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Deduplicate ttf-parser and rustybuzz face 🥞

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This commit is contained in:
Laurenz 2021-04-06 15:13:20 +02:00
parent de20a21a58
commit 464a6ff75e
5 changed files with 69 additions and 58 deletions
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2
Cargo.toml
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@ -27,7 +27,7 @@ image = { version = "0.23", default-features = false, features = ["jpeg", "png"]
miniz_oxide = "0.3"
pdf-writer = { path = "../pdf-writer" }
rustybuzz = { git = "https://github.com/laurmaedje/rustybuzz" }
ttf-parser = "0.9"
ttf-parser = "0.12"
unicode-bidi = "0.3"
unicode-xid = "0.2"
xi-unicode = "0.3"

60
src/font.rs
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@ -10,8 +10,7 @@ use crate::geom::Length;
pub struct FaceBuf {
data: Box<[u8]>,
index: u32,
ttf: ttf_parser::Face<'static>,
buzz: rustybuzz::Face<'static>,
inner: rustybuzz::Face<'static>,
units_per_em: f64,
ascender: f64,
cap_height: f64,
@ -30,23 +29,16 @@ impl FaceBuf {
self.index
}
/// Get a reference to the underlying ttf-parser face.
pub fn ttf(&self) -> &ttf_parser::Face<'_> {
/// Get a reference to the underlying ttf-parser/rustybuzz face.
pub fn ttf(&self) -> &rustybuzz::Face<'_> {
// We can't implement Deref because that would leak the internal 'static
// lifetime.
&self.ttf
&self.inner
}
/// Get a reference to the underlying rustybuzz face.
pub fn buzz(&self) -> &rustybuzz::Face<'_> {
// We can't implement Deref because that would leak the internal 'static
// lifetime.
&self.buzz
}
/// Look up a vertical metric at a given font size.
pub fn vertical_metric(&self, size: Length, metric: VerticalFontMetric) -> Length {
self.convert(size, match metric {
/// Look up a vertical metric.
pub fn vertical_metric(&self, metric: VerticalFontMetric) -> EmLength {
self.convert(match metric {
VerticalFontMetric::Ascender => self.ascender,
VerticalFontMetric::CapHeight => self.cap_height,
VerticalFontMetric::XHeight => self.x_height,
@ -55,9 +47,9 @@ impl FaceBuf {
})
}
/// Convert from font units to a length at a given font size.
pub fn convert(&self, size: Length, units: impl Into<f64>) -> Length {
units.into() / self.units_per_em * size
/// Convert from font units to an em length length.
pub fn convert(&self, units: impl Into<f64>) -> EmLength {
EmLength(units.into() / self.units_per_em)
}
}
@ -70,21 +62,19 @@ impl FaceFromVec for FaceBuf {
let slice: &'static [u8] =
unsafe { std::slice::from_raw_parts(data.as_ptr(), data.len()) };
let ttf = ttf_parser::Face::from_slice(slice, index).ok()?;
let buzz = rustybuzz::Face::from_slice(slice, index)?;
let inner = rustybuzz::Face::from_slice(slice, index)?;
// Look up some metrics we may need often.
let units_per_em = ttf.units_per_em().unwrap_or(1000);
let ascender = ttf.typographic_ascender().unwrap_or(ttf.ascender());
let cap_height = ttf.capital_height().filter(|&h| h > 0).unwrap_or(ascender);
let x_height = ttf.x_height().filter(|&h| h > 0).unwrap_or(ascender);
let descender = ttf.typographic_descender().unwrap_or(ttf.descender());
let units_per_em = inner.units_per_em();
let ascender = inner.typographic_ascender().unwrap_or(inner.ascender());
let cap_height = inner.capital_height().filter(|&h| h > 0).unwrap_or(ascender);
let x_height = inner.x_height().filter(|&h| h > 0).unwrap_or(ascender);
let descender = inner.typographic_descender().unwrap_or(inner.descender());
Some(Self {
data,
index,
ttf,
buzz,
inner,
units_per_em: f64::from(units_per_em),
ascender: f64::from(ascender),
cap_height: f64::from(cap_height),
@ -94,6 +84,22 @@ impl FaceFromVec for FaceBuf {
}
}
/// A length in resolved em units.
#[derive(Default, Debug, Copy, Clone, PartialEq, PartialOrd)]
pub struct EmLength(f64);
impl EmLength {
/// Convert to a length at the given font size.
pub fn scale(self, size: Length) -> Length {
self.0 * size
}
/// Get the number of em units.
pub fn get(self) -> f64 {
self.0
}
}
/// Identifies a vertical metric of a font.
#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd)]
pub enum VerticalFontMetric {

