\chapter{Introduction}\label{Introduction}
-\section{Motivation}
+Early electronic document formats such as PostScript were motivated by a need to print documents onto a paper medium. In the PostScript standard, this lead to a model of the document as a program; a series of instructions to be executed by an interpreter which would result in ``ink'' being placed on ``pages'' of a fixed size\cite{plrm}.
-Early electronic document formats such as PostScript were motivated by a need to print documents onto a paper medium. In the PostScript standard, this lead to a model of the document as a program; a series of instructions to be executed by an interpreter which would result in ``ink'' being placed on ``pages'' of a fixed size\cite{plrm}. The ubiquitous Portable Document Format (PDF) standard provides many enhancements to PostScript taking into account desktop publishing requirements\cite{cheng2002portable}, but it is still fundamentally based on the same imaging model\cite{pdfref17}. This idea of a document as a static ``page'' has lead to limited precision in these and other traditional document formats.
+The ubiquitous Portable Document Format (PDF) standard provides many enhancements to PostScript taking into account desktop publishing requirements \cite{cheng2002portable}, but it is still fundamentally based on the same imaging model \cite{pdfref17}. This idea of a document as a static ``page'' has lead to limitations on what could be achieved with a digital document viewers \cite{hayes2012pixels}.
-The emergence of the internet, web browsers, XML/HTML, JavaScript and related technologies has seen a revolution in the ways in which information can be presented digitally, and the PDF standard itself has begun to move beyond static text and figures\cite{hayes2012pixels, barnes2013embedding}. However, the popular document formats are still designed with the intention of showing information at either a single, fixed level of detail, or a small range of levels.
+The emergence of the internet, web browsers, XML/HTML, JavaScript and related technologies has seen a revolution in the ways in which information can be presented digitally, and the PDF standard itself has begun to move beyond static text and figures \cite{hayes2012pixels, barnes2013embedding}. However, the popular document formats are still designed with the intention of showing information at either a single, fixed level of detail, or a small range of levels.
-As most digital display devices are smaller than physical paper medium, all useful viewers are able to ``zoom'' to a subset of the document. Vector graphics formats including PostScript, PDF and SVG support rasterisation at different zoom levels\cite{plrm, pdfref17, svg2011-1.1}, but the use of fixed precision floating point numbers causes problems due to imprecision either far from the origin, or at a high level of detail\cite{goldberg1991whatevery, goldberg1992thedesign}.
+As most digital display devices are smaller than physical paper medium, all useful viewers are able to ``zoom'' to a subset of the document. Vector graphics formats including PostScript, PDF and SVG support rasterisation at different zoom levels \cite{plrm, pdfref17, svg2011-1.1}, but the use of fixed precision floating point numbers causes problems due to imprecision either far from the origin, or at a high level of detail \cite{goldberg1991whatevery, goldberg1992thedesign}.
-We are now seeing a widespread use of mobile computing devices with touch screens, where the display size is typically much smaller than paper pages and traditional computer monitors; it seems that there is much to be gained by breaking free of the restricted precision of traditional document formats.
+There are many possible applications for documents in which precision is unlimited. Several areas of use include: visualisation of extremely large or infinite data sets; visualisation of high precision numerical computations; digital artwork; computer aided design; and maps.
-\section{Overview}
+The goal of this work is to explore to explore the limitations of floating point arithmetic and possible approaches to achieving arbitrary precision document formats. In collaboration with Gow \cite{thesisGow} we have implemented a proof of concept document viewer compatable with a subset of the SVG standard as a starting point for our research.
-The remainder of this document will be organised as follows: In Chapter \ref{Proposal} we give an overview of the current state of the research in document formats, and the motivation for implementing ``infinite precision'' in a document format. We will outline our approach to research in collaboration with David Gow\cite{proposalGow}. In Chapter \ref{Background} we provide more detailed background examining the literature related to rendering, interpreting, and creating document formats, as well as possible techniques for increased and possibly infinite precision. In Chapter \ref{Progress} gives the current state of our research and the progress towards the goals outlined in Chapter \ref{Introduction}.
+With the aim of being able to correctly insert and render ``detail'' (constructed by importing test SVG images) seperated by arbitrary distance, this work explores the limitations in floating point arithmetic and how these may be mitigated
+
+Using the Rational representation of the GNU Multiple Precision (GMP) library \cite{granlund2004GMP} we are able to implement correct rendering of SVG test images seperated by extremely large distances. We will present measurements of rendering accuracy and performance for our implementation.
+
+An alternative implementation based on a spatial approach to constructing the document is discussed by Gow \cite{thesisGow}.
git.ucc.asn.au / ipdf / sam.git / blobdiff
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