Move everything into `crates/` directory

1 files changed, 0 insertions, 973 deletions

diff --git a/library/src/text/shaping.rs b/library/src/text/shaping.rs
deleted file mode 100644
index ec8812fe..00000000
--- a/library/src/text/shaping.rs
+++ /dev/null
@@ -1,973 +0,0 @@
-use std::borrow::Cow;
-use std::ops::Range;
-use std::str::FromStr;
-
-use az::SaturatingAs;
-use rustybuzz::{Feature, Tag, UnicodeBuffer};
-use typst::font::{Font, FontStyle, FontVariant};
-use typst::util::SliceExt;
-use unicode_script::{Script, UnicodeScript};
-
-use super::{decorate, FontFamily, NumberType, NumberWidth, TextElem};
-use crate::layout::SpanMapper;
-use crate::prelude::*;
-
-/// The result of shaping text.
-///
-/// This type contains owned or borrowed shaped text runs, which can be
-/// measured, used to reshape substrings more quickly and converted into a
-/// frame.
-pub struct ShapedText<'a> {
-    /// The start of the text in the full paragraph.
-    pub base: usize,
-    /// The text that was shaped.
-    pub text: &'a str,
-    /// The text direction.
-    pub dir: Dir,
-    /// The text language.
-    pub lang: Lang,
-    /// The text region.
-    pub region: Option<Region>,
-    /// The text's style properties.
-    pub styles: StyleChain<'a>,
-    /// The font variant.
-    pub variant: FontVariant,
-    /// The font size.
-    pub size: Abs,
-    /// The width of the text's bounding box.
-    pub width: Abs,
-    /// The shaped glyphs.
-    pub glyphs: Cow<'a, [ShapedGlyph]>,
-}
-
-/// A single glyph resulting from shaping.
-#[derive(Debug, Clone)]
-pub struct ShapedGlyph {
-    /// The font the glyph is contained in.
-    pub font: Font,
-    /// The glyph's index in the font.
-    pub glyph_id: u16,
-    /// The advance width of the glyph.
-    pub x_advance: Em,
-    /// The horizontal offset of the glyph.
-    pub x_offset: Em,
-    /// The vertical offset of the glyph.
-    pub y_offset: Em,
-    /// The adjustability of the glyph.
-    pub adjustability: Adjustability,
-    /// The byte range of this glyph's cluster in the full paragraph. A cluster
-    /// is a sequence of one or multiple glyphs that cannot be separated and
-    /// must always be treated as a union.
-    ///
-    /// The range values of the glyphs in a [`ShapedText`] should not
-    /// overlap with each other, and they should be monotonically
-    /// increasing (for left-to-right or top-to-bottom text) or
-    /// monotonically decreasing (for right-to-left or bottom-to-top
-    /// text).
-    pub range: Range<usize>,
-    /// Whether splitting the shaping result before this glyph would yield the
-    /// same results as shaping the parts to both sides of `text_index`
-    /// separately.
-    pub safe_to_break: bool,
-    /// The first char in this glyph's cluster.
-    pub c: char,
-    /// The source code location of the glyph and its byte offset within it.
-    pub span: (Span, u16),
-}
-
-#[derive(Debug, Clone, Default)]
-pub struct Adjustability {
-    /// The left and right strechability
-    pub stretchability: (Em, Em),
-    /// The left and right shrinkability
-    pub shrinkability: (Em, Em),
-}
-
-impl ShapedGlyph {
-    /// Whether the glyph is a space.
-    pub fn is_space(&self) -> bool {
-        matches!(self.c, ' ' | '\u{00A0}' | '　')
-    }
-
-    /// Whether the glyph is justifiable.
-    pub fn is_justifiable(&self) -> bool {
-        // GB style is not relevant here.
-        self.is_space()
-            || self.is_cjk_script()
-            || self.is_cjk_left_aligned_punctuation(true)
-            || self.is_cjk_right_aligned_punctuation()
-            || self.is_cjk_center_aligned_punctuation(true)
-    }
-
-    pub fn is_cjk_script(&self) -> bool {
-        use Script::*;
-        // U+30FC: Katakana-Hiragana Prolonged Sound Mark
-        matches!(self.c.script(), Hiragana | Katakana | Han) || self.c == '\u{30FC}'
-    }
-
-    pub fn is_cjk_punctuation(&self) -> bool {
-        self.is_cjk_left_aligned_punctuation(true)
-            || self.is_cjk_right_aligned_punctuation()
-            || self.is_cjk_center_aligned_punctuation(true)
-    }
-
-    /// See <https://www.w3.org/TR/clreq/#punctuation_width_adjustment>
-    pub fn is_cjk_left_aligned_punctuation(&self, gb_style: bool) -> bool {
-        // CJK quotation marks shares codepoints with latin quotation marks.
