vendor

egui/crates/egui_demo_lib/src/syntax_highlighting.rs

@@ -0,0 +1,506 @@
+use egui::text::LayoutJob;
+
+/// View some code with syntax highlighting and selection.
+pub fn code_view_ui(ui: &mut egui::Ui, mut code: &str) {
+    let language = "rs";
+    let theme = CodeTheme::from_memory(ui.ctx());
+
+    let mut layouter = |ui: &egui::Ui, string: &str, _wrap_width: f32| {
+        let layout_job = highlight(ui.ctx(), &theme, string, language);
+        // layout_job.wrap.max_width = wrap_width; // no wrapping
+        ui.fonts(|f| f.layout_job(layout_job))
+    };
+
+    ui.add(
+        egui::TextEdit::multiline(&mut code)
+            .font(egui::TextStyle::Monospace) // for cursor height
+            .code_editor()
+            .desired_rows(1)
+            .lock_focus(true)
+            .layouter(&mut layouter),
+    );
+}
+
+/// Memoized Code highlighting
+pub fn highlight(ctx: &egui::Context, theme: &CodeTheme, code: &str, language: &str) -> LayoutJob {
+    impl egui::util::cache::ComputerMut<(&CodeTheme, &str, &str), LayoutJob> for Highlighter {
+        fn compute(&mut self, (theme, code, lang): (&CodeTheme, &str, &str)) -> LayoutJob {
+            self.highlight(theme, code, lang)
+        }
+    }
+
+    type HighlightCache = egui::util::cache::FrameCache<LayoutJob, Highlighter>;
+
+    ctx.memory_mut(|mem| {
+        mem.caches
+            .cache::<HighlightCache>()
+            .get((theme, code, language))
+    })
+}
+
+// ----------------------------------------------------------------------------
+
+#[cfg(not(feature = "syntect"))]
+#[derive(Clone, Copy, PartialEq)]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[derive(enum_map::Enum)]
+enum TokenType {
+    Comment,
+    Keyword,
+    Literal,
+    StringLiteral,
+    Punctuation,
+    Whitespace,
+}
+
+#[cfg(feature = "syntect")]
+#[derive(Clone, Copy, Hash, PartialEq)]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+enum SyntectTheme {
+    Base16EightiesDark,
+    Base16MochaDark,
+    Base16OceanDark,
+    Base16OceanLight,
+    InspiredGitHub,
+    SolarizedDark,
+    SolarizedLight,
+}
+
+#[cfg(feature = "syntect")]
+impl SyntectTheme {
+    fn all() -> impl ExactSizeIterator<Item = Self> {
+        [
+            Self::Base16EightiesDark,
+            Self::Base16MochaDark,
+            Self::Base16OceanDark,
+            Self::Base16OceanLight,
+            Self::InspiredGitHub,
+            Self::SolarizedDark,
+            Self::SolarizedLight,
+        ]
+        .iter()
+        .copied()
+    }
+
+    fn name(&self) -> &'static str {
+        match self {
+            Self::Base16EightiesDark => "Base16 Eighties (dark)",
+            Self::Base16MochaDark => "Base16 Mocha (dark)",
+            Self::Base16OceanDark => "Base16 Ocean (dark)",
+            Self::Base16OceanLight => "Base16 Ocean (light)",
+            Self::InspiredGitHub => "InspiredGitHub (light)",
+            Self::SolarizedDark => "Solarized (dark)",
+            Self::SolarizedLight => "Solarized (light)",
+        }
+    }
+
+    fn syntect_key_name(&self) -> &'static str {
+        match self {
+            Self::Base16EightiesDark => "base16-eighties.dark",
+            Self::Base16MochaDark => "base16-mocha.dark",
+            Self::Base16OceanDark => "base16-ocean.dark",
+            Self::Base16OceanLight => "base16-ocean.light",
+            Self::InspiredGitHub => "InspiredGitHub",
+            Self::SolarizedDark => "Solarized (dark)",
+            Self::SolarizedLight => "Solarized (light)",
+        }
+    }
+
+    pub fn is_dark(&self) -> bool {
+        match self {
+            Self::Base16EightiesDark
+            | Self::Base16MochaDark
+            | Self::Base16OceanDark
+            | Self::SolarizedDark => true,
+
+            Self::Base16OceanLight | Self::InspiredGitHub | Self::SolarizedLight => false,
+        }
+    }
+}
+
+#[derive(Clone, Hash, PartialEq)]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[cfg_attr(feature = "serde", serde(default))]
+pub struct CodeTheme {
+    dark_mode: bool,
+
+    #[cfg(feature = "syntect")]
+    syntect_theme: SyntectTheme,
+
+    #[cfg(not(feature = "syntect"))]
+    formats: enum_map::EnumMap<TokenType, egui::TextFormat>,
+}
+
+impl Default for CodeTheme {
+    fn default() -> Self {
+        Self::dark()
+    }
+}
+
