Move all crates to a top-level crates folder

Co-Authored-By: Max Brunsfeld <maxbrunsfeld@gmail.com>

crates/gpui/src/text_layout.rs

@@ -0,0 +1,728 @@
+use crate::{
+    color::Color,
+    fonts::{FontId, GlyphId},
+    geometry::{
+        rect::RectF,
+        vector::{vec2f, Vector2F},
+    },
+    platform, scene, FontSystem, PaintContext,
+};
+use ordered_float::OrderedFloat;
+use parking_lot::{Mutex, RwLock, RwLockUpgradableReadGuard};
+use smallvec::SmallVec;
+use std::{
+    borrow::Borrow,
+    collections::HashMap,
+    hash::{Hash, Hasher},
+    iter,
+    sync::Arc,
+};
+
+pub struct TextLayoutCache {
+    prev_frame: Mutex<HashMap<CacheKeyValue, Arc<LineLayout>>>,
+    curr_frame: RwLock<HashMap<CacheKeyValue, Arc<LineLayout>>>,
+    fonts: Arc<dyn platform::FontSystem>,
+}
+
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+pub struct RunStyle {
+    pub color: Color,
+    pub font_id: FontId,
+    pub underline: bool,
+}
+
+impl TextLayoutCache {
+    pub fn new(fonts: Arc<dyn platform::FontSystem>) -> Self {
+        Self {
+            prev_frame: Mutex::new(HashMap::new()),
+            curr_frame: RwLock::new(HashMap::new()),
+            fonts,
+        }
+    }
+
+    pub fn finish_frame(&self) {
+        let mut prev_frame = self.prev_frame.lock();
+        let mut curr_frame = self.curr_frame.write();
+        std::mem::swap(&mut *prev_frame, &mut *curr_frame);
+        curr_frame.clear();
+    }
+
+    pub fn layout_str<'a>(
+        &'a self,
+        text: &'a str,
+        font_size: f32,
+        runs: &'a [(usize, RunStyle)],
+    ) -> Line {
+        let key = &CacheKeyRef {
+            text,
+            font_size: OrderedFloat(font_size),
+            runs,
+        } as &dyn CacheKey;
+        let curr_frame = self.curr_frame.upgradable_read();
+        if let Some(layout) = curr_frame.get(key) {
+            return Line::new(layout.clone(), runs);
+        }
+
+        let mut curr_frame = RwLockUpgradableReadGuard::upgrade(curr_frame);
+        if let Some((key, layout)) = self.prev_frame.lock().remove_entry(key) {
+            curr_frame.insert(key, layout.clone());
+            Line::new(layout.clone(), runs)
+        } else {
+            let layout = Arc::new(self.fonts.layout_line(text, font_size, runs));
+            let key = CacheKeyValue {
+                text: text.into(),
+                font_size: OrderedFloat(font_size),
+                runs: SmallVec::from(runs),
+            };
+            curr_frame.insert(key, layout.clone());
+            Line::new(layout, runs)
+        }
+    }
+}
+
+trait CacheKey {
+    fn key<'a>(&'a self) -> CacheKeyRef<'a>;
+}
+
+impl<'a> PartialEq for (dyn CacheKey + 'a) {
+    fn eq(&self, other: &dyn CacheKey) -> bool {
+        self.key() == other.key()
+    }
+}
+
+impl<'a> Eq for (dyn CacheKey + 'a) {}
+
+impl<'a> Hash for (dyn CacheKey + 'a) {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.key().hash(state)
+    }
+}
+
+#[derive(Eq, PartialEq)]
+struct CacheKeyValue {
+    text: String,
+    font_size: OrderedFloat<f32>,
+    runs: SmallVec<[(usize, RunStyle); 1]>,
+}
+
+impl CacheKey for CacheKeyValue {
+    fn key<'a>(&'a self) -> CacheKeyRef<'a> {
+        CacheKeyRef {
+            text: &self.text.as_str(),
+            font_size: self.font_size,
+            runs: self.runs.as_slice(),
+        }
+    }
+}
+
+impl Hash for CacheKeyValue {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.key().hash(state);
+    }
+}
+
+impl<'a> Borrow<dyn CacheKey + 'a> for CacheKeyValue {
+    fn borrow(&self) -> &(dyn CacheKey + 'a) {
+        self as &dyn CacheKey
+    }
+}
+
+#[derive(Copy, Clone)]
+struct CacheKeyRef<'a> {
+    text: &'a str,
+    font_size: OrderedFloat<f32>,
+    runs: &'a [(usize, RunStyle)],
+}
+
+impl<'a> CacheKey for CacheKeyRef<'a> {
+    fn key<'b>(&'b self) -> CacheKeyRef<'b> {
+        *self
+    }
+}
+
+impl<'a> PartialEq for CacheKeyRef<'a> {
+    fn eq(&self, other: &Self) -> bool {
+        self.text == other.text
+            && self.font_size == other.font_size
+            && self.runs.len() == other.runs.len()
+            && self.runs.iter().zip(other.runs.iter()).all(
+                |((len_a, style_a), (len_b, style_b))| {
+                    len_a == len_b && style_a.font_id == style_b.font_id
+                },
+            )
+    }
+}
+
+impl<'a> Hash for CacheKeyRef<'a> {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.text.hash(state);
+        self.font_size.hash(state);
+        for (len, style_id) in self.runs {
+            len.hash(state);
+            style_id.font_id.hash(state);
+        }
+    }
+}
+
+#[derive(Default, Debug)]
