#### 4.2.6 Predefined constants

• Maths constants: $i$, $\pi$, $e$.
• The TeXgraph version number is stored in the constant called version.
• The constant Windows comes with the value 0 or 1 according to your operating system.
• The constant GUI comes with the value 0 or 1 showing that you are using TeXgraph’s gui or not.
• The jump constant: jump . This constant is used to separate connex components of a polyline. We must also add that the polylines are automatically clipped by TeXgraph according to a rectangle that is the current window when drawing.
• Exemple(s): the equation $y=1∕x$ can be drawn from the following polyline with the command: [Seq(t+i/t,t,-5,0,0.1), jump, Seq(t+i/t,t,0,5,0.1)].
• The Nil constant. This is a non-value constant, that can be used to make comparisons. For example if we want to know if the variable $x$ is not empty : if x<>Nil then ....
• Constants that are strings:
• InitialPath: Path to the TeXgraph directory (here are the executables and scripts).
• DocPath: path to the doc TeXgraph directory. That directory contains docs int pdf format (eg: TeXgraph.pdf)

Example: The command Exec("xpdf","TeXgraph.pdf",DocPath), will open the TeXgraph.pdf file with the program xpdf.

• UserMacPath: path to the user macros directory. Under linux this is the directory :

\$HOME/TeXgraphMac and under windows it has to be created by the user and the path must be in the environment variable TeXgraphMac. When the user is loading a macro file (*.mac) or a model file (*.mod) TeXgraph is seeking in the current directory, then in the directory UserMacPath and finally in the macros subdirectory of the directory indicated in the string : InitialPath.

• TmpPath: Path to a temporary directory. This is the directory \$HOME/.TeXgraph under linux, and c:\tmp under windows.
• JavaviewPath: Path to the file javaview.jar if you have installed it. Its value has to be defined in the config file: menu Preferences/Configuration file.
• LF: Insert a line feed when the string is displayed.
• Diese: returns the hash character (used as delimiter in TeXgraph source files).
• DirSep: returns the separating character used by the system for paths to files.
• ND: means “ non defined”. It is containing the string "_ND". It is used when opening csv files to indicate empty elements.
• The exporting constants: tex, teg, pst, pgf, eps, psf, tkz, pdf, epsc, pdfc, svg et bmp, These are the possible values of the constant ExportMode (set by TeXgraph at exporting time). Added to those, for the 3D, the constants: obj, geom, jvx.
• Constants: Xmin, Xmax, Ymin, Ymax: those are setting the graphical window. Xscale and Yscale: représentents (in cm) the scale on Ox and Oy axes. The constants can only be modified by the menu or the function Fenetre.
• Constants : margeG, margeD, margeH, margeB: those are defining the margins around the graphic (in cm). Those constants can only be modified with the menu or the function Marges.
• The constants line, linearc, bezier, curve, arc, ellipticArc, ellipse, circle, closepath, move: Those are needed to build paths in the command Path.
• The graphic constants:
• Colors: there is a dedicated dedicated chapter.
• Line styles:
• noline [=-1],
• solid [=0],
• dashed [=1],
• dotted [=2],
• userdash [=3], this style is using the variable DashPattern that is defining the pattern, which is a length list (unit: points) using the form: [line length, jump length, line length, jump length, ...]. For example DashPattern:=[2,3,0.1,3] will alternatively give lines and points.
• Line endings:
• butt: straight end at the last point (default),
• round: rounded end after last point,
• square: square end after the last point.
• Join lines:
• miter: miter join. The variable Miterlimit (set to 10) permits to handle the spikes length.
• round: rounded join (default),
• bevel: bevel join.
• Line thickness (using the tenth of a TEX point):
• thinlines [=2],
• thicklines [=8],
• Thicklines [=14], the variable Width can also set the thickness.
• Point style (à la pstricks):
• dot [=0],
• dotcircle [=1],
• square [=2],
• square’ [=3] (filled square),
• plus [=4],
• times [=5],
• asterisk [=6],
• oplus [=7],
• otimes [=8],
• diamond [=9],
• diamond’ [=10],
• triangle [=11],
• triangle’ [=12],
• pentagon [=13],
• pentagon’ [=14],
• Label styles (by default the text is horizontally and vertically centered )
• left : the reference point is on the left of the text,
• right : the reference point is on the right of the text,
• top : the reference point is at the top of the text,
• bottom : the reference point is at the bottom of the text,
• baseline : the reference point is the text baseline,
• framed: the text is framed,
• special: the text is written as is in the exported file (it is not displayed on the screen). This is allowing to write directly in a LaTeX or pgf or pstricks file (even eps).
• stacked: the text can be written on several paragraphs (ie: paragraph jumps are allowed).

Example: LabelStyle := top+framed, the text is horizontally centered, the reference point is at the top of the text, and the text is framed.

• Fill styles for polygons (hatches are calculated by TeXgraph for the LaTeX output):
• none [=0]: empty.
• full [=1]: the polygon is filled with the color given in FillColor, without effect in the tex export.
• bdiag [=2]: oriented hatches SW -> NE (45 degrees angle),
• hvcross [=3]: combined horizontal and vertical styles ,
• diagcross [=4]: combined bdiag and fdiag styles,
• fdiag [=5]: oriented hatches NW -> SE (45 degrees),
• horizontal [=6]: horizontal hatches,
• vertical [=7]: vertical hatches.
• Labels size:
• tiny,
• scriptsize,
• footnotesize,
• small,
• normalsize,
• large,
• Large,
• LARGE,
• huge,
• Huge.