doc-en/.svn/text-base/par-projectiondroite-en.tex.svn-base

   1 \section{Lines}
   2
   3 \subsection{Direct definition}
   4
   5 The object \texttt{droite} allows us to define and draw a \Index{line}. In
   6 the \texttt{pst-solides3d} package, a line in 2D is defined by its
   7 two end-points.
   8
   9 We use the option \Lkeyword{args} to specify the end-points of the
  10 chosen line. We can use coordinates or named points.
  11
  12 As with points and vectors, we can save the coordinates of the
  13 line with the option \Lkeyword{name}.
  14
  15 \begin{LTXexample}[width=7.5cm]
  16 \begin{pspicture}(-3,-3)(4,3.5)%
  17 \psframe*[linecolor=blue!50](-3,-3)(4,3.5)
  18 \psset{viewpoint=50 30 15,Decran=60}
  19 \psset{solidmemory}
  20 %% definition du plan de projection
  21 \psSolid[object=plan,
  22    definition=equation,
  23    args={[1 0 0 0] 90},
  24    planmarks,name=monplan]
  25 \psset{plan=monplan}
  26 %% definition du point A
  27 \psProjection[object=point,
  28    name=A,text=A,
  29    pos=ur](-2,1.25)
  30 \psProjection[object=point,
  31    name=B,text=B,
  32    pos=ur](1,.75)
  33 \psProjection[object=droite,
  34    linecolor=blue,
  35    args=0 0 1 .5]
  36 \psProjection[object=droite,
  37    linecolor=orange,
  38    args=A B]
  39 \composeSolid
  40 \end{pspicture}
  41 \end{LTXexample}
  42
  43
  44 \subsection{Some other definitions}
  45
  46 There are other methods to define a line in 2D. The options
  47 \Lkeyword{definition} and \Lkeyword{args} are used in these variants:
  48
  49
  50
  51 \begin{itemize}
  52
  53 \item \texttt{\Lkeyword{definition}=\Lkeyval{horizontale}};
  54 \texttt{\Lkeyword{args}=$b$}.
  55
  56 The line with equation $y=b$.
  57
  58 \item \texttt{\Lkeyword{definition}=\Lkeyval{verticale}};
  59 \texttt{\Lkeyword{args}=$a$}.
  60
  61 The line with equation $x=a$.
  62
  63 \item \texttt{\Lkeyword{definition}=\Lkeyval{paral}};
  64 \texttt{\Lkeyword{args}=$d$ $A$}.
  65
  66 A line parallel to $d$ passing through
  67 $A$.
  68
  69 \item \texttt{\Lkeyword{definition}=\Lkeyword{perp}};
  70 \texttt{\Lkeyword{args}=$d$ $A$}.
  71
  72 A line perpendicular to $d$ passing
  73 through $A$.
  74
  75 \item \texttt{\Lkeyword{definition}=\Lkeyval{mediatrice}};
  76 \texttt{\Lkeyword{args}=$A$ $B$}.
  77
  78 The perpendicular bisector of the line
  79 segment $[AB]$.
  80
  81 \item \texttt{\Lkeyword{definition}=\Lkeyword{bissectrice}};
  82 \texttt{\Lkeyword{args}=$A$ $B$ $C$}.
  83
  84 The bisector of the angle $\widehat
  85 {ABC}$.
  86
  87 \item \texttt{\Lkeyword{definition}=\Lkeyword{axesymdroite}};
  88 \texttt{\Lkeyword{args}=$d$ $D$}.
  89
  90 The reflection of the line $d$ in the
  91 line $D$.
  92
  93 \item \texttt{\Lkeyword{definition}=\Lkeyword{rotatedroite}};
  94 \texttt{\Lkeyword{args}=$d$ $I$ $r$}.
  95
  96 The image of the line $d$ after a
  97 rotation with centre $I$ through an angle $r$ (in degrees)
  98
  99 \item \texttt{\Lkeyword{definition}=\Lkeyword{translatedroite}};
 100 \texttt{\Lkeyword{args}=$d$ $u$}.
 101
 102 The image of the line $d$ shifted by the vector $\vec u$.
 103
 104 \end{itemize}
 105
 106 \endinput