Syntax highlighting example

examples/syntax/Cargo.toml

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+[package]
+name = "syntax"
+version = "0.1.0"
+authors = ["Jeremy Soller <jeremy@system76.com>"]
+edition = "2021"
+license = "MIT OR Apache-2.0"
+publish = false
+
+[dependencies]
+cosmic-text = { path = "../../" }
+env_logger = "0.9"
+fontdb = "0.9"
+log = "0.4"
+orbclient = "0.3.35"
+syntect = "5.0"

examples/syntax/src/main.rs

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+// SPDX-License-Identifier: MIT OR Apache-2.0
+
+use cosmic_text::{Attrs, Color, Family, FontSystem, Style, SwashCache,
+    TextAction, TextBuffer, TextBufferLine, TextMetrics, Weight};
+use orbclient::{EventOption, Renderer, Window, WindowFlag};
+use std::{env, fs, process, thread, time::{Duration, Instant}};
+
+fn main() {
+    env_logger::init();
+
+    let font_system = FontSystem::new();
+
+    let text = if let Some(arg) = env::args().nth(1) {
+        fs::read_to_string(&arg).expect("failed to open file")
+    } else {
+        "Markdown can have **bold**, *italic*, and `code` styles".to_string()
+    };
+
+    let mut window = Window::new_flags(
+        -1,
+        -1,
+        1024,
+        768,
+        &format!("COSMIC TEXT - {}", font_system.locale),
+        &[WindowFlag::Resizable],
+    )
+    .unwrap();
+
+    let attrs = Attrs::new()
+        .monospaced(true)
+        .family(Family::Monospace);
+    let mut buffer = TextBuffer::new(
+        &font_system,
+        attrs,
+        TextMetrics::new(14, 20)
+    );
+
+    buffer.set_size(
+        window.width() as i32,
+        window.height() as i32
+    );
+
+    {
+        use syntect::easy::HighlightLines;
+        use syntect::parsing::SyntaxSet;
+        use syntect::highlighting::{ThemeSet, FontStyle, Style as SyntectStyle};
+        use syntect::util::LinesWithEndings;
+
+        // Load these once at the start of your program
+        let ps = SyntaxSet::load_defaults_newlines();
+        let ts = ThemeSet::load_defaults();
+
+        let syntax = ps.find_syntax_by_extension("rs").unwrap();
+        let mut h = HighlightLines::new(syntax, &ts.themes["base16-ocean.dark"]);
+        for (line_i, highlight_line) in LinesWithEndings::from(&text).enumerate() { // LinesWithEndings enables use of newlines mode
+            while line_i >= buffer.lines.len() {
+                buffer.lines.push(TextBufferLine::new(String::new(), attrs));
+            }
+
+            let ranges: Vec<(SyntectStyle, &str)> = h.highlight_line(highlight_line, &ps).unwrap();
+
+            let line = &mut buffer.lines[line_i];
+            for (style, string) in ranges.iter() {
+                let string_trim = match string.lines().next() {
+                    Some(some) => some,
+                    None => continue,
+                };
+
+                let start = line.text.len();
+                line.text.push_str(string_trim);
+                let end = line.text.len();
+                line.attrs_list.add_span(
+                    start,
+                    end,
+                    attrs
+                        .color(Color::rgba(
+                            style.foreground.r,
+                            style.foreground.g,
+                            style.foreground.b,
+                            style.foreground.a,
+                        ))
+                        //TODO: background
+                        .style(if style.font_style.contains(FontStyle::ITALIC) {
+                            Style::Italic
+                        } else {
+                            Style::Normal
+                        })
+                        .weight(if style.font_style.contains(FontStyle::BOLD) {
+                            Weight::BOLD
+                        } else {
+                            Weight::NORMAL
+                        })
+                        //TODO: underline
+                );
+                line.reset();
+            }
+        }
+    }
+
+    let mut swash_cache = SwashCache::new(&font_system);
+
+    //TODO: make window not async?
+    let mut mouse_x = -1;
+    let mut mouse_y = -1;
+    let mut mouse_left = false;
+    loop {
+        let bg_color = orbclient::Color::rgb(0x34, 0x34, 0x34);
+        let font_color = orbclient::Color::rgb(0xFF, 0xFF, 0xFF);
+
+        if buffer.cursor_moved {
+            buffer.shape_until_cursor();
+            buffer.cursor_moved = false;
+        } else {
+            buffer.shape_until_scroll();
+        }
+
+        if buffer.redraw {
+            let instant = Instant::now();
+
+            window.set(bg_color);
+
+            buffer.draw(&mut swash_cache, font_color.data, |x, y, w, h, color| {
+                window.rect(x, y, w, h, orbclient::Color { data: color });
+            });
+
+            window.sync();
+
+            buffer.redraw = false;
+
+            let duration = instant.elapsed();
+            log::debug!("redraw: {:?}", duration);
+        }
+
+        for event in window.events() {
+            match event.to_option() {
+                EventOption::Mouse(mouse) => {
+                    mouse_x = mouse.x;
+                    mouse_y = mouse.y;
+                    if mouse_left {
+                        buffer.action(TextAction::Drag { x: mouse_x, y: mouse_y });
+                    }
+                },
+                EventOption::Button(button) => {
+                    mouse_left = button.left;
+                    if mouse_left {
+                        buffer.action(TextAction::Click { x: mouse_x, y: mouse_y });
+                    }
+                },
+                EventOption::Resize(resize) => {
+                    buffer.set_size(resize.width as i32, resize.height as i32);
+                },
+                EventOption::Quit(_) => process::exit(0),
+                _ => (),
+            }
+        }
+
+        thread::sleep(Duration::from_millis(1));
+    }
+}

syntax.sh

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+RUST_LOG=cosmic_text=debug cargo run --release --package syntax -- "$@"