manual/bbox.tex

   1 \chapter{Module bbox}
   2
   3 \label{bbox}
   4
   5 The \texttt{bbox} module contains the definition of the \texttt{bbox}
   6 class representing bounding boxes of graphical elements like paths,
   7 canvases, etc.\ used in \PyX. Usually, you obtain \texttt{bbox}
   8 instances as return values of the corresponding \texttt{bbox())}
   9 method, but you may also construct a bounding box by yourself.
  10
  11 \section{bbox constructor}
  12
  13 The \texttt{bbox} constructor accepts the following keyword arguments
  14
  15 \medskip
  16 \begin{tabularx}{\linewidth}{l>{\raggedright\arraybackslash}X}
  17 keyword & description\\
  18 \hline
  19 \texttt{llx}&\texttt{None} (default) for $-\infty$ or $x$-position of
  20 the lower left corner of the bbox (in user units)\\
  21 \texttt{lly}&\texttt{None} (default) for $-\infty$ or $y$-position of
  22 the lower left corner of the bbox (in user units)\\
  23 \texttt{urx}&\texttt{None} (default) for $\infty$ or $x$-position of
  24 the upper right corner of the bbox (in user units)\\
  25 \texttt{ury}&\texttt{None} (default) for $\infty$ or $y$-position of
  26 the upper right corner of the bbox (in user units)
  27 \end{tabularx}
  28
  29 \section{bbox methods}
  30
  31 %Instances of the \texttt{bbox} class offer the following methods:
  32 %\medskip
  33
  34 \begin{tabularx}
  35   {\linewidth}
  36   {>{\hsize=.85\hsize}X>{\raggedright\arraybackslash\hsize=1.15\hsize}X}
  37   \texttt{bbox} method & function \\
  38   \hline
  39   \texttt{intersects(other)} & returns \texttt{1} if the \texttt{bbox} instance
  40   and \texttt{other} intersect with each other.\\
  41   \texttt{transformed(self, trafo)}& returns \texttt{self} transformed
  42   by transformation \texttt{trafo}.\\
  43   \texttt{enlarged(all=0, bottom=None,
  44     \newline\phantom{enlarged(}left=None, top=None,
  45     \newline\phantom{enlarged(}right=None)} &
  46   return the bounding box enlarged by the given amount (in visual
  47   units). \texttt{all} is the default for all other directions, which
  48   is used whenever \texttt{None} is given for the corresponding
  49   direction.\\
  50   \texttt{path()} or \texttt{rect()} & return the \texttt{path} corresponding to the
  51   bounding box rectangle.\\
  52   \texttt{height()} & returns the height of the bounding box (in \PyX{}
  53   lengths).\\
  54   \texttt{width()} & returns the width of the bounding box (in \PyX{}
  55   lengths).\\
  56   \texttt{top()} & returns the $y$-position of the top of the bounding
  57   box (in \PyX{} lengths).\\
  58   \texttt{bottom()} & returns the $y$-position of the bottom of the
  59   bounding box (in \PyX{} lengths).\\
  60   \texttt{left()} & returns the $x$-position of the left side of the
  61   bounding box (in \PyX{} lengths).\\
  62   \texttt{right()} & returns the $x$-position of the right side of the
  63   bounding box (in \PyX{} lengths).\\
  64   \end{tabularx}
  65 \medskip
  66
  67 Furthermore, two bounding boxes can be added (giving the bounding box
  68 enclosing both) and multiplied (giving the intersection of both
  69 bounding boxes).
  70
  71 %%% Local Variables:
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  73 %%% TeX-master: "manual.tex"
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