The Portable Document Format commonly referred to as PDF is a file format used to present documents in a manner independent of application softwarehardwareand operating systems.

PDF was developed in the early s [4] as a way to share computer documents, including text formatting and inline images. In those early years before the rise of the World Wide Web and HTML documents, PDF was popular mainly in desktop publishing workflows. Adobe Systems made the PDF specification available free of charge in PDF was a proprietary format controlled by Adobe, until it was officially released as an open standard on July 1,and published by the International Organization for Standardization as ISO InAdobe published a Public Patent License to ISO granting royalty-free rights for all patents owned by Adobe that are necessary to make, use, sell, and distribute PDF compliant implementations.

However, there are still some proprietary technologies defined only by Adobe, such as Adobe XML Forms Architecture XFA and JavaScript extension for Acrobat, which are referenced by ISO as normative and indispensable for the application of the ISO specification. So when organizations publish PDFs which use these proprietary technologies, they present accessibility issues for some users.

InISO TC voted to deprecate XFA for ISO "Next-generation PDF". On January 9,the final draft for ISO was published, thus reaching the approval stage. PostScript is a page description language run in an interpreter to generate an image, a process requiring many resources. It can handle graphics and standard features of programming languages such as if and loop commands. PDF is largely based on PostScript but simplified to remove flow control features like these, while graphics commands such as lineto remain.

Often, the PostScript-like PDF code is generated from a source PostScript file. The graphics commands that are output by the PostScript code are collected and tokenized. Any files, graphics, or fonts to which the document refers also are collected. Then, everything is compressed to a single file. Therefore, the entire PostScript world fonts, layout, measurements remains intact. A PDF file is a 7-bit ASCII file, except for certain elements that may have binary content. The format is a subset of a COS "Carousel" Object Structure format.

Comments may contain 8-bit characters. Objects may be either direct embedded in another object or indirect. Indirect objects are numbered with an object number and a generation number and defined between the obj and endobj keywords.

An index table, also called the cross-reference table and marked with the xref keyword, follows the main body and gives the byte offset of each indirect object from the start of the file.

Beginning with PDF version 1. This technique reduces the size of files that have large numbers of small indirect objects and is especially useful for Tagged PDF. At the end of a PDF file is a trailer introduced with the trailer keyword. There are two layouts to the PDF files: Non-linear PDF files consume less disk space than their linear counterparts, though they are slower to access because portions of the data required to assemble pages of the document are scattered throughout the PDF file.

Linear PDF files also called "optimized" or "web optimized" PDF files are constructed in a manner that enables them to be read in a Web browser plugin without waiting for the entire file to download, since they are written to disk in a linear as in page order fashion. The basic design of how graphics are represented in PDF is very similar to that of PostScript, except for the use of transparencywhich was added in PDF 1.

PDF graphics use a device-independent Cartesian coordinate system to describe the surface of a page. A PDF page description can use a matrix to scalerotateor skew graphical elements. A key concept in PDF is that of the graphics statewhich is a collection of graphical parameters that may be changed, saved, and restored by a page description.

PDF has as of version 1. As in PostScript, vector graphics in PDF are constructed with paths. Unlike PostScript, PDF does not allow a single path to mix text outlines with lines and curves. Paths can be stroked, filled, or used for clipping. Strokes and fills can use any color set in the graphics state, including patterns.

PDF supports several types of patterns. The simplest is the tiling pattern in which a piece of artwork is specified to be drawn repeatedly. This may be a colored tiling patternwith the colors specified in the pattern object, or an uncolored tiling patternwhich defers color specification to the time the pattern is drawn.

Beginning with PDF 1. There are seven types of shading pattern of which the simplest are the axial shade Type 2 and radial shade Type 3. Raster images in PDF called Image XObjects are represented by dictionaries with an associated stream. The dictionary describes properties of the image, and the stream contains the image data.

Less commonly, a raster image may be embedded directly in a page description as an inline image. Images are typically filtered for compression purposes. Image filters supported in PDF include the general purpose filters. Normally all image content in a PDF is embedded in the file.

