Use styled chunks of text instead of plain strings

examples/hello_world.rs

@@ -6,13 +6,14 @@ use toss::terminal::Terminal;
 fn draw(f: &mut Frame) {
     f.write(
         Pos::new(0, 0),
-        "Hello world!",
-        ContentStyle::default().green(),
+        ("Hello world!", ContentStyle::default().green()),
     );
     f.write(
         Pos::new(0, 1),
+        (
             "Press any key to exit",
             ContentStyle::default().on_dark_blue(),
+        ),
     );
     f.show_cursor(Pos::new(16, 0));
 }

examples/overlapping_graphemes.rs

@@ -7,53 +7,45 @@ fn draw(f: &mut Frame) {
     f.write(
         Pos::new(0, 0),
         "Writing over wide graphemes removes the entire overwritten grapheme.",
-        ContentStyle::default(),
     );
     let under = ContentStyle::default().white().on_dark_blue();
     let over = ContentStyle::default().black().on_dark_yellow();
     for i in 0..6 {
         let delta = i - 2;
-        f.write(Pos::new(2 + i * 7, 2), "a😀", under);
-        f.write(Pos::new(2 + i * 7, 3), "a😀", under);
-        f.write(Pos::new(2 + i * 7, 4), "a😀", under);
-        f.write(Pos::new(2 + i * 7 + delta, 3), "b", over);
-        f.write(Pos::new(2 + i * 7 + delta, 4), "😈", over);
+        f.write(Pos::new(2 + i * 7, 2), ("a😀", under));
+        f.write(Pos::new(2 + i * 7, 3), ("a😀", under));
+        f.write(Pos::new(2 + i * 7, 4), ("a😀", under));
+        f.write(Pos::new(2 + i * 7 + delta, 3), ("b", over));
+        f.write(Pos::new(2 + i * 7 + delta, 4), ("😈", over));
     }
 
     f.write(
         Pos::new(0, 6),
         "Wide graphemes at the edges of the screen apply their style, but are not",
-        ContentStyle::default(),
-    );
-    f.write(
-        Pos::new(0, 7),
-        "actually rendered.",
-        ContentStyle::default(),
     );
+    f.write(Pos::new(0, 7), "actually rendered.");
     let x1 = -1;
     let x2 = f.size().width as i32 / 2 - 3;
     let x3 = f.size().width as i32 - 5;
-    f.write(Pos::new(x1, 9), "123456", under);
-    f.write(Pos::new(x1, 10), "😀😀😀", under);
-    f.write(Pos::new(x2, 9), "123456", under);
-    f.write(Pos::new(x2, 10), "😀😀😀", under);
-    f.write(Pos::new(x3, 9), "123456", under);
-    f.write(Pos::new(x3, 10), "😀😀😀", under);
+    f.write(Pos::new(x1, 9), ("123456", under));
+    f.write(Pos::new(x1, 10), ("😀😀😀", under));
+    f.write(Pos::new(x2, 9), ("123456", under));
+    f.write(Pos::new(x2, 10), ("😀😀😀", under));
+    f.write(Pos::new(x3, 9), ("123456", under));
+    f.write(Pos::new(x3, 10), ("😀😀😀", under));
 
     let scientist = "👩‍🔬";
     f.write(
         Pos::new(0, 12),
         "Most terminals ignore the zero width joiner and display this female",
-        ContentStyle::default(),
     );
     f.write(
         Pos::new(0, 13),
         "scientist emoji as a woman and a microscope: 👩‍🔬",
-        ContentStyle::default(),
     );
     for i in 0..(f.width(scientist) + 4) {
-        f.write(Pos::new(2, 15 + i as i32), scientist, under);
-        f.write(Pos::new(i as i32, 15 + i as i32), "x", over);
+        f.write(Pos::new(2, 15 + i as i32), (scientist, under));
+        f.write(Pos::new(i as i32, 15 + i as i32), ("x", over));
     }
 }
 

examples/text_wrapping.rs

@@ -1,6 +1,6 @@
 use crossterm::event::Event;
-use crossterm::style::ContentStyle;
 use toss::frame::{Frame, Pos};
+use toss::styled::Styled;
 use toss::terminal::Terminal;
 
