#### 4.2.7 Global predefined variables

The following variables are considered as predefined. So are all the variables that are loaded from a macros file that is loaded as the TeXgraph program is starting. The predefined variables do not appear in TeXgraph’s window, and are not recorded with the graphic.

The following variables correspond to the different "static fields" of the graphical elements:

• Arrows: Arrows number, first set to 0
• AutoReCalc: automatic calculation of the graphic elements, initial value:1 (for True), it can also get the value 0 (False). In the case of the value is zero for one graphic element, only the function ReCalc() (button R) can force that element to be recalculated.
• ForMinToMax: the variable value is $0$ or $1$, if it’s $1$ then the variable $t$ for the curves is following the interval [Xmin,Xmax], else this is the interval [tMin,tMax].
• Variables related to axes
• xylabelpos: labels position on the axes, default value set to bottom+left (left to the Oy axis and bottom of the Ox axis).
• xylabelsep: distance (cm) between the labels and the end of the graduations, default value set to 0.1 cm.
• xyticks: length (cm) of the graduations on the axes, default value set to 0.2 cm.
• Color: color. Default value set to black,
• DashPattern: defining the drawing lines pattern in the style userdash. That variable is length list following the format: [line length, jump length,line length, jump length, ...]. For example DashPattern:=[2,3,0.1,3] will give a line-points succession.
• DotStyle: dot style. Default value : dot,
• DotAngle: rotating angle of the points (degrees). default value set to 0,
• DotScale: dot scale. Default value set to [1,1] (Ox and Oy scale).
• DotSize: dot size. Default value set to 2+2i. the value of this variable is a complex $x+iy$. $x$ is the size (unit: points) and $y$ is a positive number: the point diameter calulated with the formula: x+y*(line thickness).
• Eofill: default: 0. The value can only be 0 or 1. The value 1 indicate that the fill mod is following the even-odd rule, and the value 0 indicate the contrary case. The even-odd mode (Eofill=1) is not always very vell handled by the GUI version of TeXgraph but there are no problems with the exports.
• FillColor: The default fill color is white,
• FillOpacity: when the variable FillStyle=full, the FillOpacity is a value between 0 and 1 (default: $1$ - no transparency). The transparency is not handled by the TeXgraph screen, but it is in the exports.
• FillStyle: default fillstyle : none,
• IsVisible: boolean value (0 or 1), showing or not the graphic element. The default value is 1 (visible)
• LabelAngle: direction of the labels relative to the horizontal, this is a degrees angle (default: 0).
• LabelSize: size of the labels. Default value: small,
• LabelStyle: the label style is by default set to 0 (horizontally and vertically centered).
• LineCap: this is defining the line ends. Default value: butt.
• LineJoin: defining the line join type. Default value: round.
• LineStyle: line styles. Default: solid. In the current windows version the lines are displayed as solid lines as soon as the thickness is above 1 pixel, even if the style is dashed or dots. This problem doesn’t occur in the exports.
• MiterLimit: this limits the length of the joints as soon as LineJoin is set to miter. Default value: 10.
• NbPoints: number of points for the curves. default : 50.
• PenMode: drawing mode, 0=normal mode, 1=NotXor mode, if a graphical element created using NotXor mode is redrawn, it is removed. Only the background is left. We can then modify the position of that element and redraw it. This technique is usefull to move objects without redrawing the others (avoiding trembling images). The default value of this variable is 0
• StrokeOpacity: Opacity/transparency handling for the lines when LineStyle is not equal to noline, this is a value between 0 and 1, defaulted to $1$, the value $1$ means no transparency. The transparency is not handled by the TeXgraph screen, but it is in the exports.
• TeXLabel: boolean variable (0 or 1) showing that the labels have (or not) to be displayed as images in the graphic interface after a TeX compilation. The default value is 0
• tMax: maximal value of the t parameter. Default :5.
• tMin: minimal value of the t parameter. Default value: $-5$.
• Width: line thickness in an integer of the tenth of point of TEX. Default value: thinlines.

Creating a graphic element does not implies that a constant with the same name is created. Though, it is possible to get the list of the points compositing the graphical element with the command Get. But the graphical element whose name we are using has to be already created or the function Get will return the Nil value.

3D related variables:

• theta and phi: these are used for surfaces projections calculations. Default values 30 and 60 degrees, respectively. The first represents the lattitude and the second is the colatitude. Those can be also modified using a button in the toolbar.
• AngleStep: represents the angular step (radians) when we turn a 3D object with the buttons with arrows on the toolbar. The default value is $\pi$/36 (5 degrees).