-        // But only the CJK ones have full width.
-        if matches!(self.c, '”' | '’')
-            && self.x_advance + self.stretchability().1 == Em::one()
-        {
-            return true;
-        }
-
-        if gb_style && matches!(self.c, '，' | '。' | '、' | '：' | '；') {
-            return true;
-        }
-
-        matches!(self.c, '》' | '）' | '』' | '」')
-    }
-
-    /// See <https://www.w3.org/TR/clreq/#punctuation_width_adjustment>
-    pub fn is_cjk_right_aligned_punctuation(&self) -> bool {
-        // CJK quotation marks shares codepoints with latin quotation marks.
-        // But only the CJK ones have full width.
-        if matches!(self.c, '“' | '‘')
-            && self.x_advance + self.stretchability().0 == Em::one()
-        {
-            return true;
-        }
-
-        matches!(self.c, '《' | '（' | '『' | '「')
-    }
-
-    /// See <https://www.w3.org/TR/clreq/#punctuation_width_adjustment>
-    pub fn is_cjk_center_aligned_punctuation(&self, gb_style: bool) -> bool {
-        if !gb_style && matches!(self.c, '，' | '。' | '、' | '：' | '；') {
-            return true;
-        }
-
-        // U+30FB: Katakana Middle Dot
-        matches!(self.c, '\u{30FB}')
-    }
-
-    pub fn base_adjustability(&self, gb_style: bool) -> Adjustability {
-        let width = self.x_advance;
-        if self.is_space() {
-            Adjustability {
-                // The number for spaces is from Knuth-Plass' paper
-                stretchability: (Em::zero(), width / 2.0),
-                shrinkability: (Em::zero(), width / 3.0),
-            }
-        } else if self.is_cjk_left_aligned_punctuation(gb_style) {
-            Adjustability {
-                stretchability: (Em::zero(), Em::zero()),
-                shrinkability: (Em::zero(), width / 2.0),
-            }
-        } else if self.is_cjk_right_aligned_punctuation() {
-            Adjustability {
-                stretchability: (Em::zero(), Em::zero()),
-                shrinkability: (width / 2.0, Em::zero()),
-            }
-        } else if self.is_cjk_center_aligned_punctuation(gb_style) {
-            Adjustability {
-                stretchability: (Em::zero(), Em::zero()),
-                shrinkability: (width / 4.0, width / 4.0),
-            }
-        } else {
-            Adjustability::default()
-        }
-    }
-
-    /// The stretchability of the character.
-    pub fn stretchability(&self) -> (Em, Em) {
-        self.adjustability.stretchability
-    }
-
-    /// The shrinkability of the character.
-    pub fn shrinkability(&self) -> (Em, Em) {
-        self.adjustability.shrinkability
-    }
-
-    /// Shrink the width of glyph on the left side.
-    pub fn shrink_left(&mut self, amount: Em) {
-        self.x_offset -= amount;
-        self.x_advance -= amount;
-        self.adjustability.shrinkability.0 -= amount;
-        self.adjustability.stretchability.0 += amount;
-    }
-
-    /// Shrink the width of glyph on the right side.
-    pub fn shrink_right(&mut self, amount: Em) {
-        self.x_advance -= amount;
-        self.adjustability.shrinkability.1 -= amount;
-        self.adjustability.stretchability.1 += amount;
-    }
-}
-
-/// A side you can go toward.
-enum Side {
-    /// To the left-hand side.
-    Left,
-    /// To the right-hand side.
-    Right,
-}
-
-impl<'a> ShapedText<'a> {
-    /// Build the shaped text's frame.
-    ///
-    /// The `justification` defines how much extra advance width each
-    /// [justifiable glyph](ShapedGlyph::is_justifiable) will get.
