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Diagram

vtk-examples/Cxx/Plotting/Diagram


Description

This example show how to create a custom vtkChartXY by providing a subclass of vtkContextItem.

Also, the example uses vtkColorSeries to specify the colors of the diagram's boxes. The vtkColorSeries scheme can be specified on the command line. If an unknown scheme is used, a list of valid schemes is provided.

Question

If you have a question about this example, please use the VTK Discourse Forum

Code

Diagram.cxx

#include <vtkBrush.h>
#include <vtkColorSeries.h>
#include <vtkContext2D.h>
#include <vtkContextActor.h>
#include <vtkContextItem.h>
#include <vtkContextScene.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkObjectFactory.h>
#include <vtkPen.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSmartPointer.h>
#include <vtkTextProperty.h>

namespace {
//----------------------------------------------------------------------------
class APIDiagram : public vtkContextItem
{
public:
  static APIDiagram* New();
  vtkTypeMacro(APIDiagram, vtkContextItem);
  APIDiagram()
  {
    this->ColorSeries = vtkSmartPointer<vtkColorSeries>::New();
    this->ColorSchemeName = "Brewer Diverging Spectral (7)";
    this->ColorSeries->SetColorSchemeByName(this->ColorSchemeName);
  }
  // Paint event for the chart, called whenever the chart needs to be drawn.
  virtual bool Paint(vtkContext2D* painter);
  void SetColorSchemeName(std::string seriesName)
  {
    this->ColorSeries->SetColorSchemeByName(seriesName);
    if (this->ColorSeries->GetColorScheme() >
        vtkColorSeries::BREWER_QUALITATIVE_SET3)
    {
      this->PrintColorSchemes();
    }
  }
  void PrintColorSchemes(ostream& os = std::cout)
  {
    int saveId = this->ColorSeries->GetColorScheme();
    for (unsigned int i = 0; i < vtkColorSeries::BREWER_QUALITATIVE_SET3; ++i)
    {
      this->ColorSeries->SetColorScheme(i);
      os << this->ColorSeries->GetColorSchemeName() << std::endl;
    }
    this->ColorSeries->SetColorScheme(saveId);
  }

protected:
  vtkSmartPointer<vtkColorSeries> ColorSeries;
  std::string ColorSchemeName;
};
} // namespace

//----------------------------------------------------------------------------
int main(int argc, char* argv[])
{
  std::string colorSchemeName = "Brewer Diverging Brown-Blue-Green (7)";
  if (argc > 1)
  {
    colorSchemeName = std::string(argv[1]);
  }

  // Set up a 2D chart actor, APIDiagram object andn add them to the renderer.
  vtkNew<APIDiagram> diagram;
  diagram->SetColorSchemeName(colorSchemeName);

  vtkNew<vtkContextActor> actor;
  actor->GetScene()->AddItem(diagram);

  vtkNew<vtkNamedColors> colors;
  vtkNew<vtkRenderer> renderer;
  renderer->SetBackground(colors->GetColor3d("Tan").GetData());

  vtkNew<vtkRenderWindow> renderWindow;
  renderWindow->SetSize(800, 600);
  renderWindow->AddRenderer(renderer);
  renderWindow->SetWindowName("Diagram");

  renderer->AddActor(actor);

  vtkNew<vtkRenderWindowInteractor> interactor;
  interactor->SetRenderWindow(renderWindow);
  renderWindow->SetMultiSamples(0);
  renderWindow->Render();

  interactor->Start();

  return EXIT_SUCCESS;
}

// Make our new derived class to draw a diagram.
vtkStandardNewMacro(APIDiagram);
// This function draws our API diagram
bool APIDiagram::Paint(vtkContext2D* painter)
{
  // Drawing a hard wired diagram 800x600 as a demonstration of the 2D API.
  painter->GetTextProp()->SetVerticalJustificationToCentered();
  painter->GetTextProp()->SetJustificationToCentered();
  painter->GetTextProp()->SetColor(0.0, 0.0, 0.0);
  painter->GetTextProp()->SetFontSize(24);
  painter->GetPen()->SetColor(0, 0, 0);

  unsigned int c = 0;
  painter->GetBrush()->SetColor(
      (this->ColorSeries->GetColorRepeating(c)).GetData());
  c++;

  painter->DrawRect(100, 50, 200, 100);
  painter->DrawString(200, 100, "OpenGL");

  painter->GetBrush()->SetColor(
      (this->ColorSeries->GetColorRepeating(c)).GetData());
  c++;
  painter->DrawRect(300, 50, 200, 100);
  painter->DrawString(400, 100, "Others?");

  painter->GetBrush()->SetColor(
      (this->ColorSeries->GetColorRepeating(c)).GetData());
  c++;
  painter->DrawRect(500, 50, 200, 100);
  painter->DrawString(600, 100, "Others?");

  painter->GetBrush()->SetColor(
      (this->ColorSeries->GetColorRepeating(c)).GetData());
  c++;
  painter->DrawRect(100, 150, 600, 100);
  painter->DrawString(400, 200, "2D API");

  painter->GetBrush()->SetColor(
      (this->ColorSeries->GetColorRepeating(c)).GetData());
  c++;
  painter->DrawRect(100, 250, 600, 200);
  painter->DrawString(400, 400, "Canvas API");

  painter->GetBrush()->SetColor(
      (this->ColorSeries->GetColorRepeating(c)).GetData());
  c++;
  painter->DrawRect(100, 250, 300, 100);
  painter->DrawString(250, 300, "Point Mark");

  painter->GetBrush()->SetColor(
      (this->ColorSeries->GetColorRepeating(c)).GetData());
  painter->DrawRect(100, 450, 600, 100);
  painter->DrawString(400, 500, "Canvas View");

  return true;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.12 FATAL_ERROR)

project(Diagram)

find_package(VTK COMPONENTS 
  CommonColor
  CommonCore
  InteractionStyle
  RenderingContext2D
  RenderingContextOpenGL2
  RenderingCore
  RenderingFreeType
  RenderingGL2PSOpenGL2
  RenderingOpenGL2
)

if (NOT VTK_FOUND)
  message(FATAL_ERROR "Diagram: 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(Diagram MACOSX_BUNDLE Diagram.cxx )
  target_link_libraries(Diagram PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
  TARGETS Diagram
  MODULES ${VTK_LIBRARIES}
)

Download and Build Diagram

Click here to download Diagram and its CMakeLists.txt file. Once the tarball Diagram.tar has been downloaded and extracted,

cd Diagram/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:

./Diagram

WINDOWS USERS

Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.