Display Methods on Fe2d

 

   GRAPE(fe, "graph-disp")()

FE2D * fe

Display the function value as a graph.

       

GRAPE(fe, "isoline-disp")()

GRAPE(fe, "isoline")(select, funct, linescal, colscal, offsetscal, highscal, max, min)

FE2D *fe;
int select; /* = 1 for "isoline-select", else 0 */
void (*funct)(); /* function specifying the level lines */
double linescal; /* density of lines */
double colscal; /* line color */
double offsetscal; /* offset */
double highscal, max, min;

Level lines of the function funct supported by the 2D triangulation of the Fe2d instance are calculated. The function can be arbitrary carrying the argument structure of Finite Element functions (see listing of struct fe2d above), if the pointer is set to NULL the absolute value of the Fe2d function is used. Depending on whether the device is in the patch or in the grid mode colored patches respectively lines are displayed. The color is generated according to a ramp in the HSV color model.

The parameters for the color model are ln(range of colormap) and ln(position of colormap). The other parameters are ln(line-distance), the distance of the isolines (only used in grid mode), and the height (i.e. z-value) of the isolines. For this method it is necessary to set the dimension_of_value and the polynomial_order entries in the structure.

GRAPE(fe, "isoline-select-disp")()

FE2D *fe;

Those particular values which are stored in the array colorbar->values (see section 6.6) are displayed. The colorbar is the one belonging to the function "fe2d-isoline-disp". The values can be chosen with a colorbar-method or with the prompt "add value" (which appears after clicking the button "iso2dclb modi"). In grid mode only these particular isolines are displayed, whereas in patch mode the values are shown by means of white lines above the colored patch image.

   GRAPE(fe, "line-graph-disp")()

FE2D * fe

Display the function value as a line-graph.

GRAPE(s, "mark-polygon-send")()

SCENE *s ;

With this method a polygon in the triangulation can be determined in the following way:

• locate some points in the triangulation;
• pick them by pressing the left mouse button;
• mark the last polygon point with pressing the middle mouse button.

Picking means in the case of a Triang2d instance as the object of the scene s the direct picking of points on the triangulation. If s->object is an instance of a superclass of Triang3d picking is performed on the current planar clipping plane (see methods clip-....-disp). The picked polygon is saved as a Triang1d instance when pressing the right mouse button. This Triang1d instance is inserted as the object of a second scene node stored as s->next_scene. This means it is inserted as the following hierarchical node.

       

GRAPE(fe, "vect-disp")()

GRAPE(fe, "vect")(length, mesh, dist, color_scal, offset_scal, max, min)

FE2D *fe;
double length , mesh, dist;
double color_scal, offset_scal, max, min;

In the case of fe->dimension_of_value 2 the values of the Fe2d function are shown at the points of a constructed rectangular mesh with mesh width mesh. The vectors' length can be regulated with the parameter length. dist is the distance of mesh from the object.

• If fe->z NIL the direction of the vectors is three-dimensional. In that case fe-> dimension_of_value > 2 is important.
• If fe->z = 2 and fe-> dimension_of_value = 2 the vectors are all of one color and are displayed within one plane. The color is either white or grey depending on the lightness of the object.
• If fe->z = 2 and fe-> dimension_of_value 2 the color of the vectors depends accordingly on the values that are calculated in the third component of the function fe->f. The colors are generated with the hsv color model and can be changed with the parameters color, offset, max and min (of the corresponding colorbar vect2dclb). An example for this case is: