|Portable Document Format (PDF)|
|File name extension|
|Internet media type|
|Type code||'PDF ' (including a single space)|
|Uniform Type Identifier||com. An Internet media type, originally called a MIME type after MIME and sometimes a Content-type after the name of a header in several protocols whose value A type code is the only mechanism used in pre- Mac OS X versions of the Macintosh Operating system to denote a file's format, in a manner similar A Uniform Type Identifier ( UTI) is a string defined by Apple Inc adobe. pdf|
|Developed by||Adobe Systems|
The Portable Document Format (PDF) is the file format created by Adobe Systems in 1993 for document exchange. A file format is a particular way to encode information for storage in a Computer file. Adobe Systems Incorporated (pronounced a-DOE-bee əˈdoʊbiː ( is an American Computer software company headquartered in San Jose California A file format is a particular way to encode information for storage in a Computer file. Adobe Systems Incorporated (pronounced a-DOE-bee əˈdoʊbiː ( is an American Computer software company headquartered in San Jose California PDF is a fixed-layout format used for representing two-dimensional documents in a manner independent of the application software, hardware, and operating system.  Each PDF file encapsulates a complete description of a 2-D document (and, with Acrobat 3-D, embedded 3-D documents) that includes the text, fonts, images, and 2-D vector graphics that compose the documents. Vector graphics is the use of geometrical primitives such as points lines, Curves and shapes or Polygon (s which are all based
PDF is an open standard, and recently took a major step towards becoming the ISO 32000. An open standard is a Standard that is publicly available and has various rights to use associated with it 
When the PDF first came in the early 1990s, its general adoption was slow.  At that time, the PDF-creation tools (Acrobat) and the viewing and printing software had to be bought. Adobe Acrobat is a family of computer programs developed by Adobe Systems, designed to view create manipulate and manage files in Adobe's Portable Document Early versions of PDF had no support for external hyperlinks, reducing its usefulness on the World Wide Web; the additional size of the PDF document compared to plain text meant significantly longer download times over the slower modems common at the time, and rendering the files was slow on less powerful machines. The World Wide Web (commonly shortened to the Web) is a system of interlinked Hypertext documents accessed via the Internet. Modem (from mo dulator- dem odulator is a device that modulates an analog carrier signal to encode Digital information Additionally, there were competing formats such as Envoy, Common Ground Digital Paper and even Adobe's own PostScript format (. In Computing, Envoy was a portable Document File format marketed by WordPerfect Corporation created as a competitor for Acrobat Pro PostScript ( PS) is a dynamically typed concatenative Programming language created by John Warnock and Charles Geschke in 1982 ps); in those early years, the PDF file was mainly popular in desktop publishing workflow. Desktop publishing (also known as DTP) combines a Personal computer and WYSIWYG page layout Software to create Publication Documents A workflow is a depiction of a sequence of operations declared as work of a person work of a simple or complex mechanism work of a group of persons work of an organization of staff
Adobe soon started distribution of its Acrobat Reader (now Adobe Reader) program at no cost, and continued supporting the original PDF, which eventually became the de facto standard for printable documents on the web (a standard web document). A de facto standard is a Standard (formal or informal that has achieved a dominant and accepted position Web document is a similar concept to Web page, except it is a broader term with the
The PDF file format has changed several times, as new versions of Adobe Acrobat were released. There have been eight versions of PDF with corresponding Acrobat releases:
Anyone may create applications that 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. Adobe Systems Incorporated (pronounced a-DOE-bee əˈdoʊbiː ( is an American Computer software company headquartered in San Jose California Royalty Free refers to a type of contract between a two entities (the licensor and licensee that is employed when licensing the rights to use content such as photographs 
The PDF combines three technologies:
PostScript is a page description language run in an interpreter to generate an image, a process requiring many resources. PostScript ( PS) is a dynamically typed concatenative Programming language created by John Warnock and Charles Geschke in 1982 A page description language (PDL is a language that describes the appearance of a printed page in a higher level than an actual output Bitmap. In Computer science, an interpreter normally means a Computer program that executes, i PDF is a file format, not a programming language, i. e. flow control commands such as
loop are removed, while graphics commands such as
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. In Computer science, lexical analysis is the process of converting a sequence of characters into a sequence of tokens Therefore, the entire PostScript world (fonts, layout, measurements) remains intact.