21
src/layout/shaping.rs
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@ -39,7 +39,7 @@ pub struct ShapedGlyph {
/// The font face the glyph is contained in.
pub face_id: FaceId,
/// The glyph's ID in the face.
pub id: GlyphId,
pub glyph_id: GlyphId,
/// The advance width of the glyph.
pub x_advance: i32,
/// The horizontal offset of the glyph.
@ -59,8 +59,6 @@ impl<'a> ShapedText<'a> {
let mut x = Length::ZERO;
for (face_id, group) in self.glyphs.as_ref().group_by_key(|g| g.face_id) {
let face = loader.face(face_id);
let pos = Point::new(x, self.baseline);
let mut text = Text {
face_id,
@ -69,10 +67,11 @@ impl<'a> ShapedText<'a> {
glyphs: vec![],
};
let face = loader.face(face_id);
for glyph in group {
let x_advance = face.convert(self.props.size, glyph.x_advance);
let x_offset = face.convert(self.props.size, glyph.x_offset);
text.glyphs.push(Glyph { id: glyph.id, x_advance, x_offset });
let x_advance = face.convert(glyph.x_advance).scale(self.props.size);
let x_offset = face.convert(glyph.x_offset).scale(self.props.size);
text.glyphs.push(Glyph { id: glyph.glyph_id, x_advance, x_offset });
x += x_advance;
}
@ -218,7 +217,7 @@ fn shape_segment<'a>(
});
// Shape!
let buffer = rustybuzz::shape(loader.face(face_id).buzz(), &[], buffer);
let buffer = rustybuzz::shape(loader.face(face_id).ttf(), &[], buffer);
let infos = buffer.glyph_infos();
let pos = buffer.glyph_positions();
@ -233,7 +232,7 @@ fn shape_segment<'a>(
// TODO: Don't ignore y_advance and y_offset.
glyphs.push(ShapedGlyph {
face_id,
id: GlyphId(info.codepoint as u16),
glyph_id: GlyphId(info.codepoint as u16),
x_advance: pos[i].x_advance,
x_offset: pos[i].x_offset,
text_index: base + cluster,
@ -306,8 +305,8 @@ fn measure(
let mut bottom = Length::ZERO;
let mut width = Length::ZERO;
let mut vertical = |face: &FaceBuf| {
top = top.max(face.vertical_metric(props.size, props.top_edge));
bottom = bottom.max(-face.vertical_metric(props.size, props.bottom_edge));
top = top.max(face.vertical_metric(props.top_edge).scale(props.size));
bottom = bottom.max(-face.vertical_metric(props.bottom_edge).scale(props.size));
};
if glyphs.is_empty() {
@ -325,7 +324,7 @@ fn measure(
vertical(face);
for glyph in group {
width += face.convert(props.size, glyph.x_advance);
width += face.convert(glyph.x_advance).scale(props.size);
}
}
}

39
src/pdf/mod.rs
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@ -15,6 +15,7 @@ use ttf_parser::{name_id, GlyphId};
use crate::color::Color;
use crate::env::{Env, ImageResource, ResourceId};
use crate::font::{EmLength, VerticalFontMetric};
use crate::geom::{self, Length, Size};
use crate::layout::{Element, Fill, Frame, Image, Shape};
@ -234,24 +235,18 @@ impl<'a> PdfExporter<'a> {
flags.insert(FontFlags::SYMBOLIC);
flags.insert(FontFlags::SMALL_CAP);
// Convert from OpenType font units to PDF glyph units.
let em_per_unit = 1.0 / ttf.units_per_em().unwrap_or(1000) as f32;
let convert = |font_unit: f32| (1000.0 * em_per_unit * font_unit).round();
let convert_i16 = |font_unit: i16| convert(font_unit as f32);
let convert_u16 = |font_unit: u16| convert(font_unit as f32);
let global_bbox = ttf.global_bounding_box();
let bbox = Rect::new(
convert_i16(global_bbox.x_min),
convert_i16(global_bbox.y_min),
convert_i16(global_bbox.x_max),
convert_i16(global_bbox.y_max),
face.convert(global_bbox.x_min).to_pdf(),
face.convert(global_bbox.y_min).to_pdf(),
face.convert(global_bbox.x_max).to_pdf(),
face.convert(global_bbox.y_max).to_pdf(),
);
let italic_angle = ttf.italic_angle().unwrap_or(0.0);
let ascender = convert_i16(ttf.typographic_ascender().unwrap_or(0));
let descender = convert_i16(ttf.typographic_descender().unwrap_or(0));
let cap_height = ttf.capital_height().map(convert_i16);
let ascender = face.vertical_metric(VerticalFontMetric::Ascender).to_pdf();
let descender = face.vertical_metric(VerticalFontMetric::Descender).to_pdf();
let cap_height = face.vertical_metric(VerticalFontMetric::CapHeight).to_pdf();
let stem_v = 10.0 + 0.244 * (f32::from(ttf.weight().to_number()) - 50.0);
// Write the base font object referencing the CID font.
@ -272,8 +267,8 @@ impl<'a> PdfExporter<'a> {
.individual(0, {
let num_glyphs = ttf.number_of_glyphs();
(0 .. num_glyphs).map(|g| {
let advance = ttf.glyph_hor_advance(GlyphId(g));
convert_u16(advance.unwrap_or(0))
let x = ttf.glyph_hor_advance(GlyphId(g)).unwrap_or(0);
face.convert(x).to_pdf()
})
});
@ -286,7 +281,7 @@ impl<'a> PdfExporter<'a> {
.italic_angle(italic_angle)
.ascent(ascender)
.descent(descender)
.cap_height(cap_height.unwrap_or(ascender))
.cap_height(cap_height)
.stem_v(stem_v)
.font_file2(refs.data);
@ -571,3 +566,15 @@ where
self.to_layout.iter().copied()
}
}
/// Additional methods for [`EmLength`].
trait EmLengthExt {
/// Convert an em length to a number of PDF font units.
fn to_pdf(self) -> f32;
}
impl EmLengthExt for EmLength {
fn to_pdf(self) -> f32 {
1000.0 * self.get() as f32
}
}

5
tests/typeset.rs
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@ -418,9 +418,8 @@ fn draw_text(canvas: &mut Pixmap, env: &Env, ts: Transform, shaped: &Text) {
let mut x = 0.0;
for glyph in &shaped.glyphs {
let units_per_em = ttf.units_per_em().unwrap_or(1000);
let s = (shaped.size / units_per_em as f64).to_pt() as f32;
let units_per_em = ttf.units_per_em();
let s = shaped.size.to_pt() as f32 / units_per_em as f32;
let dx = glyph.x_offset.to_pt() as f32;
let ts = ts.pre_translate(x + dx, 0.0);