Add background styling to span / rich text

1 files changed, 52 insertions, 1 deletions

diff --git a/graphics/src/text/paragraph.rs b/graphics/src/text/paragraph.rs
index da703ceb..540e669b 100644
--- a/graphics/src/text/paragraph.rs
+++ b/graphics/src/text/paragraph.rs
@@ -2,7 +2,7 @@
 use crate::core;
 use crate::core::alignment;
 use crate::core::text::{Hit, Shaping, Span, Text};
-use crate::core::{Font, Point, Size};
+use crate::core::{Font, Point, Rectangle, Size};
 use crate::text;
 
 use std::fmt;
@@ -251,6 +251,57 @@ impl core::text::Paragraph for Paragraph {
         Some(glyph.metadata)
     }
 
+    fn span_bounds(&self, index: usize) -> Vec<Rectangle> {
+        let internal = self.internal();
+
+        let mut current_bounds = None;
+
+        let mut bounds = internal
+            .buffer
+            .layout_runs()
+            .flat_map(|run| {
+                let line_top = run.line_top;
+                let line_height = run.line_height;
+
+                run.glyphs
+                    .iter()
+                    .map(move |glyph| (line_top, line_height, glyph))
+            })
+            .skip_while(|(_, _, glyph)| glyph.metadata != index)
+            .take_while(|(_, _, glyph)| glyph.metadata == index)
+            .fold(vec![], |mut spans, (line_top, line_height, glyph)| {
+                let y = line_top + glyph.y;
+
+                let new_bounds = || {
+                    Rectangle::new(
+                        Point::new(glyph.x, y),
+                        Size::new(
+                            glyph.w,
+                            glyph.line_height_opt.unwrap_or(line_height),
+                        ),
+                    )
+                };
+
+                match current_bounds.as_mut() {
+                    None => {
+                        current_bounds = Some(new_bounds());
+                    }
+                    Some(bounds) if y != bounds.y => {
+                        spans.push(*bounds);
+                        *bounds = new_bounds();
+                    }
+                    Some(bounds) => {
+                        bounds.width += glyph.w;
+                    }
+                }
+
+                spans
+            });
+
+        bounds.extend(current_bounds);
+        bounds
+    }
+
     fn grapheme_position(&self, line: usize, index: usize) -> Option<Point> {
         use unicode_segmentation::UnicodeSegmentation;