As a document format, PDF has several advantages over PostScript:
A PDF file consists primarily of objects, of which there are eight types:
Objects may be either direct (embedded in another object) or indirect. Indirect objects are numbered with an object number and a generation number. An index table called the xref table gives the byte offset of each indirect object from the start of the file.  This design allows for efficient random access to the objects in the file, and also allows for small changes to be made without rewriting the entire file (incremental update). In Computer science, random access (sometimes called direct access) is the ability to access an arbitrary element of a sequence in equal time Beginning with PDF version 1. 5, indirect objects may also be located in special streams known as object streams. This technique reduces the size of files that have large numbers of small indirect objects and is especially useful for Tagged PDF.
There are two layouts to the PDF files—non-linear (not “optimized”) and linear (“optimized”). 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, since they are written to disk in a linear (as in page order) fashion.  PDF files may be optimized using Adobe Acrobat software or pdfopt, which is part of GPL Ghostscript. Adobe Acrobat is a family of computer programs developed by Adobe Systems, designed to view create manipulate and manage files in Adobe's Portable Document
The basic design of how graphics are represented in PDF is very similar to that of PostScript, except for the use of transparency, which was added in PDF 1. Graphics (from Greek grc [[wiktγραφικός γραφικός]] see -graphy) are Visual presentations on some surface such as a wall Transparency is possible in a number of graphics file formats 4.
PDF graphics use a device independent Cartesian coordinate system to describe the surface of a page. Device Independent also is the full name of the DVI file format. In Mathematics, the Cartesian coordinate system (also called rectangular coordinate system) is used to determine each point uniquely in a plane A PDF page description can use a matrix to scale, rotate, or skew graphical elements. In Mathematics, a matrix (plural matrices) is a rectangular table of elements (or entries) which may be Numbers or more generally The concept of scale is applicable if a system is represented proportionally by another system A rotation is a movement of an object in a circular motion A two- Dimensional object rotates around a center (or point) of rotation Skew or skew lines lie on different planes They are neither parallel nor intersecting A key concept in PDF is that of the graphics state, which is a collection of graphical parameters that may be changed, saved, and restored by a page description. PDF has (as of version 1. 6) 24 graphics state properties, of which some of the most important are:
Vector graphics in PDF, as in PostScript, are constructed with paths. In 2D graphics In 2D computer graphics, a clipping path is a closed Vector path, or shape used to cut out an image in current Image editing A Color model is an abstract mathematical model describing the way Colors can be represented as Tuples of numbers typically as three or four values or color components In Computer graphics, alpha compositing is the process of combining an image with a background to create the appearance of partial transparency Paths are usually composed of lines and cubic Bezier curves, but can also be constructed from the outlines of text. In the mathematical field of Numerical analysis, a Bézier curve is a Parametric curve important in Computer graphics and related fields 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. In 2D graphics In 2D computer graphics, a clipping path is a closed Vector path, or shape used to cut out an image in current Image editing 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 pattern, with the colors specified in the pattern object, or an uncolored tiling pattern, which defers color specification to the time the pattern is drawn. Beginning with PDF 1. 3 there is also a shading pattern, which draws continuously varying colors. There are seven types of shading pattern of which the simplest are the radial shade (Type 2) and axial 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
and the image-specific 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. Standardized subsets of PDF, including PDF/A and PDF/X, prohibit these techniques. ISO 19005-12005 is an ISO Standard that was published on October 1 2005 Document Management - Electronic document file format for long term preservation PDF/X is an umbrella term for several ISO standards that define a subset of the PDF standard
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. In Typography, a typeface is a set of one or more Fonts designed with stylistic unity each comprising a coordinated set of Glyphs A typeface usually comprises 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 CFF), TrueType, and (beginning with PDF 1. PostScript fonts are Outline font specifications developed by Adobe for professional digital typesetting, which uses PostScript file format to TrueType is an Outline font standard originally developed by Apple Computer in the late 1980s as a competitor to Adobe 's Type 1 fonts 6) OpenType. OpenType is a scalable format for Computer fonts initially developed by Microsoft, later joined by Adobe Systems. Additionally PDF supports the Type 3 variant in which the components of the font are described by PDF graphic operators.