+impl CodeTheme {
+    pub fn from_style(style: &egui::Style) -> Self {
+        if style.visuals.dark_mode {
+            Self::dark()
+        } else {
+            Self::light()
+        }
+    }
+
+    pub fn from_memory(ctx: &egui::Context) -> Self {
+        if ctx.style().visuals.dark_mode {
+            ctx.data_mut(|d| {
+                d.get_persisted(egui::Id::new("dark"))
+                    .unwrap_or_else(CodeTheme::dark)
+            })
+        } else {
+            ctx.data_mut(|d| {
+                d.get_persisted(egui::Id::new("light"))
+                    .unwrap_or_else(CodeTheme::light)
+            })
+        }
+    }
+
+    pub fn store_in_memory(self, ctx: &egui::Context) {
+        if self.dark_mode {
+            ctx.data_mut(|d| d.insert_persisted(egui::Id::new("dark"), self));
+        } else {
+            ctx.data_mut(|d| d.insert_persisted(egui::Id::new("light"), self));
+        }
+    }
+}
+
+#[cfg(feature = "syntect")]
+impl CodeTheme {
+    pub fn dark() -> Self {
+        Self {
+            dark_mode: true,
+            syntect_theme: SyntectTheme::Base16MochaDark,
+        }
+    }
+
+    pub fn light() -> Self {
+        Self {
+            dark_mode: false,
+            syntect_theme: SyntectTheme::SolarizedLight,
+        }
+    }
+
+    pub fn ui(&mut self, ui: &mut egui::Ui) {
+        egui::widgets::global_dark_light_mode_buttons(ui);
+
+        for theme in SyntectTheme::all() {
+            if theme.is_dark() == self.dark_mode {
+                ui.radio_value(&mut self.syntect_theme, theme, theme.name());
+            }
+        }
+    }
+}
+
+#[cfg(not(feature = "syntect"))]
+impl CodeTheme {
+    pub fn dark() -> Self {
+        let font_id = egui::FontId::monospace(10.0);
+        use egui::{Color32, TextFormat};
+        Self {
+            dark_mode: true,
+            formats: enum_map::enum_map![
+                TokenType::Comment => TextFormat::simple(font_id.clone(), Color32::from_gray(120)),
+                TokenType::Keyword => TextFormat::simple(font_id.clone(), Color32::from_rgb(255, 100, 100)),
+                TokenType::Literal => TextFormat::simple(font_id.clone(), Color32::from_rgb(87, 165, 171)),
+                TokenType::StringLiteral => TextFormat::simple(font_id.clone(), Color32::from_rgb(109, 147, 226)),
+                TokenType::Punctuation => TextFormat::simple(font_id.clone(), Color32::LIGHT_GRAY),
+                TokenType::Whitespace => TextFormat::simple(font_id.clone(), Color32::TRANSPARENT),
+            ],
+        }
+    }
+
+    pub fn light() -> Self {
+        let font_id = egui::FontId::monospace(10.0);
+        use egui::{Color32, TextFormat};
+        Self {
+            dark_mode: false,
+            #[cfg(not(feature = "syntect"))]
+            formats: enum_map::enum_map![
+                TokenType::Comment => TextFormat::simple(font_id.clone(), Color32::GRAY),
+                TokenType::Keyword => TextFormat::simple(font_id.clone(), Color32::from_rgb(235, 0, 0)),
+                TokenType::Literal => TextFormat::simple(font_id.clone(), Color32::from_rgb(153, 134, 255)),
+                TokenType::StringLiteral => TextFormat::simple(font_id.clone(), Color32::from_rgb(37, 203, 105)),
+                TokenType::Punctuation => TextFormat::simple(font_id.clone(), Color32::DARK_GRAY),
+                TokenType::Whitespace => TextFormat::simple(font_id.clone(), Color32::TRANSPARENT),
+            ],
+        }
+    }
+
+    pub fn ui(&mut self, ui: &mut egui::Ui) {
+        ui.horizontal_top(|ui| {
+            let selected_id = egui::Id::null();
+            let mut selected_tt: TokenType =
+                ui.data_mut(|d| *d.get_persisted_mut_or(selected_id, TokenType::Comment));
+
+            ui.vertical(|ui| {
+                ui.set_width(150.0);
+                egui::widgets::global_dark_light_mode_buttons(ui);
+
+                ui.add_space(8.0);
+                ui.separator();
+                ui.add_space(8.0);
+
+                ui.scope(|ui| {
+                    for (tt, tt_name) in [
+                        (TokenType::Comment, "// comment"),
+                        (TokenType::Keyword, "keyword"),
+                        (TokenType::Literal, "literal"),
+                        (TokenType::StringLiteral, "\"string literal\""),
