librawspeed
Version:
Node.js Native Addon for LibRaw - Process RAW image files with JavaScript
318 lines (270 loc) • 11.2 kB
JavaScript
const LibRaw = require("../lib/index");
const fs = require("fs");
const path = require("path");
/**
* API 比较：基于文件 vs 基于缓冲区
*
* 此示例演示了传统基于文件的 API 和新的基于缓冲区的 API 之间的差异，
* 突出了每种方法的优势。
*/
async function apiComparisonExample(inputFile, outputDir) {
console.log("🔄 API 比较：文件 vs 缓冲区操作");
console.log("============================================");
console.log(`📁 输入: ${inputFile}`);
console.log(`📂 输出目录: ${outputDir}\n`);
// 确保输出目录存在
if (!fs.existsSync(outputDir)) {
fs.mkdirSync(outputDir, { recursive: true });
}
const processor = new LibRaw();
const baseName = path.basename(inputFile, path.extname(inputFile));
try {
// 加载 RAW 文件一次
console.log("🔄 加载 RAW 文件...");
await processor.loadFile(inputFile);
console.log("✅ RAW 文件已加载\n");
// ============== 旧方式：基于文件的 API ==============
console.log("📁 旧方式：基于文件的操作");
console.log("==================================");
const fileStartTime = Date.now();
// 传统方法：处理并写入文件
console.log("1️⃣ 处理图像...");
await processor.processImage();
console.log("2️⃣ 写入 TIFF 文件...");
const tiffPath = path.join(outputDir, `${baseName}_traditional.tiff`);
await processor.writeTIFF(tiffPath);
console.log("3️⃣ 写入 PPM 文件...");
const ppmPath = path.join(outputDir, `${baseName}_traditional.ppm`);
await processor.writePPM(ppmPath);
console.log("4️⃣ 写入缩略图...");
const thumbPath = path.join(outputDir, `${baseName}_traditional_thumb.jpg`);
await processor.writeThumbnail(thumbPath);
// 传统 JPEG 转换
console.log("5️⃣ 转换为 JPEG...");
const jpegPath = path.join(outputDir, `${baseName}_traditional.jpg`);
await processor.convertToJPEG(jpegPath, {
quality: 85,
width: 1920,
});
const fileEndTime = Date.now();
const fileProcessingTime = fileEndTime - fileStartTime;
console.log(`✅ 基于文件的处理完成，用时 ${fileProcessingTime}ms`);
// 检查文件大小
const fileSizes = {
tiff: fs.statSync(tiffPath).size,
ppm: fs.statSync(ppmPath).size,
thumb: fs.statSync(thumbPath).size,
jpeg: fs.statSync(jpegPath).size,
};
console.log("📊 文件大小:");
Object.entries(fileSizes).forEach(([format, size]) => {
console.log(
` ${format.toUpperCase()}: ${(size / 1024 / 1024).toFixed(2)} MB`
);
});
// ============== 新方式：基于缓冲区的 API ==============
console.log("\n🚀 新方式：基于缓冲区的操作");
console.log("===================================");
const bufferStartTime = Date.now();
// 现代方法：在内存中创建缓冲区
console.log("1️⃣ 创建 TIFF 缓冲区...");
const tiffBuffer = await processor.createTIFFBuffer({
compression: "lzw",
});
console.log("2️⃣ 创建 PPM 缓冲区...");
const ppmBuffer = await processor.createPPMBuffer();
console.log("3️⃣ 创建缩略图缓冲区...");
const thumbBuffer = await processor.createThumbnailJPEGBuffer({
quality: 85,
});
console.log("4️⃣ 创建 JPEG 缓冲区...");
const jpegBuffer = await processor.createJPEGBuffer({
quality: 85,
width: 1920,
});
// 额外：并行创建多种格式
console.log("5️⃣ 并行创建其他格式...");
const [webpBuffer, avifBuffer, pngBuffer] = await Promise.all([
processor.createWebPBuffer({ quality: 80, width: 1920 }),
processor.createAVIFBuffer({ quality: 50, width: 1920 }),
processor.createPNGBuffer({ width: 800, compressionLevel: 6 }),
]);
const bufferEndTime = Date.now();
const bufferProcessingTime = bufferEndTime - bufferStartTime;
console.log(
`✅ 基于缓冲区的处理完成，用时 ${bufferProcessingTime}ms`
);
// 将缓冲区保存到文件进行比较（可选步骤）
console.log("6️⃣ 将缓冲区保存到文件进行比较...");
fs.writeFileSync(
path.join(outputDir, `${baseName}_buffer.tiff`),
tiffBuffer.buffer
);
fs.writeFileSync(
path.join(outputDir, `${baseName}_buffer.ppm`),
ppmBuffer.buffer
);
fs.writeFileSync(
path.join(outputDir, `${baseName}_buffer_thumb.jpg`),
thumbBuffer.buffer
);
fs.writeFileSync(
path.join(outputDir, `${baseName}_buffer.jpg`),
jpegBuffer.buffer
);
fs.writeFileSync(
path.join(outputDir, `${baseName}_buffer.webp`),
webpBuffer.buffer
);
fs.writeFileSync(
path.join(outputDir, `${baseName}_buffer.avif`),
avifBuffer.buffer
);
fs.writeFileSync(
path.join(outputDir, `${baseName}_buffer.png`),
pngBuffer.buffer
);
console.log("📊 缓冲区大小:");
const buffers = {
TIFF: tiffBuffer.buffer,
PPM: ppmBuffer.buffer,
Thumbnail: thumbBuffer.buffer,
JPEG: jpegBuffer.buffer,
WebP: webpBuffer.buffer,
AVIF: avifBuffer.buffer,
PNG: pngBuffer.buffer,
};
Object.entries(buffers).forEach(([format, buffer]) => {
console.log(
` ${format}: ${(buffer.length / 1024 / 1024).toFixed(2)} MB`
);
});
// ============== 性能比较 ==============
console.log("\n⚡ 性能比较");
console.log("========================");
