BoxWidget2
VTKExamples/Cxx/Widgets/BoxWidget2
Description
This example uses a {{class|vtkBoxWidget2}} to manipulate an actor. The widget only contains the interaction logic; the actual box is drawn by the accompanying {{class|vtkBoxRepresentation}}.
Contrary to the older {{class|vtkBoxWidget|older implementation}}, this widget doesn't provide functionality to assign it to one or more actors, so that has to be implemented manually. The box is dimensioned and positioned by passing a bounding box to PlaceWidget
method, with the SetPlaceFactor
method providing a scaling factor in relation to that bounding box. The transformations applied to the box can be used to manipulate any number of object(s), via a custom callback class, which is passed to the box widget through the AddObserver
method.
The older implementation {{class|vtkBoxWidget}} provides functionality to receive a {{class|vtkProp3D}} for the initial positioning and sizing, but the transformation synchronization still needs to be done manually. See for a simple example of how to use it.
Code
BoxWidget2.cxx
#include <vtkSmartPointer.h>
// For the rendering pipeline setup:
#include <vtkConeSource.h>
#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkInteractorStyleTrackballCamera.h>
// For vtkBoxWidget2:
#include <vtkBoxWidget2.h>
#include <vtkBoxRepresentation.h>
#include <vtkCommand.h>
#include <vtkTransform.h>
class vtkBoxCallback : public vtkCommand
{
public:
static vtkBoxCallback *New()
{
return new vtkBoxCallback;
}
vtkSmartPointer<vtkActor> m_actor;
void SetActor( vtkSmartPointer<vtkActor> actor )
{
m_actor = actor;
}
virtual void Execute( vtkObject *caller, unsigned long, void* )
{
vtkSmartPointer<vtkBoxWidget2> boxWidget =
vtkBoxWidget2::SafeDownCast(caller);
vtkSmartPointer<vtkTransform> t =
vtkSmartPointer<vtkTransform>::New();
vtkBoxRepresentation::SafeDownCast( boxWidget->GetRepresentation() )->GetTransform( t );
this->m_actor->SetUserTransform( t );
}
vtkBoxCallback(){}
};
int main( int vtkNotUsed( argc ), char* vtkNotUsed( argv )[] )
{
vtkSmartPointer<vtkConeSource> coneSource =
vtkSmartPointer<vtkConeSource>::New();
coneSource->SetHeight( 1.5 );
vtkSmartPointer<vtkPolyDataMapper> mapper =
vtkSmartPointer<vtkPolyDataMapper>::New();
mapper->SetInputConnection( coneSource->GetOutputPort() );
vtkSmartPointer<vtkActor> actor = vtkSmartPointer<vtkActor>::New();
actor->SetMapper( mapper );
vtkSmartPointer<vtkRenderer> renderer =
vtkSmartPointer<vtkRenderer>::New();
renderer->AddActor(actor);
renderer->ResetCamera(); // Reposition camera so the whole scene is visible
vtkSmartPointer<vtkRenderWindow> renderWindow =
vtkSmartPointer<vtkRenderWindow>::New();
renderWindow->AddRenderer( renderer );
vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
vtkSmartPointer<vtkRenderWindowInteractor>::New();
renderWindowInteractor->SetRenderWindow( renderWindow );
// Use the "trackball camera" interactor style, rather than the default "joystick camera"
vtkSmartPointer<vtkInteractorStyleTrackballCamera> style =
vtkSmartPointer<vtkInteractorStyleTrackballCamera>::New();
renderWindowInteractor->SetInteractorStyle( style );
vtkSmartPointer<vtkBoxWidget2> boxWidget =
vtkSmartPointer<vtkBoxWidget2>::New();
boxWidget->SetInteractor( renderWindowInteractor );
boxWidget->GetRepresentation()->SetPlaceFactor( 1 ); // Default is 0.5
boxWidget->GetRepresentation()->PlaceWidget(actor->GetBounds());
// Set up a callback for the interactor to call so we can manipulate the actor
vtkSmartPointer<vtkBoxCallback> boxCallback =
vtkSmartPointer<vtkBoxCallback>::New();
boxCallback->SetActor(actor);
boxWidget->AddObserver( vtkCommand::InteractionEvent, boxCallback );
boxWidget->On();
renderWindowInteractor->Start();
return EXIT_SUCCESS;
}
CMakeLists.txt
cmake_minimum_required(VERSION 2.8)
PROJECT(BoxWidget2)
find_package(VTK REQUIRED)
include(${VTK_USE_FILE})
add_executable(BoxWidget2 MACOSX_BUNDLE BoxWidget2.cxx)
target_link_libraries(BoxWidget2 ${VTK_LIBRARIES})
Download and Build BoxWidget2
Click here to download BoxWidget2 and its CMakeLists.txt file. Once the tarball BoxWidget2.tar has been downloaded and extracted,
cd BoxWidget2/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:
./BoxWidget2
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.