+                        (TokenType::Punctuation, "punctuation ;"),
+                        // (TokenType::Whitespace, "whitespace"),
+                    ] {
+                        let format = &mut self.formats[tt];
+                        ui.style_mut().override_font_id = Some(format.font_id.clone());
+                        ui.visuals_mut().override_text_color = Some(format.color);
+                        ui.radio_value(&mut selected_tt, tt, tt_name);
+                    }
+                });
+
+                let reset_value = if self.dark_mode {
+                    CodeTheme::dark()
+                } else {
+                    CodeTheme::light()
+                };
+
+                if ui
+                    .add_enabled(*self != reset_value, egui::Button::new("Reset theme"))
+                    .clicked()
+                {
+                    *self = reset_value;
+                }
+            });
+
+            ui.add_space(16.0);
+
+            ui.data_mut(|d| d.insert_persisted(selected_id, selected_tt));
+
+            egui::Frame::group(ui.style())
+                .inner_margin(egui::Vec2::splat(2.0))
+                .show(ui, |ui| {
+                    // ui.group(|ui| {
+                    ui.style_mut().override_text_style = Some(egui::TextStyle::Small);
+                    ui.spacing_mut().slider_width = 128.0; // Controls color picker size
+                    egui::widgets::color_picker::color_picker_color32(
+                        ui,
+                        &mut self.formats[selected_tt].color,
+                        egui::color_picker::Alpha::Opaque,
+                    );
+                });
+        });
+    }
+}
+
+// ----------------------------------------------------------------------------
+
+#[cfg(feature = "syntect")]
+struct Highlighter {
+    ps: syntect::parsing::SyntaxSet,
+    ts: syntect::highlighting::ThemeSet,
+}
+
+#[cfg(feature = "syntect")]
+impl Default for Highlighter {
+    fn default() -> Self {
+        Self {
+            ps: syntect::parsing::SyntaxSet::load_defaults_newlines(),
+            ts: syntect::highlighting::ThemeSet::load_defaults(),
+        }
+    }
+}
+
+#[cfg(feature = "syntect")]
+impl Highlighter {
+    #[allow(clippy::unused_self, clippy::unnecessary_wraps)]
+    fn highlight(&self, theme: &CodeTheme, code: &str, lang: &str) -> LayoutJob {
+        self.highlight_impl(theme, code, lang).unwrap_or_else(|| {
+            // Fallback:
+            LayoutJob::simple(
+                code.into(),
+                egui::FontId::monospace(12.0),
+                if theme.dark_mode {
+                    egui::Color32::LIGHT_GRAY
+                } else {
+                    egui::Color32::DARK_GRAY
+                },
+                f32::INFINITY,
+            )
+        })
+    }
+
+    fn highlight_impl(&self, theme: &CodeTheme, text: &str, language: &str) -> Option<LayoutJob> {
+        use syntect::easy::HighlightLines;
+        use syntect::highlighting::FontStyle;
+        use syntect::util::LinesWithEndings;
+
+        let syntax = self
+            .ps
+            .find_syntax_by_name(language)
+            .or_else(|| self.ps.find_syntax_by_extension(language))?;
+
+        let theme = theme.syntect_theme.syntect_key_name();
+        let mut h = HighlightLines::new(syntax, &self.ts.themes[theme]);
+
+        use egui::text::{LayoutSection, TextFormat};
+
+        let mut job = LayoutJob {
+            text: text.into(),
+            ..Default::default()
+        };
+
+        for line in LinesWithEndings::from(text) {
+            for (style, range) in h.highlight_line(line, &self.ps).ok()? {
+                let fg = style.foreground;
+                let text_color = egui::Color32::from_rgb(fg.r, fg.g, fg.b);
+                let italics = style.font_style.contains(FontStyle::ITALIC);
+                let underline = style.font_style.contains(FontStyle::ITALIC);
+                let underline = if underline {
+                    egui::Stroke::new(1.0, text_color)
+                } else {
+                    egui::Stroke::NONE
+                };
+                job.sections.push(LayoutSection {
+                    leading_space: 0.0,
+                    byte_range: as_byte_range(text, range),
+                    format: TextFormat {
