PDF Reference third edition Adobe Portable Document Format Version 1.4 Adobe Systems Incorporated ADDISON–WESLEY Boston • San Francisco • New York • Toronto • Montreal London • Munich • Paris • Madrid Capetown • Sydney • Tokyo • Singapore • Mexico City Library of Congress Cataloging-in-Publication Data PDF reference : Adobe portable document format version 1.4 / Adobe Systems Incorporated. — 3rd ed. p. cm. Includes bibliographical references and index. ISBN 0-201-75839-3 (alk. paper) 1. Adobe Acrobat. 2. Portable document software. I. Adobe Systems. QA76.76.T49 P38 2001 005.7 ′ 2—dc21 2001053899 © 1985–2001 Adobe Systems Incorporated. All rights reserved. NOTICE: All information contained herein is the property of Adobe Systems Incorporated. No part of this publication (whether in hardcopy or electronic form) may be reproduced or trans- mitted, in any form or by any means, electronic, mechanical, photocopying, recording, or other- wise, without the prior written consent of the publisher. Adobe, the Adobe logo, Acrobat, the Acrobat logo, Acrobat Capture, Acrobat Reader, Adobe Garamond, Aldus, Distiller, ePaper, Extreme, FrameMaker, Illustrator, InDesign, Minion, Myriad, PageMaker, Photoshop, Poetica, PostScript, and XMP are either registered trademarks or trade- marks of Adobe Systems Incorporated in the United States and/or other countries. Microsoft and Windows are either registered trademarks or trademarks of Microsoft Corporation in the United States and/or other countries. Apple, Mac, Mac OS, Macintosh, QuickDraw, and TrueType are trademarks of Apple Computer, Inc., registered in the United States and other countries. KanjiTalk is a trademark of Apple Computer, Inc. UNIX is a registered trademark of The Open Group. Unicode is a registered trademark of Unicode, Inc. Java is a trademark of Sun Microsystems, Inc. JavaScript is a registered trademark of Netscape Communications Corporation. QuarkXPress is a trademark of Quark, Inc. and/or certain of the Quark Affiliated Companies, Reg. U.S. Pat. & Tm. Off. and in many other countries. PANTONE is a registered trademark and Hexachrome is a trademark of Pantone, Inc. PANOSE is a trademark of Hewlett-Packard Company. OEB is a trade- mark of the Open eBook Forum. Helvetica and Times are registered trademarks of Linotype-Hell AG and/or its subsidiaries. Arial and Times New Roman are trademarks of The Monotype Corpo- ration registered in the U.S. Patent and Trademark Office and may be registered in certain other jurisdictions. ITC Zapf Dingbats is a registered trademark of International Typeface Corporation. Ryumin Light is a trademark of Morisawa & Co., Ltd. All other trademarks are the property of their respective owners. All instances of the name PostScript in the text are references to the PostScript language as defined by Adobe Systems Incorporated unless otherwise stated. The name PostScript also is used as a product trademark for Adobe Systems’ implementation of the PostScript language interpreter. Except as otherwise stated, any mention of a “PostScript output device,” “PostScript printer,” “PostScript software,” or similar item refers to a product that contains PostScript technology cre- ated or licensed by Adobe Systems Incorporated, not to one that purports to be merely compatible. This publication and the information herein are furnished AS IS, are subject to change without notice, and should not be construed as a commitment by Adobe Systems Incorporated. Adobe Systems Incorporated assumes no responsibility or liability for any errors or inaccuracies, makes no warranty of any kind (express, implied, or statutory) with respect to this publication, and expressly disclaims any and all warranties of merchantability, fitness for particular purposes, and noninfringement of third-party rights. 