+The process of creating and displaying a document is a rather universal one (\ref{documenttimeline}), though
+different document formats approach it slightly differently. A document often begins as raw content: text and images
+(be they raster or vector) and it must end up as a set of photons flying towards the reader's eyes.
+
+\begin{figure}
+ \label{documenttimeline}
+ \centering \includegraphics[width=0.8\linewidth]{figures/documenttimeline}
+ \caption{The lifecycle of a document}
+\end{figure}
+
+There are two fundamental stages by which all documents --- digital or otherwise --- are produced and displayed:
+\emph{layout} and \emph{rendering}. The \emph{layout} stage is where the positions and sizes of text and other graphics are
+determined. The text will be \emph{flowed} around graphics, the positions of individual glyphs will be placed, ensuring
+that there is no undesired overlap and that everything will fit on the page or screen.
+
+The \emph{display} stage actually produces the final output, whether as ink on paper or pixels on a computer monitor.
+Each graphical element is rasterized and composited into a single image of the target resolution.
+
+
+Different document formats cover documents in different stages of this project. Bitmapped images,
+for example, would represent the output of the final stage of the process, whereas markup languages typically specify
+a document which has not yet been processed, ready for the layout stage.
+
+Furthermore, some document formats treat the document as a program, written in
+a (usually turing complete) document language with instructions which emit shapes to be displayed. These shapes are either displayed