VTK 实例31：灰度图像直方图

  1 #include "vtkAutoInit.h" 
  2 VTK_MODULE_INIT(vtkRenderingOpenGL2);
  3 VTK_MODULE_INIT(vtkInteractionStyle);
  4 
  5 #include <vtkActor.h>
  6 #include <vtkBarChartActor.h>
  7 #include <vtkFieldData.h>
  8 #include <vtkImageAccumulate.h>
  9 #include <vtkImageData.h>
 10 #include <vtkIntArray.h>
 11 #include <vtkJPEGReader.h>
 12 #include <vtkLegendBoxActor.h>
 13 #include <vtkProperty2D.h>
 14 #include <vtkRenderer.h>
 15 #include <vtkRenderWindow.h>
 16 #include <vtkRenderWindowInteractor.h>
 17 #include <vtkSmartPointer.h>
 18 #include <vtkTextProperty.h>
 19 
 20 //测试图像：../data/lena-gray.jpg
 21 int main(int argc, char* argv[])
 22 {
 23 
 24     vtkSmartPointer<vtkJPEGReader> reader =
 25         vtkSmartPointer<vtkJPEGReader>::New();
 26     reader->SetFileName ( "lena-gray.jpg" );
 27     reader->Update();
 28 
 29     int bins   = 16;
 30     int comps  = 1;
 31 
 32     vtkSmartPointer<vtkImageAccumulate> histogram =
 33         vtkSmartPointer<vtkImageAccumulate>::New();
 34     histogram->SetInputData(reader->GetOutput());
 35     histogram->SetComponentExtent(0, bins-1, 0, 0, 0, 0);
 36     histogram->SetComponentOrigin(0, 0, 0);
 37     histogram->SetComponentSpacing(256.0/bins, 0, 0);
 38     histogram->Update();
 39 
 40     int* output = static_cast<int*>(histogram->GetOutput()->GetScalarPointer());
 41 
 42     vtkSmartPointer<vtkIntArray> frequencies = 
 43         vtkSmartPointer<vtkIntArray>::New();
 44     frequencies->SetNumberOfComponents(1);
 45 
 46     for(int j = 0; j < bins; ++j)
 47     {
 48         for(int i=0; i<comps; i++)
 49         {
 50             frequencies->InsertNextTuple1(*output++);
 51         }
 52     }
 53 
 54     vtkSmartPointer<vtkDataObject> dataObject = 
 55         vtkSmartPointer<vtkDataObject>::New();
 56     dataObject->GetFieldData()->AddArray( frequencies );
 57 
 58     vtkSmartPointer<vtkBarChartActor> barChart = 
 59         vtkSmartPointer<vtkBarChartActor>::New();
 60     barChart->SetInput(dataObject);
 61     barChart->SetTitle("Histogram");
 62     barChart->GetPositionCoordinate()->SetValue(0.05,0.05,0.0);
 63     barChart->GetPosition2Coordinate()->SetValue(0.95,0.95,0.0);
 64     barChart->GetProperty()->SetColor(0,0,0);
 65     barChart->GetTitleTextProperty()->SetColor(0,0,0);
 66     barChart->GetLabelTextProperty()->SetColor(0,0,0);
 67     barChart->GetLegendActor()->SetNumberOfEntries(dataObject->GetFieldData()->GetArray(0)->GetNumberOfTuples());
 68     barChart->LegendVisibilityOff();
 69     barChart->LabelVisibilityOff();
 70 
 71     double colors[3][3] = {
 72         { 1, 0, 0 },
 73         { 0, 1, 0 },
 74         { 0, 0, 1 } };
 75 
 76     int count = 0;
 77     for( int i = 0; i < bins; ++i )
 78     {
 79         for( int j = 0; j < comps; ++j )
 80         {
 81             barChart->SetBarColor( count++, colors[j] );
 82         }
 83     }
 84 
 85     vtkSmartPointer<vtkRenderer> renderer = 
 86         vtkSmartPointer<vtkRenderer>::New();
 87     renderer->AddActor(barChart);
 88     renderer->SetBackground(1.0, 1.0, 1.0);
 89 
 90     vtkSmartPointer<vtkRenderWindow> renderWindow = 
 91         vtkSmartPointer<vtkRenderWindow>::New();
 92     renderWindow->AddRenderer(renderer);
 93     renderWindow->SetSize(640, 480);
 94     renderWindow->Render();
 95     renderWindow->SetWindowName("ImageAccumulateExample");
 96 
 97     vtkSmartPointer<vtkRenderWindowInteractor> interactor =
 98         vtkSmartPointer<vtkRenderWindowInteractor>::New();
 99     interactor->SetRenderWindow(renderWindow);
100 
101     interactor->Initialize();
102     interactor->Start();
103 
104     return EXIT_SUCCESS;
105 }