Add background styling to span / rich text

7 files changed, 141 insertions, 16 deletions

diff --git a/core/src/renderer/null.rs b/core/src/renderer/null.rs
index d8d3c50a..5c7513c6 100644
--- a/core/src/renderer/null.rs
+++ b/core/src/renderer/null.rs
@@ -111,6 +111,10 @@ impl text::Paragraph for () {
     fn hit_span(&self, _point: Point) -> Option<usize> {
         None
     }
+
+    fn span_bounds(&self, _index: usize) -> Vec<Rectangle> {
+        vec![]
+    }
 }
 
 impl text::Editor for () {
diff --git a/core/src/text.rs b/core/src/text.rs
index aa24d85f..0bdc6851 100644
--- a/core/src/text.rs
+++ b/core/src/text.rs
@@ -8,7 +8,7 @@ pub use highlighter::Highlighter;
 pub use paragraph::Paragraph;
 
 use crate::alignment;
-use crate::{Color, Pixels, Point, Rectangle, Size};
+use crate::{Border, Color, Pixels, Point, Rectangle, Size};
 
 use std::borrow::Cow;
 use std::hash::{Hash, Hasher};
@@ -235,6 +235,8 @@ pub struct Span<'a, Link = (), Font = crate::Font> {
     pub font: Option<Font>,
     /// The [`Color`] of the [`Span`].
     pub color: Option<Color>,
+    /// The [`Background`] of the [`Span`].
+    pub background: Option<Background>,
     /// The link of the [`Span`].
     pub link: Option<Link>,
 }
@@ -248,6 +250,7 @@ impl<'a, Link, Font> Span<'a, Link, Font> {
             line_height: None,
             font: None,
             color: None,
+            background: None,
             link: None,
         }
     }
@@ -288,6 +291,21 @@ impl<'a, Link, Font> Span<'a, Link, Font> {
         self
     }
 
+    /// Sets the [`Background`] of the [`Span`].
+    pub fn background(mut self, background: impl Into<Background>) -> Self {
+        self.background = Some(background.into());
+        self
+    }
+
+    /// Sets the [`Background`] of the [`Span`], if any.
+    pub fn background_maybe(
+        mut self,
+        background: Option<impl Into<Background>>,
+    ) -> Self {
+        self.background = background.map(Into::into);
+        self
+    }
+
     /// Sets the link of the [`Span`].
     pub fn link(mut self, link: impl Into<Link>) -> Self {
         self.link = Some(link.into());
@@ -308,6 +326,7 @@ impl<'a, Link, Font> Span<'a, Link, Font> {
             line_height: self.line_height,
             font: self.font,
             color: self.color,
+            background: self.background,
             link: self.link,
         }
     }
@@ -406,3 +425,21 @@ into_fragment!(isize);
 
 into_fragment!(f32);
 into_fragment!(f64);
+
+/// The background style of text
+#[derive(Debug, Clone, Copy)]
+pub struct Background {
+    /// The background [`Color`]
+    pub color: Color,
+    /// The background [`Border`]
+    pub border: Border,
+}
+
+impl From<Color> for Background {
+    fn from(color: Color) -> Self {
+        Background {
+            color,
+            border: Border::default(),
+        }
+    }
+}
diff --git a/core/src/text/paragraph.rs b/core/src/text/paragraph.rs
index 26650793..04a97f35 100644
--- a/core/src/text/paragraph.rs
+++ b/core/src/text/paragraph.rs
@@ -1,7 +1,7 @@
 //! Draw paragraphs.
 use crate::alignment;
 use crate::text::{Difference, Hit, Span, Text};
-use crate::{Point, Size};
+use crate::{Point, Rectangle, Size};
 
 /// A text paragraph.
 pub trait Paragraph: Sized + Default {
@@ -42,6 +42,10 @@ pub trait Paragraph: Sized + Default {
     /// that was hit.
     fn hit_span(&self, point: Point) -> Option<usize>;
 
