From: Sam Moore <matches@ucc.asn.au>
Date: Wed, 21 May 2014 03:28:51 +0000 (+0800)
Subject: Horrible notes on PDF
X-Git-Url: https://git.ucc.asn.au/?a=commitdiff_plain;h=439a25f18a7a9ef114a01b11ead914d94d088ef4;p=ipdf%2Fsam.git

Horrible notes on PDF

At bus port now
---

diff --git a/chapters/Background.tex b/chapters/Background.tex
index 87d18ce..f11c1be 100644
--- a/chapters/Background.tex
+++ b/chapters/Background.tex
@@ -99,6 +99,30 @@ In this section we will consider various approaches and motivations to specifyin
 
 \subsection{The Portable Document Format}
 
+``A PDF file should be thought of as a flattened representation of a data structure
+consisting of a collection of objects that can refer to each other in any arbitrary
+way.''
+
+The PDF 1.7 standard describes a format which is \rephrase{essentially PostScript plus everything in the kitchen sink}.
+\begin{itemize}
+	\item PDF is not just crippled postscript
+	\item Objects - has a type system, like a programming language, not like the DOM where all objects are fundamentally the same - this is similar to PostScript
+	\item File structure - Header, body, reference table (location of objects in file), trailer (location of reference table and special objects)
+	\begin{itemize}
+		\item Read the file from the end
+		\item File can be updated incrementally as long as the trailer is at the end
+	\end{itemize}
+	\item Document structure - This is basically a graph, wheras the DOM is a tree
+	\item Content streams - objects but conceptually different - operators or instructions
+	\item Interactivity --- At this point, PDF suddenly changes from being PostScript to being XML
+	\begin{itemize}
+		\item 
+	\end{itemize}
+\end{itemize}
+
+The biggest difference between the PDF design philosophy and the HTML5 philosophy is the emphasis in PDF on the actual file format.
+This means PDF is more complicated but also more efficient (at least, we would hope so).
+
 
 \subsection{Scientific Computation Packages}