Implement complete screenshot functionality with multi-backend support

Cargo.toml

@@ -2,14 +2,66 @@
 name = "cosmic-screenshot"
 version = "0.1.0"
 edition = "2021"
+license = "GPL-3.0-only"
+description = "Screenshot functionality for COSMIC desktop with D-Bus interface"
+repository = "https://github.com/pop-os/cosmic-screenshot"
+
+[features]
+default = []
+debug = []
+
+[lib]
+name = "cosmic_screenshot"
+crate-type = ["cdylib", "rlib"]
+
+[[bin]]
+name = "cosmic-screenshot"
+path = "src/main.rs"
 
 [dependencies]
-ashpd = { version = "0.6.8", default-features = false, features = ["tokio"] }
+ashpd = { version = "0.11", default-features = false, features = ["tokio"] }
+async-trait = "0.1"
 chrono = { version = "0.4.24", default-features = false, features = ["alloc", "clock"] }
-dirs = "5.0.1"
-tokio = { version = "1.28.1", default-features = false, features = ["macros"] }
 clap = { version = "4.4.16", features = ["derive"] }
-zbus = { version = "3", default-features = false }
+cosmic-config = { git = "https://github.com/pop-os/libcosmic.git" }
+dirs = "5.0.1"
+futures-util = "0.3.31"
+image = "0.25"
+libc = "0.2"
+nix = { version = "0.29", features = ["process", "user", "fs"] }
+open = "5.3.0"
+serde = { version = "1.0", features = ["derive"] }
+tempfile = "3.0"
+thiserror = "1.0"
+tokio = { version = "1.41.0", features = ["full"] }
+zbus = { version = "5", default-features = false }
+
+[dependencies.libcosmic]
+git = "https://github.com/pop-os/libcosmic.git"
+# See https://github.com/pop-os/libcosmic/blob/master/Cargo.toml for available features.
+features = [
+    # Accessibility support
+#    "a11y",
+    # Uses cosmic-settings-daemon to watch for config file changes
+    "dbus-config",
+    # Support creating additional application windows.
+    "multi-window",
+    # On app startup, focuses an existing instance if the app is already open
+    "single-instance",
+    # Uses tokio as the executor for the runtime
+    "tokio",
+    # Windowing support for X11, Windows, Mac, & Redox
+    "winit",
+    # Add Wayland support to winit
+    "wayland",
+    # GPU-accelerated rendering
+    "wgpu",
+    # File dialogs
+    "xdg-portal",
+]
+default-features = false
+[build-dependencies]
+vergen = { version = "8", features = ["git", "gitcl"] }
 
 [profile.release]
 codegen-units = 1

README.md

@@ -1,3 +1,300 @@
 # cosmic-screenshot
 
-Utility for capturing screenshots via XDG Desktop Portal
+A screenshot tool for Linux desktop environments with multi-backend support, GUI, CLI, D-Bus service, and library API.
+
+## Features
+
+### Core Functionality
+- **Multi-backend screenshot system** with automatic fallback
+- **Interactive region selection** with fullscreen overlay and snipper
+- **All screenshot types**: Full desktop, current screen, window selection, interactive screen selection, and rectangular regions
+- **COSMIC UI** with persistent settings and 360p thumbnails
+- **Command-line interface** with comprehensive options
+- **D-Bus service** for system integration
+- **Library API** for use in other applications
+
+### Screenshot Backends
+- **KWin ScreenShot2**: Preferred backend with full feature support
+- **Freedesktop Portal**: Fallback backend with workspace/interactive support
+- **Automatic backend selection** with intelligent capability-based routing
+
+### User Interface
+- **COSMIC-native GUI** following official design standards
+- **Persistent settings** using cosmic-config
+- **Screenshot-on-startup** feature
+- **Memory of selection areas** across sessions (optional)
+- **Professional interaction model** with resize handles and keyboard shortcuts
+- **Native file dialogs** with directory persistence
+
+### Integration
+- **Complete D-Bus API** (`com.system76.CosmicScreenshot`)
+- **Desktop file** with multiple screenshot actions
+- **System service** support with automatic activation
+- **Multi-window architecture** with performance optimization
+- **Cross-platform compatibility** (Linux desktop environments)
+
+## Installation
+
+### From Source
+
+#### Prerequisites
+- Rust (latest stable)
+- `just` command runner
+- System libraries: libxkbcommon, wayland, vulkan, mesa, fontconfig, freetype, X11
+
+```bash
+git clone <repository-url>
+cd cosmic-screenshot
+just build-release
+```
+
+#### Debian/Ubuntu
+```bash
+sudo apt install build-essential just pkg-config \
+    libxkbcommon-dev libwayland-dev libvulkan-dev libgl-dev \
+    mesa-common-dev libinput-dev libfontconfig-dev libfreetype6-dev \
+    libx11-dev libxcursor-dev libxi-dev libxrandr-dev
+```
+
+#### Arch Linux
+```bash
+sudo pacman -S just pkg-config libxkbcommon wayland vulkan-loader \
+    mesa libinput fontconfig freetype2 libx11 libxcursor libxi libxrandr
+```
+
+### Nix/NixOS
+```bash
+# Build with Nix
+nix-build
+```
+
+## Usage
+
+### GUI Application
+```bash
+# Launch the GUI
+cosmic-screenshot gui
+
+# Or simply
+cosmic-screenshot
+```
+
+### Command Line Interface
+
+#### Basic Screenshots
+```bash
+# Full desktop screenshot
+cosmic-screenshot take --kind all
+
+# Current screen only  
+cosmic-screenshot take --kind screen
+
+# Window selection
+cosmic-screenshot take --kind window
+
+# Interactive screen selection
+cosmic-screenshot take --kind select
+
+# Interactive region selection (launches GUI)
+cosmic-screenshot take --kind region
+```
+
+#### Advanced Options
+```bash
+# Screenshot with 3 second delay
+cosmic-screenshot take --kind all --delay 3000
+
+# Save to clipboard
+cosmic-screenshot take --kind all --clipboard
+
+# Save to specific directory
+cosmic-screenshot take --kind all --output-dir ~/Pictures/Screenshots
+
+# Use specific backend
+cosmic-screenshot take --kind all --backend kwin
+
+# Combined options
+cosmic-screenshot take --kind region --delay 2000 --clipboard --output-dir ~/Desktop
+```
+
+### Backend Management
+```bash
+# List available backends
+cosmic-screenshot backends
+
+# Test D-Bus functionality
+cosmic-screenshot test-dbus
+
+# Generate D-Bus XML interface definition
+cosmic-screenshot generate-dbus-xml
+```
+
+### D-Bus Service
+```bash
+# Start the D-Bus service
+cosmic-screenshot service
+
+# Use from other applications via D-Bus
+dbus-send --session --print-reply \
+  --dest=com.system76.CosmicScreenshot \
+  /com/system76/CosmicScreenshot \
+  com.system76.CosmicScreenshot.take_screenshot \
+  string:"all" uint32:0 boolean:false string:""
+```
+
+## D-Bus API Reference
+
+### Service Information
+- **Service**: `com.system76.CosmicScreenshot`
+- **Object Path**: `/com/system76/CosmicScreenshot`
+- **Interface**: `com.system76.CosmicScreenshot`
+
+### Available Methods
+
+#### `take_screenshot(kind, delay_ms, save_to_clipboard, save_dir) → result`
+Take a screenshot with basic options.
+
+#### `take_screenshot_with_backend(kind, delay_ms, save_to_clipboard, save_dir, backend) → result`
+Take a screenshot with specific backend selection.
+
+#### `get_available_backends() → backends`
+List all available screenshot backends.
+
+#### `supports_kind(kind) → supported`
+Check if a screenshot type is supported.
+
+#### `supports_kind_with_backend(kind, backend) → supported`
+Check if a specific backend supports a screenshot type.
+
+#### `get_backend_capabilities() → capabilities`
+Get detailed capability matrix for all backends.
+
+### Screenshot Types
+- `"all"` - All screens
+- `"screen"` - Current screen  
+- `"window"` - Window under cursor
+- `"select"` - Interactive screen selection
+- `"region"` - Interactive region selection (use CLI, not supported via D-Bus)
+
+### Backend Types
+- `"auto"` - Automatic selection (default)
+- `"kwin"` - KWin ScreenShot2 backend
+- `"freedesktop"` - Freedesktop Portal backend
+
+## Library Usage
+
+Add to your `Cargo.toml`:
+```toml
+[dependencies]
+cosmic-screenshot = { path = "path/to/cosmic-screenshot" }
+```
+
+Basic usage:
+```rust
+use cosmic_screenshot::screenshot::{ScreenshotManager, ScreenshotKind, ScreenshotOptions};
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let manager = ScreenshotManager::new();
+
+    let options = ScreenshotOptions {
+        kind: ScreenshotKind::AllScreens,
+        delay_ms: 0,
+        save_to_clipboard: false,
+        save_dir: Some(PathBuf::from("~/Pictures")),
+    };
+
+    let result = manager.take_screenshot(&options).await?;
+    println!("Screenshot saved to: {:?}", result.path);
+
+    Ok(())
+}
+```
+
+## Architecture
+
+### Multi-Backend System
+cosmic-screenshot uses a backend system that automatically detects available screenshot methods and routes requests to the most appropriate backend:
+
+1. **KWin ScreenShot2**: Primary backend for KDE/Plasma environments
+2. **Freedesktop Portal**: Universal fallback for all desktop environments
+3. **Automatic Selection**: Intelligent routing based on availability and capabilities
+
+### Performance Features
+- Image handle caching
+- Window reuse for GUI performance
+- Canvas optimization
+- Single tokio runtime architecture
+
+### Settings
+User preferences saved with cosmic-config:
+- Screenshot type and backend selection
+- Delay and clipboard settings
+- Directory and selection area memory
+- Screenshot-on-startup option
+
+## Development
+
+### Building
+```bash
+# Debug build
+just build-debug
+
+# Release build with debug features
+cargo build --features debug --release
+
+# Release build
+just build-release
+
+# Run with backtrace
+just run
+
+# Linter
+just check
+```
+
+### Testing
+```bash
+# Test all backends
+cosmic-screenshot test-dbus
+
+# Test specific functionality
+cargo test
+```
+
+### Contributing
+1. Follow the existing code style and architecture
+2. Test across different desktop environments
+3. Update documentation as needed
+
+## Troubleshooting
+
+### KWin Backend Issues
+If KWin screenshots fail:
+```bash
+# Check KWin D-Bus availability
+qdbus org.kde.KWin /org/kde/KWin/ScreenShot2
+
+# Force portal fallback
+cosmic-screenshot take --kind all --backend freedesktop
+```
+
+### Permissions
+Required access:
+- D-Bus session bus
+- Screen capture (via portal/KWin authorization)
+- Output directory write permissions
+
+### Debug Information
+Enable debug logging:
+```bash
+COSMIC_SCREENSHOT_DEBUG=1 cosmic-screenshot [command]
+```
+
+## License
+
+GPL-3.0-only - see [LICENSE](LICENSE) file for details.
+
+## Dependencies
+
+Built with [libcosmic](https://github.com/pop-os/libcosmic) UI toolkit.

build.rs

@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-3.0-only
+
+use vergen::EmitBuilder;
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    EmitBuilder::builder()
+        .all_git()
+        .emit()?;
+    Ok(())
+}