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 \begin{tableii}{l|l}{textrm}{keyword}{description}
  16 \lineii{\texttt{llx}}{\texttt{None} (default) for $-\infty$ or $x$-position of the lower left corner of the bbox (in user units)}
  17 \lineii{\texttt{lly}}{\texttt{None} (default) for $-\infty$ or $y$-position of the lower left corner of the bbox (in user units)}
  18 \lineii{\texttt{urx}}{\texttt{None} (default) for $\infty$ or $x$-position of the upper right corner of the bbox (in user units)}
  19 \lineii{\texttt{ury}}{\texttt{None} (default) for $\infty$ or $y$-position of the upper right corner of the bbox (in user units)}
  20 \end{tableii}
  21
  22 \section{bbox methods}
  23
  24 \begin{tableii}{l|l}{textrm}{\texttt{bbox} method}{function}
  25 \lineii{\texttt{intersects(other)}}{returns \texttt{1} if the \texttt{bbox} instance and \texttt{other} intersect with each other.}
  26 \lineii{\texttt{transformed(self, trafo)}}{returns \texttt{self} transformed by transformation \texttt{trafo}.}
  27 \lineii{\texttt{enlarged(all=0, bottom=None, left=None, top=None, right=None)}}{return the bounding box enlarged by the given amount (in visual units). \texttt{all} is the default for all other directions, which is used whenever \texttt{None} is given for the corresponding direction.}
  28 \lineii{\texttt{path()} or \texttt{rect()}}{return the \texttt{path} corresponding to the bounding box rectangle.}
  29 \lineii{\texttt{height()}}{returns the height of the bounding box (in \PyX{} lengths).}
  30 \lineii{\texttt{width()}}{returns the width of the bounding box (in \PyX{} lengths).}
  31 \lineii{\texttt{top()}}{returns the $y$-position of the top of the bounding box (in \PyX{} lengths).}
  32 \lineii{\texttt{bottom()}}{returns the $y$-position of the bottom of the bounding box (in \PyX{} lengths).}
  33 \lineii{\texttt{left()}}{returns the $x$-position of the left side of the bounding box (in \PyX{} lengths).}
  34 \lineii{\texttt{right()}}{returns the $x$-position of the right side of the bounding box (in \PyX{} lengths).}
  35 \end{tableii}
  36
  37 Furthermore, two bounding boxes can be added (giving the bounding box
  38 enclosing both) and multiplied (giving the intersection of both
  39 bounding boxes).
  40
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