Arboard

arboard

Cross-platform clipboard library by 1Password for reading and writing text and images. Provides a unified API across macOS, Windows, and Linux (X11/Wayland).

Crate: https://crates.io/crates/arboard Docs: https://docs.rs/arboard/latest/arboard/

Key Types

Clipboard

The main entry point. Create one instance to interact with the system clipboard.

use arboard::Clipboard;

let mut clipboard = Clipboard::new()?;

Important: Clipboard::new() returns Result<Clipboard, Error> - it can fail if:

• Clipboard is not supported on the platform/environment
• Another process is holding the clipboard (rare)

ImageData

Stores raw RGBA pixel data for clipboard images.

use arboard::ImageData;
use std::borrow::Cow;

let image = ImageData {
    width: 100,
    height: 100,
    bytes: Cow::Owned(vec![0u8; 100 * 100 * 4]), // RGBA: 4 bytes per pixel
};

Pixel Format:

• Row-major order (left-to-right, top-to-bottom)
• 4 channels per pixel: Red, Green, Blue, Alpha
• Each channel is 1 byte (0-255)
• Total bytes = width * height * 4

Error

Non-exhaustive enum with these variants:

• ContentNotAvailable - Clipboard empty or wrong format
• ClipboardNotSupported - Platform/environment doesn't support clipboard
• ClipboardOccupied - Another process is using the clipboard
• ConversionFailure - Image/text couldn't be converted
• Unknown { description } - Catch-all for other errors

Usage in script-kit-gpui

The codebase uses arboard for:

1. Clipboard History Monitoring (src/clipboard_history/monitor.rs)

   • Polls clipboard every 50-500ms
   • Captures both text and images
   • Uses content hashing for deduplication

2. Copy to Clipboard (src/clipboard_history/clipboard.rs)

   • Restores entries from history
   • Handles both text and image content types

3. Selected Text Operations (src/selected_text.rs)

   • Save/restore clipboard during text replacement
   • Clipboard-based paste simulation

4. Text Injection (src/text_injector.rs)

   • Snippet expansion via clipboard + Cmd+V
   • Preserves original clipboard contents

Pattern: Save and Restore

script-kit-gpui consistently uses this pattern when temporarily using the clipboard:

use arboard::Clipboard;
use anyhow::{Context, Result};

fn paste_via_clipboard(text: &str) -> Result<()> {
    let mut clipboard = Clipboard::new().context("Failed to access clipboard")?;
    
    // 1. Save original contents
    let original = clipboard.get_text().ok();
    
    // 2. Set new content
    clipboard.set_text(text).context("Failed to set clipboard")?;
    
    // 3. Perform operation (e.g., simulate Cmd+V)
    simulate_paste()?;
    
    // 4. Restore original (best effort)
    if let Some(original_text) = original {
        let _ = clipboard.set_text(&original_text);
    }
    
    Ok(())
}

Text Operations

Get Text

let mut clipboard = Clipboard::new()?;
match clipboard.get_text() {
    Ok(text) => println!("Got: {}", text),
    Err(arboard::Error::ContentNotAvailable) => println!("Empty or not text"),
    Err(e) => eprintln!("Error: {}", e),
}

Set Text

let mut clipboard = Clipboard::new()?;
clipboard.set_text("Hello, world!")?;

// Also accepts String, &String, Cow<str>
clipboard.set_text(String::from("owned"))?;

Set HTML

// HTML with plain text fallback
clipboard.set_html(
    "<b>Bold</b> text",
    Some("Bold text"), // Alt text for apps that don't support HTML
)?;

Image Operations

Get Image

let mut clipboard = Clipboard::new()?;
match clipboard.get_image() {
    Ok(image) => {
        println!("{}x{} image, {} bytes", 
            image.width, image.height, image.bytes.len());
    }
    Err(arboard::Error::ContentNotAvailable) => {
        println!("No image on clipboard");
    }
    Err(e) => eprintln!("Error: {}", e),
}

Set Image

use arboard::{Clipboard, ImageData};
use std::borrow::Cow;

let mut clipboard = Clipboard::new()?;

// Create a 2x2 red/green/blue/white test image
let pixels = vec![
    255, 0, 0, 255,    // Red pixel
    0, 255, 0, 255,    // Green pixel
    0, 0, 255, 255,    // Blue pixel
    255, 255, 255, 255, // White pixel
];

let image = ImageData {
    width: 2,
    height: 2,
    bytes: Cow::Owned(pixels),
};

clipboard.set_image(image)?;

Convert to Owned

Use to_owned_img() when you need to store the image beyond the clipboard's lifetime:

let image = clipboard.get_image()?;
let owned: ImageData<'static> = image.to_owned_img();
// Now safe to use after clipboard is dropped