+    /// Returns all bounds for the provided [`Span`] index of the [`Paragraph`].
+    /// A [`Span`] can have multiple bounds for each line it's on.
+    fn span_bounds(&self, index: usize) -> Vec<Rectangle>;
+
     /// Returns the distance to the given grapheme index in the [`Paragraph`].
     fn grapheme_position(&self, line: usize, index: usize) -> Option<Point>;
 
diff --git a/examples/markdown/src/main.rs b/examples/markdown/src/main.rs
index 173cb389..db40d0b9 100644
--- a/examples/markdown/src/main.rs
+++ b/examples/markdown/src/main.rs
@@ -28,8 +28,11 @@ impl Markdown {
         (
             Self {
                 content: text_editor::Content::with_text(INITIAL_CONTENT),
-                items: markdown::parse(INITIAL_CONTENT, theme.palette())
-                    .collect(),
+                items: markdown::parse(
+                    INITIAL_CONTENT,
+                    theme.extended_palette(),
+                )
+                .collect(),
                 theme,
             },
             widget::focus_next(),
@@ -46,7 +49,7 @@ impl Markdown {
                 if is_edit {
                     self.items = markdown::parse(
                         &self.content.text(),
-                        self.theme.palette(),
+                        self.theme.extended_palette(),
                     )
                     .collect();
                 }
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;
 
diff --git a/widget/src/markdown.rs b/widget/src/markdown.rs
index 9cfd3c33..6cd8535e 100644
--- a/widget/src/markdown.rs
+++ b/widget/src/markdown.rs
@@ -4,9 +4,12 @@
 //! in code blocks.
 //!
 //! Only the variants of [`Item`] are currently supported.
+use crate::core::border;
 use crate::core::font::{self, Font};
 use crate::core::padding;
-use crate::core::theme::{self, Theme};
+use crate::core::text::Background;
+use crate::core::theme::palette;
+use crate::core::theme::Theme;
 use crate::core::{self, Element, Length, Pixels};
 use crate::{column, container, rich_text, row, scrollable, span, text};
 
@@ -34,10 +37,10 @@ pub enum Item {
 }
 
 /// Parse the given Markdown content.
-pub fn parse(
-    markdown: &str,
-    palette: theme::Palette,
-) -> impl Iterator<Item = Item> + '_ {
+pub fn parse<'a>(
+    markdown: &'a str,
+    palette: &'a palette::Extended,
+) -> impl Iterator<Item = Item> + 'a {
     struct List {
         start: Option<u64>,
         items: Vec<Vec<Item>>,
@@ -247,7 +250,7 @@ pub fn parse(
             };
 
             let span = if let Some(link) = link.as_ref() {
-                span.color(palette.primary).link(link.clone())
+                span.color(palette.primary.base.color).link(link.clone())
             } else {
                 span
             };
@@ -257,10 +260,15 @@ pub fn parse(
             None
         }
         pulldown_cmark::Event::Code(code) if !metadata && !table => {
-            let span = span(code.into_string()).font(Font::MONOSPACE);
+            let span = span(code.into_string())
+                .font(Font::MONOSPACE)
+                .background(Background {
+                    color: palette.background.weak.color,
+                    border: border::rounded(2),
+                });
 
             let span = if let Some(link) = link.as_ref() {
-                span.color(palette.primary).link(link.clone())
+                span.color(palette.primary.base.color).link(link.clone())
             } else {
                 span
             };
diff --git a/widget/src/text/rich.rs b/widget/src/text/rich.rs
index 9c0e2fac..832a3ae7 100644
--- a/widget/src/text/rich.rs
+++ b/widget/src/text/rich.rs
@@ -9,8 +9,8 @@ use crate::core::widget::text::{
 };
 use crate::core::widget::tree::{self, Tree};
 use crate::core::{
-    self, Clipboard, Color, Element, Event, Layout, Length, Pixels, Rectangle,
-    Shell, Size, Widget,
+    self, Clipboard, Color, Element, Event, Layout, Length, Pixels, Point,
+    Rectangle, Shell, Size, Widget,
 };
 
 use std::borrow::Cow;
@@ -246,6 +246,24 @@ where
 
         let style = theme.style(&self.class);
 
+        // Draw backgrounds
+        for (index, span) in self.spans.iter().enumerate() {
+            if let Some(background) = span.background {
+                let translation = layout.position() - Point::ORIGIN;
+
+                for bounds in state.paragraph.span_bounds(index) {
+                    renderer.fill_quad(
+                        renderer::Quad {
+                            bounds: bounds + translation,
+                            border: background.border,
+                            ..Default::default()
+                        },
+                        background.color,
+                    );
+                }
+            }
+        }
+
         text::draw(
             renderer,
             defaults,