Android UI Assist MCP Server

import { captureScreenshot } from './adb'; import { ScreenshotResponse } from '../types'; // Get image dimensions from PNG data export function getPNGDimensions(pngData: Buffer): { width: number; height: number } { // PNG signature: 89 50 4E 47 0D 0A 1A 0A if (pngData.length < 24 || pngData.toString('hex', 0, 8) !== '89504e470d0a1a0a') { throw new Error('Invalid PNG data'); } // The first chunk is IHDR which starts at byte 8 // The chunk length is at bytes 8-11 (big-endian) // The chunk type is at bytes 12-15 // The width is at bytes 16-19 (big-endian) // The height is at bytes 20-23 (big-endian) const width = pngData.readUInt32BE(16); const height = pngData.readUInt32BE(20); return { width, height }; } // Convert binary data to base64 export function binaryToBase64(data: Buffer): string { return data.toString('base64'); } // Capture screenshot and return formatted response export async function captureScreenshotResponse(deviceId?: string): Promise<ScreenshotResponse> { try { // Capture screenshot as binary data (now returns Buffer directly) const buffer = captureScreenshot(deviceId); // Get image dimensions const { width, height } = getPNGDimensions(buffer); // Convert to base64 const base64Data = binaryToBase64(buffer); // Return formatted response return { data: base64Data, format: 'png', width, height, deviceId: deviceId || 'default', timestamp: Date.now(), }; } catch (error) { throw new Error( `Failed to capture screenshot: ${error instanceof Error ? error.message : String(error)}` ); } }