KochanekSplineDemo
Repository source: KochanekSplineDemo
Description¶
The example provides vtkSliderWidgets to change tension, continuity and bias of the vtkKochanekSpline.
- tension - Changes the length of the tangent vector
- bias - Primarily changes the direction of the tangent vector
- continuity - Changes the sharpness in change between tangents
Seealso
This wikipedia article describes the controls in detail.
Other languages
See (PythonicAPI)
Question
If you have a question about this example, please use the VTK Discourse Forum
Code¶
KochanekSplineDemo.cxx
#include <vtkActor.h>
#include <vtkActor2D.h>
#include <vtkCommand.h>
#include <vtkGlyph3DMapper.h>
#include <vtkKochanekSpline.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkParametricFunctionSource.h>
#include <vtkParametricSpline.h>
#include <vtkPoints.h>
#include <vtkPolyData.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkProperty2D.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSliderRepresentation2D.h>
#include <vtkSliderWidget.h>
#include <vtkSphereSource.h>
#include <vtkTextMapper.h>
#include <vtkTextProperty.h>
namespace {
void MakeTensionWidget(vtkSliderWidget*, vtkParametricFunctionSource*,
vtkParametricSpline*, vtkRenderer*,
vtkRenderWindowInteractor*);
void MakeContinuityWidget(vtkSliderWidget*, vtkParametricFunctionSource*,
vtkParametricSpline*, vtkRenderer*,
vtkRenderWindowInteractor*);
void MakeBiasWidget(vtkSliderWidget*, vtkParametricFunctionSource*,
vtkParametricSpline*, vtkRenderer*,
vtkRenderWindowInteractor*);
void SetSliderColors(vtkSliderRepresentation2D* slider);
} // namespace
int main(int, char*[])
{
vtkNew<vtkNamedColors> colors;
int numberOfPoints = 7;
vtkNew<vtkPoints> points;
points->SetNumberOfPoints(numberOfPoints);
double radius = 1.0;
double delta = 2.0 * vtkMath::Pi() / double(numberOfPoints);
for (int n = 0; n < numberOfPoints; ++n)
{
double theta = delta * n;
double x = radius * std::cos(theta);
double y = radius * std::sin(theta);
double z = n * (vtkMath::Pi() / numberOfPoints);
points->SetPoint(n, x, y, z);
}
vtkNew<vtkKochanekSpline> xSpline;
vtkNew<vtkKochanekSpline> ySpline;
vtkNew<vtkKochanekSpline> zSpline;
vtkNew<vtkParametricSpline> spline;
spline->SetXSpline(xSpline);
spline->SetYSpline(ySpline);
spline->SetZSpline(zSpline);
spline->SetPoints(points);
vtkNew<vtkParametricFunctionSource> functionSource;
functionSource->SetParametricFunction(spline);
functionSource->SetUResolution(50 * numberOfPoints);
functionSource->SetVResolution(50 * numberOfPoints);
functionSource->SetWResolution(50 * numberOfPoints);
functionSource->Update();
// Setup actor and mapper.
vtkNew<vtkPolyDataMapper> mapper;
mapper->SetInputConnection(functionSource->GetOutputPort());
vtkNew<vtkActor> actor;
actor->SetMapper(mapper);
actor->GetProperty()->SetColor(colors->GetColor3d("DarkSlateGrey").GetData());
actor->GetProperty()->SetLineWidth(3.0);
// Glyph the points.
vtkNew<vtkSphereSource> sphere;
sphere->SetPhiResolution(21);
sphere->SetThetaResolution(21);
sphere->SetRadius(.1);
// Create a polydata to store everything in.
vtkNew<vtkPolyData> polyData;
polyData->SetPoints(points);
vtkNew<vtkGlyph3DMapper> pointMapper;
pointMapper->SetInputData(polyData);
pointMapper->SetSourceConnection(sphere->GetOutputPort());
vtkNew<vtkActor> pointActor;
pointActor->SetMapper(pointMapper);
pointActor->GetProperty()->SetColor(colors->GetColor3d("Peacock").GetData());
pointActor->GetProperty()->SetOpacity(.5);
;
// Setup render window, renderer, and interactor.