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 built-in encodings, including WinAnsi, MacRoman, and a large number of encodings for East Asian languages. (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. Microsoft Windows is a series of Software Operating systems and Graphical user interfaces produced by Microsoft. Macintosh, commonly nicknamed Mac is a Brand name which covers several lines of Personal computers designed developed and marketed by Apple Inc ) The encoding mechanisms in PDF were designed for Type 1 fonts, and the rules for applying them to TrueType fonts are complex.
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: each object drawn on the page completely replaced anything previously marked in the same location. In PDF 1. 4 the imaging model was extended to allow transparency. 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. 3 and earlier specifications. 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 view completely wrong in an older viewer without warning.
The transparency extensions are based on the key concepts of transparency groups, blending modes, shape, and alpha. The model is closely aligned with the features of Adobe Illustrator version 9. Adobe Illustrator is a vector-based drawing program developed and marketed by Adobe Systems. The blend modes were based on those used by Adobe Photoshop at the time. When the PDF 1. 4 specification was published the formulas for calculating blend modes were kept secret by Adobe. They have since been published. 
PDF files may contain interactive elements such as annotations and form fields.
A PDF may contain structure information to enable better text extraction and accessibility.
A PDF file may be encrypted for security, or digitally signed for authentication.
The standard security provided by Acrobat® PDF consists of two different methods and two different passwords, "user password" and "owner password". A PDF document may be protected by password to open ('user' password) and the document may also specify operations that should be restricted even when the document is decrypted: printing; copying text and graphics out of the document; modifying the document; and adding or modifying text notes and AcroForm fields (using 'owner' password).
A large number of software products exist that are designed to 'recover' passwords, effectively removing any security applied in this way (see, for example the original PDF password recovery specialists, Elcomsoft: http://www.elcomsoft.com/). For this reason several companies (including Drumlin, FileOpen and LockLizard) have produced solutions based stronger levels of PDF file encryption coupled with central DRM services. Solutions such as these require the use of proprietary readers, which are typically provided free of charge.
Proper subsets of PDF have been, or are being, standardized under ISO for several constituencies:
A PDF/H variant (PDF for Healthcare) is being developed. PDF/X is an umbrella term for several ISO standards that define a subset of the PDF standard ISO 19005-12005 is an ISO Standard that was published on October 1 2005 Document Management - Electronic document file format for long term preservation PDF/UA (PDF/Universal Accessibility is a Standards Committee formed by AIIM.  However, it may consist more of a set of "best practices" than of a specific format or subset.
Adobe is exploring an XML-based next-generation PDF codenamed Mars. A page description markup language is a type of markup language that is used to describe the appearance of a printed page A code name or cryptonym is a word or name used clandestinely to refer to another name or word  Information about the Mars file format is published by Adobe at http://www.adobe.com/go/mars and also .
The format of graphic elements of Mars is sometimes described simply as "SVG", but according to the version 0. 8 draft specification of November 2007 (§3 Mars SVG Support) the format is actually merely similar to SVG: it contains both additions to and subtractions from SVG, so it is in general neither viewable by nor creatable with standard SVG tools: some things will look noticeably different between SVG viewers and Mars viewers.