+pub struct Line {
+    layout: Arc<LineLayout>,
+    style_runs: SmallVec<[(u32, Color, bool); 32]>,
+}
+
+#[derive(Default, Debug)]
+pub struct LineLayout {
+    pub width: f32,
+    pub ascent: f32,
+    pub descent: f32,
+    pub runs: Vec<Run>,
+    pub len: usize,
+    pub font_size: f32,
+}
+
+#[derive(Debug)]
+pub struct Run {
+    pub font_id: FontId,
+    pub glyphs: Vec<Glyph>,
+}
+
+#[derive(Debug)]
+pub struct Glyph {
+    pub id: GlyphId,
+    pub position: Vector2F,
+    pub index: usize,
+}
+
+impl Line {
+    fn new(layout: Arc<LineLayout>, runs: &[(usize, RunStyle)]) -> Self {
+        let mut style_runs = SmallVec::new();
+        for (len, style) in runs {
+            style_runs.push((*len as u32, style.color, style.underline));
+        }
+        Self { layout, style_runs }
+    }
+
+    pub fn runs(&self) -> &[Run] {
+        &self.layout.runs
+    }
+
+    pub fn width(&self) -> f32 {
+        self.layout.width
+    }
+
+    pub fn x_for_index(&self, index: usize) -> f32 {
+        for run in &self.layout.runs {
+            for glyph in &run.glyphs {
+                if glyph.index == index {
+                    return glyph.position.x();
+                }
+            }
+        }
+        self.layout.width
+    }
+
+    pub fn index_for_x(&self, x: f32) -> Option<usize> {
+        if x >= self.layout.width {
+            None
+        } else {
+            for run in self.layout.runs.iter().rev() {
+                for glyph in run.glyphs.iter().rev() {
+                    if glyph.position.x() <= x {
+                        return Some(glyph.index);
+                    }
+                }
+            }
+            Some(0)
+        }
+    }
+
+    pub fn paint(
+        &self,
+        origin: Vector2F,
+        visible_bounds: RectF,
+        line_height: f32,
+        cx: &mut PaintContext,
+    ) {
+        let padding_top = (line_height - self.layout.ascent - self.layout.descent) / 2.;
+        let baseline_offset = vec2f(0., padding_top + self.layout.ascent);
+
+        let mut style_runs = self.style_runs.iter();
+        let mut run_end = 0;
+        let mut color = Color::black();
+        let mut underline_start = None;
+
+        for run in &self.layout.runs {
+            let max_glyph_width = cx
+                .font_cache
+                .bounding_box(run.font_id, self.layout.font_size)
+                .x();
+
+            for glyph in &run.glyphs {
+                let glyph_origin = origin + baseline_offset + glyph.position;
+
+                if glyph_origin.x() + max_glyph_width < visible_bounds.origin().x() {
+                    continue;
+                }
+                if glyph_origin.x() > visible_bounds.upper_right().x() {
+                    break;
+                }
+
+                if glyph.index >= run_end {
+                    if let Some((run_len, run_color, run_underlined)) = style_runs.next() {
+                        if let Some(underline_origin) = underline_start {
+                            if !*run_underlined || *run_color != color {
+                                cx.scene.push_underline(scene::Quad {
+                                    bounds: RectF::from_points(
+                                        underline_origin,
+                                        glyph_origin + vec2f(0., 1.),
+                                    ),
+                                    background: Some(color),
+                                    border: Default::default(),
+                                    corner_radius: 0.,
+                                });
+                                underline_start = None;
+                            }
+                        }
+
+                        if *run_underlined {
+                            underline_start.get_or_insert(glyph_origin);
+                        }
+
+                        run_end += *run_len as usize;
+                        color = *run_color;
+                    } else {
+                        run_end = self.layout.len;
+                        color = Color::black();
+                        if let Some(underline_origin) = underline_start.take() {
+                            cx.scene.push_underline(scene::Quad {
+                                bounds: RectF::from_points(
+                                    underline_origin,
+                                    glyph_origin + vec2f(0., 1.),
+                                ),
+                                background: Some(color),
+                                border: Default::default(),
+                                corner_radius: 0.,
+                            });
