How did PDF files become popular? Why use PDF files?-AmindPDF

Ricardo Lee

2022-08-04 11:27

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Among computer languages, there is a special kind of language called Page Description Language (abbreviated as PDL, or Page Description Language). Generally speaking, the so-called page is a page facing the printing direction, a two-dimensional rectangular frame that encapsulates content. In general, the specific performance of PDL is to control various elements of the page: text, images, colors, curves, and coordinate systems.

PDL does not necessarily have programming properties. An example with programmatic properties is Adobe's PostScript. There are quite a few types of non-programming PDLs, such as simple DVI output by TeX, PCL developed by HP, and PDF mentioned in this question. In addition, there are some private format PDLs, which are more common in various printing equipment, such as dot-matrix printers and various printing equipment.

Both image and color handling in the page description language is straightforward. The hardest part is how fonts and text-dependent rendering work. Many of the technical details of most printers in the 1970s were public. At that time, the printers in various laboratories used the fonts inside the printer to print things. There are also a few cases where the person operating the printer can make their fonts. But in the case of computers in the 80s and 90s, the font technology in the computers used by the masses was dominated by Adobe, Microsoft, and Apple. As far as font technology is concerned, the one that has far-reaching influence in the industry is the three above, which is enduring, namely Adobe. Therefore, when Adobe designs PDF, it is a matter of course, and all font technologies can be used.

In fact, HP-led PCL is used in many places, and even in some cases, it exists like air. This kind of thing is just not known to the user, because PCL is something that the machine only needs to know. Adobe's PDF is faster than PostScript in rendering pages, so in the 1990s, it was only a matter of time before PDF replaced PostScript in industrial use. If anyone has entered the pit of PostScript, they will know that the language PostScript can do everything (including file reading and writing, etc.). But in terms of the design of PDL, many functions of PostScript are unnecessary. A recent analogy is that PDF is to PostScript what JSON is to JavaScript.

An important design point of PDF is fixed layout. The direct impact, that is, without special tools, can no longer be edited. This is the demand for printing direction. So those who say that PDF is not editable is a disadvantage, don't say it anymore, it's like saying that the disadvantage of a rooster is that it can't lay eggs. You may not have seen the grand occasion in the 1980s. At that time, PostScript itself was a very hot technology, and it finally became a very classic thing. For PDFs similar to PostScript, it is natural to seize the market in the end (but according to rumors, Adobe has spent a lot of real money to promote PDF and corresponding readers).

In the world of pirated e-books, the widely used formats are DjVu and PDF. It is difficult to say which is more popular because DjVu is more than a little more than PDF in terms of the technical concept in terms of image processing. However, in the market, high technology does not mean a high market share. But as far as the printing industry is concerned, PDF is the largest. Even a pessimistic view is that the printing industry has no choice. But fortunately, the format specification of PDF is now controlled by ISO. Even if Adobe puts some private goods in its things, PDF is already a representation of the present, and it will represent the future for a long time.