Utilities API

Sharp provides various utility functions to assist with image processing and format conversion.

Format Detection

Detect Supported Formats

import sharp from 'sharp';

// Get supported input formats
console.log('Supported input formats:', sharp.format);

// Get supported output formats
console.log('Supported output formats:', sharp.format);

Check File Format

async function checkImageFormat(filePath) {
  try {
    const metadata = await sharp(filePath).metadata();
    return {
      format: metadata.format,
      width: metadata.width,
      height: metadata.height,
      channels: metadata.channels
    };
  } catch (error) {
    return { error: error.message };
  }
}

Color Spaces

Color Spaces Constants

// Available color spaces
sharp.colourspace.srgb      // sRGB
sharp.colourspace.rgb       // RGB
sharp.colourspace.cmyk      // CMYK
sharp.colourspace.grey      // Greyscale
sharp.colourspace.multiband // Multiband
sharp.colourspace.lab       // Lab
sharp.colourspace.xyz       // XYZ
sharp.colourspace.ycbcr     // YCbCr

Color Space Conversion

// Convert to grayscale
sharp('input.jpg')
  .grayscale()
  .toFile('output.jpg');

// Convert to CMYK
sharp('input.jpg')
  .toColourspace(sharp.colourspace.cmyk)
  .tiff()
  .toFile('output.tiff');

Kernels and Filters

Adjust Kernels

// Available kernels
sharp.kernel.nearest      // Nearest neighbor
sharp.kernel.cubic        // Cubic interpolation
sharp.kernel.mitchell     // Mitchell-Netravali
sharp.kernel.lanczos2     // Lanczos 2-lobed
sharp.kernel.lanczos3     // Lanczos 3-lobed (default)

Use Custom Kernel

// Use custom kernel
sharp('input.jpg')
  .resize(300, 200, { kernel: sharp.kernel.lanczos3 })
  .toFile('output.jpg');

Position Constants

Position Options

// Available position options
sharp.position.top         // Top
sharp.position.right       // Right
sharp.position.bottom      // Bottom
sharp.position.left        // Left
sharp.position.center      // Center (default)
sharp.position.centre      // Centre (British spelling)
sharp.position.north       // North (top)
sharp.position.east        // East (right)
sharp.position.south       // South (bottom)
sharp.position.west        // West (left)
sharp.position.northeast   // Northeast
sharp.position.southeast   // Southeast
sharp.position.southwest   // Southwest
sharp.position.northwest   // Northwest

Channel Operations

Channel Constants

// Channel constants
sharp.channel.red          // Red channel
sharp.channel.green        // Green channel
sharp.channel.blue         // Blue channel
sharp.channel.alpha        // Alpha channel
sharp.channel.grey         // Grey channel

Channel Operations

// Extract red channel
sharp('input.jpg')
  .extractChannel(sharp.channel.red)
  .toFile('red-channel.jpg');

// Extract all channels
const channels = await sharp('input.jpg').separate();

Error Handling

Error Types

// Common Sharp errors
sharp.errors.InputError     // Input error
sharp.errors.ProcessError   // Process error
sharp.errors.OutputError    // Output error

Error Handling Example

try {
  await sharp('input.jpg')
    .resize(300, 200)
    .toFile('output.jpg');
} catch (error) {
  if (error instanceof sharp.errors.InputError) {
    console.error('Input file error:', error.message);
  } else if (error instanceof sharp.errors.ProcessError) {
    console.error('Process error:', error.message);
  } else if (error instanceof sharp.errors.OutputError) {
    console.error('Output error:', error.message);
  } else {
    console.error('Unknown error:', error.message);
  }
}

Performance Monitoring

Memory Usage

// Get Sharp memory usage
const stats = sharp.cache();
console.log('Cache statistics:', stats);

// Clear cache
sharp.cache(false);

Concurrent Control

// Set concurrent limit
sharp.concurrency(4); // Maximum 4 concurrent operations

// Get current concurrent count
console.log('Current concurrent count:', sharp.concurrency());

Utility Functions

Create Test Image

// Create solid color image
const redImage = sharp({
  create: {
    width: 300,
    height: 200,
    channels: 3,
    background: { r: 255, g: 0, b: 0 }
  }
});

// Create gradient image
const gradient = sharp({
  create: {
    width: 300,
    height: 200,
    channels: 3,
    background: { r: 0, g: 0, b: 0 }
  }
});

Image Composition

// Composite multiple images
const composite = await sharp('background.jpg')
  .composite([
    {
      input: 'overlay.png',
      top: 100,
      left: 100
    }
  ])
  .jpeg()
  .toBuffer();

Batch Processing Tools

Batch Resize

const fs = require('fs').promises;

async function batchResize(inputDir, outputDir, width, height) {
  const files = await fs.readdir(inputDir);
  
  for (const file of files) {
    if (file.match(/\.(jpg|jpeg|png|webp)$/i)) {
      try {
        await sharp(`${inputDir}/${file}`)
          .resize(width, height)
          .jpeg({ quality: 80 })
          .toFile(`${outputDir}/${file}`);
        
        console.log(`Processing completed: ${file}`);
      } catch (error) {
        console.error(`Processing failed ${file}:`, error.message);
      }
    }
  }
}

Batch Format Conversion

async function batchConvert(inputDir, outputDir, format) {
  const files = await fs.readdir(inputDir);
  
  for (const file of files) {
    if (file.match(/\.(jpg|jpeg|png|webp)$/i)) {
      const outputFile = file.replace(/\.[^.]+$/, `.${format}`);
      
      try {
        const image = sharp(`${inputDir}/${file}`);
        
        switch (format) {
          case 'jpg':
          case 'jpeg':
            await image.jpeg({ quality: 80 }).toFile(`${outputDir}/${outputFile}`);
            break;
          case 'png':
            await image.png().toFile(`${outputDir}/${outputFile}`);
            break;
          case 'webp':
            await image.webp({ quality: 80 }).toFile(`${outputDir}/${outputFile}`);
            break;
          case 'avif':
            await image.avif({ quality: 80 }).toFile(`${outputDir}/${outputFile}`);
            break;
        }
        
        console.log(`Conversion completed: ${file} -> ${outputFile}`);
      } catch (error) {
        console.error(`Conversion failed ${file}:`, error.message);
      }
    }
  }
}

Validation Tools

Validate Image Integrity

async function validateImage(filePath) {
  try {
    const metadata = await sharp(filePath).metadata();
    
    // Check basic properties
    if (!metadata.width || !metadata.height) {
      return { valid: false, error: 'Missing size information' };
    }
    
    if (metadata.width <= 0 || metadata.height <= 0) {
      return { valid: false, error: 'Invalid size' };
    }
    
    if (!metadata.format) {
      return { valid: false, error: 'Missing format information' };
    }
    
    // Try to process image
    await sharp(filePath).resize(1, 1).toBuffer();
    
    return { valid: true, metadata };
  } catch (error) {
    return { valid: false, error: error.message };
  }
}

Check File Size

const fs = require('fs');

function checkFileSize(filePath, maxSize = 10 * 1024 * 1024) { // 10MB in bytes
  const stats = fs.statSync(filePath);
  const sizeInMB = stats.size / (1024 * 1024);
  
  return {
    size: stats.size,
    sizeInMB,
    isValid: stats.size <= maxSize,
    maxSizeInMB: maxSize / (1024 * 1024)
  };
}

Related Links

• Sharp Constructor
• Image Processing API
• Output Format API
• Metadata API