-    pub fn build(
-        &self,
-        vt: &Vt,
-        justification_ratio: f64,
-        extra_justification: Abs,
-    ) -> Frame {
-        let (top, bottom) = self.measure(vt);
-        let size = Size::new(self.width, top + bottom);
-
-        let mut offset = Abs::zero();
-        let mut frame = Frame::new(size);
-        frame.set_baseline(top);
-
-        let shift = TextElem::baseline_in(self.styles);
-        let lang = TextElem::lang_in(self.styles);
-        let decos = TextElem::deco_in(self.styles);
-        let fill = TextElem::fill_in(self.styles);
-
-        for ((font, y_offset), group) in
-            self.glyphs.as_ref().group_by_key(|g| (g.font.clone(), g.y_offset))
-        {
-            let mut range = group[0].range.clone();
-            for glyph in group {
-                range.start = range.start.min(glyph.range.start);
-                range.end = range.end.max(glyph.range.end);
-            }
-
-            let pos = Point::new(offset, top + shift - y_offset.at(self.size));
-            let glyphs = group
-                .iter()
-                .map(|glyph| {
-                    let adjustability_left = if justification_ratio < 0.0 {
-                        glyph.shrinkability().0
-                    } else {
-                        glyph.stretchability().0
-                    };
-                    let adjustability_right = if justification_ratio < 0.0 {
-                        glyph.shrinkability().1
-                    } else {
-                        glyph.stretchability().1
-                    };
-
-                    let justification_left = adjustability_left * justification_ratio;
-                    let mut justification_right =
-                        adjustability_right * justification_ratio;
-                    if glyph.is_justifiable() {
-                        justification_right +=
-                            Em::from_length(extra_justification, self.size)
-                    }
-
-                    frame.size_mut().x += justification_left.at(self.size)
-                        + justification_right.at(self.size);
-
-                    Glyph {
-                        id: glyph.glyph_id,
-                        x_advance: glyph.x_advance
-                            + justification_left
-                            + justification_right,
-                        x_offset: glyph.x_offset + justification_left,
-                        range: (glyph.range.start - range.start).saturating_as()
-                            ..(glyph.range.end - range.start).saturating_as(),
-                        span: glyph.span,
-                    }
-                })
-                .collect();
-
-            let item = TextItem {
-                font,
-                size: self.size,
-                lang,
-                fill: fill.clone(),
-                text: self.text[range.start - self.base..range.end - self.base].into(),
-                glyphs,
-            };
-
-            let layer = frame.layer();
-            let width = item.width();
-
-            // Apply line decorations.
-            for deco in &decos {
-                decorate(&mut frame, deco, &item, shift, pos, width);
-            }
-
-            frame.insert(layer, pos, FrameItem::Text(item));
-            offset += width;
-        }
-
-        // Apply metadata.
-        frame.meta(self.styles, false);
-
-        frame
-    }
-
-    /// Measure the top and bottom extent of this text.
-    fn measure(&self, vt: &Vt) -> (Abs, Abs) {
-        let mut top = Abs::zero();
-        let mut bottom = Abs::zero();
-
-        let top_edge = TextElem::top_edge_in(self.styles);
-        let bottom_edge = TextElem::bottom_edge_in(self.styles);
-
-        // Expand top and bottom by reading the font's vertical metrics.
-        let mut expand = |font: &Font| {
-            let metrics = font.metrics();
-            top.set_max(top_edge.resolve(self.styles, metrics));
-            bottom.set_max(-bottom_edge.resolve(self.styles, metrics));
-        };
-
-        if self.glyphs.is_empty() {
-            // When there are no glyphs, we just use the vertical metrics of the
-            // first available font.
-            let world = vt.world;
-            for family in families(self.styles) {
-                if let Some(font) = world
-                    .book()
-                    .select(family.as_str(), self.variant)
-                    .and_then(|id| world.font(id))
-                {
-                    expand(&font);
-                    break;
-                }
-            }
-        } else {
-            for g in self.glyphs.iter() {
-                expand(&g.font);
-            }
-        }
-
-        (top, bottom)
-    }
-
-    /// How many glyphs are in the text where we can insert additional
-    /// space when encountering underfull lines.
-    pub fn justifiables(&self) -> usize {
-        self.glyphs.iter().filter(|g| g.is_justifiable()).count()
-    }
-
-    /// Whether the last glyph is a CJK character which should not be justified
-    /// on line end.
-    pub fn cjk_justifiable_at_last(&self) -> bool {
-        self.glyphs
-            .last()
-            .map(|g| g.is_cjk_script() || g.is_cjk_punctuation())
-            .unwrap_or(false)
-    }
-
-    /// The stretchability of the text.
