Deeper in PDF

First published at 2019-11-26

Portable Document Format (PDF)

is a file format developed by Adobe in 1992 to present documents, including text formatting and images, in a manner independent of application software, hardware, and operating systems.^[2][3] Based on the PostScript language, each PDF file encapsulates a complete description of a fixed-layout flat document, including the text, fonts, vector graphics, raster images and other information needed to display it.

数据结构

Boolean values, representing true or false
Real numbers
Integers
Strings, enclosed within parentheses ((...)) or represented as hexadecimal within single angle brackets (<...>). Strings may contain 8-bit characters.
Names, starting with a forward slash (/)
Arrays, ordered collections of objects enclosed within square brackets ([...])
Dictionaries, collections of objects indexed by names enclosed within double angle brackets (<<...>>)
Streams, usually containing large amounts of optionally compressed binary data, preceded by a dictionary and enclosed between the stream and endstream keywords.
The null object

了解 PDF 格式，就了解了计算机科学的半壁江山：

3D/数字签名/字体/图像/嵌入 js 脚本……

https://stackblitz.com/edit/vitejs-vite-6wjhj31u

想做没有做成的：支持图片/文档设置密码……