Iced Code Editor

A high-performance, canvas-based code editor widget for Iced.

This is the Rustman fork. The repo is iced-code-editor-rustman; the crate inside it is still named iced-code-editor, because Rustman consumes it through [patch.crates-io]. It is a snapshot of upstream 0.3.11 with Rustman's local patches on top: performance work in text_buffer.rs and the canvas pipeline, cursor and selection fixes, theme tweaks, and a trimmed iced feature set (no highlighter/two-face bundle). The public API matches upstream.

It is consumed by Rustman pinned to a tag. Upstream: https://github.com/LuDog71FR/iced-code-editor.

Overview

This crate provides a fully-featured code editor widget with syntax highlighting, line numbers, text selection, and comprehensive keyboard navigation for the Iced GUI framework.

Features

• Syntax highlighting for multiple programming languages via syntect
• Line numbers with styled gutter
• Text selection via mouse drag and keyboard shortcuts
• Clipboard operations (copy, paste)
• Undo/Redo with smart command grouping and configurable history
• Custom scrollbars with themed styling
• Focus management for multiple editors
• Native Iced theme support - Automatically adapts to all 23+ built-in Iced themes
• Line wrapping to split long lines
• Code folding to collapse/expand indentation-based blocks
• High performance canvas-based rendering
• Search and replace text
• Language Server Protocol (LSP) support
• Auto indentation with custom indent style
• Multiple cursors for simultaneous editing at multiple positions

Planned features

• Minimap

Quick Start

Add this to your Cargo.toml:

[dependencies]
iced = "0.14"
iced-code-editor = "0.3"

Basic Example

Here's a minimal example to integrate the code editor into your Iced application:

Note: CodeEditor does not automatically lose focus when another widget is clicked. You must call editor.lose_focus() whenever another interactive widget is activated. The pattern below uses mouse_area to detect clicks on sibling widgets.

use iced::widget::{column, container, mouse_area, text_input};
use iced::{Element, Task};
use iced_code_editor::{CodeEditor, Message as EditorMessage};

struct MyApp {
    editor: CodeEditor,
    input_value: String,
}

#[derive(Debug, Clone)]
enum Message {
    EditorEvent(EditorMessage),
    InputChanged(String),
    InputClicked,
}

impl Default for MyApp {
    fn default() -> Self {
        let code = r#"fn main() {
    println!("Hello, world!");
}
"#;

        Self {
            editor: CodeEditor::new(code, "rust"),
            input_value: String::new(),
        }
    }
}

impl MyApp {
    fn update(&mut self, message: Message) -> Task<Message> {
        match message {
            Message::EditorEvent(event) => {
                self.editor.update(&event).map(Message::EditorEvent)
            }
            Message::InputChanged(value) => {
                self.input_value = value;
                self.editor.lose_focus(); // required: transfer focus away from editor
                Task::none()
            }
            Message::InputClicked => {
                self.editor.lose_focus(); // required: transfer focus away from editor
                Task::none()
            }
        }
    }

    fn view(&self) -> Element<'_, Message> {
        let input = mouse_area(
            text_input("Type something...", &self.input_value)
                .on_input(Message::InputChanged)
                .padding(8),
        )
        .on_press(Message::InputClicked); // detect click to trigger lose_focus

        container(
            column![input, self.editor.view().map(Message::EditorEvent)]
                .spacing(10)
                .height(iced::Fill),
        )
        .padding(20)
        .into()
    }
}

fn main() -> iced::Result {
    iced::run(MyApp::update, MyApp::view)
}

Keyboard Shortcuts

The editor supports a comprehensive set of keyboard shortcuts:

Navigation

Shortcut	Action
Arrow Keys (Up, Down, Left, Right)	Move cursor
Shift + Arrows	Move cursor with selection
Home / End	Jump to start/end of line
Shift + Home / Shift + End	Select to start/end of line
Ctrl + Home / Ctrl + End	Jump to start/end of document
Page Up / Page Down	Scroll one page up/down

Editing

Shortcut	Action
Backspace	Delete character before cursor (or delete selection if text is selected)
Delete	Delete character after cursor (or delete selection if text is selected)
Shift + Delete	Delete selected text (same as Delete when selection exists)
Enter	Insert new line
Tab	Insert indent

Clipboard

Shortcut	Action
Ctrl + C or Ctrl + Insert	Copy selected text
Ctrl + V or Shift + Insert	Paste from clipboard

Undo/Redo

Shortcut	Action
Ctrl + Z	Undo last operation
Ctrl + Y	Redo last undone operation

The editor features smart command grouping - consecutive typing is grouped into single undo operations, while navigation or deletion actions create separate undo points.

Multiple Cursors

Shortcut	Action
Alt + Click	Add a cursor at the clicked position
Ctrl + Alt + Up	Add a cursor on the line above
Ctrl + Alt + Down	Add a cursor on the line below
Ctrl + D	Select the next occurrence of the current word/selection
Escape	Collapse all cursors back to one (when search dialog is closed)

All editing operations (typing, backspace, delete, enter, tab, paste) apply simultaneously to every cursor. Copy with multiple selections joins all selected texts with newlines. Paste with the same number of clipboard lines as cursors pastes one line per cursor.