-    pub fn stretchability(&self) -> Abs {
-        self.glyphs
-            .iter()
-            .map(|g| g.stretchability().0 + g.stretchability().1)
-            .sum::<Em>()
-            .at(self.size)
-    }
-
-    /// The shrinkability of the text
-    pub fn shrinkability(&self) -> Abs {
-        self.glyphs
-            .iter()
-            .map(|g| g.shrinkability().0 + g.shrinkability().1)
-            .sum::<Em>()
-            .at(self.size)
-    }
-
-    /// Reshape a range of the shaped text, reusing information from this
-    /// shaping process if possible.
-    ///
-    /// The text `range` is relative to the whole paragraph.
-    pub fn reshape(
-        &'a self,
-        vt: &Vt,
-        spans: &SpanMapper,
-        text_range: Range<usize>,
-    ) -> ShapedText<'a> {
-        let text = &self.text[text_range.start - self.base..text_range.end - self.base];
-        if let Some(glyphs) = self.slice_safe_to_break(text_range.clone()) {
-            #[cfg(debug_assertions)]
-            assert_all_glyphs_in_range(glyphs, text, text_range.clone());
-            Self {
-                base: text_range.start,
-                text,
-                dir: self.dir,
-                lang: self.lang,
-                region: self.region,
-                styles: self.styles,
-                size: self.size,
-                variant: self.variant,
-                width: glyphs.iter().map(|g| g.x_advance).sum::<Em>().at(self.size),
-                glyphs: Cow::Borrowed(glyphs),
-            }
-        } else {
-            shape(
-                vt,
-                text_range.start,
-                text,
-                spans,
-                self.styles,
-                self.dir,
-                self.lang,
-                self.region,
-            )
-        }
-    }
-
-    /// Push a hyphen to end of the text.
-    pub fn push_hyphen(&mut self, vt: &Vt) {
-        families(self.styles).find_map(|family| {
-            let world = vt.world;
-            let font = world
-                .book()
-                .select(family.as_str(), self.variant)
-                .and_then(|id| world.font(id))?;
-            let ttf = font.ttf();
-            let glyph_id = ttf.glyph_index('-')?;
-            let x_advance = font.to_em(ttf.glyph_hor_advance(glyph_id)?);
-            let range = self
-                .glyphs
-                .last()
-                .map(|g| g.range.end..g.range.end)
-                .unwrap_or_default();
-            self.width += x_advance.at(self.size);
-            self.glyphs.to_mut().push(ShapedGlyph {
-                font,
-                glyph_id: glyph_id.0,
-                x_advance,
-                x_offset: Em::zero(),
-                y_offset: Em::zero(),
-                adjustability: Adjustability::default(),
-                range,
-                safe_to_break: true,
-                c: '-',
-                span: (Span::detached(), 0),
-            });
-            Some(())
-        });
-    }
-
-    /// Find the subslice of glyphs that represent the given text range if both
-    /// sides are safe to break.
-    fn slice_safe_to_break(&self, text_range: Range<usize>) -> Option<&[ShapedGlyph]> {
-        let Range { mut start, mut end } = text_range;
-        if !self.dir.is_positive() {
-            std::mem::swap(&mut start, &mut end);
-        }
-
-        let left = self.find_safe_to_break(start, Side::Left)?;
-        let right = self.find_safe_to_break(end, Side::Right)?;
-        Some(&self.glyphs[left..right])
-    }
-
-    /// Find the glyph offset matching the text index that is most towards the
-    /// given side and safe-to-break.
-    fn find_safe_to_break(&self, text_index: usize, towards: Side) -> Option<usize> {
-        let ltr = self.dir.is_positive();
-
-        // Handle edge cases.
-        let len = self.glyphs.len();
-        if text_index == self.base {
-            return Some(if ltr { 0 } else { len });
-        } else if text_index == self.base + self.text.len() {
-            return Some(if ltr { len } else { 0 });
-        }
-
-        // Find any glyph with the text index.
-        let mut idx = self
-            .glyphs
-            .binary_search_by(|g| {
-                let ordering = g.range.start.cmp(&text_index);
-                if ltr {
-                    ordering
-                } else {
-                    ordering.reverse()
-                }
-            })
-            .ok()?;
-
-        let next = match towards {
-            Side::Left => usize::checked_sub,
-            Side::Right => usize::checked_add,
-        };
-
-        // Search for the outermost glyph with the text index.
