Independent Thread We want to run a single task in an independent thread in a convenient way in some scenarios. It is common in data process and UI interaction event, for example, we want to use QMovie object to play a gif to indicate our software is analyzing test data, Read more…
The filter vtkWarpScalar can help us to move the point along point normal by the scalar amount times the scale factor. We can change the size of the original model with it as long as there are normals in data. The following example has two renderers, the left renderer shows Read more…
We can use VTK observer-command mechanism to listen to slider value changing event and override our responding method void Execute(vtkObject *caller, unsigned long, void*) to change target item’s size. It’s easy to implement with the subclass of vtkCommand and vtkSliderWidget. The following example shows how to do it. I add Read more…
AddInputConnection is a public interface provided by vtkAlgorithm. We can use it to combine multiple input sources to get a final 3D model with some special algorithm class. The following example has two VTK algorithm classes which show us the multiple source connections. int main() { vtkSmartPointer<vtkSphereSource> sphereSource = vtkSmartPointer<vtkSphereSource>::New(); Read more…
vtkInteractorEventRecorder can be used to record VTK events in a single file and replay it by pass these events to vtkRenderWindowInteractor. Record The following code shows how to use it to save all interactive information into a file. We rotate the cone and switch its surface status between wireframe and Read more…
vtkAbstractWidget has its mechanism to handle interactive events. Here is a simple demo indicates the differences between the responses of widget and vtkInteractorStyleTrackballCamera. Example Code: int main() { vtkSmartPointer<vtkConeSource> cone = vtkSmartPointer<vtkConeSource>::New(); cone->Update(); vtkSmartPointer<vtkPolyDataMapper> coneMapper = vtkSmartPointer<vtkPolyDataMapper>::New(); coneMapper->SetInputData( cone->GetOutput() ); coneMapper->Update(); vtkSmartPointer<vtkActor> coneActor = vtkSmartPointer<vtkActor>::New(); coneActor->SetMapper( coneMapper ); vtkSmartPointer<vtkPointHandleRepresentation3D> handleRep Read more…
We often need to delete some elements in an STL set. But it causes a strange bug if we are careless sometimes. One newbie in C Plus Plus program language may write the following code to delete all odd numbers in a set. int main() { vector<int> vec{ 1, 3, Read more…
Driven class of unary_function can be used to check a single element based on special condition.Programmer can regard it as some algorithms’ parameter, such as count_if, find_if, and find_if_not.The following code shows how to write a customized unray class and use it. C++ struct Widget { int GetSpeed() const { return speed; } Widget( const Read more…
We need not sort all elements sometimes. Here are a few simple examples of STL algorithms partial_sort, nth_element, and partition. partial_sort For example, find the 5 biggest ones in 10 random numbers. #include <iostream> #include <vector> #include <cstdlib> #include <ctime> #include <algorithm> using namespace std; int main() { vector<int> values; Read more…