X-Git-Url: https://git.ucc.asn.au/?p=ipdf%2Fsam.git;a=blobdiff_plain;f=chapters%2FBackground%2FRendering%2FBezierSplines.tex;h=cf936efe3c066166ea27f5df0e90c093c4a6aff5;hp=fd0ec013051bb1bdc1527f08e96a80c5c224c81e;hb=a1ede3cfc3ef650aa0f7d3d06e78c6c6ef4cb0cc;hpb=9fcf44a0c34f393689118e913a2d17d907036c85 diff --git a/chapters/Background/Rendering/BezierSplines.tex b/chapters/Background/Rendering/BezierSplines.tex index fd0ec01..cf936ef 100644 --- a/chapters/Background/Rendering/BezierSplines.tex +++ b/chapters/Background/Rendering/BezierSplines.tex @@ -10,7 +10,7 @@ Splines may be rasterised by sampling of $y(x)$ at a number of points $x_i$ and There are many different ways to define a spline.One approach is to specify ``knots'' on the curve and choosing a fixed $n$ ($n = 3$ for ``cubic'' splines) solve for the cooefficients to generate polynomials passing through the points. Alternatively, special polynomials may be defined using ``control'' points which themselves are not part of the curve; these are convenient for graphical based editors.\end{co B{\'e}zier splines are the most straight forward way to define a curve in the standards considered in Section \ref{Document Representations}. A spline defined from two cubic B{\'e}ziers is shown in Figure \ref{spline.pdf} \end{comment} -Cubic and Quadratic B{\'e}zier Splines are used to define curved paths in the PostScript\cite{plrm}, PDF\cite{pdfref17} and SVG\cite{svg2011-1.1} standards which we will discuss in Section \ref{Document Representations}. Cubic B{\'e}ziers are also used to define vector fonts for rendering text in these standards and the {\TeX} typesetting language \cite{knuth1983metafont, knuth1984texbook}. Although he did not derive the mathematics, the usefulness of B{\'e}zier curves was realised by Pierre B{\'e}zier who used them in the 1960s for the computer aided design of automobile bodies\cite{bezier1986apersonal}. +Cubic and Quadratic B{\'e}zier Splines are used to define curved paths in the PostScript\cite{plrm}, PDF\cite{pdfref17} and SVG\cite{svg2011-1.1} standards. Cubic B{\'e}ziers are also used to define vector fonts for rendering text in these standards and the {\TeX} typesetting language \cite{knuth1983metafont, knuth1984texbook}. Although he did not derive the mathematics, the usefulness of B{\'e}zier curves was realised by Pierre B{\'e}zier who used them in the 1960s for the computer aided design of automobile bodies\cite{bezier1986apersonal}. A B{\'e}zier Curve of degree $n$ is defined by $n$ ``control points'' $\left\{P_0, ... P_n\right\}$. Points $P(t) = (x(t), y(t))$ along the curve are defined by: @@ -65,5 +65,5 @@ De Casteljau's algorithm of 1959 is often used for decomposing B{\'e}ziers into \includegraphics[width=0.7\textwidth]{figures/spline.pdf} \end{figure} \end{minipage} - \caption{Constructing a Spline from two cubic B{\'e}ziers \\ (a) Showing the Control Points (b) Representations in SVG and PostScript (c) Rendered Spline}\label{spline.pdf} + \caption{Constructing a Spline from two cubic B{\'e}ziers \\ (a) Showing the Control Points (b) Representations in SVG and PostScript (c) Rendered Spline} \label{spline.pdf} \end{figure}