Search and Replace

Shortcut	Action
Ctrl + F	Open search dialog
Ctrl + H	Open search and replace dialog
F3	Find next match
Shift + F3	Find previous match
Escape	Close search dialog

Code Folding

These shortcuts are active only when code folding is enabled:

Shortcut	Action
Ctrl + .	Toggle fold of the block at the cursor
Ctrl + K	Fold all blocks
Ctrl + J	Unfold all blocks

You can also click the fold chevrons (▼ / ▶) in the gutter to collapse or expand a block.

LSP Completion

These shortcuts are active only when the LSP completion menu is visible:

Shortcut	Action
Arrow Up	Navigate to previous completion item
Arrow Down	Navigate to next completion item
Enter	Confirm and apply selected completion
Escape	Close completion menu
Arrow Left / Arrow Right	Clear completion menu

Usage Examples

Changing Themes

The editor uses TokyoNightStorm as the default theme. It automatically adapts to any Iced theme. All 23+ built-in Iced themes are supported:

use iced_code_editor::theme;

// Apply any built-in Iced theme
editor.set_theme(theme::from_iced_theme(&iced::Theme::TokyoNightStorm));
editor.set_theme(theme::from_iced_theme(&iced::Theme::Dracula));
editor.set_theme(theme::from_iced_theme(&iced::Theme::Nord));
editor.set_theme(theme::from_iced_theme(&iced::Theme::CatppuccinMocha));
editor.set_theme(theme::from_iced_theme(&iced::Theme::GruvboxDark));

// Or use any theme from Theme::ALL
for theme in iced::Theme::ALL {
    editor.set_theme(theme::from_iced_theme(theme));
}

Getting and Setting Content

// Get current content
let content = editor.content();

// Check if content has been modified
if editor.is_modified() {
    println!("Editor has unsaved changes");
}

// Mark content as saved (e.g., after saving to file)
editor.mark_saved();

Enable/disable search/replace

The search/replace functionality is enabled by default. It can be toggled on or off. When disabled, search shortcuts (Ctrl+F, Ctrl+H, F3) are ignored and the search dialog is hidden:

// Disable search/replace functionality
editor.set_search_replace_enabled(false);

// Or use builder pattern during initialization
let editor = CodeEditor::new("code", "rs")
    .with_search_replace_enabled(false);

// Check current state
if editor.search_replace_enabled() {
    println!("Search and replace is available");
}

This is useful for read-only editors or when you want to provide your own search interface.

Open search/replace from your own buttons

Besides keyboard shortcuts, you can open or close the dialogs via API:

// Open search dialog (same as Ctrl+F)
let task = editor.open_search_dialog();

// Open search+replace dialog (same as Ctrl+H)
let task = editor.open_search_replace_dialog();

// Close dialog (same as Esc)
let task = editor.close_search_dialog();

Return these tasks from your app update function after mapping to your message type.

Enable/disable line wrapping

Line wrapping is enabled by default at viewport width. Long lines can be wrapped automatically at the viewport width or at a fixed column:

// Enable line wrapping at viewport width
editor.set_wrap_enabled(true);

// Wrap at a fixed column (e.g., 80 characters)
let editor = CodeEditor::new("code", "rs")
    .with_wrap_enabled(true)
    .with_wrap_column(Some(80));

// Disable wrapping
editor.set_wrap_enabled(false);

// Check current state
if editor.wrap_enabled() {
    println!("Line wrapping is active");
}

When enabled, wrapped lines show a continuation indicator (↪) in the line number gutter.

Enable/disable code folding

Code folding is enabled by default. Foldable regions are detected from indentation: a line is a fold header when the following non-blank line is more deeply indented (language-agnostic, works for Rust, Python, YAML, etc.). When enabled, a fold margin with clickable chevrons (▼ expanded, ▶ collapsed) is shown in the gutter, and a ⋯ marker appears after a collapsed block header.

// Disable code folding (chevrons hidden, all lines shown)
editor.set_folding_enabled(false);

// Or use builder pattern during initialization
let editor = CodeEditor::new("code", "rs")
    .with_folding_enabled(false);

// Check current state
if editor.folding_enabled() {
    println!("Code folding is active");
}

Folds can also be driven programmatically (useful for your own buttons or commands):

// Toggle the fold of the block whose header is a given logical line
editor.toggle_fold(0);

// Toggle / fold / unfold the innermost block containing a line
editor.toggle_fold_at(line);
editor.fold_at(line);
editor.unfold_at(line);

// Fold or unfold every block at once
editor.fold_all();
editor.unfold_all();

// Query whether a header line is collapsed
if editor.is_folded(0) {
    println!("Block at line 0 is collapsed");
}

When folding is disabled, the collapsed state is preserved (so re-enabling restores the previously collapsed blocks) but no lines are hidden.