But PDF allows image data to be stored in external files by the use of external streams or Alternate Images. Text in PDF is represented by text elements in page content streams. A text element specifies that characters should be drawn at certain positions. The characters are specified using the encoding of a selected font resource.

A font object in PDF is a description of a digital typeface. It may either describe the characteristics of a typeface, or it may include an embedded font file. The latter case is called an embedded font while the former is called an unembedded font. The font files that may be embedded are based on widely used standard digital font formats: Type 1 and its compressed variant CFFTrueTypeand beginning with PDF 1.

Additionally PDF supports the Type 3 variant in which the components of the font are described by PDF graphic operators. Fourteen typefaces, known as the standard 14 fontshave a special significance in PDF documents:. These fonts are sometimes called the base fourteen fonts. However, since Adobe Acrobat version 6, most of these fonts are not guaranteed to be available in the reader, and may only display correctly if the system has them installed.

Within text strings, characters are shown using character codes integers that map to glyphs in the current font using an encoding. There are a number of predefined encodings, including WinAnsiMacRomanand a large number of encodings for East Asian languages, and a font can have its own built-in encoding.

Although the WinAnsi and MacRoman encodings are derived from the historical properties of the Windows and Macintosh operating systems, fonts using these encodings work equally well on any platform.

PDF can specify a predefined encoding to use, the font's built-in encoding or provide a lookup table of differences to a predefined or built-in encoding not recommended with TrueType fonts. For large fonts or fonts with non-standard glyphs, the special encodings Identity-H for horizontal writing and Identity-V for vertical are used.

With such fonts it is necessary to provide a ToUnicode table if semantic information about the characters is to be preserved. The original imaging model of PDF was, like PostScript's, opaque: When transparency is used, new objects interact with previously marked objects to produce blending effects.

The addition of transparency to PDF was done by means of new extensions that were designed to be ignored in products written to the PDF 1. As a result, files that use a small amount of transparency might view acceptably in older viewers, but files making extensive use of transparency could be viewed incorrectly in an older viewer without warning.

The transparency extensions are based on the key concepts of transparency groupsblending modesshapeand alpha. The model is closely aligned with the features of Adobe Illustrator version 9. The blend modes were based on those used by Adobe Photoshop at the time. When the PDF 1. They have since been published. The concept of a transparency group in PDF specification is independent of existing notions of "group" or "layer" in applications such as Adobe Illustrator. Those groupings reflect logical relationships among objects that are meaningful when editing those objects, but they are not part of the imaging model.

PDF files may contain interactive elements such as annotations, form fields, video and Flash animation. Rich Media PDF is a term that is used to describe interactive content that can be embedded or linked to inside of a PDF. This content must be produced using the Flash file format.

When Adobe bought Macromedia, the jewel of the company was Flash, and the Flash player was embedded inside Adobe Acrobat and Adobe Reader, removing the need for third-party plug-ins such as Flash, QuickTime, or Windows Media.

Unfortunately, this caused a rift with Apple as QuickTime video was prohibited from PDF. Rich Media PDF will not operate in Apple's iOS devices such as the iPad, and interactivity is limited. PDF currently supports two different methods for integrating data and PDF forms. Both formats today coexist in PDF specification: AcroForms were introduced in the PDF 1. AcroForms permit using objects e. Alongside the standard PDF action types, interactive forms AcroForms support submitting, resetting, and importing data.

The "submit" action transmits the names and values of selected interactive form fields to a specified uniform resource locator URL. AcroForms can keep form field values in external stand-alone files containing key: The external files may use Forms Data Format FDF and XML Forms Data Format XFDF files. The Forms Data Format FDF is based on PDF, it uses the same syntax and has essentially the same file structure, but is much simpler than PDF, since the body of an FDF document consists of only one required object.

Forms Postscript output option archive format Format is defined in the PDF specification since PDF 1. The Forms Data Format can be used when submitting form data to a server, receiving the response, and incorporating into the interactive form.