 fn draw(f: &mut Frame) {
@@ -18,13 +18,10 @@ fn draw(f: &mut Frame) {
     );
 
     let breaks = f.wrap(text, f.size().width.into());
-    let lines = toss::split_at_indices(text, &breaks);
-    for (i, line) in lines.iter().enumerate() {
-        f.write(
-            Pos::new(0, i as i32),
-            line.trim_end(),
-            ContentStyle::default(),
-        );
+    let lines = Styled::default().then(text).split_at_indices(&breaks);
+    for (i, mut line) in lines.into_iter().enumerate() {
+        line.trim_end();
+        f.write(Pos::new(0, i as i32), line);
     }
 }
 

src/buffer.rs

@@ -1,6 +1,7 @@
 use crossterm::style::ContentStyle;
 use unicode_segmentation::UnicodeSegmentation;
 
+use crate::styled::Styled;
 use crate::widthdb::WidthDB;
 
 #[derive(Debug, Default, Clone, Copy, PartialEq, Eq)]
@@ -127,23 +128,23 @@ impl Buffer {
         }
     }
 
-    pub fn write(
-        &mut self,
-        widthdb: &mut WidthDB,
-        mut pos: Pos,
-        content: &str,
-        style: ContentStyle,
-    ) {
+    pub fn write(&mut self, widthdb: &mut WidthDB, mut pos: Pos, styled: &Styled) {
         // If we're not even visible, there's nothing to do
         if pos.y < 0 || pos.y >= self.size.height as i32 {
             return;
         }
         let y = pos.y as u16;
 
-        for grapheme in content.graphemes(true) {
-            let width = widthdb.grapheme_width(grapheme);
+        for styled_grapheme in styled.styled_graphemes() {
+            let width = widthdb.grapheme_width(styled_grapheme.content());
             if width > 0 {
-                self.write_grapheme(pos.x, y, width, grapheme, style);
+                self.write_grapheme(
+                    pos.x,
+                    y,
+                    width,
+                    styled_grapheme.content(),
+                    *styled_grapheme.style(),
+                );
             }
             pos.x += width as i32;
         }

src/frame.rs

@@ -4,6 +4,7 @@ use crossterm::style::ContentStyle;
 
 use crate::buffer::Buffer;
 pub use crate::buffer::{Pos, Size};
+use crate::styled::Styled;
 use crate::widthdb::WidthDB;
 use crate::wrap;
 
@@ -60,7 +61,7 @@ impl Frame {
         wrap::wrap(text, width, &mut self.widthdb)
     }
 
-    pub fn write(&mut self, pos: Pos, content: &str, style: ContentStyle) {
-        self.buffer.write(&mut self.widthdb, pos, content, style);
+    pub fn write<S: Into<Styled>>(&mut self, pos: Pos, styled: S) {
+        self.buffer.write(&mut self.widthdb, pos, &styled.into());
     }
 }

src/lib.rs

@@ -1,7 +1,6 @@
 mod buffer;
 pub mod frame;
+pub mod styled;
 pub mod terminal;
 mod widthdb;
 mod wrap;
-
-pub use wrap::split_at_indices;