Enable/disable line numbers

Line numbers are displayed by default. They can be hidden to maximize space for code:

// Hide line numbers
editor.set_line_numbers_enabled(false);

// Or use builder pattern during initialization
let editor = CodeEditor::new("code", "rs")
    .with_line_numbers_enabled(false);

// Show line numbers (default behavior)
editor.set_line_numbers_enabled(true);

// Check current state
if editor.line_numbers_enabled() {
    println!("Line numbers are visible");
}

When disabled, the gutter is completely removed (0px width), providing more horizontal space for code display.

Indentation

Auto-indentation is enabled by default: pressing Enter copies the leading whitespace of the current line to the new line. The indentation style (spaces or tab) is 4 spaces by default and controls what is inserted when pressing Tab.

// Disable auto-indentation on Enter
editor.set_auto_indent_enabled(false);

// Check current state
if editor.auto_indent_enabled() {
    println!("Auto-indentation is active");
}

use iced_code_editor::IndentStyle;

// Use 2 spaces per indent level
editor.set_indent_style(IndentStyle::Spaces(2));

// Use tabs instead of spaces
editor.set_indent_style(IndentStyle::Tab);

// Restore the default (4 spaces)
editor.set_indent_style(IndentStyle::Spaces(4));

// Check current style
match editor.indent_style() {
    IndentStyle::Spaces(n) => println!("Indenting with {n} spaces"),
    IndentStyle::Tab => println!("Indenting with tabs"),
}

Available styles via IndentStyle::ALL: Spaces(2), Spaces(4), Spaces(8), Tab.

Language Server Protocol (LSP)

LSP support provides hover documentation, auto-completion, and go-to-definition. It requires the lsp-process feature (not available on WASM):

[dependencies]
iced-code-editor = { version = "0.3", features = ["lsp-process"] }

Enable/disable LSP on an editor

// Enable LSP (attach a client and open the document)
editor.set_lsp_enabled(true);

// Disable LSP (detach the client)
editor.set_lsp_enabled(false);

Connecting an LSP server

use std::sync::mpsc;
use iced_code_editor::{LspProcessClient, LspEvent, LspDocument};

// Create a channel to receive LSP events
let (tx, rx) = mpsc::channel::<LspEvent>();

// Start the server (e.g., lua-language-server)
let client = LspProcessClient::new_with_server(
    "file:///path/to/project",
    tx,
    "lua-language-server",
)?;

// Attach the client to an editor with a document URI
editor.attach_lsp(
    Box::new(client),
    LspDocument::new("file:///path/to/file.lua", "lua"),
);

Rendering the overlay (hover + completion)

Use LspOverlayState to hold display state and view_lsp_overlay to render it:

use iced_code_editor::{LspOverlayState, LspOverlayMessage, view_lsp_overlay};

struct App {
    editor: CodeEditor,
    overlay: LspOverlayState,
}

#[derive(Clone)]
enum Message {
    LspOverlay(LspOverlayMessage),
    // ...
}

fn view(app: &App) -> Element<'_, Message> {
    // Stack the overlay on top of the editor
    stack![
        app.editor.view().map(Message::EditorEvent),
        view_lsp_overlay(
            &app.overlay,
            &app.editor,
            &app.theme,
            14.0,    // font size
            20.0,    // line height
            Message::LspOverlay,
        ),
    ].into()
}

Poll LspEvents from the channel on each tick and update the overlay state:

// On LspEvent::Hover
overlay.show_hover(text);

// On LspEvent::Completion
overlay.set_completions(items, cursor_position);

Supported servers

Out of the box, the following servers are supported (the binary must be on $PATH):

Server key	Language
lua-language-server	Lua
rust-analyzer	Rust
pylsp	Python
clangd	C / C++
typescript-language-server	JS / TS

Changing font

The default font of the editor is iced::Font::MONOSPACE. It can be changed with one of the default iced font or by loading a specific font:

let font = iced::font::Family::SansSerif;
editor.set_font(font);

The editor support CJK font.

The default font size is 14px. It can be changed:

editor.set_font_size(12.0, true);

Themes

The editor natively supports all built-in Iced themes with automatic color adaptation.

Each theme automatically provides:

• Optimized background and foreground colors
• Adaptive gutter (line numbers) styling
• Appropriate text selection colors
• Themed cursor appearance
• Custom scrollbar styling
• Subtle current line highlighting

The editor intelligently adapts colors from the Iced theme palette for optimal code readability.

Supported Languages

The editor supports syntax highlighting for numerous languages via the syntect crate:

• Rust ("rs" or "rust")
• Python ("py" or "python")
• JavaScript/TypeScript ("js", "javascript", "ts", "typescript")
• Lua ("lua")
• C/C++ ("c", "cpp", "c++")
• Java ("java")
• Go ("go")
• HTML/CSS ("html", "css")
• Markdown ("md", "markdown")
• And many more...

For a complete list, refer to the syntect documentation.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Check docs\DEV.md for more details.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Acknowledgments

• Built with Iced - A cross-platform GUI library for Rust
• Syntax highlighting powered by syntect