IBM Visualization Data Explorer Programmer's Reference

12.7 Field Construction

This section describes routines that aid in the construction of fields.

Points and Dependent Data

Some Field components are often in one-to-one correspondence with the "positions" component (e.g., "data," "colors," "opacities," and surface "normals"). (Alternatively, any of these components may be in one-to-one correspondence with the "connections" component.) If they are in one-to-one correspondence with positions (indicated by a "dep" attribute of "positions"), then they are also expected to be the same size as the positions component. The following routines aid in constructing such components.

Field DXAddPoint() Field DXAddColor(); Field DXAddFrontColor(); Field DXAddBackColor(); Field DXAddOpacity(); Field DXAddNormal(); Field DXAddPoints(); Field DXAddColors(); Field DXAddFrontColors(); Field DXAddBackColors(); Field DXAddOpacities(); Field DXAddNormals();	Add points or point-dependent data to a Field. See DXAddPoint, ...Color, ...FrontColor, ...BackColor, ...Opacity, ...Normal,.
Field DXAddFaceNormal() Field DXAddFaceNormals();	Add connection-dependent normals to a Field. See DXAddFaceNormal, DXAddFaceNormals.

Note on Use
The fourteen routines listed above are all suitable for adding a small number of points or for rapid prototyping; but for better performance, see DXAddArrayData() in "Irregular Arrays".

Connections

The routines listed here define the interpolation elements of a Field, creating a "connections" component with an appropriate "element type" attribute.

Field DXAddLine() Field DXAddTriangle(); Field DXAddQuad(); Field DXAddTetrahedron();	Add a single interpolation element to a Field. See DXAddLine, ...Triangle, ...Quad, ...Tetrahedron, ...Lines, ...Triangles, ...Quads, ...Tetrahedra.
Field DXAddLines() Field DXAddTriangles(); Field DXAddQuads(); Field DXAddTetrahedra();	Add interpolation element(s) to a Field. See DXAddLine, ...Triangle, ...Quad, ...Tetrahedron, ...Lines, ...Triangles, ...Quads, ...Tetrahedra.
Field DXSetConnections()	Sets the "connections" component of a Field as a specified Array with a specified element type. See DXSetConnections.
Array DXGetConnections()	Gets the "connections" component of a Field and checks to see if it has a specified "element type" attribute. See DXGetConnections.

Standard Components

The following routines create and manipulate standard components of a Field.

Field DXEndField()	Creates the standard components that a Field is expected to contain if they do not already exist. See DXEndField.
Error DXEndObject()	Creates the standard components that Fields are expected to contain, sharing the results when components are shared between Fields. See DXEndObject.
int DXEmptyField()	Determines whether a Field contains information. See DXEmptyField.
Field DXChangedComponentValues() Field DXChangedComponentStructure();	Both routines delete all components of a Field that are derived from a specified component. DXChangedComponentStructure() also deletes all Field components that are dependent on or refer to a specified component. See Note on Use. See DXChangedComponentValues, DXChangedComponentStructure.

Note on Use
This example illustrates one use of DXChangedComponentValues(): g = DXCopy(f, COPY_STRUCTURE); a = DXGetComponentValue(g, "positions"); b = ... modification of a ... DXSetComponentValue(g, "positions", b); DXChangedComponentValues(g, "positions");

Object DXBoundingBox()	Computes the bounding box of an Object. See DXBoundingBox.
Array DXNeighbors()	Returns the neighbors Array of a Field. See DXNeighbors.
Error DXStatistics()	Returns statistical information for an Object. See DXStatistics.
Object DXValidPositionsBoundingBox()	Computes the bounding box of the valid positions of an Object. See DXValidPositionsBoundaryBox.

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