Node.js使用Sharp.js进行图像处理的实践与技巧

npm install sharp

const sharp = require('sharp');

sharp('input.jpg')
  .toFile('output.png', (err, info) => {
    if (err) throw err;
    console.log(`Output image saved with size ${info.size}`);
  });

sharp('input.jpg')
  .toFormat('webp')
  .toFile('output.webp', (err, info) => {
    if (err) throw err;
    console.log(`Converted to WebP, output image saved with size ${info.size}`);
  });

sharp('input.jpg')
  .extract({ left: 100, top: 50, width: 300, height: 200 })
  .toFile('output_cropped.jpg', (err, info) => {
    if (err) throw err;
    console.log(`Cropped image saved with size ${info.size}`);
  });

sharp('input.jpg')
  .rotate(90)
  .toFile('output_rotated.jpg', (err, info) => {
    if (err) throw err;
    console.log(`Rotated image saved with size ${info.size}`);
  });

sharp('input.jpg')
  .resize(800, 600) // 先缩放到指定尺寸
  .sharpen() // 应用锐化滤镜
  .blur(10) // 应用模糊滤镜，参数为模糊半径
  .toFile('output_filtered.jpg', (err, info) => {
    if (err) throw err;
    console.log(`Filtered image saved with size ${info.size}`);
  });

const http = require('http');
const fs = require('fs');

http.get('http://example.com/large-image.jpg', (response) => {
  response.pipe(
    sharp()
      .resize(800, 600)
      .jpeg({ quality: 80 })
      .toBuffer((err, buffer, info) => {
        if (err) throw err;
        console.log(`Resized & compressed image has size ${info.size}`);
        fs.writeFileSync('output_from_stream.jpg', buffer);
      })
  );
});

const fs = require('fs');
const path = require('path');
const { promisify } = require('util');
const sharp = require('sharp');
const readdirAsync = promisify(fs.readdir);

async function processImages(directory, outputDir) {
  const files = await readdirAsync(directory);
  const imageFiles = files.filter((file) => /\.(jpg|png)$/i.test(file));
  
  const resizePromises = imageFiles.map(async (imageFile) => {
    const inputPath = path.join(directory, imageFile);
    const outputPath = path.join(outputDir, `${Date.now()}_${imageFile}`);
    // 进行图像处理操作
  });

  await Promise.all(resizePromises);
}

sharp('input.jpg')
  .resize(null, null, { withoutEnlargement: true })
  .toFormat('jpeg', { quality: 75 })
  .toFile('output_compressed.jpg', (err, info) => {
    if (err) throw err;
    console.log(`Compressed image saved with size ${info.size}`);
  });