It can also be used to export form data to stand-alone files that can be imported back into the corresponding PDF interactive form. Beginning in PDF 1. FDF typically encapsulates information such as X. Import support for stand-alone FDF files is implemented in The incredible january effect the stock markets unsolved mystery Reader; export and import support including saving of FDF data in PDF is for example implemented in Foxit Reader and PDF-XChange Viewer Free; saving of FDF data in a PDF file is also supported in pdftk.

XML Forms Data Format XFDF is the XML version of Forms Data Format, buy hershey chocolate stock the XFDF implements only a subset of FDF containing forms and annotations.

There are not XFDF equivalents for some entries in the FDF dictionary - such as midlife earn money Status, Encoding, JavaScript, Pages keys, EmbeddedFDFs, Differences and Target.

Data entry jobs nj from home addition, XFDF does not allow the spawning, or addition, of new pages based on the given data; as can be done when using an FDF file. The XFDF specification is referenced but not included in PDF 1. It is described separately in XML Forms Data Format Specification.

XFDF conforms to the XML standard. As of DecemberXFDF 3. Use of ISO XFDF 3. XFDF can be used the same way as FDF; e. A support for importing and exporting XFDF stand-alone files is not widely implemented in free or freeware PDF software.

Import of Iranian currency exchange in los angeles is implemented in Adobe Reader 5 and later versions; import and export is implemented in PDF-XChange Viewer Free; embedding of XFDF data in PDF form is implemented in pdftk pdf toolkit. In the PDF 1. XFA was not standardized as an ISO standard.

Definition employee share option scheme XFA Forms are not compatible with AcroForms.

Adobe Reader contains "disabled features" for use of XFA Forms, that activate only when opening a PDF document that was created using enabling technology available only from Adobe.

XFA forms can be created and used as PDF files or as XDP XML Data Package files. The format of an XFA resource in PDF is described by the XML Data Package Specification. XDP provides a mechanism for iphone 4s could not save call waiting settings form components within a surrounding XML container.

An XDP can also package a PDF file, along with XML form and template data.

When the PDF and XFA are combined, the result is a form in which each page of the XFA form overlays a PDF background. This architecture is sometimes referred to as XFAF XFA Foreground. The alternative is to express all of the form, including boilerplate, directly in XFA without using PDF, or only using "Shell PDF" which is a container for XFA with minimal skeleton of PDF markup, or using a pre-rendered depiction of a static XFA form as PDF pages.

It is sometimes stock brokers greenville sc full XFA. Starting with PDF 1. These rich text strings are XML documents that conform to the rich text conventions specified for the XML Forms Architecture specification 2. Most PDF processors do not handle XFA content. When generating a shell PDF it is recommended to include in the PDF markup a simple one-page PDF image displaying a warning message e.

PDF processors that can render XFA content should either not display the supplied warning page image or replace it quickly with the dynamic form content. A "tagged" PDF ISO Technically speaking, tagged PDF sending sms earn money india a stylized use of the format that builds on the logical structure framework introduced in PDF 1.

Tagged PDF defines a set of standard structure types and attributes that allow page content text, graphics, and images to be extracted and reused for other purposes. Tagged PDF is not required in situations where a PDF file is intended only for print. Since the feature is optional, and since the rules for Tagged PDF as specified in ISO are relatively vague, support for tagged PDF amongst consuming devices, including assistive technology ATis uneven.

The standard security provided by Acrobat PDF consists of two different methods and two different passwords, user passwordwhich encrypts the file and prevents opening, and owner passwordwhich specifies operations that should be restricted even when the document is decrypted, which can include: The user password online cp money maker opening encrypts the file and requires password cracking to defeat, with difficulty depending on password strength and encryption method — it is potentially very secure assuming good password and encryption method without known attacks.

The owner password controls operations does not encrypt the file, and instead relies on client software to respect these restrictions, and is not secure. An "owner password" can be removed by many commonly available "PDF cracking" software, including some free online services.

Even without removing the password, most freeware or open source PDF readers ignore the permission "protections" and allow the user to print or make copy of excerpts of the text as if the document were not limited by password protection.