1 2 3 4 5 6 7 8 9 CRS 04030201 First printing, December 2001 iii Contents Preface xix Chapter 1: Introduction 1 1.1 About This Book 1 1.2 Introduction to PDF 1.4 Features 4 1.3 Related Publications 5 1.4 Intellectual Property 6 Chapter 2: Overview 9 2.1 Imaging Model 10 2.2 Other General Properties 14 2.3 Using PDF 19 2.4 PDF and the PostScript Language 21 Chapter 3: Syntax 23 3.1 Lexical Conventions 24 3.2 Objects 27 3.3 Filters 41 3.4 File Structure 61 3.5 Encryption 71 3.6 Document Structure 81 3.7 Content Streams and Resources 92 3.8 Common Data Structures 98 3.9 Functions 106 3.10 File Specifications 118 Chapter 4: Graphics 131 4.1 Graphics Objects 132 4.2 Coordinate Systems 136 4.3 Graphics State 147 4.4 Path Construction and Painting 161 4.5 Color Spaces 172 4.6 Patterns 219 4.7 External Objects 261 4.8 Images 262 4.9 Form XObjects 281 4.10 PostScript XObjects 289 Contents iv Chapter 5: Text 291 5.1 Organization and Use of Fonts 292 5.2 Text State Parameters and Operators 300 5.3 Text Objects 308 5.4 Introduction to Font Data Structures 314 5.5 Simple Fonts 316 5.6 Composite Fonts 334 5.7 Font Descriptors 355 5.8 Embedded Font Programs 364 5.9 ToUnicode CMaps 368 Chapter 6: Rendering 373 6.1 CIE-Based Color to Device Color 374 6.2 Conversions among Device Color Spaces 376 6.3 Transfer Functions 380 6.4 Halftones 382 6.5 Scan Conversion Details 403 Chapter 7: Transparency 409 7.1 Overview of Transparency 410 7.2 Basic Compositing Computations 412 7.3 Transparency Groups 425 7.4 Soft Masks 439 7.5 Specifying Transparency in PDF 441 7.6 Color Space and Rendering Issues 454 Chapter 8: Interactive Features 471 8.1 Viewer Preferences 471 8.2 Document-Level Navigation 474 8.3 Page-Level Navigation 481 8.4 Annotations 488 8.5 Actions 513 8.6 Interactive Forms 528 8.7 Sounds 568 8.8 Movies 570 Chapter 9: Document Interchange 573 9.1 Procedure Sets 574 9.2 Metadata 575 9.3 File Identifiers 580 9.4 Page-Piece Dictionaries 581 9.5 Marked Content 583 9.6 Logical Structure 588 9.7 Tagged PDF 612 9.8 Accessibility Support 651 9.9 Web Capture 659 9.10 Prepress Support 676 Contents v Appendix A: Operator Summary 699 Appendix B: Operators in Type 4 Functions 703 B.1 Arithmetic Operators 703 B.2 Relational, Boolean, and Bitwise Operators 704 B.3 Conditional Operators 704 B.4 Stack Operators 704 Appendix C: Implementation Limits 705 C.1 General Implementation Limits 706 C.2 Implementation Limits Affecting Web Capture 708 Appendix D: Character Sets and Encodings 709 D.1 Latin Character Set and Encodings 711 D.2 Expert Set and MacExpertEncoding 715 D.3 Symbol Set and Encoding 718 D.4 ZapfDingbats Set and Encoding 721 Appendix E: PDF Name Registry 723 Appendix F: Linearized PDF 725 F.1 Background and Assumptions 726 F.2 Linearized PDF Document Structure 728 F.3 Hint Tables 741 F.4 Access Strategies 751 Appendix G: Example PDF Files 757 G.1 Minimal PDF File 757 G.2 Simple Text String Example 760 G.3 Simple Graphics Example 762 G.4 Page Tree Example 765 G.5 Outline Tree Example 770 G.6 Updating Example 774 Appendix H: Compatibility and Implementation Notes 783 H.1 PDF Version Numbers 783 H.2 Feature Compatibility 786 H.3 Implementation Notes 787 Bibliography 811 Index 817 vii Figures 2.1 Creating PDF files using PDF Writer 20 2.2 Creating PDF files using Acrobat Distiller 21 3.1 PDF components 24 3.2 Initial structure of a PDF file 62 3.3 Structure of an updated PDF file 70 3.4 Structure of a PDF document 82 3.5 Inheritance of attributes 92 3.6 Mapping with the Decode array 112 4.1 Graphics objects 135 4.2 Device space 138 4.3 User space 140 4.4 Relationships among coordinate systems 142 4.5 Effects of coordinate transformations 143 4.6 