Platform Specifics

macOS

• Uses NSPasteboard via objc2
• Images stored as NSImage objects
• Most reliable platform for clipboard operations
• Efficient change detection via changeCount

Windows

• Uses clipboard-win crate
• Important: Clipboard is a global object, only one thread can open it at a time
• Parallel operations may fail with ClipboardOccupied
• Image formats: CF_DIB, CF_BITMAP
• Recommended: Avoid creating Clipboard objects on multiple threads

Linux (X11/Wayland)

• Critical: Clipboard content is "hosted" by the application
• When last Clipboard instance is dropped, content may become unavailable to other apps!
• Use SetExtLinux trait for persistence options:

use arboard::{Clipboard, SetExtLinux};

let mut clipboard = Clipboard::new()?;
clipboard.set()
    .wait()  // Keep clipboard available after app exits (forks background process)
    .text("Persistent text")?;

• Primary vs Clipboard selections (X11):
  • LinuxClipboardKind::Clipboard - Ctrl+C/Ctrl+V (default)
  • LinuxClipboardKind::Primary - Middle-click paste

Builder API

For advanced operations, use the builder pattern:

let mut clipboard = Clipboard::new()?;

// Get with options
let text = clipboard.get()
    .text()?;

// Set with options  
clipboard.set()
    .text("content")?;

// Clear
clipboard.clear()?;

Integration with image Crate

script-kit-gpui converts between arboard::ImageData and the image crate:

use arboard::ImageData;
use image::RgbaImage;
use std::borrow::Cow;

// ImageData -> RgbaImage
fn to_rgba_image(img: &ImageData) -> Option<RgbaImage> {
    RgbaImage::from_raw(
        img.width as u32,
        img.height as u32,
        img.bytes.to_vec(),
    )
}

// RgbaImage -> ImageData
fn from_rgba_image(rgba: &RgbaImage) -> ImageData<'static> {
    ImageData {
        width: rgba.width() as usize,
        height: rgba.height() as usize,
        bytes: Cow::Owned(rgba.as_raw().clone()),
    }
}

Anti-patterns

Don't hold Clipboard across await points

// BAD: Clipboard held during async operation
let mut clipboard = Clipboard::new()?;
let text = clipboard.get_text()?;
some_async_operation().await; // Other processes blocked!
clipboard.set_text(&modified)?;

// GOOD: Drop clipboard before await
let text = {
    let mut clipboard = Clipboard::new()?;
    clipboard.get_text()?
};
some_async_operation().await;
{
    let mut clipboard = Clipboard::new()?;
    clipboard.set_text(&modified)?;
}

Don't assume content type

// BAD: Panics if clipboard has image
let text = clipboard.get_text().unwrap();

// GOOD: Handle both content types
if let Ok(text) = clipboard.get_text() {
    handle_text(&text);
} else if let Ok(image) = clipboard.get_image() {
    handle_image(&image);
}

Don't poll clipboard content directly on Linux

// BAD: Expensive on Linux (reads full payload)
loop {
    let content = clipboard.get_text();
    thread::sleep(Duration::from_millis(100));
}

// GOOD: Use OS-level change detection when available
// (macOS: NSPasteboard.changeCount, Windows: clipboard sequence number)

Don't forget to handle errors

// BAD: Silent failure
let _ = clipboard.set_text("text");

// GOOD: Log or propagate errors
clipboard.set_text("text").context("Failed to set clipboard")?;

Don't create ImageData with wrong byte count

// BAD: Bytes don't match dimensions
let image = ImageData {
    width: 100,
    height: 100,
    bytes: Cow::Owned(vec![0u8; 1000]), // Should be 40000!
};

// GOOD: Validate or compute correctly
let width = 100;
let height = 100;
let bytes = vec![0u8; width * height * 4];
let image = ImageData { width, height, bytes: Cow::Owned(bytes) };

Error Handling Best Practices

use arboard::{Clipboard, Error};
use anyhow::{Context, Result};

fn clipboard_operation() -> Result<String> {
    let mut clipboard = Clipboard::new()
        .context("Failed to access clipboard")?;
    
    match clipboard.get_text() {
        Ok(text) => Ok(text),
        Err(Error::ContentNotAvailable) => {
            // Empty clipboard is often expected
            Ok(String::new())
        }
        Err(Error::ClipboardOccupied) => {
            // Retry logic might help
            anyhow::bail!("Clipboard busy, try again")
        }
        Err(e) => {
            anyhow::bail!("Clipboard error: {}", e)
        }
    }
}

Feature Flags

• image-data (default) - Enable image support
• wayland-data-control - Use wl-clipboard protocol on Wayland

[dependencies]
arboard = { version = "3.6", default-features = false }  # Text only
arboard = { version = "3.6", features = ["image-data"] }  # With images