Improve performance of layout lines

examples/text/src/font/layout.rs

@@ -1,7 +1,8 @@
 use core::marker::PhantomData;
 
+use super::FontLineIndex;
+
 pub struct FontLayoutGlyph<'a, T: 'a> {
-    pub line_i: usize,
     pub start: usize,
     pub end: usize,
     pub x: f32,
@@ -14,6 +15,7 @@ pub struct FontLayoutGlyph<'a, T: 'a> {
 }
 
 pub struct FontLayoutLine<'a> {
+    pub line_i: FontLineIndex,
     pub glyphs: Vec<FontLayoutGlyph<'a, ()>>,
 }
 

examples/text/src/font/matches.rs

@@ -1,11 +1,11 @@
-use super::{Font, FontShapeGlyph, FontShapeLine, FontShapeSpan};
+use super::{Font, FontLineIndex, FontShapeGlyph, FontShapeLine, FontShapeSpan};
 
 pub struct FontMatches<'a> {
     pub fonts: Vec<&'a Font<'a>>,
 }
 
 impl<'a> FontMatches<'a> {
-    fn shape_span(&self, line_i: usize, line: &str, start_span: usize, end_span: usize) -> FontShapeSpan {
+    fn shape_span(&self, line: &str, start_span: usize, end_span: usize) -> FontShapeSpan {
         let span = &line[start_span..end_span];
 
         let mut spans_by_font = Vec::with_capacity(self.fonts.len());
@@ -44,7 +44,6 @@ impl<'a> FontMatches<'a> {
                 let inner = font.rusttype.glyph(rusttype::GlyphId(info.glyph_id as u16));
 
                 glyphs.push(FontShapeGlyph {
-                    line_i,
                     start: start_span + info.cluster as usize,
                     end: end_span, // Set later
                     x_advance,
@@ -114,7 +113,7 @@ impl<'a> FontMatches<'a> {
         spans_by_font.remove(least_misses_i).1
     }
 
-    pub fn shape_line(&self, line_i: usize, line: &str) -> FontShapeLine {
+    pub fn shape_line(&self, line_i: FontLineIndex, line: &str) -> FontShapeLine {
         use unicode_script::{Script, UnicodeScript};
 
         //TODO: more special handling of characters
@@ -130,7 +129,7 @@ impl<'a> FontMatches<'a> {
             let cur = c.script();
             if prev != cur && prev != Script::Unknown {
                 // No combination, start new span
-                spans.push(self.shape_span(line_i, line, start, i));
+                spans.push(self.shape_span(line, start, i));
                 start = i;
                 prev = Script::Unknown;
             } else {
@@ -138,7 +137,7 @@ impl<'a> FontMatches<'a> {
             }
         }
 
-        spans.push(self.shape_span(line_i, line, start, line.len()));
+        spans.push(self.shape_span(line, start, line.len()));
 
         let bidi = unicode_bidi::BidiInfo::new(line, None);
         let rtl = if bidi.paragraphs.is_empty() {
@@ -149,6 +148,7 @@ impl<'a> FontMatches<'a> {
         };
 
         FontShapeLine {
+            line_i,
             rtl,
             spans,
         }

examples/text/src/font/mod.rs

@@ -10,6 +10,19 @@ mod shape;
 pub use self::system::*;
 mod system;
 
+#[derive(Clone, Copy, Eq, PartialEq, Ord, PartialOrd)]
+pub struct FontLineIndex(usize);
+
+impl FontLineIndex {
+    pub fn new(index: usize) -> Self {
+        Self(index)
+    }
+
+    pub fn get(&self) -> usize {
+        self.0
+    }
+}
+
 pub struct Font<'a> {
     data: &'a [u8],
     pub rustybuzz: rustybuzz::Face<'a>,

examples/text/src/font/shape.rs

@@ -2,10 +2,9 @@
 use ab_glyph::Font;
 use core::marker::PhantomData;
 
-use super::{FontLayoutGlyph, FontLayoutLine};
+use super::{FontLayoutGlyph, FontLayoutLine, FontLineIndex};
 
 pub struct FontShapeGlyph<'a> {
-    pub line_i: usize,
     pub start: usize,
     pub end: usize,
     pub x_advance: f32,
@@ -26,12 +25,13 @@ pub struct FontShapeSpan<'a> {
 }
 
 pub struct FontShapeLine<'a> {
+    pub line_i: FontLineIndex,
     pub rtl: bool,
     pub spans: Vec<FontShapeSpan<'a>>,
 }
 
 impl<'a> FontShapeLine<'a> {
-    pub fn layout(&self, font_size: i32, line_width: i32, lines: &mut Vec<FontLayoutLine<'a>>) {
+    pub fn layout(&self, font_size: i32, line_width: i32, layout_lines: &mut Vec<FontLayoutLine<'a>>, mut layout_i: usize) {
         let mut push_line = true;
         let mut glyphs = Vec::new();
 
@@ -62,7 +62,10 @@ impl<'a> FontShapeLine<'a> {
                     if x < 0.0 {
                         let mut glyphs_swap = Vec::new();
                         std::mem::swap(&mut glyphs, &mut glyphs_swap);
-                        lines.push(FontLayoutLine { glyphs: glyphs_swap });
+                        layout_lines.push(FontLayoutLine {
+                            line_i: self.line_i,
+                            glyphs: glyphs_swap
+                        });
 
                         x = line_width as f32 - x_advance;
                         y = 0.0;
@@ -71,8 +74,11 @@ impl<'a> FontShapeLine<'a> {
                     if x + x_advance > line_width as f32 {
                         let mut glyphs_swap = Vec::new();
                         std::mem::swap(&mut glyphs, &mut glyphs_swap);
-                        lines.push(FontLayoutLine { glyphs: glyphs_swap });
-                        push_line = false;
+                        layout_lines.insert(layout_i, FontLayoutLine {
+                            line_i: self.line_i,
+                            glyphs: glyphs_swap
+                        });
+                        layout_i += 1;
 
                         x = 0.0;
                         y = 0.0;
@@ -99,7 +105,6 @@ impl<'a> FontShapeLine<'a> {
                     ));
 
                 glyphs.push(FontLayoutGlyph {
-                    line_i: glyph.line_i,
                     start: glyph.start,
                     end: glyph.end,
                     x,
@@ -119,7 +124,11 @@ impl<'a> FontShapeLine<'a> {
         }
 
         if push_line {
-            lines.push(FontLayoutLine { glyphs });
+            layout_lines.insert(layout_i, FontLayoutLine {
+                line_i: self.line_i,
+                glyphs
+            });
+            layout_i += 1;
         }
     }
 }