The object \Lkeyword{polygone} allows us to define a \Index{polygon}. We use
the option \Lkeyword{args} to specify the list of vertices:
\texttt{[object=polygone,args=$A_0$ $A_1$ \ldots $A_n$]}
There are other ways to define a polygon in 2D. The options
\Lkeyword{definition} and \Lkeyword{args} support these methods:
\begin{itemize}
%% syntaxe : pol u --> pol'
\item \texttt{\Lkeyword{definition}=\Lkeyword{translatepol}};
\texttt{\Lkeyword{args}=$pol$ $u$}.
Translation of the polygon $pol$ by the
vector $\vec u$
%% syntaxe : pol u --> pol'
\item \texttt{\Lkeyword{definition}=\Lkeyword{rotatepol}};
\texttt{\Lkeyword{args}=$pol$ $I$ $\alpha $}.
Image of the polygon $pol$
after a rotation with centre $I$ and angle $\alpha $
%% syntaxe : pol I alpha --> pol'
\item \texttt{\Lkeyword{definition}=\Lkeyword{hompol}};
\texttt{\Lkeyword{args}=$pol$ $I$ $\alpha $}.
Image of the polygon $pol$
after a homothety (dilation) with centre $I$ and ratio $\alpha$.
%% syntaxe : pol I --> pol'
\item \texttt{\Lkeyword{definition}=\Lkeyword{sympol}};
\texttt{\Lkeyword{args}=$pol$ $I$}.
Image of the polygon $pol$ after a
reflection in the point $I$.
%% syntaxe : pol D --> pol'
\item \texttt{\Lkeyword{definition}=\Lkeyword{axesympol}};
\texttt{\Lkeyword{args}=$pol$ $d$}.
Image of the polygon $pol$ after a
reflection in the line $d$.
\end{itemize}
In the following example we define, name and draw the polygon with
vertices $(-1,0)$, $(-3, 1)$, $(0, 2)$, then---in blue---the
image after a rotation about the point $(-1,0)$ through an angle
$-45$. Finally, we translate the polygon with the vector shift
$(2,-2)$ by directly incorporating \textit{jps code} within the
argument of \Lkeyword{definition}.
