How does PDF benefit you?

PDF files: what are they?

The Portable Technology Document Data Format (PDF) was created in 1992 and is a critical file format for displaying documents. It allows for independent display, regardless of the application analysis software, hardware, or operational management systems used. This includes formatting of text content as well as images. Utilizing the PostScript language, each PDF file contains all the necessary information to accurately display a fixed asset layout plan document, such as web text, fonts, vector graphics, raster images, and other enterprise data.

In addition to links and buttons, form fields, audio, video, and business logic, PDF documents are now an open standard of the International Organization for Standardization (ISO).

PDF's advantages

Compatibility is perfect

It is a portable document format, which means anyone can view and open PDF files,combine pdfs for free windows, regardless of what operating system, software, hardware they are using, whether it is a PC, cell phone, or tablet.

Protect your data by paying attention to security

Personal or confidential information can be sent securely using PDF files. They can be encrypted, which means only authorized individuals can access the information in the file. Moreover, the format is hard to edit, protecting your data from unauthorized access.

A broader audience

Anyone can open and read PDF files, regardless of what software they have installed on their computers.

4. Great for sharing and collaborating

Due to their small size, ease of creation, and compatibility with most devices, PDF files are great for sharing and collaboration. Businesses and professionals use PDF to send documents electronically.

It is easier to customize PDF files

With PDFs, you can track information such as surveys, tax documents, and even recipes. Since PDFs are easy to open on most devices, you don't have to worry about data loss.

PDF's history (background)

To meet this goal, Adobe designed the PDF file format to support cross-platform publishing and distribution of multimedia-integrated information, especially Web-based information.

For ordinary readers, PDF production of e-books with the texture and reading effect of paper books can vividly show the original appearance, and can be adjusted to display the reader's size at will.

Technical characteristics of PDF documents

Technical characteristics of PDF documents

A PDF file system consists of vector graphics, text, and bitmap graphics. PDF files include mainly the following types of content:

It will be stored as a stream of typeset text (non-plain text encoding).

Shapes and lines are used in vector graphics for illustrations and designs;

Photographic and other types of raster graphics

Documents with multimedia objects.

PDF documents will also support links (in documents or web pages), forms, JavaScript (available as a plug-in for Acrobat 3.0), and any other embedded content that can be handled by a plug-in in future versions.

Three technologies are combined in PDF:

As a declarative form of generating layouts and graphics, PostScript pages are equivalent to a programming language.

Font embedding replacement system that allows fonts to move with documents.

Structured storage system for bundling these elements and any related content into a single file.

An explanation of the PDF format

There are four main parts to a PDF file.

Structure of the PDF format

The header

This is the first line of the PDF file that specifies the version number of the PDF that a document carries for use. As an alternative to using hexadecimal editors (Sublime Text, etc.), teachers are able to design the PDF file for version 1.7 as follows.

The body

There are a number of objects in the Body part of a PDF document, including text streams, images, multimedia elements, etc. The Body section contains all the data displayed to the user in the document.

The first number identifies the object and the second number indicates whether or not the object has been modified since it was first created. If the second number is zero, the object has not been modified.

It should contain the contents of the object between < < and >, terminated by the keyword ENDOBJ.

Tables of external references (cross-references)

References to all objects within the document manager are contained in an xref cross-reference table. The purpose of the cross-reference table is to allow access to objects in the document through randomized access control, so we must be able to find our own specific service objects without students having to read the entire PDF document. In the cross-reference table, each development object is represented by a 20 byte entry.

In the example above, we can see that we have four subsections (note that these four lines contain only two numbers). A 20-byte entry (including the CRLF) represents each object. The first line indicates the number of objects, and the second line indicates the number of objects in the current subregion.

The trailer

The PDF file ends with a trailer.

This PDF file contains 190 objects.

As indicated by /Root 1 0 R, the root object number is 1.

Cross-reference table for the offset address, so that we can find PDF document management in the development of all the relative address of the object, which improves access to the investigation of the object, like document indexing.

PDF advantages of PDF

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