+                        }
+                    }
+                }
+
+                cx.scene.push_glyph(scene::Glyph {
+                    font_id: run.font_id,
+                    font_size: self.layout.font_size,
+                    id: glyph.id,
+                    origin: glyph_origin,
+                    color,
+                });
+            }
+        }
+
+        if let Some(underline_start) = underline_start.take() {
+            let line_end = origin + baseline_offset + vec2f(self.layout.width, 0.);
+
+            cx.scene.push_underline(scene::Quad {
+                bounds: RectF::from_points(underline_start, line_end + vec2f(0., 1.)),
+                background: Some(color),
+                border: Default::default(),
+                corner_radius: 0.,
+            });
+        }
+    }
+
+    pub fn paint_wrapped(
+        &self,
+        origin: Vector2F,
+        visible_bounds: RectF,
+        line_height: f32,
+        boundaries: impl IntoIterator<Item = ShapedBoundary>,
+        cx: &mut PaintContext,
+    ) {
+        let padding_top = (line_height - self.layout.ascent - self.layout.descent) / 2.;
+        let baseline_origin = vec2f(0., padding_top + self.layout.ascent);
+
+        let mut boundaries = boundaries.into_iter().peekable();
+        let mut color_runs = self.style_runs.iter();
+        let mut color_end = 0;
+        let mut color = Color::black();
+
+        let mut glyph_origin = vec2f(0., 0.);
+        let mut prev_position = 0.;
+        for run in &self.layout.runs {
+            for (glyph_ix, glyph) in run.glyphs.iter().enumerate() {
+                if boundaries.peek().map_or(false, |b| b.glyph_ix == glyph_ix) {
+                    boundaries.next();
+                    glyph_origin = vec2f(0., glyph_origin.y() + line_height);
+                } else {
+                    glyph_origin.set_x(glyph_origin.x() + glyph.position.x() - prev_position);
+                }
+                prev_position = glyph.position.x();
+
+                if glyph.index >= color_end {
+                    if let Some(next_run) = color_runs.next() {
+                        color_end += next_run.0 as usize;
+                        color = next_run.1;
+                    } else {
+                        color_end = self.layout.len;
+                        color = Color::black();
+                    }
+                }
+
+                let glyph_bounds = RectF::new(
+                    origin + glyph_origin,
+                    cx.font_cache
+                        .bounding_box(run.font_id, self.layout.font_size),
+                );
+                if glyph_bounds.intersects(visible_bounds) {
+                    cx.scene.push_glyph(scene::Glyph {
+                        font_id: run.font_id,
+                        font_size: self.layout.font_size,
+                        id: glyph.id,
+                        origin: glyph_bounds.origin() + baseline_origin,
+                        color,
+                    });
+                }
+            }
+        }
+    }
+}
+
+impl Run {
+    pub fn glyphs(&self) -> &[Glyph] {
+        &self.glyphs
+    }
+}
+
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+pub struct Boundary {
+    pub ix: usize,
+    pub next_indent: u32,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
+pub struct ShapedBoundary {
+    pub run_ix: usize,
+    pub glyph_ix: usize,
+}
+
+impl Boundary {
+    fn new(ix: usize, next_indent: u32) -> Self {
+        Self { ix, next_indent }
+    }
+}
+
+pub struct LineWrapper {
+    font_system: Arc<dyn FontSystem>,
+    pub(crate) font_id: FontId,
+    pub(crate) font_size: f32,
+    cached_ascii_char_widths: [f32; 128],
+    cached_other_char_widths: HashMap<char, f32>,
+}
+
+impl LineWrapper {
+    pub const MAX_INDENT: u32 = 256;
+
+    pub fn new(font_id: FontId, font_size: f32, font_system: Arc<dyn FontSystem>) -> Self {
+        Self {
+            font_system,
+            font_id,
+            font_size,
+            cached_ascii_char_widths: [f32::NAN; 128],
+            cached_other_char_widths: HashMap::new(),
+        }
+    }
+
+    pub fn wrap_line<'a>(
+        &'a mut self,
+        line: &'a str,
+        wrap_width: f32,
+    ) -> impl Iterator<Item = Boundary> + 'a {
+        let mut width = 0.0;
+        let mut first_non_whitespace_ix = None;
+        let mut indent = None;
+        let mut last_candidate_ix = 0;
+        let mut last_candidate_width = 0.0;
+        let mut last_wrap_ix = 0;
+        let mut prev_c = '\0';
+        let mut char_indices = line.char_indices();
+        iter::from_fn(move || {