+                        font_id: egui::FontId::monospace(12.0),
+                        color: text_color,
+                        italics,
+                        underline,
+                        ..Default::default()
+                    },
+                });
+            }
+        }
+
+        Some(job)
+    }
+}
+
+#[cfg(feature = "syntect")]
+fn as_byte_range(whole: &str, range: &str) -> std::ops::Range<usize> {
+    let whole_start = whole.as_ptr() as usize;
+    let range_start = range.as_ptr() as usize;
+    assert!(whole_start <= range_start);
+    assert!(range_start + range.len() <= whole_start + whole.len());
+    let offset = range_start - whole_start;
+    offset..(offset + range.len())
+}
+
+// ----------------------------------------------------------------------------
+
+#[cfg(not(feature = "syntect"))]
+#[derive(Default)]
+struct Highlighter {}
+
+#[cfg(not(feature = "syntect"))]
+impl Highlighter {
+    #[allow(clippy::unused_self, clippy::unnecessary_wraps)]
+    fn highlight(&self, theme: &CodeTheme, mut text: &str, _language: &str) -> LayoutJob {
+        // Extremely simple syntax highlighter for when we compile without syntect
+
+        let mut job = LayoutJob::default();
+
+        while !text.is_empty() {
+            if text.starts_with("//") {
+                let end = text.find('\n').unwrap_or(text.len());
+                job.append(&text[..end], 0.0, theme.formats[TokenType::Comment].clone());
+                text = &text[end..];
+            } else if text.starts_with('"') {
+                let end = text[1..]
+                    .find('"')
+                    .map(|i| i + 2)
+                    .or_else(|| text.find('\n'))
+                    .unwrap_or(text.len());
+                job.append(
+                    &text[..end],
+                    0.0,
+                    theme.formats[TokenType::StringLiteral].clone(),
+                );
+                text = &text[end..];
+            } else if text.starts_with(|c: char| c.is_ascii_alphanumeric()) {
+                let end = text[1..]
+                    .find(|c: char| !c.is_ascii_alphanumeric())
+                    .map_or_else(|| text.len(), |i| i + 1);
+                let word = &text[..end];
+                let tt = if is_keyword(word) {
+                    TokenType::Keyword
+                } else {
+                    TokenType::Literal
+                };
+                job.append(word, 0.0, theme.formats[tt].clone());
+                text = &text[end..];
+            } else if text.starts_with(|c: char| c.is_ascii_whitespace()) {
+                let end = text[1..]
+                    .find(|c: char| !c.is_ascii_whitespace())
+                    .map_or_else(|| text.len(), |i| i + 1);
+                job.append(
+                    &text[..end],
+                    0.0,
+                    theme.formats[TokenType::Whitespace].clone(),
+                );
+                text = &text[end..];
+            } else {
+                let mut it = text.char_indices();
+                it.next();
+                let end = it.next().map_or(text.len(), |(idx, _chr)| idx);
+                job.append(
+                    &text[..end],
+                    0.0,
+                    theme.formats[TokenType::Punctuation].clone(),
+                );
+                text = &text[end..];
+            }
+        }
+
+        job
+    }
+}
+
+#[cfg(not(feature = "syntect"))]
+fn is_keyword(word: &str) -> bool {
+    matches!(
+        word,
+        "as" | "async"
+            | "await"
+            | "break"
+            | "const"
+            | "continue"
+            | "crate"
+            | "dyn"
+            | "else"
+            | "enum"
+            | "extern"
+            | "false"
+            | "fn"
+            | "for"
+            | "if"
+            | "impl"
+            | "in"
+            | "let"
+            | "loop"
+            | "match"
+            | "mod"
+            | "move"
+            | "mut"
+            | "pub"
+            | "ref"
+            | "return"
+            | "self"
+            | "Self"
+            | "static"
+            | "struct"
+            | "super"
+            | "trait"
+            | "true"
+            | "type"
+            | "unsafe"
+            | "use"
+            | "where"
+            | "while"
+    )
+}