manual/pattern.tex

   1 \chapter{Module \module{pattern}}
   2 \label{pattern}
   3
   4 \sectionauthor{J\"org Lehmann}{joergl@users.sourceforge.net}
   5
   6 This module contains the \class{pattern} class, whichs allows the definition of PostScript Tiling
   7 patterns (cf.\ Sect.~4.9 of the PostScript Language Reference Manual)
   8 which may then be used to fill paths. In addition, a number of
   9 predefined hatch patterns are included.
  10
  11
  12 \declaremodule{}{pattern}
  13
  14 \section{Class \class{pattern}}
  15
  16 The classes \class{pattern} and \class{canvas} differ only in their
  17 constructor and in the absence of a \method{writeEPSfile()} method in
  18 the former. The \class{pattern} constructor accepts the following
  19 keyword arguments:
  20
  21 \medskip
  22 \begin{tableii}{l|l}{textrm}{keyword}{description}
  23 \lineii{\texttt{painttype}}{\texttt{1} (default) for coloured patterns or \texttt{2} for uncoloured patterns}
  24 \lineii{\texttt{tilingtype}}{\texttt{1} (default) for constant spacing tilings (patterns are spaced constantly by a multiple of a device pixel), \texttt{2} for undistorted pattern cell, whereby the spacing may vary by as much as one device pixel, or \texttt{3} for constant spacing and faster tiling which behaves as tiling type \texttt{1} but with additional distortion allowed to permit a more efficient implementation.}
  25 \lineii{\texttt{xstep}}{desired horizontal spacing between pattern cells, use \texttt{None} (default) for automatic calculation from pattern bounding box.}
  26 \lineii{\texttt{ystep}}{desired vertical spacing between pattern cells, use \texttt{None} (default) for automatic calculation from pattern bounding box.}
  27 \lineii{\texttt{bbox}}{bounding box of pattern. Use \texttt{None} for an automatic determination of the bounding box (including an enlargement by \texttt{bboxenlarge} pts on each side.)}
  28 \lineii{\texttt{trafo}}{additional transformation applied to pattern or \texttt{None} (default). This may be used to rotate the pattern or to shift its phase (by a translation).}
  29 \lineii{\texttt{bboxenlarge}}{enlargement when using the automatic bounding box determination; default is 5 pts.}
  30 \end{tableii}
  31 \medskip
  32
  33 After you have created a pattern instance, you define the pattern
  34 shape by drawing in it like in an ordinary canvas. To use the pattern,
  35 you simply pass the pattern instance to a \method{stroke()},
  36 \method{fill()}, \method{draw()} or \method{set()} method of the
  37 canvas, just like you would do with a colour, etc.
  38
  39
  40
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