Specter MCP

/** * Image Utilities * Screenshot compression and processing using sharp */ import sharp from 'sharp'; import { ScreenshotData } from '../models/ui-context.js'; import { DEFAULTS } from '../models/constants.js'; /** * Options for screenshot compression */ export interface CompressionOptions { /** JPEG quality (1-100, default: 50) */ quality?: number; /** Maximum dimension (width or height) */ maxDimension?: number; /** Output format */ format?: 'jpeg' | 'png'; } /** * Compress a screenshot buffer */ export async function compressScreenshot( input: Buffer, options: CompressionOptions = {} ): Promise<ScreenshotData> { const { quality = DEFAULTS.SCREENSHOT_QUALITY, maxDimension, format = 'jpeg', } = options; let processor = sharp(input); // Get original metadata const metadata = await processor.metadata(); const originalWidth = metadata.width || 0; const originalHeight = metadata.height || 0; // Resize if maxDimension is specified if (maxDimension && (originalWidth > maxDimension || originalHeight > maxDimension)) { const aspectRatio = originalWidth / originalHeight; let newWidth: number; let newHeight: number; if (originalWidth > originalHeight) { newWidth = maxDimension; newHeight = Math.round(maxDimension / aspectRatio); } else { newHeight = maxDimension; newWidth = Math.round(maxDimension * aspectRatio); } processor = processor.resize(newWidth, newHeight, { fit: 'inside', withoutEnlargement: true, }); } // Apply format-specific compression let outputBuffer: Buffer; if (format === 'jpeg') { outputBuffer = await processor .jpeg({ quality, mozjpeg: true, }) .toBuffer(); } else { outputBuffer = await processor .png({ compressionLevel: Math.round((100 - quality) / 10), }) .toBuffer(); } // Get output metadata const outputMetadata = await sharp(outputBuffer).metadata(); return { data: outputBuffer.toString('base64'), format, width: outputMetadata.width || originalWidth, height: outputMetadata.height || originalHeight, sizeBytes: outputBuffer.length, compressed: true, quality, }; } /** * Resize a screenshot to maximum dimension while maintaining aspect ratio */ export async function resizeScreenshot( input: Buffer, maxDimension: number ): Promise<Buffer> { const metadata = await sharp(input).metadata(); const width = metadata.width || 0; const height = metadata.height || 0; if (width <= maxDimension && height <= maxDimension) { return input; } return sharp(input) .resize(maxDimension, maxDimension, { fit: 'inside', withoutEnlargement: true, }) .toBuffer(); } /** * Get image metadata */ export async function getImageMetadata( input: Buffer ): Promise<{ width: number; height: number; format: string }> { const metadata = await sharp(input).metadata(); return { width: metadata.width || 0, height: metadata.height || 0, format: metadata.format || 'unknown', }; } /** * Convert image to base64 without compression */ export function bufferToBase64(buffer: Buffer): string { return buffer.toString('base64'); } /** * Detect image format from buffer */ export function detectImageFormat(buffer: Buffer): 'png' | 'jpeg' | 'unknown' { if (buffer.length < 4) return 'unknown'; // PNG magic bytes: 89 50 4E 47 if ( buffer[0] === 0x89 && buffer[1] === 0x50 && buffer[2] === 0x4e && buffer[3] === 0x47 ) { return 'png'; } // JPEG magic bytes: FF D8 FF if (buffer[0] === 0xff && buffer[1] === 0xd8 && buffer[2] === 0xff) { return 'jpeg'; } return 'unknown'; } /** * Create a placeholder ScreenshotData when screenshot capture is skipped */ export function createEmptyScreenshot(): ScreenshotData { return { data: '', format: 'png', width: 0, height: 0, sizeBytes: 0, compressed: false, }; } /** * Calculate compression ratio */ export function calculateCompressionRatio( originalSize: number, compressedSize: number ): number { if (originalSize === 0) return 0; return Math.round((1 - compressedSize / originalSize) * 100); }