T> {
152    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
153        if self.is_uniform() {
154            f.write_str("Sides::splat(")?;
155            self.left.fmt(f)?;
156            f.write_str(")")
157        } else {
158            f.debug_struct("Sides")
159                .field("left", &self.left)
160                .field("top", &self.top)
161                .field("right", &self.right)
162                .field("bottom", &self.bottom)
163                .finish()
164        }
165    }
166}
167
168impl<T: Reflect> Reflect for Sides<Option<T>> {
169    fn input() -> CastInfo {
170        T::input() + Dict::input()
171    }
172
173    fn output() -> CastInfo {
174        T::output() + Dict::output()
175    }
176
177    fn castable(value: &Value) -> bool {
178        Dict::castable(value) || T::castable(value)
179    }
180}
181
182impl<T> IntoValue for Sides<Option<T>>
183where
184    T: PartialEq + IntoValue,
185{
186    fn into_value(self) -> Value {
187        if self.is_uniform() {
188            if let Some(left) = self.left {
189                return left.into_value();
190            }
191        }
192
193        let mut dict = Dict::new();
194        let mut handle = |key: &str, component: Option<T>| {
195            if let Some(c) = component {
196                dict.insert(key.into(), c.into_value());
197            }
198        };
199
200        handle("left", self.left);
201        handle("top", self.top);
202        handle("right", self.right);
203        handle("bottom", self.bottom);
204
205        Value::Dict(dict)
206    }
207}
208
209impl<T> FromValue for Sides<Option<T>>
210where
211    T: Default + FromValue + Clone,
212{
213    fn from_value(mut value: Value) -> HintedStrResult<Self> {
214        let expected_keys = ["left", "top", "right", "bottom", "x", "y", "rest"];
215        if let Value::Dict(dict) = &mut value {
216            if dict.is_empty() {
217                return Ok(Self::splat(None));
218            } else if dict.iter().any(|(key, _)| expected_keys.contains(&key.as_str())) {
219                let mut take = |key| dict.take(key).ok().map(T::from_value).transpose();
220                let rest = take("rest")?;
221                let x = take("x")?.or_else(|| rest.clone());
222                let y = take("y")?.or_else(|| rest.clone());
223                let sides = Sides {
224                    left: take("left")?.or_else(|| x.clone()),
225                    top: take("top")?.or_else(|| y.clone()),
226                    right: take("right")?.or_else(|| x.clone()),
227                    bottom: take("bottom")?.or_else(|| y.clone()),
228                };
229
230                dict.finish(&expected_keys)?;
231                return Ok(sides);
232            }
233        }
234
235        if T::castable(&value) {
236            Ok(Self::splat(Some(T::from_value(value)?)))
237        } else if let Value::Dict(dict) = &value {
238            let keys = dict.iter().map(|kv| kv.0.as_str()).collect();
239            // Do not hint at expected_keys, because T may be castable from Dict
240            // objects with other sets of expected keys.
241            Err(Dict::unexpected_keys(keys, None).into())
242        } else {
243            Err(Self::error(&value))
244        }
245    }
246}
247
248impl<T: Resolve> Resolve for Sides<T> {
249    type Output = Sides<T::Output>;
250
251    fn resolve(self, styles: StyleChain) -> Self::Output {
252        self.map(|v| v.resolve(styles))
253    }
254}
255
256impl<T: Fold> Fold for Sides<Option<T>> {
257    fn fold(self, outer: Self) -> Self {
258        // Usually, folding an inner `None` with an `outer` prefers the
259        // explicit `None`. However, here `None` means unspecified and thus
260        // we want `outer`, so we use `fold_or` to opt into such behavior.
261        self.zip(outer).map(|(inner, outer)| inner.fold_or(outer))
262    }
263}
264
265/// The four sides of objects.
266#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
267pub enum Side {
268    /// The left side.
269    Left,
270    /// The top side.
271    Top,
272    /// The right side.
273    Right,
274    /// The bottom side.
275    Bottom,
276}
277
278impl Side {
279    /// The opposite side.
280    pub fn inv(self) -> Self {
281        match self {
282            Self::Left => Self::Right,
283            Self::Top => Self::Bottom,
284            Self::Right => Self::Left,
285            Self::Bottom => Self::Top,
286        }
287    }
288
289    /// The next side, clockwise.
290    pub fn next_cw(self) -> Self {
291        match self {
292            Self::Left => Self::Top,
293            Self::Top => Self::Right,
294            Self::Right => Self::Bottom,
295            Self::Bottom => Self::Left,
296        }
297    }
298
299    /// The next side, counter-clockwise.
300    pub fn next_ccw(self) -> Self {
301        match self {
302            Self::Left => Self::Bottom,
303            Self::Top => Self::Left,
304            Self::Right => Self::Top,
305            Self::Bottom => Self::Right,
306        }
307    }
308
309    /// The first corner of the side in clockwise order.
310    pub fn start_corner(self) -> Corner {
311        match self {
312            Self::Left => Corner::BottomLeft,
313            Self::Top => Corner::TopLeft,
314            Self::Right => Corner::TopRight,
315            Self::Bottom => Corner::BottomRight,
316        }
317    }
318
319    /// The second corner of the side in clockwise order.
320    pub fn end_corner(self) -> Corner {
321        self.next_cw().start_corner()
322    }
323
324    /// Return the corresponding axis.
325    pub fn axis(self) -> Axis {
326        match self {
327            Self::Left | Self::Right => Axis::Y,
328            Self::Top | Self::Bottom => Axis::X,
329        }
330    }
331}
332
333cast! {
334    Side,
335    self => Alignment::from(self).into_value(),
336    align: Alignment => match align {
337        Alignment::LEFT => Self::Left,
338        Alignment::RIGHT => Self::Right,
339        Alignment::TOP => Self::Top,
340        Alignment::BOTTOM => Self::Bottom,
341        _ => bail!("cannot convert this alignment to a side"),
342    },
343}
typst_library/layout/sides.rs

typst_library/layout/
sides.rs