+            while let Some((ix, c)) = char_indices.next() {
+                if c == '\n' {
+                    continue;
+                }
+
+                if self.is_boundary(prev_c, c) && first_non_whitespace_ix.is_some() {
+                    last_candidate_ix = ix;
+                    last_candidate_width = width;
+                }
+
+                if c != ' ' && first_non_whitespace_ix.is_none() {
+                    first_non_whitespace_ix = Some(ix);
+                }
+
+                let char_width = self.width_for_char(c);
+                width += char_width;
+                if width > wrap_width && ix > last_wrap_ix {
+                    if let (None, Some(first_non_whitespace_ix)) = (indent, first_non_whitespace_ix)
+                    {
+                        indent = Some(
+                            Self::MAX_INDENT.min((first_non_whitespace_ix - last_wrap_ix) as u32),
+                        );
+                    }
+
+                    if last_candidate_ix > 0 {
+                        last_wrap_ix = last_candidate_ix;
+                        width -= last_candidate_width;
+                        last_candidate_ix = 0;
+                    } else {
+                        last_wrap_ix = ix;
+                        width = char_width;
+                    }
+
+                    let indent_width =
+                        indent.map(|indent| indent as f32 * self.width_for_char(' '));
+                    width += indent_width.unwrap_or(0.);
+
+                    return Some(Boundary::new(last_wrap_ix, indent.unwrap_or(0)));
+                }
+                prev_c = c;
+            }
+
+            None
+        })
+    }
+
+    pub fn wrap_shaped_line<'a>(
+        &'a mut self,
+        str: &'a str,
+        line: &'a Line,
+        wrap_width: f32,
+    ) -> impl Iterator<Item = ShapedBoundary> + 'a {
+        let mut first_non_whitespace_ix = None;
+        let mut last_candidate_ix = None;
+        let mut last_candidate_x = 0.0;
+        let mut last_wrap_ix = ShapedBoundary {
+            run_ix: 0,
+            glyph_ix: 0,
+        };
+        let mut last_wrap_x = 0.;
+        let mut prev_c = '\0';
+        let mut glyphs = line
+            .runs()
+            .iter()
+            .enumerate()
+            .flat_map(move |(run_ix, run)| {
+                run.glyphs()
+                    .iter()
+                    .enumerate()
+                    .map(move |(glyph_ix, glyph)| {
+                        let character = str[glyph.index..].chars().next().unwrap();
+                        (
+                            ShapedBoundary { run_ix, glyph_ix },
+                            character,
+                            glyph.position.x(),
+                        )
+                    })
+            })
+            .peekable();
+
+        iter::from_fn(move || {
+            while let Some((ix, c, x)) = glyphs.next() {
+                if c == '\n' {
+                    continue;
+                }
+
+                if self.is_boundary(prev_c, c) && first_non_whitespace_ix.is_some() {
+                    last_candidate_ix = Some(ix);
+                    last_candidate_x = x;
+                }
+
+                if c != ' ' && first_non_whitespace_ix.is_none() {
+                    first_non_whitespace_ix = Some(ix);
+                }
+
+                let next_x = glyphs.peek().map_or(line.width(), |(_, _, x)| *x);
+                let width = next_x - last_wrap_x;
+                if width > wrap_width && ix > last_wrap_ix {
+                    if let Some(last_candidate_ix) = last_candidate_ix.take() {
+                        last_wrap_ix = last_candidate_ix;
+                        last_wrap_x = last_candidate_x;
+                    } else {
+                        last_wrap_ix = ix;
+                        last_wrap_x = x;
+                    }
+
+                    return Some(last_wrap_ix);
+                }
+                prev_c = c;
+            }
+
+            None
+        })
+    }
+
+    fn is_boundary(&self, prev: char, next: char) -> bool {
+        (prev == ' ') && (next != ' ')
+    }
+
+    #[inline(always)]
+    fn width_for_char(&mut self, c: char) -> f32 {
+        if (c as u32) < 128 {
+            let mut width = self.cached_ascii_char_widths[c as usize];
+            if width.is_nan() {
+                width = self.compute_width_for_char(c);
+                self.cached_ascii_char_widths[c as usize] = width;
+            }
+            width
+        } else {
+            let mut width = self
+                .cached_other_char_widths
+                .get(&c)