console.log(`📁 基于文件的方法: ${fileProcessingTime}ms`);
console.log(`🚀 基于缓冲区的方法: ${bufferProcessingTime}ms`);
const speedImprovement =
((fileProcessingTime - bufferProcessingTime) / fileProcessingTime) * 100;
if (speedImprovement > 0) {
console.log(
`🏆 缓冲区方法快 ${speedImprovement.toFixed(1)}%！`
);
} else {
console.log(
`📊 性能差异: ${Math.abs(speedImprovement).toFixed(1)}%`
);
}
// ============== 使用案例建议 ==============
console.log("\n💡 何时使用每种方法");
console.log("=============================");
console.log("\n📁 使用基于文件的 API 当:");
console.log(" • 您需要将最终图像保存到磁盘");
console.log(" • 处理大图像（内存限制）");
console.log(" • 构建传统桌面应用程序");
console.log(" • 创建永久存档");
console.log(" • 与基于文件的工作流程集成");
console.log("\n🚀 使用基于缓冲区的 API 当:");
console.log(" • 构建 Web 服务和 API");
console.log(" • 上传到云存储");
console.log(" • 创建图像处理管道");
console.log(" • 实时图像处理");
console.log(" • 无服务器/ Lambda 函数");
console.log(" • 流式图像数据");
console.log(" • 从单一源创建多种格式");
// ============== 代码示例 ==============
console.log("\n📝 代码示例");
console.log("================");
console.log("\n📁 基于文件的方法:");
console.log("```javascript");
console.log("// 传统方式");
console.log('await processor.loadFile("input.raw");');
console.log("await processor.processImage();");
console.log(
'await processor.convertToJPEG("output.jpg", { quality: 85 });'
);
console.log('// 文件现在在磁盘上的 "output.jpg"');
console.log("```");
console.log("\n🚀 基于缓冲区的方法:");
console.log("```javascript");
console.log("// 现代方式");
console.log('await processor.loadFile("input.raw");');
console.log(
"const result = await processor.createJPEGBuffer({ quality: 85 });"
);
console.log("// result.buffer 包含 JPEG 数据");
console.log("// 直接使用，无需文件 I/O");
console.log("```");
console.log("\n🌐 Web 服务示例:");
console.log("```javascript");
console.log('app.post("/convert", async (req, res) => {');
console.log(" const processor = new LibRaw();");
console.log(" await processor.loadBuffer(req.body);");
console.log(" const result = await processor.createJPEGBuffer({");
console.log(" quality: 85,");
console.log(" width: 1920");
console.log(" });");
console.log(' res.set("Content-Type", "image/jpeg");');
console.log(" res.send(result.buffer);");
console.log("});");
console.log("```");
console.log("\n☁️ 云存储示例:");
console.log("```javascript");
console.log(
"const result = await processor.createJPEGBuffer({ quality: 90 });"
);
console.log(
'await cloudBucket.file("processed.jpg").save(result.buffer, {'
);
console.log(" metadata: {");
console.log(' contentType: "image/jpeg",');
console.log(' cacheControl: "public, max-age=31536000"');
console.log(" }");
console.log("});");
console.log("```");
// ============== FORMAT COMPARISON ==============
console.log("\n🎨 Format Efficiency Comparison");
console.log("===============================");
const formats = [
{ name: "AVIF", buffer: avifBuffer.buffer, extension: ".avif" },
{ name: "WebP", buffer: webpBuffer.buffer, extension: ".webp" },
{ name: "JPEG", buffer: jpegBuffer.buffer, extension: ".jpg" },
{ name: "PNG", buffer: pngBuffer.buffer, extension: ".png" },
{ name: "TIFF", buffer: tiffBuffer.buffer, extension: ".tiff" },
];
// Sort by file size (smallest first)
formats.sort((a, b) => a.buffer.length - b.buffer.length);
console.log("📊 Formats ranked by file size (smallest to largest):");
formats.forEach((format, index) => {
const sizeMB = (format.buffer.length / 1024 / 1024).toFixed(2);
const emoji =
index === 0 ? "🏆" : index === 1 ? "🥈" : index === 2 ? "🥉" : "📊";
console.log(` ${emoji} ${format.name}: ${sizeMB} MB`);
});
// Cleanup
await processor.close();
console.log("\n✅ API comparison complete!");
console.log("\n🎯 Key Takeaway: Choose the right API for your use case");
console.log(" • File-based: Traditional workflows, disk storage");
console.log(" • Buffer-based: Modern web services, cloud applications");
} catch (error) {
console.error("\n❌ Error:", error.message);
console.error("\nMake sure you have:");
console.error("1. Built the addon: npm run build");
console.error("2. Installed Sharp: npm install sharp");
console.error("3. Provided a valid RAW file");
}
}
// 使用说明
if (process.argv.length < 3) {
console.log(
"用法: node api-comparison-example.js <raw文件路径> [输出目录]"
);
console.log(
"示例: node api-comparison-example.js ../sample-images/IMG_1234.CR2 ./comparison-output"
);
process.exit(1);
}
const inputFile = process.argv[2];
const outputDir = process.argv[3] || "./comparison-output";
apiComparisonExample(inputFile, outputDir);