PDF files can be created specifically to be accessible for disabled people. Current PDF file formats can include tags (XML), text equivalents, captions, audio descriptions, et cetera. Don't change "Extensible" Some software, such as Adobe InDesign, can automatically produce tagged PDFs. Adobe InDesign is a Desktop publishing (DTP software application produced by Adobe Systems. Leading screen readers, including JAWS, Window-Eyes, Hal, and Kurzweil 1000 and 3000 can read tagged PDFs; current versions of the Acrobat and Acrobat Reader programs can also read PDFs aloud. A screen reader is a software application that attempts to identify and interpret what is being displayed on the screen (or more accurately sent to standard output JAWS (an acronym for Job Access With Speech) is a Screen reader, a software program for visually impaired users produced by the Blind and Low Vision Window-Eyes is a Screen reader that makes a Computer usable by someone who is blind or has low vision. Kurzweil Educational Systems, Inc is an American based company that specializes in providing reading and writing software to assist people who are blind or partially Moreover, tagged PDFs can be re-flowed and magnified for readers with visual impairments. Problems remain with adding tags to older PDFs and those that are generated from scanned documents. In these cases, accessibility tags and re-flowing are unavailable, and must be created either manually or with OCR techniques. Optical character recognition, usually abbreviated to OCR, is the Mechanical or electronic translation of Images of handwritten typewritten These processes are inaccessible to some disabled people. PDF/UA, the PDF/Universal Accessibility Committee, an activity of AIIM, is working on a specification for PDF accessibility based on the PDF 1. PDF/UA (PDF/Universal Accessibility is a Standards Committee formed by AIIM. The Association for Information and Image Management or AIIM (pronounced aim) is an international industry association focused on Enterprise content management 6 specification.
One of the major problems with PDF accessibility is that PDF documents 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 read (useful for people with poor eyesight). The content view is displayed when the document is re-flowed to Acrobat (useful for people with mobility disability). For a PDF document to be accessible, the three views must be consistent with each other.
PDF format attachments carrying viruses were first discovered in 2001. This virus, which was named "OUTLOOK. PDFWorm” or “Peachy”, uses Microsoft Outlook to send itself as an attachment to an Adobe PDF file. Microsoft Outlook or Outlook (full name Microsoft Office Outlook since Outlook 2003 is a Personal information manager from Microsoft, and is  Virus researchers found that the PDF file viruses activated with Adobe Acrobat, but not with Acrobat Reader. As with all file formats, caution is advised. An up-to-date antivirus program is paramount.
PDFs may be encrypted so that a password is needed to view or edit the contents. The PDF Reference defines both 40-bit and 128-bit encryption, both making use of a complex system of RC4 and MD5. In Cryptography, RC4 (also known as ARC4 or ARCFOUR meaning Alleged RC4 see below is the most widely-used software In Cryptography, MD5 ( Message-Digest algorithm 5) is a widely used partially insecure Cryptographic hash function with a 128- Bit hash value The PDF Reference also defines ways in which third parties can define their own encryption systems for use in PDF.
PDF files may also contain embedded DRM restrictions that provide further controls that limit copying, editing or printing. Digital rights management ( DRM) is a generic term that refers to Access control technologies used by hardware manufacturers publishers and Copyright holders The restrictions on copying, editing, or printing depend on the reader software to obey them, so the security they provide is limited. Printable documents especially might be saved instead as bitmaps and subject to OCR. Optical character recognition, usually abbreviated to OCR, is the Mechanical or electronic translation of Images of handwritten typewritten
The PDF Reference has technical details or see  for an end-user overview. Like HTML files, PDF files may submit information to a web server. This could be used to track the IP address of the client PC, a process known as phoning home. An Internet Protocol ( IP) address is a numerical identification ( Logical address) that is assigned to devices participating in a Computer network Phoning home is unsually surreptitious communication between applications or hardware installed at end-user sites and their manufacturers or developers After update 7. 0. 5 to Acrobat Reader, the user will be notified "via a dialogue box that the author of the file is auditing usage of the file, and be offered the option of continuing". 
Through their LiveCycle Policy Server product, Adobe provides a method to set security policies on specific documents. This can include requiring a user to authenticate and limiting the time frame 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. " Each document open and close event can also be tracked by the policy server. Policy servers can be set up privately or Adobe offers a public service through Adobe Online Services.
