html2pptx/bin/html2pptx.js

#!/usr/bin/env node
/**
 * html2pptx — HTML to editable PPTX export engine
 *
 * Usage:
 *   html2pptx <input.html> [output.pptx]
 *   html2pptx <input.html> -o <output.pptx> -p <port>
 *
 * Process:
 *   1. Start local HTTP server to host the HTML
 *   2. Chrome headless (Playwright) opens the page
 *   3. Extract each slide's element positions, text, and styles
 *   4. Generate PPTX with pptxgenjs
 */

const { chromium } = require('playwright');
const http = require('http');
const fs = require('fs');
const path = require('path');
const PptxGenJS = require('pptxgenjs');

// ====== CLI argument parsing ======

function parseArgs() {
  const args = process.argv.slice(2);
  if (args.length === 0) {
    console.error('Usage: html2pptx <input.html> [output.pptx]');
    console.error('       html2pptx <input.html> -o <output.pptx> -p <port>');
    process.exit(1);
  }

  const inputPath = path.resolve(args[0]);
  const parsed = path.parse(inputPath);
  let outputPath = path.join(parsed.dir, parsed.name + '.pptx');
  let port;

  for (let i = 1; i < args.length; i++) {
    if (args[i] === '-o' && i + 1 < args.length) {
      outputPath = path.resolve(args[++i]);
    } else if (args[i] === '-p' && i + 1 < args.length) {
      port = parseInt(args[++i], 10);
    } else if (!args[i].startsWith('-')) {
      outputPath = path.resolve(args[i]);
    }
  }

  return { inputPath, outputPath, port };
}

// ====== Color parsing (Node.js side) ======

function parseCSSColor(color, fallback) {
  if (!color || color === 'transparent' || color === 'rgba(0, 0, 0, 0)') return fallback || '#000000';

  // Already #rrggbb
  if (/^#[0-9a-f]{6}$/i.test(color)) return color.toLowerCase();
  // #rgb → #rrggbb
  if (/^#[0-9a-f]{3}$/i.test(color)) {
    return '#' + color[1] + color[1] + color[2] + color[2] + color[3] + color[3];
  }

  // rgb(r, g, b) / rgba(r, g, b, a)
  const m = color.match(/rgba?\((\d+),\s*(\d+),\s*(\d+)/);
  if (m) {
    return '#' + m.slice(1, 4).map(c => parseInt(c).toString(16).padStart(2, '0')).join('');
  }

  return fallback || '#000000';
}

function parseFontWeight(w) {
  if (w === 'bold') return true;
  const n = parseInt(w, 10);
  return n >= 600;
}

function normalizeAlign(align) {
  switch (align) {
    case 'left': case 'center': case 'right': case 'justify': return align;
    case 'start': return 'left';
    case 'end': return 'right';
    default: return 'left';
  }
}

// ====== Main ======

async function main() {
  const { inputPath, outputPath, port: cliPort } = parseArgs();

  if (!fs.existsSync(inputPath)) {
    console.error('文件不存在:', inputPath);
    process.exit(1);
  }

  const TIMEOUT_MS = 30000;
  const startTime = Date.now();
  let server, browser;

  try {
    // ------ 1. HTTP server ------
    const baseDir = path.dirname(inputPath);
    const MIME = {
      '.html': 'text/html; charset=utf-8',
      '.css': 'text/css; charset=utf-8',
      '.js': 'application/javascript; charset=utf-8',
      '.png': 'image/png',
      '.jpg': 'image/jpeg',
      '.jpeg': 'image/jpeg',
      '.svg': 'image/svg+xml',
    };

    server = http.createServer((req, res) => {
      const reqPath = req.url === '/' ? '/' + path.basename(inputPath) : req.url;
      const filePath = path.join(baseDir, reqPath);
      // Prevent directory traversal
      if (!filePath.startsWith(baseDir)) {
        res.writeHead(404);
        res.end('Not Found');
        return;
      }
      if (fs.existsSync(filePath) && fs.statSync(filePath).isFile()) {
        const ext = path.extname(filePath).toLowerCase();
        res.writeHead(200, { 'Content-Type': MIME[ext] || 'application/octet-stream' });
        res.end(fs.readFileSync(filePath));
      } else {
        res.writeHead(404);
        res.end('Not Found');
      }
    });

    const port = cliPort || 0;
    await new Promise((resolve, reject) => {
      server.listen(port, '127.0.0.1', resolve);
      server.on('error', reject);
    });
    const actualPort = server.address().port;
    console.log('HTTP 服务已启动: http://127.0.0.1:' + actualPort + '/');

    if (Date.now() - startTime > TIMEOUT_MS) throw new Error('导出超时');

    // ------ 2. Chrome headless ------
    browser = await chromium.launch({ headless: true });
    const page = await browser.newPage({ viewport: { width: 1280, height: 720 } });

    if (Date.now() - startTime > TIMEOUT_MS) throw new Error('导出超时');

    await page.goto('http://127.0.0.1:' + actualPort + '/', {
      waitUntil: 'networkidle',
      timeout: 15000,
    });
    console.log('页面加载完成');

