CallData
VTKExamples/Cxx/Interaction/CallData
Description
This example demonstrates the use of 'calldata' in a vtkCallbackCommand. Here, we create a custom VTK filter to invoke an event to which we attach a value (the 'calldata'). We use a timer to modify and update the filter so that the event is triggered repeatedly, demonstrating the pass-via-calldata.
Code
CallData.cxx
#include "vtkObjectFactory.h"
#include "vtkCommand.h"
#include "vtkCallbackCommand.h"
#include "vtkStreamingDemandDrivenPipeline.h"
#include "vtkInformationVector.h"
#include "vtkInformation.h"
#include "vtkDataObject.h"
#include "vtkSmartPointer.h"
#include "vtkAppendPolyData.h"
#include "vtkSphereSource.h"
#include "vtkPolyDataAlgorithm.h"
#include "vtkRenderer.h"
#include "vtkRenderWindow.h"
#include "vtkRenderWindowInteractor.h"
class vtkMyTestFilter : public vtkPolyDataAlgorithm
{
public:
vtkTypeMacro(vtkMyTestFilter,vtkPolyDataAlgorithm);
static vtkMyTestFilter *New();
int RefreshEvent;
protected:
vtkMyTestFilter()
{
this->SetNumberOfInputPorts(0);
this->RefreshEvent = vtkCommand::UserEvent + 1;
this->Counter = 0;
}
int RequestData(vtkInformation *, vtkInformationVector **, vtkInformationVector *)
{
this->InvokeEvent(this->RefreshEvent, &this->Counter);
this->Counter++;
return 1;
}
private:
vtkMyTestFilter(const vtkMyTestFilter&); // Not implemented.
void operator=(const vtkMyTestFilter&); // Not implemented.
unsigned int Counter;
};
vtkStandardNewMacro(vtkMyTestFilter);
static void CallbackFunction(vtkObject* caller,
long unsigned int eventId,
void* clientData,
void* callData );
class vtkTimerCallback : public vtkCommand
{
public:
static vtkTimerCallback *New()
{
vtkTimerCallback *cb = new vtkTimerCallback;
return cb;
}
virtual void Execute(vtkObject *vtkNotUsed(caller),
unsigned long vtkNotUsed(eventId),
void *vtkNotUsed(callData))
{
TestFilter->Modified();
TestFilter->Update();
}
vtkMyTestFilter* TestFilter;
};
int main(int, char *[])
{
// Create a renderer, render window, and interactor
vtkSmartPointer<vtkRenderer> renderer =
vtkSmartPointer<vtkRenderer>::New();
vtkSmartPointer<vtkRenderWindow> renderWindow =
vtkSmartPointer<vtkRenderWindow>::New();
renderWindow->AddRenderer(renderer);
vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
vtkSmartPointer<vtkRenderWindowInteractor>::New();
renderWindowInteractor->SetRenderWindow(renderWindow);
vtkSmartPointer<vtkMyTestFilter> testFilter =
vtkSmartPointer<vtkMyTestFilter>::New();
vtkSmartPointer<vtkCallbackCommand> callback =
vtkSmartPointer<vtkCallbackCommand>::New();
callback->SetCallback(CallbackFunction );
testFilter->AddObserver(testFilter->RefreshEvent, callback);
testFilter->Update();
renderWindow->Render();
renderWindowInteractor->Initialize();
// Sign up to receive TimerEvent
vtkSmartPointer<vtkTimerCallback> timerCallback =
vtkSmartPointer<vtkTimerCallback>::New();
timerCallback->TestFilter = testFilter;
renderWindowInteractor->AddObserver(vtkCommand::TimerEvent, timerCallback);
renderWindowInteractor->CreateRepeatingTimer(100);
renderWindowInteractor->Start();
return EXIT_SUCCESS;
}
void CallbackFunction(vtkObject* vtkNotUsed(caller),
long unsigned int vtkNotUsed(eventId),
void* vtkNotUsed(clientData),
void* callData )
{
unsigned int* callDataCasted = reinterpret_cast<unsigned int*>(callData);
std::cout << *callDataCasted << std::endl;
}
CMakeLists.txt
cmake_minimum_required(VERSION 2.8)
PROJECT(CallData)
find_package(VTK REQUIRED)
include(${VTK_USE_FILE})
add_executable(CallData MACOSX_BUNDLE CallData.cxx)
target_link_libraries(CallData ${VTK_LIBRARIES})
Download and Build CallData
Click here to download CallData and its CMakeLists.txt file. Once the tarball CallData.tar has been downloaded and extracted,
cd CallData/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:
./CallData
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.