With the release of Acrobat 8 Professional, users can now enable the save feature in a PDF file for distribution to people with Adobe Reader 7. 0 and later thus eliminating the need for Reader Extensions for this particular application. According to Adobe, this feature only applies to ad-hoc forms distribution and data collection. The license agreement for Acrobat 8 Professional limits this functionality to 500 unique users, or 500 submissions (see paragraph 14. 13. 3 of the End User License Agreement for Acrobat 8 Professional). Other privileges remain the domain only of LiveCycle Reader Extensions, and it is also needed for bulk or automated operations.
Compared to the PostScript format, PDF lacks e. g. the notion of "tray selection"; this can be used to indicate that some pages of a document must be printed on a different type of paper.
Such features are not omissions from the PDF format, whose scope only covers electronic documents. The JDF standard covers such aspects; however, it is a complex standard, which as of 2007 is still not widely implemented. Job Definition Format (JDF is a Technical standard being developed by the Graphic arts industry to facilitate cross-vendor Workflow implementations of This hinders the replacement of PostScript by PDF.
A PDF file is often a combination of vector graphics, text, and raster graphics. Vector graphics is the use of geometrical primitives such as points lines, Curves and shapes or Polygon (s which are all based In Computer graphics, a raster graphics image or bitmap, is a Data structure representing a generally rectangular grid of Pixels The basic types of content in a PDF are:
PDF 1. 6 supports interactive 3D documents embedded in the PDF.
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.
There are fourteen typefaces that have a special significance to PDF documents: Times Roman (in standard, italic, bold, and bold italic), Courier (in standard, oblique, bold and bold oblique), Helvetica (in standard, oblique, bold and bold oblique), Symbol and Zapf Dingbats. Times New Roman is a Serif Typeface commissioned by the British newspaper The Times, in 1931, designed by Stanley Courier is a monospaced Slab serif typeface designed to resemble the output from a strike-on typewriter Helvetica is the name of a widely used Sans-serif Typeface developed in 1957 by Swiss Typeface designer Max Miedinger. Symbol is one of the four standard fonts available on most PostScript -based printers Zapf Dingbats is one of the more common Dingbat Typefaces It was designed by the Typographer Hermann Zapf in 1978 and licensed by International These should always be present (actually present or a close substitute) and so need not be embedded in a PDF.  PDF viewers must know about the metrics of these fonts. Other fonts may be substituted if they are not embedded in a PDF.
|PDF Version||Year of Publication||new features||supported by Adobe Reader version|
|1. 2||FlateDecode||Acrobat Reader 3. 0|
|1. 3||2000||Acrobat Reader 4. 0|
|1. 4||2001||JBIG2, transparency||Acrobat Reader 5. JBIG2 is an Image compression standard for bi-level images developed by the Joint Bi-level Image Experts Group. 0|
|1. 5||2003||JPEG2000||Adobe Reader 6. JPEG 2000 is a Wavelet -based Image compression standard It was created by the Joint Photographic Experts Group committee in the year 2000 with the intention 0|
|1. 6||2004||Adobe Reader 7. 0|
|1. 7||2007||Adobe Reader 8. 0|
Readers for many platforms are available, such as Adobe Reader, Foxit, Preview, Sumatra, Xpdf, Evince, Okular, KPDF, Drumlin PDF reader and ePDFView; there are also front-ends for many platforms to Ghostscript. In Computing, a platform describes some sort of Hardware architecture or Software framework (including Application frameworks, that allows Adobe Acrobat is a family of computer programs developed by Adobe Systems, designed to view create manipulate and manage files in Adobe's Portable Document Foxit Reader is a multilingual PDF reader The basic reader can be downloaded for free while advanced plugins are available for a cost Preview is Mac OS X 's application for displaying images and Portable Document Format (PDF documents Sumatra (also spelled Sumatera) is the sixth largest island in the world (approximately 470000 km² and is the largest island entirely in Indonesia (two Xpdf is an Open source PDF viewer for the X Window System and Motif. Evince is a document viewer for PDF, PostScript, DjVu, TIFF and DVI documents for the GNOME Desktop environment Okular is the document viewer for KDE 4. It is based on KPDF and it replaced KPDF KGhostView, KFax, KFaxview, KDVI in KDE 4 KPDF is a free PDF reader based on Xpdf. It is integrated with the KDE Desktop environment, so it embeds very well in Konqueror Drumlin PDF Reader is a Freeware PDF reader and secure publisher Ghostscript is a suite of Software based on an interpreter for Adobe Systems ' PostScript and Portable Document Format (PDF Page description PDF readers are generally free.
