Plotting text, symbols, and lines

For overplotting of text one can use the command LABEL/GRAPHIC  . The text will be plotted in the font style set with the FONT keyword in the SET/GRAPHIC command. E.g. with LABEL/GRAPHIC and running in FONT=1 text will be generated in the roman font type. LABEL/GRAPHIC make use of the built-in features of AGL. These features allow to change font, draw subscripts and superscripts, scale the text size, or draw various symbols, all within the text string. All these possibility become available by including metacharacters in the text string. Currently, AGL knows the metacharacter set listed in Table 6.3.

 

Table 6.3: Meta Character in AGL and MIDAS

Metacharacter	Meaning
\{	begin grouping
\}	end grouping
\^	move the following part of the string up by half a character
\!u	move the following part of the string up by half a character
\_	move the following part of the string down by half a character
\!d	move the following part of the string down by half a character
\<	backspace by a single character
\+	increase character size by 20%
\-	decrease character size by 20%
\!	force interpretation of the following part as a metasequence
	(this is needed to allow metasequences starting with 'n'
	not to be interpreted as newlines)
\0	select font 0 (Default font)
\1	select font 1 (Quality roman font)
\2	select font 2 (Greek font)
\3	select font 3 (Script font)
\4	select font 4 (Old English)
\5	select font 5 (Tiny roman font)
\[	increase line width (bolding; optional)
\]	decrease line width (bolding; optional)
\#<n>	draw marker number <n> into the line
\n	perform a `newline'
~~	draw a single '~' character (must be following by a blank)
\~	draw a single '\~' character (must be following by a blank)
~\	draw a single ' $\backslash$' character (must be following by a blank)
\\	draw a single ' $\backslash$' character (must be following by a blank)

 

The character `~' can also be used instead of ` $\backslash$' as metacharacter flag. The `~' is more suited to C programs where ' $\backslash$' has a special meaning. All selections made by metacharacters are valid from the point in the string where they are defined up either to the end of current group (the part of the string enclosed in $\backslash${... $\backslash$}) or to the end of the string. If the metacharacter sequence is more than one character long (escape not included, of course), it must be followed by a blank space.
Example:

     LABEL/GRAP "e\{\!u(x\{\!u2\}+y\{\!u2\})\}= -
                 (\alpha +\beta ) sin\{\!u2\}\theta "

This command will produce the label $e^{(x^2+y^2)}=(\alpha+\beta)\sin^2\theta$ at a position which the user should give via cursor input.

MIDAS/AGL also interprets a set of `TEX-like' keywords as listed in table 6.4. Due to the fact that most of them represent special characters and symbols to be printed, only the names are listed; the symbols can only be seen by LABEL/GRAPHIC or the command TUTORIAL/GRAPH.

Besides overplotting of text strings, the user can also overplot lines (up to six different line types, depending on the device), and symbols (more than twenty). Depending on the device, up to four different line widths can be used. The selection of line properties and of symbol type can be done with SET/GRAPH, or, at least for line and symbol type, on the command line.

 

Table: TEX-like Characters for text strings in MIDAS Graphics

\AA \Alpha \Aquarius \Aries

\Beta \Cancer \Capricorn \Chi

\Delta \Earth \Epsilon \Eta

\Gamma \Gemini \Iota \Jupiter

\Kappa \Lambda \Leo \Libra

\Mars \Mercury \Moon \Mu

\Neptune \Nu \Omega \Omicron

\PI \Phi \Pisces \Pluto

\Psi \Rho \Sagittarius \Saturn

\Scorpio \Sigma \Sqrt \Tau

\Taurus \Theta \Upsilon \Uranus

\Venus \Virgo \Xi \Zeta

\aleph \alpha \asteroid \beta

\bigcirc \black \blue \cent

\chi \circ \cyan \clover

\clubsuit \comet \dag \ddag

\default \delta \diamond \div

\downarro \epsilon \equinox \equiv

\eta \firtree \gamma \ge

\greek \green \hbar \heart

\infty \int \iota \italic

\kappa \lambda \larrow \le

\magenta \mp \mu \!nabla

\!ne \!nu \odot \oint

\old \omega \omicron \oplus

\otimes \palmtree \paragraph \parallel

\partial \perp \phi \pi

\pm \propto \psi \red

\rho \rightarrow \roman \script

\shield \sigma \snow \spade

\sqrt \sum \tau \theta

\times \tiny \uparrow \upsilon

\varepsilon \varphi \vartheta \white

\xi \yellow \zeta

 

The command OVERPLOT/LINE  offers the possibility to overplot a line. Similarly, OVERPLOT/SYMBOL  overplots symbols. Both commands can be used interactively using the graphics cursor, or by giving the coordinates on the command line. Grid lines, connecting the major and/or minor tick marks can be drawn with the command OVERPLOT/GRID .