+                .copied()
+                .unwrap_or(f32::NAN);
+            if width.is_nan() {
+                width = self.compute_width_for_char(c);
+                self.cached_other_char_widths.insert(c, width);
+            }
+            width
+        }
+    }
+
+    fn compute_width_for_char(&self, c: char) -> f32 {
+        self.font_system
+            .layout_line(
+                &c.to_string(),
+                self.font_size,
+                &[(
+                    1,
+                    RunStyle {
+                        font_id: self.font_id,
+                        color: Default::default(),
+                        underline: false,
+                    },
+                )],
+            )
+            .width
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::fonts::{Properties, Weight};
+
+    #[crate::test(self)]
+    fn test_wrap_line(cx: &mut crate::MutableAppContext) {
+        let font_cache = cx.font_cache().clone();
+        let font_system = cx.platform().fonts();
+        let family = font_cache.load_family(&["Courier"]).unwrap();
+        let font_id = font_cache.select_font(family, &Default::default()).unwrap();
+
+        let mut wrapper = LineWrapper::new(font_id, 16., font_system);
+        assert_eq!(
+            wrapper
+                .wrap_line("aa bbb cccc ddddd eeee", 72.0)
+                .collect::<Vec<_>>(),
+            &[
+                Boundary::new(7, 0),
+                Boundary::new(12, 0),
+                Boundary::new(18, 0)
+            ],
+        );
+        assert_eq!(
+            wrapper
+                .wrap_line("aaa aaaaaaaaaaaaaaaaaa", 72.0)
+                .collect::<Vec<_>>(),
+            &[
+                Boundary::new(4, 0),
+                Boundary::new(11, 0),
+                Boundary::new(18, 0)
+            ],
+        );
+        assert_eq!(
+            wrapper.wrap_line("     aaaaaaa", 72.).collect::<Vec<_>>(),
+            &[
+                Boundary::new(7, 5),
+                Boundary::new(9, 5),
+                Boundary::new(11, 5),
+            ]
+        );
+        assert_eq!(
+            wrapper
+                .wrap_line("                            ", 72.)
+                .collect::<Vec<_>>(),
+            &[
+                Boundary::new(7, 0),
+                Boundary::new(14, 0),
+                Boundary::new(21, 0)
+            ]
+        );
+        assert_eq!(
+            wrapper
+                .wrap_line("          aaaaaaaaaaaaaa", 72.)
+                .collect::<Vec<_>>(),
+            &[
+                Boundary::new(7, 0),
+                Boundary::new(14, 3),
+                Boundary::new(18, 3),
+                Boundary::new(22, 3),
+            ]
+        );
+    }
+
+    #[crate::test(self, retries = 5)]
+    fn test_wrap_shaped_line(cx: &mut crate::MutableAppContext) {
+        // This is failing intermittently on CI and we don't have time to figure it out
+        let font_cache = cx.font_cache().clone();
+        let font_system = cx.platform().fonts();
+        let text_layout_cache = TextLayoutCache::new(font_system.clone());
+
+        let family = font_cache.load_family(&["Helvetica"]).unwrap();
+        let font_id = font_cache.select_font(family, &Default::default()).unwrap();
+        let normal = RunStyle {
+            font_id,
+            color: Default::default(),
+            underline: false,
+        };
+        let bold = RunStyle {
+            font_id: font_cache
+                .select_font(
+                    family,
+                    &Properties {
+                        weight: Weight::BOLD,
+                        ..Default::default()
+                    },
+                )
+                .unwrap(),
+            color: Default::default(),
+            underline: false,
+        };
+
+        let text = "aa bbb cccc ddddd eeee";
+        let line = text_layout_cache.layout_str(
+            text,
+            16.0,
+            &[(4, normal), (5, bold), (6, normal), (1, bold), (7, normal)],
+        );
+
+        let mut wrapper = LineWrapper::new(font_id, 16., font_system);
+        assert_eq!(
+            wrapper
+                .wrap_shaped_line(&text, &line, 72.0)
+                .collect::<Vec<_>>(),
+            &[
+                ShapedBoundary {
+                    run_ix: 1,
+                    glyph_ix: 3
+                },
+                ShapedBoundary {
+                    run_ix: 2,
+                    glyph_ix: 3
+                },
+                ShapedBoundary {
+                    run_ix: 4,
+                    glyph_ix: 2
+                }
+            ],
+        );
+    }
+}