1.2 MathGL features

MathGL can plot a wide range of graphics. It includes:

• one-dimensional (Plot, Area, Bars, Step, Stem, Torus, Chart, Error, Tube, Mark, see section 1D plotting);
• two-dimensional plots (Mesh, Surf, Dens, Cont, ContF, Boxs, Axial, Fall, Belt, Tile, see section 2D plotting);
• three-dimensional plots (Surf3, Dens3, Cont3, ContF3, Cloud-like, see section 3D plotting);
• dual data plots: vector fields Vect and VectC, flow threads Flow, mapping chart Map, surfaces and isosurfaces, transparent or colored (i.e. with transparency or color varied) by other data SurfA, SurfC, Surf3A, Surf3C (see section Dual plotting);
• and so on. For details see see section MathGL core.

In fact, I created the functions for drawing of all the types of scientific plots that I know. The list of plots is growing; if you need some special type of a plot then please email me e-mail and it will appear in the new version.

I tried to make plots as nice looking as possible: e.g., a surface can be transparent and highlighted by several (up to 10) light sources. Most of the drawing functions have 2 variants: simple one for the fast plotting of data, complex one for specifying of the exact position of the plot (including parametric representation). Resulting image can be saved in bitmap (with the help of mglGraphZB, mglGraphGL) PNG, JPEG, TIFF, BMP format or in vector EPS or SVG format (with the help of mglGraphPS), or in IDTF format (with the help of mglGraphIDTF) which can be converted into U3D.

All texts are drawn by vector fonts, which allows for high scalability and portability. Texts may contain commands for: some of the TeX-like symbols, changing index (upper or lower indexes) and the style of font inside the text string (see section mglFont class). Texts of ticks are rotated with axis rotation. It is possible to create a legend of plot and put text in an arbitrary position on the plot. Arbitrary text encoding (by the help of function setlocale()) and UTF-16 encoding are supported.

Special mglData class is used for data encapsulation (see section mglData class). In addition to a safe creation and deletion of data arrays it includes functions for data processing (smoothing, differentiating, integrating, interpolating and so on) and reading of data files with automatic size determination. Class mglData can handle arrays with up to three dimensions (arrays which depend on up to 3 independent indexes a_ijk). Using an array with higher number of dimensions is not meaningful, because I do not know how it can be plotted. Data filling and modification may be done manually or by textual formulas.

The mglFormula class allows a fast evaluation of a textual mathematical expression (see section mglFormula class). It is based on string precompilation to tree-like code at the creation of class instance. At evaluation stage code performs only fast tree-walk and returns the value of the expression. In addition to changing data values, textual formulas are also used for drawing in arbitrary curvilinear coordinates. A set of such curvilinear coordinates is limited only by user</samp>&rsquo;s imagination rather than a fixed list like: polar, parabolic, spherical, and so on.