4 With the
\verb|unit| module
\PyX{} makes available classes and
5 functions for the specification and manipulation of lengths. As usual,
6 lengths consist of a number together with a measurement unit, e.g.,
7 \unit[1]{cm
},
\unit[50]{points
},
\unit[0.42]{inch
}. In addition,
8 lengths in
\PyX{} are composed of the five types ``true'', ``user'',
9 ``visual'', ``width'', and ``
\TeX'', e.g.,
\unit[1]{user cm
},
10 \unit[50]{true points
}, $(
0.42\
\mathrm{visual
} +
0.2\
11 \mathrm{width
})$ inch. As their names indicate, they serve different
12 purposes. True lengths are not scalable and are mainly used for return
13 values of
\PyX{} functions. The other length types can be rescaled by
14 the user and differ with respect to the type of object they are
18 \item[user length:
] used for lengths of graphical objects like
20 \item[visual length:
] used for sizes of visual elements, like arrows,
21 graph symbols, axis ticks, etc.
22 \item[width length:
] used for line widths
23 \item[\TeX{} length:
] used for all
\TeX{} and
\LaTeX{} output
26 For instance, if you only want thicker lines for a publication
27 version of your figure, you can just rescale the width lengths. How
28 this all works, is described in the following sections.
30 \section{Class length
}
32 The constructor of the
\verb|length| class accepts as first argument
33 either a number or a string:
35 \item \verb|length(number)| means a user length in units of the default
36 unit, defined via
\verb|unit.set(defaultunit=defaultunit)|.
37 \item For
\verb|length(string)|, the
\verb|string| has to consist of a
38 maximum of three parts separated by one or more whitespaces:
40 \item[quantifier:
] integer/float value. Optional, defaults to
\verb|
1|.
41 \item[type:
] \verb|"t"| (true),
\verb|"u"| (user),
\verb|"v"|
42 (visual),
\verb|"w"| (width),
44 Optional, defaults to
\verb|"u"|.
45 \item[unit:
] \verb|"m"|,
\verb|"cm"|,
\verb|"mm"|,
\verb|"inch"|, or
46 \verb|"pt"|. Optional, defaults to the default unit.
49 The default for the first argument is chosen in such a way that
50 \texttt{5*length()==length(
5)
}. Note that the default unit is
51 initially set to
\verb|"cm"|, but can be changed at any time by the
52 user. For instance, use
55 unit.set(defaultunit="inch")
58 if you want to specify per default every length in inches.
59 Furthermore, the scaling of the user, visual and width types can be
60 changed with the
\verb|set| function, as well. To this end,
\verb|set|
61 accepts the named arguments
\verb|uscale|,
\verb|vscale|, and
62 \verb|wscale|. For example, if you like to change the thickness of all
63 lines (with predefined linewidths) by a factor of two, just insert
69 at the beginning of your program.
71 To complete the discussion of the
\verb|length| class, we mention,
72 that as expected
\PyX{} lengths can be added, subtracted, multiplied by
73 a numerical factor, converted to a string and compared with each other.
75 \section{Subclasses of length
}
77 A number of subclasses of
\verb|length| are already predefined. They
78 only differ by their defaults for
\verb|type| and
\verb|unit|. Note
79 that again the default value for the quantifier is
\verb|
1|, such
80 that, for instance,
\texttt{5*m(
1)==m(
5)
}.
84 \begin{tabular
}{lll|lll
}
85 Subclass of
\texttt{length
} & Type & Unit & Subclass of
\texttt{length
} & Type & Unit\\
87 \texttt{m(x)
} & user & m &
\texttt{v
\_m(x)
} & visual & m\\
88 \texttt{cm(x)
} & user & cm &
\texttt{v
\_cm(x)
} & visual & cm\\
89 \texttt{mm(x)
} & user & mm &
\texttt{v
\_mm(x)
} & visual & mm\\
90 \texttt{inch(x)
} & user & inch &
\texttt{v
\_inch(x)
} & visual & inch\\
91 \texttt{pt(x)
} & user & points &
\texttt{v
\_pt(x)
} & visual & points\\
92 \texttt{t
\_m(x)
} & true & m &
\texttt{w
\_m(x)
} & width & m\\
93 \texttt{t
\_cm(x)
} & true & cm &
\texttt{w
\_cm(x)
} & width & cm\\
94 \texttt{t
\_mm(x)
} & true & mm &
\texttt{w
\_mm(x)
} & width & mm\\
95 \texttt{t
\_inch(x)
} & true & inch &
\texttt{w
\_inch(x)
} & width & inch\\
96 \texttt{t
\_pt(x)
} & true & points &
\texttt{w
\_pt(x)
} & width & points\\
97 \texttt{u
\_m(x)
} & user & m &
\texttt{x
\_m(x)
} &
\TeX & m \\
98 \texttt{u
\_cm(x)
} & user & cm &
\texttt{x
\_cm(x)
} &
\TeX & cm \\
99 \texttt{u
\_mm(x)
} & user & mm &
\texttt{x
\_mm(x)
} &
\TeX & mm \\
100 \texttt{u
\_inch(x)
} & user & inch &
\texttt{x
\_inch(x)
} &
\TeX & inch \\
101 \texttt{u
\_pt(x)
} & user & points &
\texttt{x
\_pt(x)
} &
\TeX & points\\
106 Here,
\verb|x| is either a number or a string, which, as mentioned
107 above, defaults to
\texttt{1}.
109 \section{Conversion functions
}
110 If you want to know the value of a
\PyX{} length in certain units, you
111 may use the predefined conversion functions which are given in the
117 \texttt{tom(l)
} &
\texttt{l
} in units of m\\
118 \texttt{tocm(l)
} &
\texttt{l
} in units of cm\\
119 \texttt{tomm(l)
} &
\texttt{l
} in units of mm\\
120 \texttt{toinch(l)
} &
\texttt{l
} in units of inch\\
121 \texttt{topt(l)
} &
\texttt{l
} in units of points\\
124 If
\verb|l| is not yet a
\verb|length| instance, it is converted first
125 into one, as described above. You can also specify a tuple, if you
126 want to convert multiple lengths at once.
132 %\subsection{Example 1}
138 %%% TeX-master: "manual.tex"
