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/*=========================================================================
Program: Visualization Toolkit
Module: vtkStreamLine.h
Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
All rights reserved.
See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the above copyright notice for more information.
=========================================================================*/
/**
* @class vtkStreamLine
* @brief generate streamline in arbitrary dataset
*
* vtkStreamLine is a filter that generates a streamline for an arbitrary
* dataset. A streamline is a line that is everywhere tangent to the vector
* field. Scalar values also are calculated along the streamline and can be
* used to color the line. Streamlines are calculated by integrating from
* a starting point through the vector field. Integration can be performed
* forward in time (see where the line goes), backward in time (see where the
* line came from), or in both directions. It also is possible to compute
* vorticity along the streamline. Vorticity is the projection (i.e., dot
* product) of the flow rotation on the velocity vector, i.e., the rotation
* of flow around the streamline.
*
* vtkStreamLine defines the instance variable StepLength. This parameter
* controls the time increment used to generate individual points along
* the streamline(s). Smaller values result in more line
* primitives but smoother streamlines. The StepLength instance variable is
* defined in terms of time (i.e., the distance that the particle travels in
* the specified time period). Thus, the line segments will be smaller in areas
* of low velocity and larger in regions of high velocity. (NOTE: This is
* different than the IntegrationStepLength defined by the superclass
* vtkStreamer. IntegrationStepLength is used to control integration step
* size and is expressed as a fraction of the cell length.) The StepLength
* instance variable is important because subclasses of vtkStreamLine (e.g.,
* vtkDashedStreamLine) depend on this value to build their representation.
*
* @sa
* vtkStreamer vtkDashedStreamLine vtkStreamPoints
*/
#ifndef vtkStreamLine_h
#define vtkStreamLine_h
#include "vtkFiltersFlowPathsModule.h" // For export macro
#include "vtkStreamer.h"
#ifndef VTK_LEGACY_REMOVE
class VTKFILTERSFLOWPATHS_EXPORT vtkStreamLine : public vtkStreamer
{
public:
vtkTypeMacro(vtkStreamLine,vtkStreamer);
void PrintSelf(ostream& os, vtkIndent indent);
/**
* Construct object with step size set to 1.0.
*/
static vtkStreamLine *New();
//@{
/**
* Specify the length of a line segment. The length is expressed in terms of
* elapsed time. Smaller values result in smoother appearing streamlines, but
* greater numbers of line primitives.
*/
vtkSetClampMacro(StepLength,double,0.000001,VTK_DOUBLE_MAX);
vtkGetMacro(StepLength,double);
//@}
protected:
vtkStreamLine();
~vtkStreamLine() {}
// Convert streamer array into vtkPolyData
virtual int RequestData(vtkInformation *, vtkInformationVector **, vtkInformationVector *);
// the length of line primitives
double StepLength;
private:
vtkStreamLine(const vtkStreamLine&) VTK_DELETE_FUNCTION;
void operator=(const vtkStreamLine&) VTK_DELETE_FUNCTION;
};
#endif // VTK_LEGACY_REMOVE
#endif
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