-        while let Some(next) = next(idx, 1) {
-            if self.glyphs.get(next).map_or(true, |g| g.range.start != text_index) {
-                break;
-            }
-            idx = next;
-        }
-
-        // RTL needs offset one because the left side of the range should be
-        // exclusive and the right side inclusive, contrary to the normal
-        // behaviour of ranges.
-        self.glyphs[idx].safe_to_break.then_some(idx + usize::from(!ltr))
-    }
-}
-
-impl Debug for ShapedText<'_> {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        self.text.fmt(f)
-    }
-}
-
-/// Holds shaping results and metadata common to all shaped segments.
-struct ShapingContext<'a, 'v> {
-    vt: &'a Vt<'v>,
-    spans: &'a SpanMapper,
-    glyphs: Vec<ShapedGlyph>,
-    used: Vec<Font>,
-    styles: StyleChain<'a>,
-    size: Abs,
-    variant: FontVariant,
-    tags: Vec<rustybuzz::Feature>,
-    fallback: bool,
-    dir: Dir,
-}
-
-/// Shape text into [`ShapedText`].
-#[allow(clippy::too_many_arguments)]
-pub fn shape<'a>(
-    vt: &Vt,
-    base: usize,
-    text: &'a str,
-    spans: &SpanMapper,
-    styles: StyleChain<'a>,
-    dir: Dir,
-    lang: Lang,
-    region: Option<Region>,
-) -> ShapedText<'a> {
-    let size = TextElem::size_in(styles);
-    let mut ctx = ShapingContext {
-        vt,
-        spans,
-        size,
-        glyphs: vec![],
-        used: vec![],
-        styles,
-        variant: variant(styles),
-        tags: tags(styles),
-        fallback: TextElem::fallback_in(styles),
-        dir,
-    };
-
-    if !text.is_empty() {
-        shape_segment(&mut ctx, base, text, families(styles));
-    }
-
-    track_and_space(&mut ctx);
-    calculate_adjustability(&mut ctx, lang, region);
-
-    #[cfg(debug_assertions)]
-    assert_all_glyphs_in_range(&ctx.glyphs, text, base..(base + text.len()));
-    #[cfg(debug_assertions)]
-    assert_glyph_ranges_in_order(&ctx.glyphs, dir);
-
-    ShapedText {
-        base,
-        text,
-        dir,
-        lang,
-        region,
-        styles,
-        variant: ctx.variant,
-        size,
-        width: ctx.glyphs.iter().map(|g| g.x_advance).sum::<Em>().at(size),
-        glyphs: Cow::Owned(ctx.glyphs),
-    }
-}
-
-/// Shape text with font fallback using the `families` iterator.
-fn shape_segment(
-    ctx: &mut ShapingContext,
-    base: usize,
-    text: &str,
-    mut families: impl Iterator<Item = FontFamily> + Clone,
-) {
-    // Fonts dont have newlines and tabs.
-    if text.chars().all(|c| c == '\n' || c == '\t') {
-        return;
-    }
-
-    // Find the next available family.
-    let world = ctx.vt.world;
-    let book = world.book();
-    let mut selection = families.find_map(|family| {
-        book.select(family.as_str(), ctx.variant)
-            .and_then(|id| world.font(id))
-            .filter(|font| !ctx.used.contains(font))
-    });
-
-    // Do font fallback if the families are exhausted and fallback is enabled.
-    if selection.is_none() && ctx.fallback {
-        let first = ctx.used.first().map(Font::info);
-        selection = book
-            .select_fallback(first, ctx.variant, text)
-            .and_then(|id| world.font(id))
-            .filter(|font| !ctx.used.contains(font));
-    }
-
-    // Extract the font id or shape notdef glyphs if we couldn't find any font.
-    let Some(font) = selection else {
-        if let Some(font) = ctx.used.first().cloned() {
-            shape_tofus(ctx, base, text, font);
-        }
-        return;
-    };
-
-    ctx.used.push(font.clone());
-
-    // Fill the buffer with our text.
