{"id":10021348,"date":"2026-04-27T22:55:53","date_gmt":"2026-04-27T14:55:53","guid":{"rendered":"https:\/\/itmax.cn\/?p=10021348"},"modified":"2026-04-27T22:55:53","modified_gmt":"2026-04-27T14:55:53","slug":"%e5%9c%a8%e7%ba%bfpdf%e5%8e%8b%e7%bc%a9%e5%b7%a5%e5%85%b7%e6%a0%b8%e5%bf%83js%e5%ae%9e%e7%8e%b0","status":"publish","type":"post","link":"https:\/\/itmax.cn\/?p=10021348","title":{"rendered":"\u5728\u7ebfPDF\u538b\u7f29\u5de5\u5177\u6838\u5fc3JS\u5b9e\u73b0"},"content":{"rendered":"<p>\u8fd9\u7bc7\u53ea\u8bb2\u672c\u9879\u76ee\u91cc\u201cPDF\u538b\u7f29\u201d\u5de5\u5177\u7684\u529f\u80fd\u5c42 JavaScript \u5b9e\u73b0\u3002\u6574\u4e2a\u94fe\u8def\u53ef\u4ee5\u6982\u62ec\u4e3a\uff1a<\/p>\n<p><code>\u9009\u62e9 PDF -&gt; \u89e3\u6790\u538b\u7f29\u53c2\u6570 -&gt; \u8bfb\u53d6\u5e76\u52a0\u8f7d PDF -&gt; \u627e\u51fa\u53ef\u91cd\u538b\u7f29\u7684 JPEG \u56fe\u7247\u6d41 -&gt; \u91cd\u65b0\u7f16\u7801 -&gt; \u751f\u6210\u65b0 PDF -&gt; \u4e0b\u8f7d\u7ed3\u679c<\/code><\/p>\n<p>\u8fd9\u4e2a\u5de5\u5177\u7684\u6838\u5fc3\u601d\u8def\u5f88\u660e\u786e\uff1a\u4e0d\u76f4\u63a5\u201c\u91cd\u5199\u6574\u4e2a PDF\u201d\uff0c\u800c\u662f\u4f18\u5148\u5904\u7406 PDF \u5185\u5df2\u7ecf\u5b58\u5728\u7684 JPEG \u56fe\u7247\u8d44\u6e90\uff0c\u518d\u628a\u5904\u7406\u540e\u7684\u5185\u5bb9\u91cd\u65b0\u4fdd\u5b58\u6210\u65b0\u7684 PDF \u6587\u4ef6\u3002<\/p>\n<blockquote><p>\u5728\u7ebf\u5de5\u5177\u7f51\u5740\uff1a<a href=\"https:\/\/link.segmentfault.com\/?enc=ipgQApOai8Wl58xEOuFzAg%3D%3D.EqhhD6QuDGdoZVNdjc85AnwBAbosvcV2w5wV1h5d0Yk0ErERt6VNfLraTgfooYfe\" rel=\"nofollow noopener noreferrer\" target=\"_blank\">https:\/\/see-tool.com\/pdf-compress<\/a>  <br \/>\u5de5\u5177\u622a\u56fe\uff1a  <br \/><img loading=\"lazy\" decoding=\"async\" width=\"723\" height=\"451\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/bVdoq5W\" alt=\"\" title=\"\"><\/p><\/blockquote>\n<h2>1. \u53c2\u6570\u5148\u5f52\u4e00\u5316\uff0c\u907f\u514d\u538b\u7f29\u6d41\u7a0b\u5206\u652f\u5931\u63a7<\/h2>\n<p>\u5de5\u5177\u652f\u6301\u4e24\u79cd\u6a21\u5f0f\uff1a<code>jpeg-only<\/code> \u548c <code>condense-lite<\/code>\u3002\u524d\u8005\u771f\u6b63\u5904\u7406 PDF \u5185\u56fe\u7247\uff0c\u540e\u8005\u4e3b\u8981\u505a\u8f7b\u91cf\u6574\u7406\u3002\u538b\u7f29\u524d\u4f1a\u5148\u628a\u7b97\u6cd5\u3001\u753b\u8d28\u548c\u7f29\u653e\u6bd4\u4f8b\u7edf\u4e00\u6210\u7a33\u5b9a\u503c\u3002<\/p>\n<pre><code class=\"js\">function resolveAlgorithm(algorithm) {\n  if (algorithm === PDF_COMPRESS_ALGORITHM_CONDENSE_LITE) {\n    return PDF_COMPRESS_ALGORITHM_CONDENSE_LITE;\n  }\n  return PDF_COMPRESS_ALGORITHM_JPEG_ONLY;\n}\n\nfunction resolveQuality(level) {\n  return QUALITY_MAP[level] || QUALITY_MAP.medium;\n}\n\nfunction resolveScale(scale) {\n  var value = Number(scale);\n  if (!Number.isFinite(value) || value &lt;= 0 || value &gt; 1) {\n    return 1;\n  }\n  return value;\n}<\/code><\/pre>\n<p>\u8fd9\u6837\u505a\u7684\u597d\u5904\u662f\uff0c\u540e\u9762\u7684\u538b\u7f29\u4e3b\u6d41\u7a0b\u53ea\u63a5\u6536\u89c4\u8303\u53c2\u6570\uff0c\u4e0d\u9700\u8981\u5230\u5904\u5224\u65ad\u975e\u6cd5\u8f93\u5165\u3002<\/p>\n<h2>2. \u5148\u4ece PDF \u91cc\u7b5b\u51fa\u771f\u6b63\u53ef\u538b\u7f29\u7684 JPEG \u56fe\u7247\u6d41<\/h2>\n<p>PDF \u91cc\u5e76\u4e0d\u662f\u6240\u6709\u8d44\u6e90\u90fd\u9002\u5408\u538b\u7f29\u3002\u5b9e\u73b0\u91cc\u4f1a\u904d\u5386 PDF \u7684\u95f4\u63a5\u5bf9\u8c61\uff0c\u53ea\u4fdd\u7559\u540c\u65f6\u6ee1\u8db3\u8fd9\u51e0\u4e2a\u6761\u4ef6\u7684\u5bf9\u8c61\uff1a<\/p>\n<ul>\n<li>\u7c7b\u578b\u662f <code>XObject<\/code><\/li>\n<li>\u5b50\u7c7b\u578b\u662f <code>Image<\/code><\/li>\n<li>\u8fc7\u6ee4\u5668\u91cc\u5305\u542b <code>DCTDecode<\/code><\/li>\n<\/ul>\n<pre><code class=\"js\">function listJpegStreams(pdfDoc) {\n  var imageStreams = [];\n  var entries = pdfDoc.context.enumerateIndirectObjects();\n\n  for (var i = 0; i &lt; entries.length; i += 1) {\n    var obj = entries[i][1];\n    if (!(obj instanceof PDFRawStream)) continue;\n\n    var dict = obj.dict;\n    var type = dict.get(PDFName.of(&quot;Type&quot;));\n    var subtype = dict.get(PDFName.of(&quot;Subtype&quot;));\n    var filter = dict.get(PDFName.of(&quot;Filter&quot;));\n    var filterText = filter ? String(filter.toString()) : &quot;&quot;;\n\n    if (String(type || &quot;&quot;) !== &quot;\/XObject&quot;) continue;\n    if (String(subtype || &quot;&quot;) !== &quot;\/Image&quot;) continue;\n    if (filterText.indexOf(&quot;DCTDecode&quot;) === -1) continue;\n\n    imageStreams.push({ obj: obj });\n  }\n\n  return imageStreams;\n}<\/code><\/pre>\n<p>\u8fd9\u91cc\u7684\u5173\u952e\u70b9\u662f\u53ea\u5904\u7406 JPEG \u6d41\u3002\u8fd9\u6837\u53ef\u4ee5\u907f\u5f00\u5f88\u591a\u590d\u6742\u683c\u5f0f\u5206\u652f\uff0c\u8ba9\u538b\u7f29\u884c\u4e3a\u66f4\u53ef\u63a7\u3002<\/p>\n<h2>3. \u56fe\u7247\u91cd\u538b\u7f29\u7684\u6838\u5fc3\u662f\u201c\u8f6c\u6210\u4f4d\u56fe\u518d\u91cd\u65b0\u7f16\u7801\u201d<\/h2>\n<p>\u62ff\u5230 JPEG \u5b57\u8282\u540e\uff0c\u4e0d\u662f\u76f4\u63a5\u6539\u4e8c\u8fdb\u5236\uff0c\u800c\u662f\u8d70\u6d4f\u89c8\u5668\u56fe\u50cf\u94fe\u8def\uff1a<code>Blob -&gt; ObjectURL -&gt; Image -&gt; Canvas -&gt; toBlob<\/code>\u3002<\/p>\n<pre><code class=\"js\">function recompressJpegBytes(bytes, scale, quality) {\n  return new Promise(function (resolve) {\n    var blob = new Blob([bytes], { type: &quot;image\/jpeg&quot; });\n    var objectUrl = URL.createObjectURL(blob);\n    var image = new Image();\n\n    image.onload = function () {\n      var width = Math.max(1, Math.floor(image.width * scale));\n      var height = Math.max(1, Math.floor(image.height * scale));\n      var