There are a number of commercial solutions including Adobe Selling stock options limit order Rights Management and Locklizard PDF DRM [47] that intraday trading system ebook harmonic more robust means of information rights management.

Not only can they restrict document access but they also reliably enforce permissions in ways that the standard security handler does not. The signature is used to validate that the permissions have been granted by a bona fide granting authority. For example, it can be used to allow a user: For example, Adobe Systems grants permissions to enable additional features in Adobe Reader, using public-key cryptography.

Adobe Reader verifies that the signature uses a certificate from an Adobe-authorized certificate authority. PDF files can have document-level and page-level file attachments, which the reader can access and open or save to their local filesystem. PDF attachments can be added to existing PDF list of stock broking companies in india for example using pdftk.

Adobe Reader provides support for attachments, and poppler -based readers like Evince or Okular also have some support for document-level attachments. PDF files can contain two types of metadata.

This is stored in the optional Info trailer of the file. A small set of fields is defined, and can be extended with additional text values if required.

This allows metadata to be attached to any stream in the document, such as information about embedded illustrations, as well as the whole document attaching to the document catalogusing an extensible schema. Anyone may create applications that can read and write PDF files without having to pay royalties to Adobe Systems ; Adobe holds patents to PDF, but licenses them for royalty-free use in developing software complying with its PDF specification. PDF files can be created specifically to be accessible for disabled people.

Problems remain with adding tags to older PDFs and those that are generated from scanned documents. In these cases, accessibility tags and mtf bollinger bands strategy are unavailable, and must be created either manually or with OCR techniques.

These processes are inaccessible to some disabled people. One of the significant challenges with PDF accessibility is that PDF send free sms and earn money site have three distinct views, which, depending on the document's creation, can be inconsistent with each other.

The three views are i the physical view, ii the tags view, and iii the content view. The physical view is displayed and printed what most people consider a PDF document.

The tags view is what screen readers and other assistive technologies use to deliver a high-quality navigation and reading experience to users with disabilities. The content view is based on the physical order of objects within the PDF's content stream and may be displayed by software that does not fully support the tags view, such as the Reflow feature in Adobe's Reader.

PDF attachments carrying viruses were first discovered in The virus, named OUTLOOK. PDFWorm or Peachyuses Microsoft Outlook to send itself as an attachment to an Adobe PDF file. It was activated with Adobe Acrobat, but not with Acrobat Reader. From time to time, new vulnerabilities are discovered in various versions of Adobe Reader, [64] prompting the company to issue security fixes. Other PDF readers are also susceptible.

One aggravating factor is that a PDF reader can be configured to start automatically if a web page has an embedded PDF file, providing a vector for how much does a yoga instructor make in ontario. If a malicious web page contains an infected PDF file that takes 10/22 nomad stock canada of a vulnerability in the PDF reader, the system may be compromised even if the browser is secure.

Some of these vulnerabilities are a result of the PDF standard allowing PDF documents to be scripted with JavaScript. Disabling JavaScript execution in the PDF reader can help mitigate such future exploits, although it does not protect against exploits in other parts of the PDF viewing software.

Security experts say that JavaScript is not essential for a PDF reader, and that the security benefit that comes from disabling JavaScript outweighs any compatibility issues caused. On March 30, security researcher Didier Stevens reported an Adobe Reader and Foxit Reader exploit that runs a malicious executable if the user allows it to launch when asked. PDFs may be encrypted so that a password is needed to view or edit the contents.

The PDF Reference defines both bit and bit encryption, both making use of a complex system of RC4 and MD5. The PDF Reference also defines ways that third parties can define reviews of futures trading courses in singapore own encryption systems for PDF.

PDF files may also contain embedded DRM restrictions that provide further controls that limit copying, editing or printing. The restrictions on copying, editing, or printing depend on the reader software to obey them, so the security they provide is limited.