-    let mut buffer = UnicodeBuffer::new();
-    buffer.push_str(text);
-    buffer.set_language(language(ctx.styles));
-    buffer.set_direction(match ctx.dir {
-        Dir::LTR => rustybuzz::Direction::LeftToRight,
-        Dir::RTL => rustybuzz::Direction::RightToLeft,
-        _ => unimplemented!("vertical text layout"),
-    });
-
-    // Shape!
-    let buffer = rustybuzz::shape(font.rusty(), &ctx.tags, buffer);
-    let infos = buffer.glyph_infos();
-    let pos = buffer.glyph_positions();
-    let ltr = ctx.dir.is_positive();
-
-    // Collect the shaped glyphs, doing fallback and shaping parts again with
-    // the next font if necessary.
-    let mut i = 0;
-    while i < infos.len() {
-        let info = &infos[i];
-        let cluster = info.cluster as usize;
-
-        // Add the glyph to the shaped output.
-        if info.glyph_id != 0 {
-            // Determine the text range of the glyph.
-            let start = base + cluster;
-            let end = base
-                + if ltr { i.checked_add(1) } else { i.checked_sub(1) }
-                    .and_then(|last| infos.get(last))
-                    .map_or(text.len(), |info| info.cluster as usize);
-
-            ctx.glyphs.push(ShapedGlyph {
-                font: font.clone(),
-                glyph_id: info.glyph_id as u16,
-                // TODO: Don't ignore y_advance.
-                x_advance: font.to_em(pos[i].x_advance),
-                x_offset: font.to_em(pos[i].x_offset),
-                y_offset: font.to_em(pos[i].y_offset),
-                adjustability: Adjustability::default(),
-                range: start..end,
-                safe_to_break: !info.unsafe_to_break(),
-                c: text[cluster..].chars().next().unwrap(),
-                span: ctx.spans.span_at(start),
-            });
-        } else {
-            // First, search for the end of the tofu sequence.
-            let k = i;
-            while infos.get(i + 1).map_or(false, |info| info.glyph_id == 0) {
-                i += 1;
-            }
-
-            // Then, determine the start and end text index for the tofu
-            // sequence.
-            //
-            // Examples:
-            // Everything is shown in visual order. Tofus are written as "_".
-            // We want to find out that the tofus span the text `2..6`.
-            // Note that the clusters are longer than 1 char.
-            //
-            // Left-to-right:
-            // Text:     h a l i h a l l o
-            // Glyphs:   A   _   _   C   E
-            // Clusters: 0   2   4   6   8
-            //              k=1 i=2
-            //
-            // Right-to-left:
-            // Text:     O L L A H I L A H
-            // Glyphs:   E   C   _   _   A
-            // Clusters: 8   6   4   2   0
-            //                  k=2 i=3
-            let start = infos[if ltr { k } else { i }].cluster as usize;
-            let end = if ltr { i.checked_add(1) } else { k.checked_sub(1) }
-                .and_then(|last| infos.get(last))
-                .map_or(text.len(), |info| info.cluster as usize);
-
-            // Trim half-baked cluster.
-            let remove = base + start..base + end;
-            while ctx.glyphs.last().map_or(false, |g| remove.contains(&g.range.start)) {
-                ctx.glyphs.pop();
-            }
-
-            // Recursively shape the tofu sequence with the next family.
-            shape_segment(ctx, base + start, &text[start..end], families.clone());
-        }
-
-        i += 1;
-    }
-
-    ctx.used.pop();
-}
-
-/// Shape the text with tofus from the given font.
-fn shape_tofus(ctx: &mut ShapingContext, base: usize, text: &str, font: Font) {
-    let x_advance = font.advance(0).unwrap_or_default();
-    let add_glyph = |(cluster, c): (usize, char)| {
-        let start = base + cluster;
-        let end = start + c.len_utf8();
-        ctx.glyphs.push(ShapedGlyph {
-            font: font.clone(),
-            glyph_id: 0,
-            x_advance,
-            x_offset: Em::zero(),
-            y_offset: Em::zero(),
-            adjustability: Adjustability::default(),
-            range: start..end,
-            safe_to_break: true,
-            c,
-            span: ctx.spans.span_at(start),
-        });
-    };
-    if ctx.dir.is_positive() {
-        text.char_indices().for_each(add_glyph);
-    } else {
-        text.char_indices().rev().for_each(add_glyph);
-    }
-}
-
-/// Apply tracking and spacing to the shaped glyphs.
