Invented by Adobe Systems over 20 years ago, the Portable Document Format (PDF) is now an open standard for electronic document exchange maintained by the International Organization for Standardization (ISO). When you convert documents, forms, graphics, and web pages to PDF, they look just like they would if printed.
PDF
TL;DR Multiple trailers allow for Incremental Updates in PDFs. New changes (data/objects) are appended to the file end, preventing a full rewrite. Each trailer... You might have encountered a situation where you tried to read from pdf or other text input streams and writing the raw data into... Recently I have been working on a problem with SVG & the HTML5 Canvas that causes bad looking output in some of our files.... TL;DR: PDFs use complex binary/compressed data that standard text editors can’t read. To inspect the internal structure, use JPedal (for debugging content streams), RUPS... Every glyf inside a PDF file can have a display value and a different extraction value. This is useful because often you need to... Text is defined in the PDF file format as a display value (normally what you see onscreen) and an extraction value. It is useful... 