vtkNew<vtkRenderer> renderer;
vtkNew<vtkRenderWindow> renderWindow;
renderWindow->AddRenderer(renderer);
renderWindow->SetSize(640, 480);
renderWindow->SetWindowName("KochanekSpline");
vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
renderWindowInteractor->SetRenderWindow(renderWindow);
renderer->AddActor(actor);
renderer->AddActor(pointActor);
;
renderer->SetBackground(colors->GetColor3d("Silver").GetData());
renderWindow->Render();
vtkNew<vtkSliderWidget> tensionWidget;
MakeTensionWidget(tensionWidget, functionSource, spline, renderer,
renderWindowInteractor);
vtkNew<vtkSliderWidget> continuityWidget;
MakeContinuityWidget(continuityWidget, functionSource, spline, renderer,
renderWindowInteractor);
vtkNew<vtkSliderWidget> biasWidget;
MakeBiasWidget(biasWidget, functionSource, spline, renderer,
renderWindowInteractor);
renderWindow->Render();
renderWindowInteractor->Start();
return EXIT_SUCCESS;
}
namespace {
// These callbacks do the actual work.
// Callbacks for the interactions
class SliderCallbackTension : public vtkCommand
{
public:
static SliderCallbackTension* New()
{
return new SliderCallbackTension;
}
virtual void Execute(vtkObject* caller, unsigned long, void*)
{
vtkSliderWidget* sliderWidget = reinterpret_cast<vtkSliderWidget*>(caller);
double value = static_cast<vtkSliderRepresentation2D*>(
sliderWidget->GetRepresentation())
->GetValue();
dynamic_cast<vtkKochanekSpline*>(this->ParametricSpline->GetXSpline())
->SetDefaultTension(value);
dynamic_cast<vtkKochanekSpline*>(this->ParametricSpline->GetYSpline())
->SetDefaultTension(value);
dynamic_cast<vtkKochanekSpline*>(this->ParametricSpline->GetZSpline())
->SetDefaultTension(value);
ParametricSource->Modified();
ParametricSource->Update();
}
SliderCallbackTension() : ParametricSource(0), ParametricSpline(0)
{
}
vtkParametricSpline* ParametricSpline;
vtkParametricFunctionSource* ParametricSource;
};
void MakeTensionWidget(vtkSliderWidget* widget,
vtkParametricFunctionSource* parametricSource,
vtkParametricSpline* parametricSpline,
vtkRenderer* renderer,
vtkRenderWindowInteractor* interactor)
{
// Setup a slider widget for each varying parameter.
double tubeWidth(.005);
double sliderLength(.02);
double titleHeight(.02);
double labelHeight(.02);
vtkNew<vtkSliderRepresentation2D> sliderRepTension;
sliderRepTension->SetRenderer(renderer);
sliderRepTension->SetMinimumValue(-1.0);
sliderRepTension->SetMaximumValue(1.0);
sliderRepTension->SetValue(
dynamic_cast<vtkKochanekSpline*>(parametricSpline->GetXSpline())
->GetDefaultTension());
sliderRepTension->SetTitleText("Tension");
sliderRepTension->SetRenderer(renderer);
sliderRepTension->GetPoint1Coordinate()->SetValue(0.1, 0.1);
sliderRepTension->GetPoint1Coordinate()
->SetCoordinateSystemToNormalizedViewport();
sliderRepTension->GetPoint2Coordinate()->SetValue(0.3, 0.1);
sliderRepTension->GetPoint2Coordinate()
->SetCoordinateSystemToNormalizedViewport();
sliderRepTension->SetTubeWidth(tubeWidth);
sliderRepTension->SetSliderLength(sliderLength);
sliderRepTension->SetTitleHeight(titleHeight);
sliderRepTension->SetLabelHeight(labelHeight);
sliderRepTension->SetEndCapLength(tubeWidth * 1.5);
sliderRepTension->SetSliderWidth(tubeWidth * 1.5);
sliderRepTension->BuildRepresentation();
SetSliderColors(sliderRepTension);
widget->SetRepresentation(sliderRepTension);
widget->SetAnimationModeToAnimate();
widget->SetNumberOfAnimationSteps(10);
widget->SetInteractor(interactor);
widget->EnabledOn();
vtkNew<SliderCallbackTension> callbackTension;
callbackTension->ParametricSpline = parametricSpline;
callbackTension->ParametricSource = parametricSource;
widget->AddObserver(vtkCommand::InteractionEvent, callbackTension);
}
class SliderCallbackContinuity : public vtkCommand
{
public:
static SliderCallbackContinuity* New()
{
return new SliderCallbackContinuity;
}
virtual void Execute(vtkObject* caller, unsigned long, void*)
{
vtkSliderWidget* sliderWidget = reinterpret_cast<vtkSliderWidget*>(caller);
double value = static_cast<vtkSliderRepresentation2D*>(
sliderWidget->GetRepresentation())
->GetValue();
dynamic_cast<vtkKochanekSpline*>(this->ParametricSpline->GetXSpline())
->SetDefaultContinuity(value);
dynamic_cast<vtkKochanekSpline*>(this->ParametricSpline->GetYSpline())
->SetDefaultContinuity(value);
dynamic_cast<vtkKochanekSpline*>(this->ParametricSpline->GetZSpline())
->SetDefaultContinuity(value);
ParametricSource->Modified();
ParametricSource->Update();
}
SliderCallbackContinuity() : ParametricSource(0), ParametricSpline(0)
{
}
vtkParametricSpline* ParametricSpline;
vtkParametricFunctionSource* ParametricSource;
};
void MakeContinuityWidget(vtkSliderWidget* widget,
vtkParametricFunctionSource* parametricSource,
vtkParametricSpline* parametricSpline,
vtkRenderer* renderer,
vtkRenderWindowInteractor* interactor)
{
// Setup a slider widget for each varying parameter.
