Wrap text in a unicode-aware way

examples/text_wrapping.rs

@@ -0,0 +1,60 @@
+use crossterm::event::Event;
+use crossterm::style::ContentStyle;
+use toss::frame::{Frame, Pos};
+use toss::terminal::{Redraw, Terminal};
+
+fn draw(f: &mut Frame) {
+    let text = concat!(
+        "This is a short paragraph in order to demonstrate unicode-aware word wrapping. ",
+        "Resize your terminal to different widths to try it out. ",
+        "After this sentence come two newlines, so it should always break here.\n",
+        "\n",
+        "Since the wrapping algorithm is aware of the Unicode Standard Annex #14, ",
+        "it understands things like nonbreaking spaces: ",
+        "This\u{00a0}sentence\u{00a0}is\u{00a0}separated\u{00a0}by\u{00a0}nonbreaking\u{00a0}spaces.\n",
+        "\n",
+        "It can also properly handle wide graphemes (like emoji 🤔), ",
+        "including ones usually displayed incorrectly by terminal emulators, like 👩‍🔬 (a female scientist emoji).",
+    );
+    // TODO Actually use nbsp
+
+    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(),
+        );
+    }
+}
+
+fn render_frame(term: &mut Terminal) {
+    loop {
+        // Must be called before rendering, otherwise the terminal has out-of-date
+        // size information and will present garbage.
+        term.autoresize().unwrap();
+
+        draw(term.frame());
+
+        if term.present().unwrap() == Redraw::NotRequired {
+            break;
+        }
+    }
+}
+
+fn main() {
+    // Automatically enters alternate screen and enables raw mode
+    let mut term = Terminal::new().unwrap();
+
+    loop {
+        // Render and display a frame. A full frame is displayed on the terminal
+        // once this function exits.
+        render_frame(&mut term);
+
+        // Exit if the user presses any buttons
+        if !matches!(crossterm::event::read().unwrap(), Event::Resize(_, _)) {
+            break;
+        }
+    }
+}