-fn track_and_space(ctx: &mut ShapingContext) {
-    let tracking = Em::from_length(TextElem::tracking_in(ctx.styles), ctx.size);
-    let spacing =
-        TextElem::spacing_in(ctx.styles).map(|abs| Em::from_length(abs, ctx.size));
-
-    let mut glyphs = ctx.glyphs.iter_mut().peekable();
-    while let Some(glyph) = glyphs.next() {
-        // Make non-breaking space same width as normal space.
-        if glyph.c == '\u{00A0}' {
-            glyph.x_advance -= nbsp_delta(&glyph.font).unwrap_or_default();
-        }
-
-        if glyph.is_space() {
-            glyph.x_advance = spacing.relative_to(glyph.x_advance);
-        }
-
-        if glyphs
-            .peek()
-            .map_or(false, |next| glyph.range.start != next.range.start)
-        {
-            glyph.x_advance += tracking;
-        }
-    }
-}
-
-pub fn is_gb_style(lang: Lang, region: Option<Region>) -> bool {
-    // Most CJK variants, including zh-CN, ja-JP, zh-SG, zh-MY use GB-style punctuation,
-    // while zh-HK and zh-TW use alternative style. We default to use GB-style.
-    !(lang == Lang::CHINESE
-        && matches!(region.as_ref().map(Region::as_str), Some("TW" | "HK")))
-}
-
-/// Calculate stretchability and shrinkability of each glyph,
-/// and CJK punctuation adjustments according to Chinese Layout Requirements.
-fn calculate_adjustability(ctx: &mut ShapingContext, lang: Lang, region: Option<Region>) {
-    let gb_style = is_gb_style(lang, region);
-
-    for glyph in &mut ctx.glyphs {
-        glyph.adjustability = glyph.base_adjustability(gb_style);
-    }
-
-    let mut glyphs = ctx.glyphs.iter_mut().peekable();
-    while let Some(glyph) = glyphs.next() {
-        // Only GB style needs further adjustment.
-        if glyph.is_cjk_punctuation() && !gb_style {
-            continue;
-        }
-
-        // Now we apply consecutive punctuation adjustment, specified in Chinese Layout
-        // Requirements, section 3.1.6.1 Punctuation Adjustment Space, and Japanese Layout
-        // Requirements, section 3.1 Line Composition Rules for Punctuation Marks
-        let Some(next) = glyphs.peek_mut() else { continue };
-        let width = glyph.x_advance;
-        let delta = width / 2.0;
-        if glyph.is_cjk_punctuation()
-            && next.is_cjk_punctuation()
-            && (glyph.shrinkability().1 + next.shrinkability().0) >= delta
-        {
-            let left_delta = glyph.shrinkability().1.min(delta);
-            glyph.shrink_right(left_delta);
-            next.shrink_left(delta - left_delta);
-        }
-    }
-}
-
-/// Difference between non-breaking and normal space.
-fn nbsp_delta(font: &Font) -> Option<Em> {
-    let space = font.ttf().glyph_index(' ')?.0;
-    let nbsp = font.ttf().glyph_index('\u{00A0}')?.0;
-    Some(font.advance(nbsp)? - font.advance(space)?)
-}
-
-/// Resolve the font variant.
-pub fn variant(styles: StyleChain) -> FontVariant {
-    let mut variant = FontVariant::new(
-        TextElem::style_in(styles),
-        TextElem::weight_in(styles),
-        TextElem::stretch_in(styles),
-    );
-
-    let delta = TextElem::delta_in(styles);
-    variant.weight = variant
-        .weight
-        .thicken(delta.clamp(i16::MIN as i64, i16::MAX as i64) as i16);
-
-    if TextElem::emph_in(styles) {
-        variant.style = match variant.style {
-            FontStyle::Normal => FontStyle::Italic,
-            FontStyle::Italic => FontStyle::Normal,
-            FontStyle::Oblique => FontStyle::Normal,
-        }
-    }
-
-    variant
-}
-
-/// Resolve a prioritized iterator over the font families.
-pub fn families(styles: StyleChain) -> impl Iterator<Item = FontFamily> + Clone {
-    const FALLBACKS: &[&str] = &[
-        "linux libertine",
-        "twitter color emoji",
-        "noto color emoji",
-        "apple color emoji",
-        "segoe ui emoji",
-    ];
-
-    let tail = if TextElem::fallback_in(styles) { FALLBACKS } else { &[] };
-    TextElem::font_in(styles)
-        .into_iter()
-        .chain(tail.iter().copied().map(FontFamily::new))
-}
-
-/// Collect the tags of the OpenType features to apply.