There are many software options for creating PDFs, including the PDF printing capabilities built in to Mac OS X and some versions of Linux, the multi-platform OpenOffice.org, Microsoft Office (an additional free download from Microsoft is required), Wordperfect since version 9, numerous PDF print drivers for Microsoft Windows, the pdfTeX typesetting system, the DocBook PDF tools and Adobe Acrobat itself. Mac OS X (mæk oʊ ɛs tɛn is a line of computer Operating systems developed marketed and sold by Apple Inc, the latest of which is pre-loaded on all currently Linux (commonly pronounced ˈlɪnəks OpenOfficeorg ( OOo or OOo) is a free Cross-platform office application suite available for a number of different computer Microsoft Office is a set of interrelated desktop applications servers and services collectively referred to as an Office suite, for the Microsoft Windows and WordPerfect is a proprietary Word processing application At the height of its popularity in the late 1980s and early 1990s it was the De facto Microsoft Windows is a series of Software Operating systems and Graphical user interfaces produced by Microsoft. pdfTeX is an extension of Knuth 's typesetting program TeX, and was originally written and developed into a publicly usable product by Hàn Thế Thành as a DocBook is a semantic Markup language for technical Documentation. Adobe Acrobat is a family of computer programs developed by Adobe Systems, designed to view create manipulate and manage files in Adobe's Portable Document
There is also specialized software for editing PDF files, though the choices are much more limited and often expensive. Adobe Acrobat Professional is one example of software that allows the user to annotate (highlight, add notes to) already created PDF files. Adobe Acrobat is a family of computer programs developed by Adobe Systems, designed to view create manipulate and manage files in Adobe's Portable Document A free one is PDFedit. PDFedit is a free PDF editor for Unix-like Operating systems (including Cygwin on top of Windows) As of version 0. 46, Inkscape also allows PDF editing through an intermediate translation step involving poppler. Inkscape is a free and Open source Vector graphics editor application Poppler is a Free software library for viewing PDF documents it is maintained by Freedesktop
AGFA introduced and shipped Apogee, the very first prepress workflow system based on PDF in 1997.
PDF was selected as the "native" metafile format for Mac OS X, replacing the PICT format of the earlier Mac OS. Metafile is a generic term for a file format that can store multiple types of data PICT is a graphics File format introduced on the original Apple Macintosh computer as its standard Metafile format Mac OS is the trademarked name for a series of Graphical user interface -based Operating systems developed by Apple Inc 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". Quartz specifically refers to a pair of Mac OS X technologies each part of the Core Graphics framework Quartz 2D and Quartz Compositor. Display PostScript (or DPS) is an on-screen display system As the name implies DPS uses the PostScript (PS imaging model and language to generate on-screen graphics The Preview application can display PDF files, as can version 2. 0 and later of the Safari web browser. Safari is a Web browser developed by Apple Inc and included in Mac OS X. System-level support for PDF allows Mac OS X applications to create PDF documents automatically, provided they support the Print command. When taking a screenshot under Mac OS X versions 10. 0 through 10. 3, the image was also captured as a PDF; in 10. 4 and 10. 5 the default behaviour is set to capture as a PNG file, though this behaviour can be set back to PDF if required. Portable Network Graphics ( PNG) is a bitmapped image format that employs Lossless data compression.
Some 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 consider 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 coming ISO standard, ISO 32000. The Free Software Foundation ( FSF) is a Non-profit corporation founded by Richard Stallman on 4 October 1985 to support the Free software movement The Free Software Foundation ( FSF) is a Non-profit corporation founded by Richard Stallman on 4 October 1985 to support the Free software movement "