src/styled.rs

@@ -0,0 +1,170 @@
+use crossterm::style::{ContentStyle, StyledContent};
+use unicode_segmentation::UnicodeSegmentation;
+
+#[derive(Debug, Clone)]
+pub struct Chunk {
+    string: String,
+    style: ContentStyle,
+}
+
+impl Chunk {
+    pub fn new<S: ToString>(string: S, style: ContentStyle) -> Self {
+        Self {
+            string: string.to_string(),
+            style,
+        }
+    }
+
+    pub fn plain<S: ToString>(string: S) -> Self {
+        Self::new(string, ContentStyle::default())
+    }
+
+    pub fn split_at(&self, mid: usize) -> (Self, Self) {
+        let (lstr, rstr) = self.string.split_at(mid);
+        let left = Self {
+            string: lstr.to_string(),
+            style: self.style,
+        };
+        let right = Self {
+            string: rstr.to_string(),
+            style: self.style,
+        };
+        (left, right)
+    }
+}
+
+impl From<&str> for Chunk {
+    fn from(str: &str) -> Self {
+        Self::plain(str)
+    }
+}
+
+impl From<String> for Chunk {
+    fn from(string: String) -> Self {
+        Self::plain(string)
+    }
+}
+
+impl From<&String> for Chunk {
+    fn from(string: &String) -> Self {
+        Self::plain(string)
+    }
+}
+
+impl<S: ToString> From<(S,)> for Chunk {
+    fn from(tuple: (S,)) -> Self {
+        Self::plain(tuple.0)
+    }
+}
+
+impl<S: ToString> From<(S, ContentStyle)> for Chunk {
+    fn from(tuple: (S, ContentStyle)) -> Self {
+        Self::new(tuple.0, tuple.1)
+    }
+}
+
+#[derive(Debug, Default, Clone)]
+pub struct Styled(Vec<Chunk>);
+
+impl Styled {
+    pub fn new<C: Into<Chunk>>(chunk: C) -> Self {
+        Self::default().then(chunk)
+    }
+
+    pub fn then<C: Into<Chunk>>(mut self, chunk: C) -> Self {
+        self.0.push(chunk.into());
+        self
+    }
+
+    pub fn and_then(mut self, other: Styled) -> Self {
+        self.0.extend(other.0);
+        self
+    }
+
+    pub fn text(&self) -> String {
+        self.0.iter().flat_map(|c| c.string.chars()).collect()
+    }
+
+    pub fn graphemes(&self) -> impl Iterator<Item = &str> {
+        self.0.iter().flat_map(|c| c.string.graphemes(true))
+    }
+
+    pub fn grapheme_indices(&self) -> impl Iterator<Item = (usize, &str)> {
+        self.0
+            .iter()
+            .scan(0, |s, c| {
+                let offset = *s;
+                *s += c.string.len();
+                Some((offset, c))
+            })
+            .flat_map(|(o, c)| {
+                c.string
+                    .grapheme_indices(true)
+                    .map(move |(gi, g)| (o + gi, g))
+            })
+    }
+
+    pub fn styled_graphemes(&self) -> impl Iterator<Item = StyledContent<&str>> {
+        self.0.iter().flat_map(|c| {
+            c.string
+                .graphemes(true)
+                .map(|g| StyledContent::new(c.style, g))
+        })
+    }
+
+    pub fn split_at(self, mid: usize) -> (Self, Self) {
+        let mut left = vec![];
+        let mut right = vec![];
+        let mut offset = 0;
+        for chunk in self.0 {
+            let len = chunk.string.len();
+            if offset >= mid {
+                right.push(chunk);
+            } else if offset + len > mid {
+                let (lchunk, rchunk) = chunk.split_at(mid - offset);
+                left.push(lchunk);
+                right.push(rchunk);
+            } else {
+                left.push(chunk);
+            }
+            offset += len;
+        }
+        (Self(left), Self(right))
+    }
+
+    pub fn split_at_indices(self, indices: &[usize]) -> Vec<Self> {
+        let mut lines = vec![];
+
+        let mut rest = self;
+        let mut offset = 0;
+
+        for i in indices {
+            let (left, right) = rest.split_at(i - offset);
+            lines.push(left);
+            rest = right;
+            offset = *i;
+        }
+
+        lines.push(rest);
+
+        lines
+    }
+
+    pub fn trim_end(&mut self) {
+        while let Some(last) = self.0.last_mut() {
+            let trimmed = last.string.trim_end();
+            if trimmed.is_empty() {
+                self.0.pop();
+            } else {
+                last.string = trimmed.to_string();
+                break;
+            }
+        }
+    }
+}
+
+impl<C: Into<Chunk>> From<C> for Styled {
+    fn from(chunk: C) -> Self {
+        Self::new(chunk)
+    }
+}

src/wrap.rs

@@ -75,21 +75,3 @@ pub fn wrap(text: &str, width: usize, widthdb: &mut WidthDB) -> Vec<usize> {
 
     breaks
 }
-
-pub fn split_at_indices<'a>(s: &'a str, indices: &[usize]) -> Vec<&'a str> {
-    let mut slices = vec![];
-
-    let mut rest = s;
-    let mut offset = 0;
-
-    for i in indices {
-        let (left, right) = rest.split_at(i - offset);
-        slices.push(left);
-        rest = right;
-        offset = *i;
-    }
-
-    slices.push(rest);
-
-    slices
-}