double tubeWidth(.005);
double sliderLength(.02);
double titleHeight(.02);
double labelHeight(.02);
vtkNew<vtkSliderRepresentation2D> sliderRepContinuity;
sliderRepContinuity->SetRenderer(renderer);
sliderRepContinuity->SetMinimumValue(-1.0);
sliderRepContinuity->SetMaximumValue(1.0);
sliderRepContinuity->SetValue(
dynamic_cast<vtkKochanekSpline*>(parametricSpline->GetXSpline())
->GetDefaultContinuity());
sliderRepContinuity->SetTitleText("Continuity");
sliderRepContinuity->SetRenderer(renderer);
sliderRepContinuity->GetPoint1Coordinate()->SetValue(0.4, 0.1);
sliderRepContinuity->GetPoint1Coordinate()
->SetCoordinateSystemToNormalizedViewport();
sliderRepContinuity->GetPoint2Coordinate()->SetValue(0.6, 0.1);
sliderRepContinuity->GetPoint2Coordinate()
->SetCoordinateSystemToNormalizedViewport();
sliderRepContinuity->SetTubeWidth(tubeWidth);
sliderRepContinuity->SetSliderLength(sliderLength);
sliderRepContinuity->SetTitleHeight(titleHeight);
sliderRepContinuity->SetLabelHeight(labelHeight);
sliderRepContinuity->SetEndCapLength(tubeWidth * 1.5);
sliderRepContinuity->SetSliderWidth(tubeWidth * 1.5);
sliderRepContinuity->BuildRepresentation();
SetSliderColors(sliderRepContinuity);
widget->SetRepresentation(sliderRepContinuity);
widget->SetAnimationModeToAnimate();
widget->SetNumberOfAnimationSteps(10);
widget->SetInteractor(interactor);
widget->EnabledOn();
vtkNew<SliderCallbackContinuity> callbackContinuity;
callbackContinuity->ParametricSpline = parametricSpline;
callbackContinuity->ParametricSource = parametricSource;
widget->AddObserver(vtkCommand::InteractionEvent, callbackContinuity);
}
class SliderCallbackBias : public vtkCommand
{
public:
static SliderCallbackBias* New()
{
return new SliderCallbackBias;
}
virtual void Execute(vtkObject* caller, unsigned long, void*)
{
vtkSliderWidget* sliderWidget = reinterpret_cast<vtkSliderWidget*>(caller);
double value = static_cast<vtkSliderRepresentation2D*>(
sliderWidget->GetRepresentation())
->GetValue();
dynamic_cast<vtkKochanekSpline*>(this->ParametricSpline->GetXSpline())
->SetDefaultBias(value);
dynamic_cast<vtkKochanekSpline*>(this->ParametricSpline->GetYSpline())
->SetDefaultBias(value);
dynamic_cast<vtkKochanekSpline*>(this->ParametricSpline->GetZSpline())
->SetDefaultBias(value);
ParametricSource->Modified();
ParametricSource->Update();
}
SliderCallbackBias() : ParametricSource(0), ParametricSpline(0)
{
}
vtkParametricSpline* ParametricSpline;
vtkParametricFunctionSource* ParametricSource;
};
void MakeBiasWidget(vtkSliderWidget* widget,
vtkParametricFunctionSource* parametricSource,
vtkParametricSpline* parametricSpline,
vtkRenderer* renderer,
vtkRenderWindowInteractor* interactor)
{
// Setup a slider widget for each varying parameter.
