Add external span IDs

Signed-off-by: Nico Burns <[email protected]>

examples/swash_render/src/main.rs

@@ -81,9 +81,9 @@ fn main() {
             ..Default::default()
         };
 
-        let mut builder = layout_cx.tree_builder(&mut font_cx, display_scale, &root_style);
+        let mut builder = layout_cx.tree_builder(&mut font_cx, display_scale, 0, &root_style);
 
-        builder.push_style_modification_span(&[bold_style]);
+        builder.push_style_modification_span(1, &[bold_style]);
         builder.push_text(&text[0..5]);
         builder.pop_style_span();
 
@@ -108,14 +108,14 @@ fn main() {
         builder.push_text(&text[50..141]);
 
         // Set the underline style
-        builder.push_style_modification_span(&[underline_style]);
+        builder.push_style_modification_span(2, &[underline_style]);
         builder.push_text(&text[141..150]);
 
         builder.pop_style_span();
         builder.push_text(&text[150..155]);
 
         // Set the strikethrough style
-        builder.push_style_modification_span(&[strikethrough_style]);
+        builder.push_style_modification_span(3, &[strikethrough_style]);
         builder.push_text(&text[155..168]);
 
         // Build the builder into a Layout

parley/src/builder.rs

@@ -69,22 +69,24 @@ pub struct TreeBuilder<'a, B: Brush> {
 }
 
 impl<B: Brush> TreeBuilder<'_, B> {
-    pub fn push_style_span(&mut self, style: TextStyle<'_, B>) {
+    pub fn push_style_span(&mut self, id: u64, style: TextStyle<'_, B>) {
         let resolved = self
             .lcx
             .rcx
             .resolve_entire_style_set(self.fcx, &style, self.scale);
-        self.lcx.tree_style_builder.push_style_span(resolved);
+        self.lcx.tree_style_builder.push_style_span(id, resolved);
     }
 
     pub fn push_style_modification_span<'s, 'iter>(
         &mut self,
+        id: u64,
         properties: impl IntoIterator<Item = &'iter StyleProperty<'s, B>>,
     ) where
         's: 'iter,
         B: 'iter,
     {
         self.lcx.tree_style_builder.push_style_modification_span(
+            id,
             properties
                 .into_iter()
                 .map(|p| self.lcx.rcx.resolve_property(self.fcx, p, self.scale)),
@@ -156,7 +158,7 @@ fn build_into_layout<B: Brush>(
     layout
         .data
         .styles
-        .extend(lcx.styles.iter().map(|s| s.style.as_layout_style()));
+        .extend(lcx.styles.iter().map(|s| s.as_layout_style()));
 
     // Sort the inline boxes as subsequent code assumes that they are in text index order.
     // Note: It's important that this is a stable sort to allow users to control the order of contiguous inline boxes

parley/src/context.rs

@@ -83,12 +83,14 @@ impl<B: Brush> LayoutContext<B> {
         &'a mut self,
         fcx: &'a mut FontContext,
         scale: f32,
+        root_node_id: u64,
         raw_style: &TextStyle<'_, B>,
     ) -> TreeBuilder<'a, B> {
         self.begin();
 
         let resolved_root_style = self.resolve_style_set(fcx, scale, raw_style);
-        self.tree_style_builder.begin(resolved_root_style);
+        self.tree_style_builder
+            .begin(root_node_id, resolved_root_style);
 
         fcx.source_cache.prune(128, false);
 

parley/src/layout/cluster.rs

@@ -90,6 +90,14 @@ impl<'a, B: Brush> Cluster<'a, B> {
         self.run.clone()
     }
 
+    /// The external ID associated with the cluster.
+    ///    - For layouts built with the `RangedBuilder` this will always be 0
+    ///    - For layouts built with the `TreeBuilder` this will the ID associated with the
+    ///      deepest style span that contains this cluster.
+    pub fn external_span_id(&self) -> u64 {
+        self.run.layout.data.styles[self.data.style_index as usize].id
+    }
+
     /// Returns the path that contains the set of indices to reach the cluster
     /// from a layout.
     pub fn path(&self) -> ClusterPath {

parley/src/layout/mod.rs

@@ -249,6 +249,8 @@ pub struct Line<'a, B: Brush> {
 /// Style properties.
 #[derive(Clone, Debug)]
 pub struct Style<B: Brush> {
+    /// External ID for the style span
+    pub id: u64,
     /// Brush for drawing glyphs.
     pub brush: B,
     /// Underline decoration.

parley/src/resolve/mod.rs

@@ -26,10 +26,24 @@ use swash::text::Language;
 /// Style with an associated range.
 #[derive(Debug, Clone)]
 pub(crate) struct RangedStyle<B: Brush> {
+    pub(crate) id: u64,
     pub(crate) style: ResolvedStyle<B>,
     pub(crate) range: Range<usize>,
 }
 
