Refactor text shaping

crates/types/src/lib.rs

@@ -58,6 +58,17 @@ pub enum CursorEventKind {
     Deselect = 3,
 }
 
+#[repr(C)]
+#[derive(Copy, Clone, Debug, Pod, Zeroable)]
+pub struct GlyphPosition {
+    pub face: u16,
+    pub index: u16,
+    pub hori_advance: i32,
+    pub vert_advance: i32,
+    pub xoff: i32,
+    pub yoff: i32,
+}
+
 #[cfg(feature = "glam")]
 mod glam_interop {
     use super::*;

src/text.rs

@@ -10,6 +10,7 @@ use allsorts::pathfinder_geometry::{line_segment::LineSegment2F, vector::Vector2
 use allsorts::tables::{glyf::GlyfTable, loca::LocaTable};
 use allsorts::tables::{FontTableProvider, SfntVersion};
 use allsorts::{tag, Font as AllsortsFont};
+use canary_types::GlyphPosition;
 use lyon::path::Path;
 use ouroboros::self_referencing;
 
@@ -131,6 +132,10 @@ pub struct GlyphMesh {
 #[self_referencing]
 pub struct Font {
     file_buffer: Vec<u8>,
+    face_index: u16,
+    script: u32,
+    direction: TextDirection,
+    vertical: bool,
 
     #[borrows(file_buffer)]
     #[covariant]
@@ -146,9 +151,19 @@ pub struct Font {
 }
 
 impl Font {
-    pub fn load(file_buffer: Vec<u8>) -> Self {
+    pub fn load(
+        face_index: u16,
+        script: u32,
+        direction: TextDirection,
+        vertical: bool,
+        file_buffer: Vec<u8>,
+    ) -> Self {
         FontBuilder {
             file_buffer,
+            face_index,
+            script,
+            direction,
+            vertical,
             read_scope_builder: |buffer| ReadScope::new(buffer),
             font_data_builder: |scope| scope.read::<FontData<'_>>().unwrap(),
             inner_builder: |font_data| {
@@ -163,6 +178,39 @@ impl Font {
     pub fn create_glyph_cache(&self) -> GlyphCache {
         GlyphCache::new(self.borrow_inner())
     }
+
+    pub fn shape(&mut self, text: &str) -> Vec<GlyphPosition> {
+        let face_index = *self.borrow_face_index() as u16;
+        let presentation = MatchingPresentation::Required;
+        let script = *self.borrow_script();
+        let lang_tag = None;
+        let features = allsorts::gsub::Features::default();
+        let kerning = true;
+        let direction = *self.borrow_direction();
+        let vertical = *self.borrow_vertical();
+
+        self.with_inner_mut(|font| {
+            let mapped = font.map_glyphs(text, script, presentation);
+            let infos = font
+                .shape(mapped, script, lang_tag, &features, kerning)
+                .unwrap();
+            let mut layout = GlyphLayout::new(font, &infos, direction, vertical);
+            let positions = layout.glyph_positions().unwrap();
+            let mut glyphs = Vec::with_capacity(positions.len());
+            for (glyph, position) in infos.iter().zip(&positions) {
+                glyphs.push(GlyphPosition {
+                    face: face_index,
+                    index: glyph.glyph.glyph_index,
+                    hori_advance: position.hori_advance,
+                    vert_advance: position.vert_advance,
+                    xoff: position.x_offset,
+                    yoff: position.y_offset,
+                });
+            }
+
+            glyphs
+        })
+    }
 }
 
 pub struct DummyText {
@@ -173,29 +221,17 @@ pub struct DummyText {
 impl Default for DummyText {
     fn default() -> Self {
         let script = tag::LATN;
-        let buffer = include_bytes!("linja-pona-4.9.otf");
-        let text = "toki o! nimi mi li [_mun_alasa_sona]. toki+pona li pona.";
-        let mut font = Font::load(buffer.to_vec());
-        let mut cache = font.create_glyph_cache();
-
-        let glyphs = font
-            .with_inner_mut(|font| font.map_glyphs(&text, script, MatchingPresentation::Required));
-
-        let lang_tag = None;
-        let features = allsorts::gsub::Features::default();
-        let kerning = true;
-        let infos = font.with_inner_mut(|font| {
-            font.shape(glyphs, script, lang_tag, &features, kerning)
-                .unwrap()
-        });
-
+        let face_index = 0;
         let direction = TextDirection::LeftToRight;
         let vertical = false;
+        let buffer = include_bytes!("linja-pona-4.9.otf");
+        let mut font = Font::load(face_index, script, direction, vertical, buffer.to_vec());
 
-        let positions = font.with_inner_mut(|font| {
-            let mut layout = GlyphLayout::new(font, &infos, direction, vertical);
-            layout.glyph_positions().unwrap()
-        });
+        let mut cache = font.create_glyph_cache();
+
+        let text = "toki o! nimi mi li [_mun_alasa_sona]. toki+pona li pona.";
+
+        let glyphs = font.shape(text);
 
         let mut mesh = Self {
             vertices: Vec::new(),
@@ -204,12 +240,12 @@ impl Default for DummyText {
 
         let mut xcur = 0;
         let mut ycur = 0;
-        for (glyph, position) in infos.iter().zip(&positions) {
-            let xpos = xcur + position.x_offset;
-            let ypos = ycur + position.y_offset;
-            xcur += position.hori_advance;
-            ycur += position.vert_advance;
-            cache.draw(&mut mesh, glyph.glyph.glyph_index, xpos, ypos);
+        for glyph in glyphs.iter() {
+            let xpos = xcur + glyph.xoff;
+            let ypos = ycur + glyph.yoff;
+            xcur += glyph.hori_advance;
+            ycur += glyph.vert_advance;
+            cache.draw(&mut mesh, glyph.index, xpos, ypos);
         }
 
         mesh