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History of PDF. The Portable Document Format (PDF) was created by Adobe Systems, introduced at the Windows and OS/2 Conference in January 1993 and remained a proprietary format until it was released as an open standard in 2008. Since then, it has been under the control of an International Organization for Standardization (ISO) committee of ...
2000年の日本（2000ねんのにほん）では、2000年（平成12年）の日本の出来事・流行・世相などについてまとめる。 他の紀年法 [ 編集 ] 日本では、 西暦 の他にも以下の 紀年法 を使用している。
- History
- Technical Details
- File Format
- Imaging Model
- Additional Features
- Licensing
- Security
- Software
- Alternatives
- See Also
Development of PDF began in 1991 when John Warnock wrote a paper for a project then code-named Camelot, in which he proposed the creation of a simplified version of PostScript called Interchange PostScript (IPS). Unlike traditional PostScript, which was tightly focused on rendering print jobsto output devices, IPS would be optimized for displaying ...
A PDF file is often a combination of vector graphics, text, and bitmap graphics. The basic types of content in a PDF are: 1. Typeset text stored as content streams (i.e., not encoded in plain text); 2. Vector graphics for illustrations and designs that consist of shapes and lines; 3. Raster graphics for photographs and other types of images; and 4....
A PDF file is organized using ASCII characters, except for certain elements that may have binary content.The file starts with a header containing a magic number (as a readable string) and the version of the format, for example %PDF-1.7. The format is a subset of a COS ("Carousel" Object Structure) format. A COS tree file consists primarily of objec...
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 1.4. 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 scale, rotate, or skew graphical elements. A ke...
Logical structure and accessibility
A "tagged" PDF (see clause 14.8 in ISO 32000) includes document structure and semantics information to enable reliable text extraction and accessibility. Technically speaking, tagged PDF is a stylized use of the format that builds on the logical structure framework introduced in PDF 1.3. 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...
Optional Content Groups
With the introduction of PDF version 1.5 (2003) came the concept of Layers. Layers, more formally known as Optional Content Groups (OCGs), refer to sections of content in a PDF document that can be selectively viewed or hidden by document authors or viewers. This capability is useful in CAD drawings, layered artwork, maps, multi-language documents, etc. Basically, it consists of an Optional Content Properties Dictionary added to the document root. This dictionary contains an array of Optional...
Encryption and signatures
A PDF file may be encrypted, for security, in which case a password is needed to view or edit the contents. PDF 2.0 defines 256-bit AES encryption as the standard for PDF 2.0 files. The PDF Reference also defines ways that third parties can define their own encryption systems for PDF. PDF files may be digitally signed, to provide secure authentication; complete details on implementing digital signatures in PDF are provided in ISO 32000-2. PDF files may also contain embedded DRMrestrictions th...
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.
Changes to content
In November 2019, researchers from Ruhr University Bochum and Hackmanit GmbH published attacks on digitally signed PDFs. They showed how to change the visible content in a signed PDF without invalidating the signature in 21 of 22 desktop PDF viewers and 6 of 8 online validation services by abusing implementation flaws.At the same conference, they additionally showed how to exfiltrate the plaintext of encrypted content in PDFs. In 2021, they showed new so-called shadow attacks on PDFs that abu...
Malware vulnerability
PDF files can be infected with viruses, Trojans, and other malware. They can have hidden JavaScript code that might exploit vulnerabilities in a PDF, hidden objects executed when the file that hides them is opened, and, less commonly, a malicious PDF can launch malware. PDF attachments carrying viruses were first discovered in 2001. The virus, named OUTLOOK.PDFWorm or Peachy, uses Microsoft Outlookto send itself as an attached Adobe PDF file. It was activated with Adobe Acrobat, but not with...
Viewers and editors
Many PDF viewers are provided free of charge from a variety of sources. Programs to manipulate and edit PDF files are available, usually for purchase. There are many software options for creating PDFs, including the PDF printing capabilities built into macOS, iOS, and most Linux distributions. Much document processing software including LibreOffice, Microsoft Office 2007 (if updated to SP2) and later, WordPerfect 9, and Scribus can export documents in PDF format. There are many PDF print driv...
Printing
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 rasterization. RIPs capable of processing PDF directly include the Adobe PDF Print Engine from Adobe Systems and Jaws and the Harlequin RIP from Global Graphics. In 1993, the Jaws raster image processor from Global Graphics became the first shipping prepress RIP that interpreted PDF natively...
Native display model
PDF was selected as the "native" metafile format for Mac OS X, replacing 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 2.0 and later of the Safariweb browser. System-level support for PDF allows Mac OS X applications to create PDF documents automatically, provided they support the OS-stand...
The Open XML Paper Specification is a competing format used both as a page description language and as the native print spooler format for Microsoft Windows since Windows Vista. Mixed Object: Document Content Architecture is a competing format. MO:DCA-P is a part of Advanced Function Presentation.
- June 15, 1993; 30 years ago
- ISO 32000-2
- 2.0
2000 ( MM) was a century leap year starting on Saturday of the Gregorian calendar, the 2000th year of the Common Era (CE) and Anno Domini (AD) designations, the 1000th and last year of the 2nd millennium, the 100th and last year of the 20th century, and the 1st year of the 2000s decade. 2000 was designated as the International Year for the ...
ISBN 978-87-7357-487-4. The searchable online edition contains over 1,900 biographies from the Middle Ages to the present. (in Danish) [1] Kraks Blå Bog (Who's Who in Denmark) online edition, 8219 biographies as of 2012. [update] -3, (in Danish) [1] Metherell, David, Paul Guthrie.
Geographies of Digital Exclusion Data and Inequality (PDF). Radical Geography. London: Pluto Press. ISBN 978-1-78680-742-7. Wikipedia as source material. Wikipedia is free content which anybody can edit, use, modify, and distribute. Several books have used Wikipedia as source material or as their data source while others have compiled articles ...
PDFは、1990年代初めに、文書共有を目的として開発された。. 文書の書式とインラインの図表を保持し、異なるプラットフォームのコンピュータのユーザー間で文書を閲覧するために互換性のあるアプリケーションを利用できない場合にも文書を共有できる ...
