Optimizer to Compress PDF Files

1//---------------------------------------------------------------------------------------
2// Copyright (c) 2001-2019 by Apryse Software Inc. All Rights Reserved.
3// Consult legal.txt regarding legal and license information.
4//---------------------------------------------------------------------------------------
5
6//---------------------------------------------------------------------------------------
7// The following sample illustrates how to reduce PDF file size using 'pdftron.PDF.Optimizer'.
8// The sample also shows how to simplify and optimize PDF documents for viewing on mobile devices
9// and on the Web using 'pdftron.PDF.Flattener'.
10//
11// @note Both 'Optimizer' and 'Flattener' are separately licensable add-on options to the core PDFNet license.
12//
13// ----
14//
15// 'pdftron.PDF.Optimizer' can be used to optimize PDF documents by reducing the file size, removing
16// redundant information, and compressing data streams using the latest in image compression technology.
17//
18// PDF Optimizer can compress and shrink PDF file size with the following operations:
19// - Remove duplicated fonts, images, ICC profiles, and any other data stream.
20// - Optionally convert high-quality or print-ready PDF files to small, efficient and web-ready PDF.
21// - Optionally down-sample large images to a given resolution.
22// - Optionally compress or recompress PDF images using JBIG2 and JPEG2000 compression formats.
23// - Compress uncompressed streams and remove unused PDF objects.
24//
25// ----
26//
27// 'pdftron.PDF.Flattener' can be used to speed-up PDF rendering on mobile devices and on the Web by
28// simplifying page content (e.g. flattening complex graphics into images) while maintaining vector text
29// whenever possible.
30//
31// Flattener can also be used to simplify process of writing custom converters from PDF to other formats.
32// In this case, Flattener can be used as first step in the conversion pipeline to reduce any PDF to a
33// very simple representation (e.g. vector text on top of a background image).
34//---------------------------------------------------------------------------------------
35
36(exports => {
37
38
39  const PDFNet = exports.Core.PDFNet;
40
41  exports.runOptimizerTest = () => {
42    const main = async () => {
43      const inputPath = '../TestFiles/';
44      const inputFilename = 'newsletter';
45
46      // The first step in every application using PDFNet is to initialize the
47      // library and set the path to common PDF resources. The library is usually
48      // initialized only once, but calling Initialize() multiple times is also fine.
49
50      //--------------------------------------------------------------------------------
51      // Example 1) Simple optimization of a pdf with default settings.
52      //
53      try {
54        const doc = await PDFNet.PDFDoc.createFromURL(inputPath + inputFilename + '.pdf');
55        doc.initSecurityHandler();
56        await doc.lock();
57        await PDFNet.Optimizer.optimize(doc);
58        const docbuf = await doc.saveMemoryBuffer(PDFNet.SDFDoc.SaveOptions.e_linearized);
59        saveBufferAsPDFDoc(docbuf, inputFilename + '_opt1.pdf');
60      } catch (err) {
61        console.log(err);
62      }
63
64      //--------------------------------------------------------------------------------
65      // Example 2) Reduce image quality and use jpeg compression for
66      // non monochrome images.
67      try {
68        const doc = await PDFNet.PDFDoc.createFromURL(inputPath + inputFilename + '.pdf');
69        doc.initSecurityHandler();
70        await doc.lock();
71        const imageSettings = new PDFNet.Optimizer.ImageSettings();
72
73        // low quality jpeg compression
74        imageSettings.setCompressionMode(PDFNet.Optimizer.ImageSettings.CompressionMode.e_jpeg);
75        imageSettings.setQuality(1);
76
77        // Set the output dpi to be standard screen resolution
78        imageSettings.setImageDPI(144, 96);
79
80        // this option will recompress images not compressed with
81        // jpeg compression and use the result if the new image
82        // is smaller.
83        imageSettings.forceRecompression(true);
84
85        // this option is not commonly used since it can
86        // potentially lead to larger files.  It should be enabled
87        // only if the output compression specified should be applied
88        // to every image of a given type regardless of the output image size
89        // imageSettings.forceChanges(true);
90
91        const optSettings = new PDFNet.Optimizer.OptimizerSettings();
92        optSettings.setColorImageSettings(imageSettings);
93        optSettings.setGrayscaleImageSettings(imageSettings);
94
95        // use the same settings for both color and grayscale images
96        await PDFNet.Optimizer.optimize(doc, optSettings);
97
98        const docbuf = await doc.saveMemoryBuffer(PDFNet.SDFDoc.SaveOptions.e_linearized);
99        saveBufferAsPDFDoc(docbuf, inputFilename + '_opt2.pdf');
100      } catch (err) {
101        console.log(err);
102      }
103
104      //--------------------------------------------------------------------------------
105      // Example 3) Use monochrome image settings and default settings
106      // for color and grayscale images.
107      try {
108        const doc = await PDFNet.PDFDoc.createFromURL(inputPath + inputFilename + '.pdf');
109        doc.initSecurityHandler();
110        await doc.lock();
111
112        const monoImageSettings = new PDFNet.Optimizer.MonoImageSettings();
113
114        monoImageSettings.setCompressionMode(PDFNet.Optimizer.MonoImageSettings.CompressionMode.e_jbig2);
115        monoImageSettings.forceRecompression(true);
116
117        const optSettings = new PDFNet.Optimizer.OptimizerSettings();
118
119        optSettings.setMonoImageSettings(monoImageSettings);
120
121        await PDFNet.Optimizer.optimize(doc, optSettings);
122
123        const docbuf = await doc.saveMemoryBuffer(PDFNet.SDFDoc.SaveOptions.e_linearized);
124        saveBufferAsPDFDoc(docbuf, inputFilename + '_opt3.pdf');
125      } catch (err) {
126        console.log(err);
127      }
128
129      // ----------------------------------------------------------------------
130      // Example 4) Use Flattener to simplify content in this document
131      // using default settings
132      try {
133        const doc = await PDFNet.PDFDoc.createFromURL(inputPath + 'TigerText.pdf');
134        doc.initSecurityHandler();
135        await doc.lock();
136
137        const fl = await PDFNet.Flattener.create();
138
139        // The following lines can increase the resolution of background
140        // images.
141        // fl.setDPI(300);
142        // fl.setMaximumImagePixels(5000000);
143
144        // This line can be used to output Flate compressed background
145        // images rather than DCTDecode compressed images which is the default
146        // fl.setPreferJPG(false);
147
148        // In order to adjust thresholds for when text is Flattened
149        // the following function can be used.
150        // fl.setThreshold(PDFNet.Flattener.Threshold.e_keep_most);
151
152        // We use e_fast option here since it is usually preferable
153        // to avoid Flattening simple pages in terms of size and
154        // rendering speed. If the desire is to simplify the
155        // document for processing such that it contains only text and
156        // a background image e_simple should be used instead.
157        await fl.process(doc, PDFNet.Flattener.Mode.e_fast);
158
159        const docbuf = await doc.saveMemoryBuffer(PDFNet.SDFDoc.SaveOptions.e_linearized);
160        saveBufferAsPDFDoc(docbuf, 'TigerText_flatten.pdf');
161      } catch (err) {
162        console.log(err);
163      }
164    };
165
166    // add your own license key as the second parameter, e.g. PDFNet.runWithCleanup(main, 'YOUR_LICENSE_KEY')
167    PDFNet.runWithCleanup(main);
168  };
169  exports.runOptimizerTest();
170})(window);
171// eslint-disable-next-line spaced-comment
172//# sourceURL=OptimizerTest.js