double tubeWidth(.005);
double sliderLength(.02);
double titleHeight(.02);
double labelHeight(.02);
vtkNew<vtkSliderRepresentation2D> sliderRepBias;
sliderRepBias->SetRenderer(renderer);
sliderRepBias->SetMinimumValue(-1.0);
sliderRepBias->SetMaximumValue(1.0);
sliderRepBias->SetValue(
dynamic_cast<vtkKochanekSpline*>(parametricSpline->GetXSpline())
->GetDefaultBias());
sliderRepBias->SetTitleText("Bias");
sliderRepBias->SetRenderer(renderer);
sliderRepBias->GetPoint1Coordinate()->SetValue(0.7, 0.1);
sliderRepBias->GetPoint1Coordinate()
->SetCoordinateSystemToNormalizedViewport();
sliderRepBias->GetPoint2Coordinate()->SetValue(0.9, 0.1);
sliderRepBias->GetPoint2Coordinate()
->SetCoordinateSystemToNormalizedViewport();
sliderRepBias->SetTubeWidth(tubeWidth);
sliderRepBias->SetSliderLength(sliderLength);
sliderRepBias->SetTitleHeight(titleHeight);
sliderRepBias->SetLabelHeight(labelHeight);
sliderRepBias->SetEndCapLength(tubeWidth * 1.5);
sliderRepBias->SetSliderWidth(tubeWidth * 1.5);
sliderRepBias->BuildRepresentation();
SetSliderColors(sliderRepBias);
widget->SetRepresentation(sliderRepBias);
widget->SetAnimationModeToAnimate();
widget->SetNumberOfAnimationSteps(10);
widget->SetInteractor(interactor);
widget->EnabledOn();
vtkNew<SliderCallbackBias> callbackBias;
callbackBias->ParametricSpline = parametricSpline;
callbackBias->ParametricSource = parametricSource;
widget->AddObserver(vtkCommand::InteractionEvent, callbackBias);
}
void SetSliderColors(vtkSliderRepresentation2D* slider)
{
vtkNew<vtkNamedColors> colors;
// Set color properties:
// Change the color of the knob that slides.
slider->GetSliderProperty()->SetColor(colors->GetColor3d("Peru").GetData());
// Change the color of the text indicating what the slider controls.
slider->GetTitleProperty()->SetColor(
colors->GetColor3d("OrangeRed").GetData());
// Change the color of the text displaying the value.
slider->GetLabelProperty()->SetColor(
colors->GetColor3d("OrangeRed").GetData());
// Change the color of the knob when the mouse is held on it.
slider->GetSelectedProperty()->SetColor(
colors->GetColor3d("DeepPink").GetData());
// Change the color of the bar.
slider->GetTubeProperty()->SetColor(colors->GetColor3d("Gold").GetData());
// Change the color of the ends of the bar.
slider->GetCapProperty()->SetColor(colors->GetColor3d("Gold").GetData());
}
} // namespace
CMakeLists.txt¶
cmake_minimum_required(VERSION 3.12 FATAL_ERROR)
project(KochanekSplineDemo)
find_package(VTK COMPONENTS
CommonColor
CommonComputationalGeometry
CommonCore
CommonDataModel
FiltersSources
InteractionStyle
InteractionWidgets
RenderingContextOpenGL2
RenderingCore
RenderingFreeType
RenderingGL2PSOpenGL2
RenderingOpenGL2
)
if (NOT VTK_FOUND)
message(FATAL_ERROR "KochanekSplineDemo: Unable to find the VTK build folder.")
endif()
# Prevent a "command line is too long" failure in Windows.
set(CMAKE_NINJA_FORCE_RESPONSE_FILE "ON" CACHE BOOL "Force Ninja to use response files.")
add_executable(KochanekSplineDemo MACOSX_BUNDLE KochanekSplineDemo.cxx )
target_link_libraries(KochanekSplineDemo PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
TARGETS KochanekSplineDemo
MODULES ${VTK_LIBRARIES}
)
Download and Build KochanekSplineDemo¶
Click here to download KochanekSplineDemo and its CMakeLists.txt file. Once the tarball KochanekSplineDemo.tar has been downloaded and extracted,
cd KochanekSplineDemo/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:
./KochanekSplineDemo
WINDOWS USERS
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.