PDF (Portable Document Format) is a structured document format. It is the famous American publishing and image processing software Adobe was first released in 1993 (version 1.0), the same year the launch of its corresponding supporting software product line AdobeAcrobat1.0 version. Subsequently,pdf to word converter offline software free download full version Adobe modified and upgraded it in 1994 released version 1.1, and launched a supporting software product series Adobe Acrobat2.0 and 2.1. subsequent PDF 1.2 version released on November 27, 1996, the corresponding supporting software product series Adobe Acrobat has been upgraded to version 3.0 . By the end of 1997, the International Organization for Standardization (ISO) has begun to PDF as an international standard.

1.PDF and PS comparison

PS language (PostScript language, that is, the page description language) is also owned by Adobe's de facto printing industry standards, can describe the beautiful layout, in the current printing field dominates.word to pdf converter online i love pdf PDF is developed by the PS, they are almost the same in terms of describing the page's ability to describe the same method of description is similar. PDF uses the same imaging model as PS to represent the text and graphics. And PS language, PDF's page description instructions to the selected area of the color to draw the page. Colored areas can be letter outlines, areas defined by lines and curves, and bitmaps. The color can be arbitrary, any graphics on the page can be cut into other shapes. The page is completely empty at first, and various commands draw different shapes on the page; the new shapes are opaque and can overwrite the old ones.

Although this is also the case, PDF compared with PS, there are still very different. This is mainly manifested in the existence of the following we several issues in terms of: PDF documents can contain data interaction research objects, such as hyperlinks, interactive forms, etc., while the PS does not. PDF is an important file system structure, while the PS is as a programming language,merge word documents online i love pdf therefore, PDF has a higher processing efficiency than PS. PDF's rigorous management of the structure of the analysis of the definition of the degree of application allows for the degree of which the between an object to choose random access, while PS can only be accessed in a certain order of the overall situation. For example, to control the access control of a PS file in the 100th page, then the teacher must be in the first order to explain the first 99 pages, in order to really find the 100th page, while in the PDF of each page of the access is the same as the fastest. PDF also contains the specifications of the size of the font, such as font description of the information so that in the case of font does not exist, you can effectively font simulation (not just simple font), to ensure the display of the document information. Alternative), to ensure the consistency of the display of document information.

2. PDF features

PDF characteristics can be summarized as follows: and materiality. PDF files support 7-bit ASCII code and binary code, can be correctly transmitted in a variety of network environments. Support for interactive operations. PDF contains interactive objects, such as interactive forms and hyperlinks. Supports sound, animation. Supports randomized access to page content to improve the speed of various page operations. Supports incremental changes to facilitate small changes and improve efficiency. Supports multiple compression encoding methods for a more compact file structure. Independent fonts. PDF files can have their own font description information, so that the user's system in the absence of the required fonts, you can still ensure that the document is displayed correctly. Independent platform. PDF documents with software and hardware platform independence. This feature is very suitable for the transmission of network information exchange, to avoid the trouble of garbled code. Security Control Center. PDF documents support different levels of security control, which is very important for the protection of copyrighted electronic publications can be set according to the security requirements of different electronic publications at different levels of security.

Portable Document Format pdf software PDF features