GNU Octave - Text Properties

GNU Octave Manual Version 3
by John W. Eaton, David Bateman, Søren Hauberg
Paperback (6"x9"), 568 pages
ISBN 095461206X
RRP £24.95 ($39.95)

Get a printed copy>>>

GNU Octave Manual Version 3

Buy the book here >>>
learn more

15.2.2.5 Text Properties

string: The character string contained by the text object.
units: May be "normalized" or "graph".
position: The coordinates of the text object.
rotation: The angle of rotation for the displayed text, measured in degrees.
horizontalalignment: May be "left", "center", or "right".
color: The color of the text. See section 15.2.4 Colors.
fontname: The font used for the text.
fontsize: The size of the font, in points to use.
fontangle: Flag whether the font is italic or normal. Valid values are 'normal', 'italic' and 'oblique'.
fontweight: Flag whether the font is bold, etc. Valid values are 'normal', 'bold', 'demi' or 'light'.
interpreter: Determines how the text is rendered. Valid values are 'none', 'tex' or 'latex'.

All text objects, including titles, labels, legends, and text, include the property 'interpreter', this property determines the manner in which special control sequences in the text are rendered. If the interpreter is set to 'none', then no rendering occurs. At this point the 'latex' option is not implemented and so the 'latex' interpreter also does not interpret the text.

The 'tex' option implements a subset of TeX functionality in the rendering of the text. This allows the insertion of special characters such as Greek or mathematical symbols within the text. The special characters are also inserted with a code starting with the back-slash (\) character, as in the table Table 15-7.

In addition, the formatting of the text can be changed within the string with the codes

	\bf	Bold font
	\it	Italic font
	\sl	Oblique Font
	\rm	Normal font

These are be used in conjunction with the { and } characters to limit the change in the font to part of the string. For example

xlabel ('{\bf H} = a {\bf V}')

where the character 'a' will not appear in a bold font. Note that to avoid having Octave interpret the backslash characters in the strings, the strings should be in single quotes. It is also possible to change the fontname and size within the text

	\fontname{`fontname`}	Specify the font to use
	\fontsize{`size`}	Specify the size of the font to use

Finally, the superscript and subscripting can be controlled with the '^' and '_' characters. If the '^' or '_' is followed by a { character, then all of the block surrounded by the { } pair is super- or sub-scripted. Without the { } pair, only the character immediately following the '^' or '_' is super- or sub-scripted.

\forall	\exists	\ni
\cong	\Delta	\Phi
\Gamma	\vartheta	\Lambda
\Pi	\Theta	\Sigma
\varsigma	\Omega	\Xi
\Psi	\perp	\alpha
\beta	\chi	\delta
\epsilon	\phi	\gamma
\eta	\iota	\varphi
\kappa	\lambda	\mu
\nu	\o	\pi
\theta	\rho	\sigma
\tau	\upsilon	\varpi
\omega	\xi	\psi
\zeta	\sim	\Upsilon
\prime	\leq	\infty
\clubsuit	\diamondsuit	\heartsuit
\spadesuit	\leftrightarrow	\leftarrow
\uparrow	\rightarrow	\downarrow
\circ	\pm	\geq
\times	\propto	\partial
\bullet	\div	\neq
\equiv	\approx	\ldots
\mid	\aleph	\Im
\Re	\wp	\otimes
\oplus	\oslash	\cap
\cup	\supset	\supseteq
\subset	\subseteq	\in
\notin	\angle	\bigrightriangledown
\langle	\rangle	\nabla
\prod	\surd	\cdot
\neg	\wedge	\vee
\Leftrightarrow	\Leftarrow	\Uparrow
\Rightarrow	\Downarrow	\diamond
\copyright	\lfloor	\lceil
\rfloor	\rceil	\int

Table 15-7: Available special characters in TeX mode

A complete example showing the capabilities of the extended text is

x = 0:0.01:3;
plot(x,erf(x));
hold on;
plot(x,x,"r");
axis([0, 3, 0, 1]);
text(0.65, 0.6175, strcat('\leftarrow x = {2/\surd\pi',
' {\fontsize{16}\int_{\fontsize{8}0}^{\fontsize{8}x}}',
' e^{-t^2} dt} = 0.6175'))

GNU Octave Manual Version 3

See the print edition