canvas = document.createElement(&quot;canvas&quot;);\n      var context = canvas.getContext(&quot;2d&quot;);\n\n      canvas.width = width;\n      canvas.height = height;\n      context.fillStyle = &quot;#FFFFFF&quot;;\n      context.fillRect(0, 0, width, height);\n      context.drawImage(image, 0, 0, width, height);\n\n      canvas.toBlob(function (nextBlob) {\n        URL.revokeObjectURL(objectUrl);\n        if (!nextBlob) return resolve(null);\n        nextBlob.arrayBuffer().then(function (buffer) {\n          resolve({\n            buffer: new Uint8Array(buffer),\n            width: width,\n            height: height,\n          });\n        });\n      }, &quot;image\/jpeg&quot;, quality);\n    };\n\n    image.src = objectUrl;\n  });\n}<\/code><\/pre>\n<p>\u8fd9\u4e00\u6b65\u51b3\u5b9a\u4e86\u538b\u7f29\u6548\u679c\uff1a<\/p>\n<ul>\n<li><code>quality<\/code> \u63a7\u5236 JPEG \u8f93\u51fa\u8d28\u91cf<\/li>\n<li><code>scale<\/code> \u63a7\u5236\u50cf\u7d20\u5c3a\u5bf8\u7f29\u653e<\/li>\n<li><code>fillRect + drawImage<\/code> \u4fdd\u8bc1\u91cd\u65b0\u7ed8\u5236\u540e\u7684\u56fe\u50cf\u80fd\u7a33\u5b9a\u5bfc\u51fa<\/li>\n<\/ul>\n<h2>4. \u4e3b\u6d41\u7a0b\u6309\u201c\u8bfb\u6587\u4ef6\u3001\u626b\u56fe\u7247\u3001\u66ff\u6362\u6d41\u3001\u4fdd\u5b58\u7ed3\u679c\u201d\u63a8\u8fdb<\/h2>\n<p>\u771f\u6b63\u7684\u5165\u53e3\u51fd\u6570\u662f <code>compressPdfFile<\/code>\u3002\u5b83\u4f1a\u5148\u8bfb\u53d6\u6587\u4ef6\uff0c\u518d\u7528 <code>pdf-lib<\/code> \u52a0\u8f7d PDF\uff0c\u7136\u540e\u6839\u636e\u6a21\u5f0f\u51b3\u5b9a\u662f\u5426\u904d\u5386 JPEG \u56fe\u7247\u6d41\u3002<\/p>\n<pre><code class=\"js\">var originalBytes = await file.arrayBuffer();\nvar pdfDoc = await PDFDocument.load(originalBytes, {\n  updateMetadata: false,\n});\n\nvar jpegStreams = listJpegStreams(pdfDoc);\n\nfor (var i = 0; i &lt; jpegStreams.length; i += 1) {\n  var stream = jpegStreams[i].obj;\n  var streamBytes = stream.contents;\n  var converted = await recompressJpegBytes(streamBytes, scale, quality);\n\n  if (\n    converted &amp;&amp;\n    converted.buffer &amp;&amp;\n    converted.buffer.byteLength &lt; streamBytes.byteLength\n  ) {\n    stream.contents = converted.buffer;\n    if (scale !== 1) {\n      stream.dict.set(PDFName.of(&quot;Width&quot;), pdfDoc.context.obj(converted.width));\n      stream.dict.set(PDFName.of(&quot;Height&quot;), pdfDoc.context.obj(converted.height));\n    }\n  }\n}<\/code><\/pre>\n<p>\u8fd9\u91cc\u6709\u4e2a\u5f88\u91cd\u8981\u7684\u5224\u65ad\uff1a\u53ea\u6709\u65b0\u56fe\u7247\u5b57\u8282\u66f4\u5c0f\uff0c\u624d\u4f1a\u66ff\u6362\u539f\u59cb\u6d41\u3002\u8fd9\u6837\u4e0d\u4f1a\u56e0\u4e3a\u91cd\u590d\u7f16\u7801\u53cd\u800c\u628a\u6587\u4ef6\u53d8\u5927\u3002<\/p>\n<h2>5. \u5143\u6570\u636e\u6e05\u7406\u662f\u53e6\u4e00\u6761\u72ec\u7acb\u538b\u7f29\u652f\u7ebf<\/h2>\n<p>\u9664\u4e86\u56fe\u7247\u91cd\u7f16\u7801\uff0c\u8fd9\u4e2a\u5de5\u5177\u8fd8\u652f\u6301\u79fb\u9664\u5143\u6570\u636e\u3002\u5b9e\u73b0\u4e0a\u4f1a\u5220\u9664\u6587\u6863\u4fe1\u606f\u5b57\u5178\u548c\u76ee\u5f55\u4e0a\u7684 <code>Metadata<\/code>\u3002<\/p>\n<pre><code class=\"js\">function stripPdfMetadata(pdfDoc) {\n  var context = pdfDoc.context;\n  var catalog = pdfDoc.catalog;\n  var infoRef = context.trailerInfo.Info;\n\n  if (infoRef) {\n    context.delete(infoRef);\n    context.trailerInfo.Info = undefined;\n  }\n\n  if (catalog &amp;&amp; catalog.has(PDFName.of(&quot;Metadata&quot;))) {\n    catalog.delete(PDFName.of(&quot;Metadata&quot;));\n  }\n}<\/code><\/pre>\n<p>\u8fd9\u90e8\u5206\u4e0d\u4f9d\u8d56\u56fe\u7247\u5185\u5bb9\uff0c\u6240\u4ee5\u5373\u4f7f PDF \u91cc\u6ca1\u6709\u53ef\u5904\u7406\u7684 JPEG\uff0c\u4ecd\u7136\u53ef\u80fd\u901a\u8fc7\u6e05\u7406\u5143\u6570\u636e\u5f97\u5230\u66f4\u5c0f\u7684\u7ed3\u679c\u6587\u4ef6\u3002<\/p>\n<h2>6. \u8fdb\u5ea6\u3001\u53d6\u6d88\u548c\u7ed3\u679c\u4fe1\u606f\u90fd\u5728\u540c\u4e00\u6761\u72b6\u6001\u94fe\u4e0a<\/h2>\n<p>\u9875\u9762\u5c42\u4e0d\u662f\u7b80\u5355\u5730\u8c03\u7528\u4e00\u6b21\u538b\u7f29\u51fd\u6570\uff0c\u800c\u662f\u628a\u538b\u7f29\u8fc7\u7a0b\u62c6\u6210\u53ef\u611f\u77e5\u7684\u9636\u6bb5\uff1a\u8bfb\u53d6\u3001\u89e3\u6790\u3001\u626b\u63cf\u56fe\u7247\u3001\u91cd\u7f16\u7801\u3001\u6e05\u7406\u5143\u6570\u636e\u3001\u4fdd\u5b58\u5b8c\u6210\u3002<\/p>\n<pre><code class=\"js\">var result = await compressPdfFile(\n  this.selectedFile,\n  {\n    algorithm: this.algorithm,\n    quality: this.qualityLevel,\n    scale: this.scaleValue,\n    removeMetadata: this.removeMetadata,\n    cancelToken: this.cancelToken,\n  },\n  function (progress) {\n    self.progressPercent = Math.max(0, Math.min(100, progress.percent || 0));\n    self.progressStage = String(progress.stage || &quot;&quot;);\n    self.progressTotal = Number(progress.total) || 0;\n    self.progressProcessed = Number(progress.processed) || 0;\n    self.progressReplacedCount = Number(progress.replacedCount) || 0;\n  },\n);<\/code><\/pre>\n<p>\u53d6\u6d88\u673a\u5236\u4e5f\u5f88\u76f4\u63a5\uff0c\u672c\u8d28\u4e0a\u662f\u4e00\u4e2a\u5171\u4eab\u6807\u8bb0\uff1a<\/p>\n<pre><code class=\"js\">export function createPdfCompressCancelToken() {\n  return { cancelled: false };\n}\n\nfunction throwIfCancelled(cancelToken) {\n  if (cancelToken &amp;&amp; cancelToken.cancelled) {\n    throw createPdfCompressCancelledError();\n  }\n}<\/code><\/pre>\n<p>\u538b\u7f29\u6d41\u7a0b\u4e2d\u7684\u5173\u952e\u8282\u70b9\u90fd\u4f1a\u68c0\u67e5\u8fd9\u4e2a\u6807\u8bb0\uff0c\u8fd9\u6837\u7528\u6237\u70b9\u53d6\u6d88\u540e\uff0c\u4efb\u52a1\u80fd\u5728\u4e0b\u4e00\u6bb5\u5f02\u6b65\u8fb9\u754c\u53ca\u65f6\u505c\u6b62\u3002<\/p>\n<h2>7. \u5bfc\u51fa\u7ed3\u679c\u65f6\u987a\u624b\u8865\u9f50\u201c\u7528\u6237\u53ef\u7406\u89e3\u201d\u7684\u4fe1\u606f<\/h2>\n<p>\u538b\u7f29\u5b8c\u6210\u540e\uff0c\u5de5\u5177\u4e0d\u4f1a\u53ea\u8fd4\u56de\u4e00\u4e2a <code>Blob<\/code>\uff0c\u8fd8\u4f1a\u628a\u8f93\u51fa\u6587\u4ef6\u540d\u3001\u538b\u7f29\u524d\u540e\u4f53\u79ef\u3001\u66ff\u6362\u56fe\u7247\u6570\u91cf\u3001\u538b\u7f29\u6bd4\u4f8b\u4e00\u8d77\u6574\u7406\u51fa\u6765\u3002<\/p>\n<pre><code class=\"js\">var result = {\n  outputBlob: outputBlob,\n  outputName: buildCompressedPdfName(file &amp;&amp; file.name),\n  jpegCount: jpegCount,\n  replacedCount: replacedCount,\n  metadataRemoved: metadataRemoved,\n  originalSize: Number(file &amp;&amp; file.size) || 0,\n  outputSize: outputBlob.size,\n  ratio: getPdfCompressionRatio(file &amp;&amp; file.size, outputBlob.size),\n  algorithm: algorithm,\n};<\/code><\/pre>\n<p>\u8fd9\u6837\u9875\u9762\u5c42\u53ea\u9700\u8981\u63a5\u7ed3\u679c\u5e76\u521b\u5efa\u4e0b\u8f7d\u94fe\u63a5\uff0c\u5c31\u80fd\u5b8c\u6574\u5c55\u793a\u8fd9\u6b21\u538b\u7f29\u662f\u5426\u751f\u6548\u3001\u538b\u7f29\u4e86\u591a\u5c11\u3001\u5b9e\u9645\u5904\u7406\u4e86\u591a\u5c11\u5f20\u56fe\u7247\u3002<\/p>\n<p>\u8fd9\u5957 PDF \u538b\u7f29\u529f\u80fd\u7684\u6838\u5fc3\u5e76\u4e0d\u590d\u6742\uff0c\u91cd\u70b9\u662f\u628a\u6d4f\u89c8\u5668\u56fe\u50cf\u80fd\u529b\u548c <code>pdf-lib<\/code> \u7684\u5bf9\u8c61\u64cd\u4f5c\u4e32\u8d77\u6765\uff1a\u5148\u5b9a\u4f4d PDF \u5185\u53ef\u5904\u7406\u7684 JPEG \u8d44\u6e90\uff0c\u518d\u91cd\u7f16\u7801\u3001\u66ff\u6362\u3001\u4fdd\u5b58\uff0c\u6700\u540e\u628a\u6574\u4e2a\u8fc7\u7a0b\u5305\u88c5\u6210\u666e\u901a\u7528\u6237\u53ef\u76f4\u63a5\u4f7f\u7528\u7684 Vue \u5de5\u5177\u3002<\/p>\n<p><a href=\"https:\/\/segmentfault.com\/a\/1190000047730723\">https:\/\/segmentfault.com\/a\/1190000047730723<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u8fd9\u7bc7\u53ea\u8bb2\u672c\u9879\u76ee\u91cc\u201cPDF\u538b\u7f29\u201d\u5de5\u5177\u7684\u529f\u80fd\u5c42 JavaScript \u5b9e\u73b0\u3002\u6574\u4e2a\u94fe\u8def\u53ef\u4ee5\u6982\u62ec\u4e3a\uff1a \u9009\u62e9 PDF &#8211; [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[4],"tags":[],"class_list":["post-10021348","post","type-post","status-publish","format-standard","hentry","category-share"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/posts\/10021348","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=10021348"}],"version-history":[{"count":0,"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/posts\/10021348\/revisions"}],"wp:attachment":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=10021348"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=10021348"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=10021348"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}