    // ------ 3. DOM extraction (in-browser) ------
    const slidesData = await page.evaluate(() => {
      // ----- Slide detection -----
      let slides = document.querySelectorAll(
        'section[data-slide], section.slide, section'
      );
      if (slides.length <= 1) {
        slides = document.querySelectorAll('[data-slide]');
      }
      slides = Array.from(slides).filter(function (s) {
        var r = s.getBoundingClientRect();
        return r.width > 0 && r.height > 0;
      });

      // Tags that are purely structural containers — skip when they have no direct text
      var CONTAINER_TAGS = new Set([
        'div', 'section', 'ul', 'ol', 'nav', 'header', 'footer',
        'main', 'aside', 'article', 'form', 'fieldset', 'table',
        'thead', 'tbody', 'tfoot', 'tr', 'figure',
      ]);

      function hasDirectText(el) {
        var nodes = el.childNodes;
        for (var i = 0; i < nodes.length; i++) {
          if (nodes[i].nodeType === 3 && nodes[i].textContent.trim()) return true;
        }
        return false;
      }

      return slides.map(function (slide) {
        var slideRect = slide.getBoundingClientRect();
        var allEls = slide.querySelectorAll('*');
        var elements = [];

        for (var i = 0; i < allEls.length; i++) {
          var el = allEls[i];
          var text = (el.textContent || '').trim();
          if (!text) continue;

          var rect = el.getBoundingClientRect();
          if (rect.width === 0 || rect.height === 0) continue;

          var tag = el.tagName.toLowerCase();
          var directText = hasDirectText(el);

          // Skip structural containers that have no direct text (e.g. wrapper divs)
          if (CONTAINER_TAGS.has(tag) && !directText) continue;

          var style = window.getComputedStyle(el);

          elements.push({
            text: text.substring(0, 2000),
            x: rect.left - slideRect.left,
            y: rect.top - slideRect.top,
            width: rect.width,
            height: rect.height,
            fontSize: parseFloat(style.fontSize) || 14,
            fontFamily: style.fontFamily || 'Arial',
            color: style.color || '#000000',
            fontWeight: style.fontWeight || 'normal',
            fontStyle: style.fontStyle || 'normal',
            textAlign: style.textAlign || 'left',
            backgroundColor: style.backgroundColor || 'transparent',
          });
        }

        // Slide background
        var bg = window.getComputedStyle(slide).backgroundColor;
        var bgColor =
          bg &&
          bg !== 'rgba(0, 0, 0, 0)' &&
          bg !== 'transparent'
            ? bg
            : '#FFFFFF';

        return {
          width: slideRect.width,
          height: slideRect.height,
          bgColor: bgColor,
          elements: elements,
        };
      });
    });

    console.log('提取到 ' + slidesData.length + ' 页幻灯片');

    if (Date.now() - startTime > TIMEOUT_MS) throw new Error('导出超时');

    // ------ 4. PPTX generation ------
    var pptx = new PptxGenJS();
    pptx.defineLayout({ name: 'CUSTOM', width: 10, height: 5.625 });
    pptx.layout = 'CUSTOM';

    for (var s = 0; s < slidesData.length; s++) {
      var slideData = slidesData[s];
      var slide = pptx.addSlide();

      // Background
      slide.background = { fill: parseCSSColor(slideData.bgColor, '#FFFFFF') };

      // Scale factors: HTML pixels → PPT inches
      var scaleX = 10 / slideData.width;
      var scaleY = 5.625 / slideData.height;

      // Sort top-to-bottom, left-to-right
      slideData.elements.sort(function (a, b) {
        return a.y - b.y || a.x - b.x;
      });

      for (var e = 0; e < slideData.elements.length; e++) {
        var el = slideData.elements[e];
        var t = (el.text || '').trim();
        if (!t) continue;

        try {
          var x = Math.max(el.x * scaleX, 0);
          var y = Math.max(el.y * scaleY, 0);
          var w = Math.max(el.width * scaleX, 0.3);
          var h = Math.max(el.height * scaleY, 0.2);

          // Font size: proportional to slide height
          // CSS px → inches at 96dpi → scaled to PPTX slide height → pt (/72 inches per pt)
          var fontSize = el.fontSize * scaleY * 72;
          fontSize = Math.max(fontSize, 8);

          slide.addText(t, {
            x: x,
            y: y,
            w: w,
            h: h,
            fontSize: fontSize,
            fontFace: (el.fontFamily || 'Arial').split(',')[0].trim().replace(/['"]/g, ''),
            color: parseCSSColor(el.color, '#000000'),
            bold: parseFontWeight(el.fontWeight),
            italic: el.fontStyle === 'italic' || el.fontStyle === 'oblique',
            align: normalizeAlign(el.textAlign),
            valign: 'top',
            wrap: true,
            margin: 0,
          });
        } catch (err) {
          // Skip individual element failure
        }
      }
    }

    await pptx.writeFile({ fileName: outputPath });
    console.log('\nPPTX 已导出: ' + outputPath);
  } finally {
    if (browser) await browser.close().catch(function () {});
    if (server)
      await new Promise(function (resolve) {
        server.close(resolve);
      });
  }
}

main().catch(function (err) {
  console.error('导出失败:', err.message);
  process.exit(1);
});