Merge pull request #2516 from tarkah/feat/span-background

Add background styling to span / rich text

7 files changed, 201 insertions, 7 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/size.rs b/core/src/size.rs
index d7459355..95089236 100644
--- a/core/src/size.rs
+++ b/core/src/size.rs
@@ -99,6 +99,20 @@ impl<T> From<Size<T>> for Vector<T> {
     }
 }
 
+impl<T> std::ops::Add for Size<T>
+where
+    T: std::ops::Add<Output = T>,
+{
+    type Output = Size<T>;
+
+    fn add(self, rhs: Self) -> Self::Output {
+        Size {
+            width: self.width + rhs.width,
+            height: self.height + rhs.height,
+        }
+    }
+}
+
 impl<T> std::ops::Sub for Size<T>
 where
     T: std::ops::Sub<Output = T>,
diff --git a/core/src/text.rs b/core/src/text.rs
index aa24d85f..2f085bd8 100644
--- a/core/src/text.rs
+++ b/core/src/text.rs
@@ -8,7 +8,9 @@ pub use highlighter::Highlighter;
 pub use paragraph::Paragraph;
 
 use crate::alignment;
-use crate::{Color, Pixels, Point, Rectangle, Size};
+use crate::{
+    Background, Border, Color, Padding, Pixels, Point, Rectangle, Size,
+};
 
 use std::borrow::Cow;
 use std::hash::{Hash, Hasher};
@@ -237,6 +239,21 @@ pub struct Span<'a, Link = (), Font = crate::Font> {
     pub color: Option<Color>,
     /// The link of the [`Span`].
     pub link: Option<Link>,
+    /// The [`Highlight`] of the [`Span`].
+    pub highlight: Option<Highlight>,
+    /// The [`Padding`] of the [`Span`].
+    ///
+    /// Currently, it only affects the bounds of the [`Highlight`].
+    pub padding: Padding,
+}
+
+/// A text highlight.
+#[derive(Debug, Clone, Copy)]
+pub struct Highlight {
+    /// The [`Background`] of the highlight.
+    pub background: Background,
+    /// The [`Border`] of the highlight.
+    pub border: Border,
 }
 
 impl<'a, Link, Font> Span<'a, Link, Font> {
@@ -248,7 +265,9 @@ impl<'a, Link, Font> Span<'a, Link, Font> {
             line_height: None,
             font: None,
             color: None,
+            highlight: None,
             link: None,
+            padding: Padding::ZERO,
         }
     }
 
@@ -300,6 +319,73 @@ impl<'a, Link, Font> Span<'a, Link, Font> {
         self
     }
 
+    /// Sets the [`Background`] of the [`Span`].
+    pub fn background(self, background: impl Into<Background>) -> Self {
+        self.background_maybe(Some(background))
+    }
+
+    /// Sets the [`Background`] of the [`Span`], if any.
+    pub fn background_maybe(
+        mut self,
+        background: Option<impl Into<Background>>,
+    ) -> Self {
+        let Some(background) = background else {
+            return self;
+        };
+
+        match &mut self.highlight {
+            Some(highlight) => {
+                highlight.background = background.into();
+            }
+            None => {
+                self.highlight = Some(Highlight {
+                    background: background.into(),
+                    border: Border::default(),
+                });
+            }
+        }
+
+        self
+    }
+
+    /// Sets the [`Border`] of the [`Span`].
+    pub fn border(self, border: impl Into<Border>) -> Self {
+        self.border_maybe(Some(border))
+    }
+
+    /// Sets the [`Border`] of the [`Span`], if any.
+    pub fn border_maybe(mut self, border: Option<impl Into<Border>>) -> Self {
+        let Some(border) = border else {
+            return self;
+        };
+
+        match &mut self.highlight {
+            Some(highlight) => {
+                highlight.border = border.into();
+            }
+            None => {
+                self.highlight = Some(Highlight {
+                    border: border.into(),
+                    background: Background::Color(Color::TRANSPARENT),
+                });
+            }
+        }
+
+        self
+    }
+
+    /// Sets the [`Padding`] of the [`Span`].
+    ///
+    /// It only affects the [`background`] and [`border`] of the
+    /// [`Span`], currently.
+    ///
+    /// [`background`]: Self::background
+    /// [`border`]: Self::border
+    pub fn padding(mut self, padding: impl Into<Padding>) -> Self {
+        self.padding = padding.into();
+        self
+    }
+
     /// Turns the [`Span`] into a static one.
     pub fn to_static(self) -> Span<'static, Link, Font> {
         Span {
@@ -309,6 +395,8 @@ impl<'a, Link, Font> Span<'a, Link, Font> {
             font: self.font,
             color: self.color,
             link: self.link,
+            highlight: self.highlight,
+            padding: self.padding,
         }
     }
 }
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/graphics/src/text/paragraph.rs b/graphics/src/text/paragraph.rs
index da703ceb..b9f9c833 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 bounds = Vec::new();
+        let mut current_bounds = None;
+
+        let glyphs = 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);
+
+        for (line_top, line_height, glyph) in glyphs {
+            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(current_bounds) if y != current_bounds.y => {
+                    bounds.push(*current_bounds);
+                    *current_bounds = new_bounds();
+                }
+                Some(current_bounds) => {
+                    current_bounds.width += glyph.w;
+                }
+            }
+        }
+
+        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..9cd4a62f 100644
--- a/widget/src/markdown.rs
+++ b/widget/src/markdown.rs
@@ -4,10 +4,11 @@
 //! 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::{self, Element, Length, Pixels};
+use crate::core::{self, color, Color, Element, Length, Pixels};
 use crate::{column, container, rich_text, row, scrollable, span, text};
 
 pub use pulldown_cmark::HeadingLevel;
@@ -257,7 +258,12 @@ 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)
+                .color(Color::WHITE)
+                .background(color!(0x111111))
+                .border(border::rounded(2))
+                .padding(padding::left(2).right(2));
 
             let span = if let Some(link) = link.as_ref() {
                 span.color(palette.primary).link(link.clone())
diff --git a/widget/src/text/rich.rs b/widget/src/text/rich.rs
index 9c0e2fac..9935e6c5 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, Vector, Widget,
 };
 
 use std::borrow::Cow;
@@ -246,6 +246,33 @@ where
 
         let style = theme.style(&self.class);
 
+        for (index, span) in self.spans.iter().enumerate() {
+            if let Some(highlight) = span.highlight {
+                let translation = layout.position() - Point::ORIGIN;
+
+                for bounds in state.paragraph.span_bounds(index) {
+                    let bounds = Rectangle::new(
+                        bounds.position()
+                            - Vector::new(span.padding.left, span.padding.top),
+                        bounds.size()
+                            + Size::new(
+                                span.padding.horizontal(),
+                                span.padding.vertical(),
+                            ),
+                    );
+
+                    renderer.fill_quad(
+                        renderer::Quad {
+                            bounds: bounds + translation,
+                            border: highlight.border,
+                            ..Default::default()
+                        },
+                        highlight.background,
+                    );
+                }
+            }
+        }
+
         text::draw(
             renderer,
             defaults,