Effect of transformation order 144 4.7 Miter length 154 4.8 Cubic Bézier curve generated by the c operator 165 4.9 Cubic Bézier curves generated by the v and y operators 166 4.10 Nonzero winding number rule 170 4.11 Even-odd rule 171 4.12 Color specification 174 4.13 Color rendering 175 4.14 Component transformations in a CIE-based ABC color space 182 4.15 Component transformations in a CIE-based A color space 183 4.16 Starting a new triangle in a free-form Gouraud-shaded triangle mesh 245 4.17 Connecting triangles in a free-form Gouraud-shaded triangle mesh 246 4.18 Varying the value of the edge flag to create different shapes 247 4.19 Lattice-form triangle meshes 248 4.20 Coordinate mapping from a unit square to a four-sided Coons patch 251 4.21 Painted area and boundary of a Coons patch 252 4.22 Color values and edge flags in Coons patch meshes 254 4.23 Edge connections in a Coons patch mesh 255 4.24 Control points in a tensor-product patch 257 4.25 Typical sampled image 262 4.26 Source image coordinate system 265 4.27 Mapping the source image 266 Figures viii 5.1 Glyphs painted in 50% gray 295 5.2 Glyph outlines treated as a stroked path 296 5.3 Graphics clipped by a glyph path 297 5.4 Glyph metrics 298 5.5 Metrics for horizontal and vertical writing modes 300 5.6 Character spacing in horizontal writing 303 5.7 Word spacing in horizontal writing 303 5.8 Horizontal scaling 304 5.9 Leading 304 5.10 Text rise 307 5.11 Operation of the TJ operator in horizontal writing 312 5.12 Output from Example 5.9 327 5.13 Characteristics represented in the Flags entry of a font descriptor 359 6.1 Various halftoning effects 389 6.2 Halftone cell with a nonzero angle 396 6.3 Angled halftone cell divided into two squares 396 6.4 Halftone cell and two squares tiled across device space 397 6.5 Tiling of device space in a type 16 halftone 399 6.6 Flatness tolerance 404 6.7 Rasterization without stroke adjustment 407 8.1 Presentation timing 487 8.2 Open annotation 489 8.3 Coordinate adjustment with the NoRotate flag 494 8.4 Square and circle annotations 505 8.5 QuadPoints specification 506 8.6 FDF file structure 559 9.1 Simple Web Capture file structure 662 9.2 Complex Web Capture file structure 663 9.3 Page boundaries 678 9.4 Trapping example 688 G.1 Output of Example G.3 763 G.2 Page tree for Example G.4 765 G.3 Document outline as displayed in Example G.5 770 G.4 Document outline as displayed in Example G.6 772 Figures ix Plate 1 Additive and subtractive color Plate 2 Uncalibrated color Plate 3 Lab color space Plate 4 Color gamuts Plate 5 Rendering intents Plate 6 Duotone image Plate 7 Quadtone image Plate 8 Colored tiling pattern Plate 9 Uncolored tiling pattern Plate 10 Axial shading Plate 11 Radial shadings depicting a cone Plate 12 Radial shadings depicting a sphere Plate 13 Radial shadings with extension Plate 14 Radial shading effect Plate 15 Coons patch mesh Plate 16 Transparency groups Plate 17 Isolated and knockout groups Plate 18 RGB blend modes Plate 19 CMYK blend modes Plate 20 Blending and overprinting [...]... interchange format called the Portable Document Format Thus, these elements of the Portable Document Format may not be copied without Adobe s permission Adobe will enforce its copyright Adobe s intention is to maintain the integrity of the Portable Document Format standard This enables the public to distinguish between the Portable Document Format and other interchange formats for electronic documents... However, Adobe desires to promote the use of the Portable Document Format for information interchange among diverse products and applications Accordingly, Adobe gives anyone copyright permission, subject to the conditions stated below, to: • Prepare files whose content conforms