.. _creating_widgets: Creating Widgets **************** Goal ==== In this tutorial you will learn how to .. container:: enumeratevisibleitemswithsquare * Create your own widgets using WidgetAccessor and VTK. * Show your widget in the visualization window. Code ==== You can download the code from :download:`here <../../../../samples/cpp/tutorial_code/viz/creating_widgets.cpp>`. .. code-block:: cpp #include #include #include #include #include #include #include #include #include #include #include using namespace cv; using namespace std; /** * @class WTriangle * @brief Defining our own 3D Triangle widget */ class WTriangle : public viz::Widget3D { public: WTriangle(const Point3f &pt1, const Point3f &pt2, const Point3f &pt3, const viz::Color & color = viz::Color::white()); }; /** * @function WTriangle::WTriangle */ WTriangle::WTriangle(const Point3f &pt1, const Point3f &pt2, const Point3f &pt3, const viz::Color & color) { // Create a triangle vtkSmartPointer points = vtkSmartPointer::New(); points->InsertNextPoint(pt1.x, pt1.y, pt1.z); points->InsertNextPoint(pt2.x, pt2.y, pt2.z); points->InsertNextPoint(pt3.x, pt3.y, pt3.z); vtkSmartPointer triangle = vtkSmartPointer::New(); triangle->GetPointIds()->SetId(0,0); triangle->GetPointIds()->SetId(1,1); triangle->GetPointIds()->SetId(2,2); vtkSmartPointer cells = vtkSmartPointer::New(); cells->InsertNextCell(triangle); // Create a polydata object vtkSmartPointer polyData = vtkSmartPointer::New(); // Add the geometry and topology to the polydata polyData->SetPoints(points); polyData->SetPolys(cells); // Create mapper and actor vtkSmartPointer mapper = vtkSmartPointer::New(); #if VTK_MAJOR_VERSION <= 5 mapper->SetInput(polyData); #else mapper->SetInputData(polyData); #endif vtkSmartPointer actor = vtkSmartPointer::New(); actor->SetMapper(mapper); // Store this actor in the widget in order that visualizer can access it viz::WidgetAccessor::setProp(*this, actor); // Set the color of the widget. This has to be called after WidgetAccessor. setColor(color); } /** * @function main */ int main() { /// Create a window viz::Viz3d myWindow("Creating Widgets"); /// Create a triangle widget WTriangle tw(Point3f(0.0,0.0,0.0), Point3f(1.0,1.0,1.0), Point3f(0.0,1.0,0.0), viz::Color::red()); /// Show widget in the visualizer window myWindow.showWidget("TRIANGLE", tw); /// Start event loop myWindow.spin(); return 0; } Explanation =========== Here is the general structure of the program: * Extend Widget3D class to create a new 3D widget. .. code-block:: cpp class WTriangle : public viz::Widget3D { public: WTriangle(const Point3f &pt1, const Point3f &pt2, const Point3f &pt3, const viz::Color & color = viz::Color::white()); }; * Assign a VTK actor to the widget. .. code-block:: cpp // Store this actor in the widget in order that visualizer can access it viz::WidgetAccessor::setProp(*this, actor); * Set color of the widget. .. code-block:: cpp // Set the color of the widget. This has to be called after WidgetAccessor. setColor(color); * Construct a triangle widget and display it in the window. .. code-block:: cpp /// Create a triangle widget WTriangle tw(Point3f(0.0,0.0,0.0), Point3f(1.0,1.0,1.0), Point3f(0.0,1.0,0.0), viz::Color::red()); /// Show widget in the visualizer window myWindow.showWidget("TRIANGLE", tw); Results ======= Here is the result of the program. .. image:: images/red_triangle.png :alt: Creating Widgets :align: center