MCP Server Tauri

use super::{Screenshot, ScreenshotError}; use tauri::{Runtime, WebviewWindow}; /// Android-specific screenshot implementation using WebView.draw() /// /// This implementation captures the visible viewport by: /// 1. Getting the WebView dimensions via JNI /// 2. Creating a Bitmap with those dimensions /// 3. Creating a Canvas from the Bitmap /// 4. Drawing the WebView to the Canvas /// 5. Compressing the Bitmap to PNG bytes pub fn capture_viewport<R: Runtime>( window: &WebviewWindow<R>, ) -> Result<Screenshot, ScreenshotError> { #[cfg(target_os = "android")] { use jni::objects::{JByteArray, JValue}; use std::sync::mpsc; let (tx, rx) = mpsc::channel::<Result<Screenshot, ScreenshotError>>(); // Use Tauri's with_webview to access the Android WebView via JNI window .with_webview(move |webview| { webview .jni_handle() .exec(move |env, _activity, webview_obj| { let result: Result<Screenshot, ScreenshotError> = (|| { // Get WebView dimensions let width = env .call_method(webview_obj, "getWidth", "()I", &[]) .map_err(|e| { ScreenshotError::CaptureFailed(format!( "Failed to get width: {e}" )) })? .i() .map_err(|e| { ScreenshotError::CaptureFailed(format!("Invalid width: {e}")) })?; let height = env .call_method(webview_obj, "getHeight", "()I", &[]) .map_err(|e| { ScreenshotError::CaptureFailed(format!( "Failed to get height: {e}" )) })? .i() .map_err(|e| { ScreenshotError::CaptureFailed(format!("Invalid height: {e}")) })?; if width <= 0 || height <= 0 { return Err(ScreenshotError::CaptureFailed(format!( "Invalid WebView dimensions: {width}x{height}" ))); } // Create Bitmap with ARGB_8888 config let bitmap_class = env.find_class("android/graphics/Bitmap").map_err(|e| { ScreenshotError::CaptureFailed(format!( "Failed to find Bitmap class: {e}" )) })?; let config_class = env .find_class("android/graphics/Bitmap$Config") .map_err(|e| { ScreenshotError::CaptureFailed(format!( "Failed to find Bitmap.Config class: {e}" )) })?; let argb_8888 = env .get_static_field( &config_class, "ARGB_8888", "Landroid/graphics/Bitmap$Config;", ) .map_err(|e| { ScreenshotError::CaptureFailed(format!( "Failed to get ARGB_8888: {e}" )) })? .l() .map_err(|e| { ScreenshotError::CaptureFailed(format!( "Invalid ARGB_8888: {e}" )) })?; let bitmap = env .call_static_method( &bitmap_class, "createBitmap", "(IILandroid/graphics/Bitmap$Config;)Landroid/graphics/Bitmap;", &[ JValue::Int(width), JValue::Int(height), JValue::Object(&argb_8888), ], ) .map_err(|e| { ScreenshotError::CaptureFailed(format!( "Failed to create Bitmap: {e}" )) })? .l() .map_err(|e| { ScreenshotError::CaptureFailed(format!("Invalid Bitmap: {e}")) })?; // Create Canvas from Bitmap let canvas_class = env.find_class("android/graphics/Canvas").map_err(|e| { ScreenshotError::CaptureFailed(format!( "Failed to find Canvas class: {e}" )) })?; let canvas = env .new_object( &canvas_class, "(Landroid/graphics/Bitmap;)V", &[JValue::Object(&bitmap)], ) .map_err(|e| { ScreenshotError::CaptureFailed(format!( "Failed to create Canvas: {e}" )) })?; // Draw WebView to Canvas env.call_method( webview_obj, "draw", "(Landroid/graphics/Canvas;)V", &[JValue::Object(&canvas)], ) .map_err(|e| { ScreenshotError::CaptureFailed(format!( "Failed to draw WebView: {e}" )) })?; // Compress Bitmap to PNG bytes let baos_class = env .find_class("java/io/ByteArrayOutputStream") .map_err(|e| { ScreenshotError::CaptureFailed(format!( "Failed to find ByteArrayOutputStream class: {e}" )) })?; let baos = env.new_object(&baos_class, "()V", &[]).map_err(|e| { ScreenshotError::CaptureFailed(format!( "Failed to create ByteArrayOutputStream: {e}" )) })?; let compress_format_class = env .find_class("android/graphics/Bitmap$CompressFormat") .map_err(|e| { ScreenshotError::CaptureFailed(format!( "Failed to find CompressFormat class: {e}" )) })?; let png_format = env .get_static_field( &compress_format_class, "PNG", "Landroid/graphics/Bitmap$CompressFormat;", ) .map_err(|e| { ScreenshotError::CaptureFailed(format!( "Failed to get PNG format: {e}" )) })? .l() .map_err(|e| { ScreenshotError::CaptureFailed(format!( "Invalid PNG format: {e}" )) })?; env.call_method( &bitmap, "compress", "(Landroid/graphics/Bitmap$CompressFormat;ILjava/io/OutputStream;)Z", &[ JValue::Object(&png_format), JValue::Int(100), JValue::Object(&baos), ], ) .map_err(|e| { ScreenshotError::CaptureFailed(format!( "Failed to compress Bitmap: {e}" )) })?; // Get byte array from ByteArrayOutputStream let byte_array = env .call_method(&baos, "toByteArray", "()[B", &[]) .map_err(|e| { ScreenshotError::CaptureFailed(format!( "Failed to get byte array: {e}" )) })? .l() .map_err(|e| { ScreenshotError::CaptureFailed(format!( "Invalid byte array: {e}" )) })?; // Convert Java byte array to Rust Vec<u8> let byte_array = JByteArray::from(byte_array); let len = env.get_array_length(&byte_array).map_err(|e| { ScreenshotError::CaptureFailed(format!( "Failed to get array length: {e}" )) })? as usize; let mut data = vec![0i8; len]; env.get_byte_array_region(&byte_array, 0, &mut data) .map_err(|e| { ScreenshotError::CaptureFailed(format!( "Failed to copy byte array: {e}" )) })?; // Convert i8 to u8 (safe reinterpret) let data: Vec<u8> = data.into_iter().map(|b| b as u8).collect(); // Clean up: recycle the bitmap to free memory let _ = env.call_method(&bitmap, "recycle", "()V", &[]); Ok(Screenshot { data }) })(); let _ = tx.send(result); }); }) .map_err(|e| { ScreenshotError::CaptureFailed(format!("Failed to access webview: {e}")) })?; // Wait for result with timeout match rx.recv_timeout(std::time::Duration::from_secs(10)) { Ok(result) => result, Err(_) => Err(ScreenshotError::Timeout), } } #[cfg(not(target_os = "android"))] { let _ = window; Err(ScreenshotError::PlatformUnsupported) } }