typst_library/text/
item.rs

1use std::fmt::{self, Debug, Formatter};
2use std::ops::Range;
3
4use ecow::EcoString;
5use typst_syntax::Span;
6
7use crate::layout::{Abs, Em};
8use crate::text::{is_default_ignorable, Font, Lang, Region};
9use crate::visualize::{FixedStroke, Paint};
10
11/// A run of shaped text.
12#[derive(Clone, Eq, PartialEq, Hash)]
13pub struct TextItem {
14    /// The font the glyphs are contained in.
15    pub font: Font,
16    /// The font size.
17    pub size: Abs,
18    /// Glyph color.
19    pub fill: Paint,
20    /// Glyph stroke.
21    pub stroke: Option<FixedStroke>,
22    /// The natural language of the text.
23    pub lang: Lang,
24    /// The region of the text.
25    pub region: Option<Region>,
26    /// The item's plain text.
27    pub text: EcoString,
28    /// The glyphs. The number of glyphs may be different from the number of
29    /// characters in the plain text due to e.g. ligatures.
30    pub glyphs: Vec<Glyph>,
31}
32
33impl TextItem {
34    /// The width of the text run.
35    pub fn width(&self) -> Abs {
36        self.glyphs.iter().map(|g| g.x_advance).sum::<Em>().at(self.size)
37    }
38}
39
40impl Debug for TextItem {
41    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
42        f.write_str("Text(")?;
43        self.text.fmt(f)?;
44        f.write_str(")")
45    }
46}
47
48/// A glyph in a run of shaped text.
49#[derive(Debug, Clone, Eq, PartialEq, Hash)]
50pub struct Glyph {
51    /// The glyph's index in the font.
52    pub id: u16,
53    /// The advance width of the glyph.
54    pub x_advance: Em,
55    /// The horizontal offset of the glyph.
56    pub x_offset: Em,
57    /// The range of the glyph in its item's text. The range's length may
58    /// be more than one due to multi-byte UTF-8 encoding or ligatures.
59    pub range: Range<u16>,
60    /// The source code location of the text.
61    pub span: (Span, u16),
62}
63
64impl Glyph {
65    /// The range of the glyph in its item's text.
66    pub fn range(&self) -> Range<usize> {
67        usize::from(self.range.start)..usize::from(self.range.end)
68    }
69}
70
71/// A slice of a [`TextItem`].
72pub struct TextItemView<'a> {
73    /// The whole item this is a part of
74    pub item: &'a TextItem,
75    /// The glyphs of this slice
76    pub glyph_range: Range<usize>,
77}
78
79impl<'a> TextItemView<'a> {
80    /// Build a TextItemView for the whole contents of a TextItem.
81    pub fn full(text: &'a TextItem) -> Self {
82        Self::from_glyph_range(text, 0..text.glyphs.len())
83    }
84
85    /// Build a new [`TextItemView`] from a [`TextItem`] and a range of glyphs.
86    pub fn from_glyph_range(text: &'a TextItem, glyph_range: Range<usize>) -> Self {
87        TextItemView { item: text, glyph_range }
88    }
89
90    /// Returns an iterator over the glyphs of the slice.
91    ///
92    /// Note that the ranges are not remapped. They still point into the
93    /// original text.
94    pub fn glyphs(&self) -> &[Glyph] {
95        &self.item.glyphs[self.glyph_range.clone()]
96    }
97
98    /// The plain text for the given glyph from `glyphs()`. This is an
99    /// approximation since glyphs do not correspond 1-1 with codepoints.
100    pub fn glyph_text(&self, glyph: &Glyph) -> EcoString {
101        // Trim default ignorables which might have ended up in the glyph's
102        // cluster. Keep interior ones so that joined emojis work. All of this
103        // is a hack and needs to be reworked. See
104        // https://github.com/typst/typst/pull/5099
105        self.item.text[glyph.range()]
106            .trim_matches(is_default_ignorable)
107            .into()
108    }
109
110    /// The total width of this text slice
111    pub fn width(&self) -> Abs {
112        self.glyphs()
113            .iter()
114            .map(|g| g.x_advance)
115            .sum::<Em>()
116            .at(self.item.size)
117    }
118}
typst_library/text/item.rs

typst_library/text/
item.rs
