Iced Code Editor

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

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.

Screenshot of the demo application:

Demo App

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
High performance canvas-based rendering
Search and replace text
Language Server Protocol (LSP) support

Planned features

Multiple cursors for simultaneous editing at multiple positions
Collapse/expand blocks
Indentation-based or syntax-aware
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:

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

struct MyApp {
    editor: CodeEditor,
}

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

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

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

impl MyApp {
    fn update(&mut self, message: Message) -> Task<Message> {
        match message {
            Message::EditorEvent(event) => {
                self.editor.update(&event).map(Message::EditorEvent)
            }
        }
    }

    fn view(&self) -> Element<'_, Message> {
        container(self.editor.view().map(Message::EditorEvent))
            .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 4 spaces (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.

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

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 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.

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.

Demo Screenshot Dark Theme Demo Screenshot Light Theme

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.

Demo Application

A full-featured demo application is included in the demo-app directory, showcasing:

File operations (open, save, save as)
Theme switching
Modified state tracking
Clipboard operations
Full keyboard navigation

Run it with:

cargo run --package demo-app --release

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

iced-code-editor 0.3.7