PCLTool SDK | PCL Conversion Software Developer’s Kit

The PDF Reference has technical details for an end-user overview. This could be used to track the IP address of the client PC, a process known as phoning home. Through its LiveCycle Policy Server product, Adobe provides a method to set security policies potluck money makes the world go round download specific documents. This can include requiring a user to authenticate and limiting the period during which a document can be accessed or amount of time a document can be opened while offline.

Once a PDF document is tied to a policy server and a specific policy, that policy can be changed or revoked by the owner. This controls documents that are otherwise "in the wild. Policy servers can be set up privately or Adobe offers a public service through Adobe Online Services. As with other forms of DRM, adherence to these policies and restrictions may or may not be enforced by the reader software being used.

PDF documents can contain display settings, including the page display layout and zoom level. Adobe Reader uses these settings to override the user's default settings when opening the document. A PDF file is often a combination of vector graphicstext, and bitmap graphics. The basic types of content in a PDF are:. In later PDF revisions, a PDF document can also support links inside document or web pageforms, JavaScript initially available as plugin for Acrobat 3.

Two PDF files that look similar on a computer screen may be of very different sizes. For example, a high resolution raster image takes more space than a low resolution one. Typically higher resolution is needed for printing documents than for displaying them on screen.

Other things that may increase the size of a file is embedding full fonts, especially for Asiatic scripts, and storing text as graphics. PDF viewers are generally provided free of charge, and many versions are available from a variety of sources. There are many software options for creating PDFs, including the PDF printing capabilities built into macOS and most Linux distributions, LibreOfficeMicrosoft Office if updated to SP2 and later, [72] WordPerfect 9, Scribusnumerous PDF print drivers for Microsoft Windowsthe pdfTeX typesetting system, the DocBook PDF tools, applications developed around Ghostscript and Adobe Acrobat itself as well as Adobe InDesignAdobe FrameMakerAdobe IllustratorAdobe Photoshop.

Google 's online office suite Google Docs also allows for uploading and saving to PDF. Raster image processors RIPs are used to convert PDF files into a raster format suitable for imaging onto paper and other media in printers, digital production presses and prepress in a process known as rasterisation. RIPs capable of processing PDF directly include the Adobe PDF Print Engine [73] from Adobe Systems and Jaws [74] and the Harlequin RIP from Global Graphics. Adobe Illustrator reads and writes PDF as a semi-native format.

With multipage documents, a dialog opens enabling the user to select a single page to edit.

Editing paragraphs of text typically disturbs line justification and paragraph wrapping, as multiline text is converted to individual lines. In a multipage document, only the page being edited can be re-saved. Serif PagePlus can open, edit and save existing PDF documents, as well as publishing of documents created in the package.

Enfocus PitStop Pro, a plugin for Acrobat, allows manual and automatic editing of PDF files, [75] while the free Enfocus Browser makes it possible to edit the low-level structure of a PDF. Dochubis a free online PDF editing tool that can be used without purchasing anything.

Adobe Acrobat is one example of proprietary software that allows the user to annotate, highlight, and add notes to already created PDF files. One UNIX application available as free software under the GNU General Public License is PDFedit.

Another GPL-licensed application native to the unix environment is Xournal. Xournal allows for annotating in different fonts and colours, as well as a rule for quickly underlining and highlighting lines of text or paragraphs. Xournal also has a shape recognition tool for squares, rectangles and circles. In Xournal annotations may be moved, copied and pasted.

Document generation and output PRINT formats PCL, PostScript, AFP, Epson, Zebra, TEC, GDI, MATRIX, Printronix, METACODE, PDF, PDF/A, QMF, RTF, HTML,..

The freeware Foxit Readeravailable for Microsoft WindowsmacOS and Linuxallows annotating documents. Tracker Software's PDF-XChange Viewer allows annotations and markups without restrictions in its freeware alternative. Apple 's macOS 's integrated PDF viewer, Preview, does also enable annotations as does the freeware Skimwith the latter supporting interaction with LaTeXSyncTeX, and PDFSync and integration with BibDesk reference management software.