-fn tags(styles: StyleChain) -> Vec<Feature> {
-    let mut tags = vec![];
-    let mut feat = |tag, value| {
-        tags.push(Feature::new(Tag::from_bytes(tag), value, ..));
-    };
-
-    // Features that are on by default in Harfbuzz are only added if disabled.
-    if !TextElem::kerning_in(styles) {
-        feat(b"kern", 0);
-    }
-
-    // Features that are off by default in Harfbuzz are only added if enabled.
-    if TextElem::smallcaps_in(styles) {
-        feat(b"smcp", 1);
-    }
-
-    if TextElem::alternates_in(styles) {
-        feat(b"salt", 1);
-    }
-
-    let storage;
-    if let Some(set) = TextElem::stylistic_set_in(styles) {
-        storage = [b's', b's', b'0' + set.get() / 10, b'0' + set.get() % 10];
-        feat(&storage, 1);
-    }
-
-    if !TextElem::ligatures_in(styles) {
-        feat(b"liga", 0);
-        feat(b"clig", 0);
-    }
-
-    if TextElem::discretionary_ligatures_in(styles) {
-        feat(b"dlig", 1);
-    }
-
-    if TextElem::historical_ligatures_in(styles) {
-        feat(b"hilg", 1);
-    }
-
-    match TextElem::number_type_in(styles) {
-        Smart::Auto => {}
-        Smart::Custom(NumberType::Lining) => feat(b"lnum", 1),
-        Smart::Custom(NumberType::OldStyle) => feat(b"onum", 1),
-    }
-
-    match TextElem::number_width_in(styles) {
-        Smart::Auto => {}
-        Smart::Custom(NumberWidth::Proportional) => feat(b"pnum", 1),
-        Smart::Custom(NumberWidth::Tabular) => feat(b"tnum", 1),
-    }
-
-    if TextElem::slashed_zero_in(styles) {
-        feat(b"zero", 1);
-    }
-
-    if TextElem::fractions_in(styles) {
-        feat(b"frac", 1);
-    }
-
-    for (tag, value) in TextElem::features_in(styles).0 {
-        tags.push(Feature::new(tag, value, ..))
-    }
-
-    tags
-}
-
-/// Process the language and and region of a style chain into a
-/// rustybuzz-compatible BCP 47 language.
-fn language(styles: StyleChain) -> rustybuzz::Language {
-    let mut bcp: EcoString = TextElem::lang_in(styles).as_str().into();
-    if let Some(region) = TextElem::region_in(styles) {
-        bcp.push('-');
-        bcp.push_str(region.as_str());
-    }
-    rustybuzz::Language::from_str(&bcp).unwrap()
-}
-
-/// Returns true if all glyphs in `glyphs` have ranges within the range `range`.
-#[cfg(debug_assertions)]
-fn assert_all_glyphs_in_range(glyphs: &[ShapedGlyph], text: &str, range: Range<usize>) {
-    if glyphs
-        .iter()
-        .any(|g| g.range.start < range.start || g.range.end > range.end)
-    {
-        panic!("one or more glyphs in {text:?} fell out of range");
-    }
-}
-
-/// Asserts that the ranges of `glyphs` is in the proper order according to `dir`.
-///
-/// This asserts instead of returning a bool in order to provide a more informative message when the invariant is violated.
-#[cfg(debug_assertions)]
-fn assert_glyph_ranges_in_order(glyphs: &[ShapedGlyph], dir: Dir) {
-    if glyphs.is_empty() {
-        return;
-    }
-
-    // Iterator::is_sorted and friends are unstable as of Rust 1.70.0
-    for i in 0..(glyphs.len() - 1) {
-        let a = &glyphs[i];
-        let b = &glyphs[i + 1];
-        let ord = a.range.start.cmp(&b.range.start);
-        let ord = if dir.is_positive() { ord } else { ord.reverse() };
-        if ord == std::cmp::Ordering::Greater {
-            panic!(
-                "glyph ranges should be monotonically {}, \
-                 but found glyphs out of order:\n\n\
-                 first: {a:#?}\nsecond: {b:#?}",
-                if dir.is_positive() { "increasing" } else { "decreasing" },
-            );
-        }
-    }
-}