+impl<B: Brush> RangedStyle<B> {
+    pub(crate) fn as_layout_style(&self) -> layout::Style<B> {
+        let style = &self.style;
+        layout::Style {
+            id: self.id,
+            brush: style.brush.clone(),
+            underline: style.underline.as_layout_decoration(&style.brush),
+            strikethrough: style.strikethrough.as_layout_decoration(&style.brush),
+            line_height: style.line_height * style.font_size,
+        }
+    }
+}
+
 #[derive(Clone)]
 struct RangedProperty<B: Brush> {
     property: ResolvedProperty<B>,
@@ -475,15 +489,6 @@ impl<B: Brush> ResolvedStyle<B> {
             LetterSpacing(value) => nearly_eq(self.letter_spacing, *value),
         }
     }
-
-    pub(crate) fn as_layout_style(&self) -> layout::Style<B> {
-        layout::Style {
-            brush: self.brush.clone(),
-            underline: self.underline.as_layout_decoration(&self.brush),
-            strikethrough: self.strikethrough.as_layout_decoration(&self.brush),
-            line_height: self.line_height * self.font_size,
-        }
-    }
 }
 
 /// Underline or strikethrough decoration.

parley/src/resolve/range.rs

@@ -57,6 +57,8 @@ impl<B: Brush> RangedStyleBuilder<B> {
             return;
         }
         styles.push(RangedStyle {
+            // TODO: Implement external IDs for RangedBuilder
+            id: 0,
             style: self.default_style.clone(),
             range: 0..self.len,
         });

parley/src/resolve/tree.rs

@@ -11,7 +11,11 @@ use super::{Brush, RangedStyle, ResolvedProperty, ResolvedStyle};
 
 #[derive(Debug, Clone)]
 struct StyleTreeNode<B: Brush> {
-    parent: Option<usize>,
+    // An external id provided by the user
+    id: u64,
+    // The index of the parent in the tree Vec (*not* the id of the parent node)
+    parent_idx: Option<usize>,
+    // The styles associated with the node
     style: ResolvedStyle<B>,
 }
 
@@ -28,6 +32,9 @@ pub(crate) struct TreeStyleBuilder<B: Brush> {
 }
 
 impl<B: Brush> TreeStyleBuilder<B> {
+    fn current_span_id(&self) -> u64 {
+        self.tree[self.current_span].id
+    }
     fn current_style(&self) -> ResolvedStyle<B> {
         self.tree[self.current_span].style.clone()
     }
@@ -49,15 +56,16 @@ impl<B: Brush> Default for TreeStyleBuilder<B> {
 
 impl<B: Brush> TreeStyleBuilder<B> {
     /// Prepares the builder for accepting a style tree for text of the specified length.
-    pub(crate) fn begin(&mut self, root_style: ResolvedStyle<B>) {
+    pub(crate) fn begin(&mut self, id: u64, root_style: ResolvedStyle<B>) {
         self.tree.clear();
         self.flatted_styles.clear();
         self.white_space_collapse = WhiteSpaceCollapse::Preserve;
         self.text.clear();
         self.uncommitted_text.clear();
 
         self.tree.push(StyleTreeNode {
-            parent: None,
+            id,
+            parent_idx: None,
             style: root_style,
         });
         self.current_span = 0;
@@ -113,8 +121,9 @@ impl<B: Brush> TreeStyleBuilder<B> {
         }
 
         let range = self.text.len()..(self.text.len() + span_text.len());
+        let id = self.current_span_id();
         let style = self.current_style();
-        self.flatted_styles.push(RangedStyle { style, range });
+        self.flatted_styles.push(RangedStyle { id, style, range });
         self.text.push_str(span_text);
         self.uncommitted_text.clear();
         self.is_span_first = false;
@@ -124,11 +133,12 @@ impl<B: Brush> TreeStyleBuilder<B> {
         self.text.len()
     }
 
-    pub(crate) fn push_style_span(&mut self, style: ResolvedStyle<B>) {
+    pub(crate) fn push_style_span(&mut self, id: u64, style: ResolvedStyle<B>) {
         self.push_uncommitted_text(false);
 
         self.tree.push(StyleTreeNode {
-            parent: Some(self.current_span),
+            id,
+            parent_idx: Some(self.current_span),
             style,
         });
         self.current_span = self.tree.len() - 1;
@@ -137,20 +147,21 @@ impl<B: Brush> TreeStyleBuilder<B> {
 
     pub(crate) fn push_style_modification_span(
         &mut self,
+        id: u64,
         properties: impl Iterator<Item = ResolvedProperty<B>>,
     ) {
         let mut style = self.current_style();
         for prop in properties {
             style.apply(prop.clone());
         }
-        self.push_style_span(style);
+        self.push_style_span(id, style);
     }
 
     pub(crate) fn pop_style_span(&mut self) {
         self.push_uncommitted_text(true);
 
         self.current_span = self.tree[self.current_span]
-            .parent
+            .parent_idx
             .expect("Popped root style");
     }
 
@@ -163,7 +174,7 @@ impl<B: Brush> TreeStyleBuilder<B> {
 
     /// Computes the sequence of ranged styles.
     pub(crate) fn finish(&mut self, styles: &mut Vec<RangedStyle<B>>) -> String {
-        while self.tree[self.current_span].parent.is_some() {
+        while self.tree[self.current_span].parent_idx.is_some() {
             self.pop_style_span();
         }