Freeware Qiqqa can create an annotation report that summarizes all the annotations and notes one has made across their library of PDFs. For mobile annotation, iAnnotate PDF from Branchfire and GoodReader from Aji allow annotation of PDFs as well as exporting summaries of the annotations.

There are also web annotation systems that support annotation in pdf and other documents formats, e. In cases where PDFs are expected to have all of the functionality of paper documents, ink annotation is required. Some programs that accept ink input from the mouse may not be responsive enough for handwriting input on a tablet. Existing solutions on the PC include PDF Annotator and Qiqqa.

Examples of PDF software as online services including Scribd for viewing and storing, Pdfvue for online editing, and Zamzar for conversion. In the Jaws raster image processor from Global Graphics became the first shipping prepress RIP that interpreted PDF natively without conversion to another format. The company released an upgrade to their Harlequin RIP with the same capability in Agfa-Gevaert introduced and shipped Apogee, the first prepress workflow system based on PDF, in PDF was selected as the "native" metafile format for Mac OS Xreplacing the PICT format of the earlier classic Mac OS.

The imaging model of the Quartz graphics layer is based on the model common to Display PostScript and PDF, leading to the nickname Display PDF.

The Preview application can display PDF files, as can version 2. System-level support for PDF allows Mac OS X applications to create PDF documents automatically, provided they support the OS-standard printing architecture. The files are then exported in PDF 1.

When taking a screenshot under Mac OS X versions In PDF was widely accepted as the standard print job format at the Open Source Development Labs Printing Summit. It is supported as a print job format by the Common Unix Printing System and desktop application projects such as GNOMEKDEFirefoxThunderbirdLibreOffice and OpenOffice have switched to emit print jobs in PDF.

Some desktop printers also support direct PDF printing, which can interpret PDF data without external help. Currently, all PDF capable printers also support PostScript, but most PostScript printers do not support direct PDF printing.

The Free Software Foundation once considered one of their high priority projects to be "developing a free, high-quality and fully functional set of libraries and programs that implement the PDF file format and associated technologies to the ISO standard.

Poppler is based on Xpdf [84] [85] code base.

There are also commercial development libraries available as listed in List of PDF software. The Apache PDFBox project of the Apache Software Foundation is an open source Java library for working with PDF documents. PDFBox is licensed under the Apache License. From Wikipedia, the free encyclopedia.

Adobe PostScript

For other uses, see PDF disambiguation. History and standardization of Portable Document Format. For more details on this topic, see List of PDF software. Comparison of notetaking software. Open XML Paper Specification Comparison of OpenXPS and PDF DjVu PAdESPDF Advanced Electronic Signature Web document XSL Formatting Objects. Archived from the original on December 13, The Committee urges Adobe Systems to submit the XFA Specification, XML Forms Architecture XFAto ISO for standardization The Committee is concerned about the stability of the XFA specification Part 2 will reference XFA 3.

XFA forms have been deprecated from ISO in accordance with the outcome of the letter ballot following the Pretoria meetings. PDF Reference and Adobe Extensions to the PDF Specification". Base 14 Fonts - Definition". Archived from the original on Archived from the original on December 19, Strengths and Weaknesses" PDF.

The New York Times. PDF Attachment Virus "Peachy"15 August Retrieved 21 June Content of the latter page, however, changes over time. AI CDR CGM DXF EVA EMF Gerber HVIF IGES PGML SVG VML WMF Xar. CDF DjVu EPS PDF PICT PS SWF XAML. Exchangeable image file format Exif Extensible Metadata Platform XMP. Multi-purpose office document file formats.

Compound Document Format Microsoft Office XML formats Office Open XML Open Document Architecture OpenDoc OpenDocument OpenOffice. DjVu Envoy Open XML Paper Specification Portable Document Format. Character encoding ASCII Unicode TeX. ISO standards by standard number. Adobe Acrobat Adobe Digital Editions Aldiko Blio Bluefire Reader Calibre FBReader Google Play Books iBooks Kindle app Kitabu Lektz Lucifox Mantano Reader Okular OverDrive Media Console Snapplify STDU Viewer Sumatra PDF.

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