PDF's predecessor was PostScript. PostScript was a Forth-like programming language that contained excellent 2D graphics primitives, including bezier curves, 2D

PDF's predecessor was PostScript. PostScript was a Forth-like programming language that contained excellent 2D graphics primitives, including bezier curves, 2D transforms and most importantly, support for scalable fonts. PostScript was ground-breaking for its time and is the reason for Apple's early success. If it wasn't for PostScript and laser printers the Mac would not have been successful. PostScript was implemented in laser printers and printer drivers output PostScript language programs when you printed from an application like Notepad in Windows. High-end illustration and DTP programs output their own custom programs instead of being limited by the program output by the printer driver. Over time it became obvious that the programming language features of PostScript were not being used very much. Printer drivers typically output a fixed header containing some function definitions then they use these functions over and over for drawing the content of the page. What if these function definitions could be built in? Then the programming language capabilities such as loops and conditionals could be left out and we would still be able to do everything we're doing with PostScript. In fact the resulting technology would be even more useful because rendering a page can be done without implementing a programming language interpreter. Thus PDF was born. PDF made perfect sense in the early 90's when it was designed. Page Description Languages didn't need to be burdened with a programming language because no one was taking advantage of the language features. But then came the World Wide Web. PDF was the wrong tech for the Web, and PostScript would have been perfect. PostScript has all the capabilities of PDF, but it is also a programming language, which means you can dynamically alter how you render the page based on where you are rendering it. Alas, Adobe's direction was already set, PDF was going to be the future and PostScript is obsolete. In summary, PostScript was invented at a time when nobody needed dynamic features, and PDF was invented for a static world but then the world suddenly changed and needed dynamic features.