% this file contains description of the Bobcat graphics primitives
% used in 6.003

\section{Graphics}
\label{graphicssection}
\mainindex{graphics}

This section describes the basic graphics primitives
available on the Bobcat computers for use in 6.003.

\begin{entry}{%
\proto{position-pen}{ x y}{procedure}}

Sets the graphics pen at the point whose coordinates are $(x,y)$.  On
the Bobcat screen, both $x$ and $y$ range between $\pm 512$.
\end{entry}

\begin{entry}{%
\proto{draw-line-to}{ x y}{procedure}}

Draws a line from the current pen position to $(x,y)$ and leaves the
pen positioned at $(x,y)$.
\end{entry}

\begin{entry}{%
\proto{draw-point}{ x y}{procedure}
\proto{clear-point}{ x y}{procedure}}

Plots (respectively, clears) the point at $(x,y)$.
\end{entry}


\begin{entry}{%
\proto{clear-graphics}{}{procedure}}

Clears the screen.
\end{entry}
