DecimatePolyline
VTKExamples/Cxx/PolyData/DecimatePolyline
Description
This example shows how to [(signal processing)|decimate]]([wikipedia:Decimation) a polyline.
Code
DecimatePolyline.cxx
#include <vtkVersion.h>
#include <vtkDecimatePolylineFilter.h>
#include <vtkMath.h>
#include <vtkPolyData.h>
#include <vtkCellArray.h>
#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkProperty.h>
#include <vtkSmartPointer.h>
int main(int, char *[])
{
const unsigned int numberofpoints = 100;
vtkPolyData* circle = vtkPolyData::New();
vtkSmartPointer<vtkPoints> points = vtkSmartPointer<vtkPoints>::New();
vtkSmartPointer<vtkCellArray> lines = vtkSmartPointer<vtkCellArray>::New();
vtkIdType* lineIndices = new vtkIdType[numberofpoints+1];
for( unsigned int i = 0; i < numberofpoints; i++ )
{
const double angle = 2.0 * vtkMath::Pi() * static_cast< double >( i ) /
static_cast< double >( numberofpoints );
points->InsertPoint( static_cast< vtkIdType >( i ),
cos( angle ),
sin( angle ),
0. );
lineIndices[i] = static_cast< vtkIdType >( i );
}
lineIndices[numberofpoints] = 0;
lines->InsertNextCell( numberofpoints+1, lineIndices );
delete[] lineIndices;
circle->SetPoints( points );
circle->SetLines( lines );
vtkSmartPointer<vtkPolyDataMapper> c_mapper =
vtkSmartPointer<vtkPolyDataMapper>::New();
#if VTK_MAJOR_VERSION <= 5
c_mapper->SetInput( circle );
#else
c_mapper->SetInputData( circle );
#endif
vtkSmartPointer<vtkActor> c_actor =
vtkSmartPointer<vtkActor>::New();
c_actor->SetMapper( c_mapper );
vtkSmartPointer<vtkDecimatePolylineFilter> decimate =
vtkSmartPointer<vtkDecimatePolylineFilter>::New();
#if VTK_MAJOR_VERSION <= 5
decimate->SetInput( circle );
#else
decimate->SetInputData( circle );
#endif
decimate->SetTargetReduction( 0.95 );
decimate->Update();
vtkSmartPointer<vtkPolyDataMapper> d_mapper =
vtkSmartPointer<vtkPolyDataMapper>::New();
d_mapper->SetInputConnection( decimate->GetOutputPort() );
vtkSmartPointer<vtkActor> d_actor =
vtkSmartPointer<vtkActor>::New();
d_actor->SetMapper( d_mapper );
d_actor->GetProperty()->SetColor( 1., 0. ,0. );
vtkSmartPointer<vtkRenderer> ren =
vtkSmartPointer<vtkRenderer>::New();
ren->AddActor( c_actor );
ren->AddActor( d_actor );
vtkSmartPointer<vtkRenderWindow> renwin =
vtkSmartPointer<vtkRenderWindow>::New();
renwin->AddRenderer( ren );
vtkSmartPointer<vtkRenderWindowInteractor> iren =
vtkSmartPointer<vtkRenderWindowInteractor>::New();
iren->SetRenderWindow( renwin );
renwin->Render();
iren->Start();
circle->Delete();
return EXIT_SUCCESS;
}
CMakeLists.txt
cmake_minimum_required(VERSION 2.8)
PROJECT(DecimatePolyline)
find_package(VTK REQUIRED)
include(${VTK_USE_FILE})
add_executable(DecimatePolyline MACOSX_BUNDLE DecimatePolyline.cxx)
target_link_libraries(DecimatePolyline ${VTK_LIBRARIES})
Download and Build DecimatePolyline
Click here to download DecimatePolyline and its CMakeLists.txt file. Once the tarball DecimatePolyline.tar has been downloaded and extracted,
cd DecimatePolyline/build
If VTK is installed:
cmake ..
If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:
cmake -DVTK_DIR:PATH=/home/me/vtk_build ..
Build the project:
make
and run it:
./DecimatePolyline
WINDOWS USERS PLEASE NOTE: Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.