to the Portable Document Format • Write drivers and applications that produce output represented in the Portable Document Format. .. of Adobe publications are available on the subject of font formats, most notably the following: • Adobe Type 1 Font Format and Adobe Technical Note #5015, Type 1 Font Format Supplement • Adobe Technical Note #5176, The Compact Font Format Specification • Adobe Technical Note #5177, The Type 2 Charstring Format • Adobe Technical Note #5014, Adobe CMap and CID Font Files Specification C HA P T E R 1 6... describes version 1.4 of PDF (See implementation note 1 in Appendix H.) Throughout the book, information specific to particular versions of PDF is marked as such—for example, with indicators like (PDF 1.3) or (PDF 1.4) Features so marked may be new in the indicated version or may have been substantially redefined in that version Features designated (PDF 1.0) have generally been superseded in later versions;... copyrighted material from Adobe, or the software in any of Adobe s products that use the Portable Document Format, in whole or in part, nor does it include the right to use any Adobe patents, except as may be permitted by an official Adobe Patent Clarification Notice (see the Bibliography) Acrobat, Acrobat Capture, Acrobat Reader, ePaper, the “Get Acrobat Reader” Web logo, the Adobe PDF” Web logo, and... trademarks, service marks, and logos used by Adobe (the “Marks”) are the registered trademarks or trademarks of Adobe Systems Incorporated in the United States and other countries Nothing in this book is intended to grant you any right or license to use the Marks for any purpose CHAPTER 2 Overview 2 THE ADOBE PORTABLE DOCUMENT FORMAT (PDF) is a file format for representing documents in a manner independent of... creative contributions to the success of PDF Chuck Geschke and John Warnock May 2001 CHAPTER 1 Introduction 1 THE ADOBE PORTABLE DOCUMENT FORMAT (PDF) is the native file format of the Adobe Acrobat® family of products The goal of these products is to enable users to exchange and view electronic documents easily and reliably, independently of the environment in which they were created PDF relies on the same... Write software that accepts input in the form of the Portable Document Format and displays, prints, or otherwise interprets the contents • Copy Adobe s copyrighted list of data structures and operators, as well as the example code and PostScript language function definitions in the written specification, to the extent necessary to use the Portable Document Format for the purposes above The conditions of such... for additional publications related to PDF and the contents of this book 1.4 Intellectual Property The general idea of using an interchange format for electronic documents is in the public domain Anyone is free to devise a set of unique data structures and operators that define an interchange format for electronic documents However, Adobe Systems Incorporated owns the copyright for the particular data... of such copyright permission are: • Software that accepts input in the form of the Portable Document Format must respect the access permissions specified in that document Accessing the docu- S E C T IO N 1 4 7 Intellectual Property ment in ways not permitted by the document s access permissions is a violation of the document author’s copyright • Anyone who uses the copyrighted list of data structures . operators 16 6 4 .10 Nonzero winding number rule 17 0 4 .11 Even-odd rule 17 1 4 .12 Color specification 17 4 4 .13 Color rendering 17 5 4 . 14 Component. Chapter 4: Graphics 13 1 4 .1 Graphics Objects 13 2 4. 2 Coordinate Systems 13 6 4. 3 Graphics State 14 7 4. 4 Path Construction and Painting 16 1 4. 5 Color Spaces 17 2 4. 6