[WIP] Vertical alignment

examples/swash_render/src/main.rs

@@ -52,7 +52,7 @@ fn main() {
     let bg_color = Rgba([255, 255, 255, 255]);
 
     // Padding around the output image
-    let padding = 20;
+    let padding = (20f32 * display_scale).round() as u32;
 
     // Create a FontContext, LayoutContext and ScaleContext
     //
@@ -92,21 +92,21 @@ fn main() {
 
         builder.push_text(&text[5..40]);
 
-        builder.push_inline_box(InlineBox {
-            id: 0,
-            index: 0,
-            width: 50.0,
-            height: 50.0,
-        });
+        builder.push_inline_box(InlineBox::new(
+            0,
+            0,
+            50.0 * display_scale,
+            50.0 * display_scale,
+        ));
 
         builder.push_text(&text[40..50]);
 
-        builder.push_inline_box(InlineBox {
-            id: 1,
-            index: 50,
-            width: 50.0,
-            height: 30.0,
-        });
+        builder.push_inline_box(InlineBox::new(
+            1,
+            50,
+            50.0 * display_scale,
+            30.0 * display_scale,
+        ));
 
         builder.push_text(&text[50..141]);
 
@@ -147,18 +147,18 @@ fn main() {
         builder.push(underline_style, 141..150);
         builder.push(strikethrough_style, 155..168);
 
-        builder.push_inline_box(InlineBox {
-            id: 0,
-            index: 40,
-            width: 50.0,
-            height: 50.0,
-        });
-        builder.push_inline_box(InlineBox {
-            id: 1,
-            index: 50,
-            width: 50.0,
-            height: 30.0,
-        });
+        builder.push_inline_box(InlineBox::new(
+            0,
+            40,
+            50.0 * display_scale,
+            50.0 * display_scale,
+        ));
+        builder.push_inline_box(InlineBox::new(
+            1,
+            50,
+            50.0 * display_scale,
+            30.0 * display_scale,
+        ));
 
         // Build the builder into a Layout
         // let mut layout: Layout<ColorBrush> = builder.build(&text);

examples/tiny_skia_render/src/main.rs

@@ -87,12 +87,7 @@ fn main() {
     builder.push(StyleProperty::Underline(true), 141..150);
     builder.push(StyleProperty::Strikethrough(true), 155..168);
 
-    builder.push_inline_box(InlineBox {
-        id: 0,
-        index: 40,
-        width: 50.0,
-        height: 50.0,
-    });
+    builder.push_inline_box(InlineBox::new(0, 40, 50.0, 50.0));
 
     // Build the builder into a Layout
     let mut layout: Layout<ColorBrush> = builder.build(&text);

parley/src/inline_box.rs

@@ -1,6 +1,8 @@
 // Copyright 2024 the Parley Authors
 // SPDX-License-Identifier: Apache-2.0 OR MIT
 
+use crate::{ResolvedBaselineShift, VerticalAlign};
+
 /// A box to be laid out inline with text
 #[derive(Debug, Clone)]
 pub struct InlineBox {
@@ -14,4 +16,21 @@ pub struct InlineBox {
     pub width: f32,
     /// The height of the box in pixels
     pub height: f32,
+    /// The baseline along which this item is aligned.
+    pub vertical_align: VerticalAlign,
+    /// Additional baseline alignment applied afterwards.
+    pub baseline_shift: ResolvedBaselineShift,
+}
+
+impl InlineBox {
+    pub fn new(id: u64, index: usize, width: f32, height: f32) -> Self {
+        Self {
+            id,
+            index,
+            width,
+            height,
+            vertical_align: Default::default(),
+            baseline_shift: Default::default(),
+        }
+    }
 }

parley/src/layout/data.rs

@@ -86,6 +86,40 @@ pub(crate) struct RunData {
     pub(crate) advance: f32,
 }
 
+impl RunData {
+    pub(crate) fn unique_styles<'a, 'b, B: Brush>(
+        &'a self,
+        layout: &'b LayoutData<B>,
+        mut cb: impl FnMut(&'b Style<B>),
+    ) {
+        let glyph_start = self.glyph_start;
+        for cluster in &layout.clusters[self.cluster_range.clone()] {
+            if cluster.glyph_len != 0xFF && cluster.has_divergent_styles() {
+                let mut start = glyph_start + cluster.glyph_offset as usize;
+                let end = start + cluster.glyph_len as usize;
+
+                'runs: loop {
+                    let start_glyph = &layout.glyphs[start];
+                    cb(&layout.styles[start_glyph.style_index()]);
+
+                    loop {
+                        start += 1;
+
+                        if start >= end {
+                            break 'runs;
+                        }
+                        if layout.glyphs[start].style_index != start_glyph.style_index {
+                            break;
+                        }
+                    }
+                }
+            } else {
+                cb(&layout.styles[cluster.style_index as usize]);
+            }
+        }
+    }
+}
+
 #[derive(Copy, Clone, Default, PartialEq, Debug)]
 pub enum BreakReason {
     #[default]
@@ -335,6 +369,8 @@ impl<B: Brush> LayoutData<B> {
                 ascent: metrics.ascent,
                 descent: metrics.descent,
                 leading: metrics.leading,
+                x_height: metrics.x_height,
+                font_size,
                 underline_offset: metrics.underline_offset,
                 underline_size: metrics.stroke_size,
                 strikethrough_offset: metrics.strikeout_offset,