# Does vtk not allow changing display images?

**URL:** https://discourse.vtk.org/t/does-vtk-not-allow-changing-display-images/10831
**Category:** Support
**Tags:** code
**Created:** [February 28, 2023, 9:43am UTC](https://discourse.vtk.org/t/does-vtk-not-allow-changing-display-images/10831 "2023-02-28T09:43:26Z")
**Posts on this page:** 2
**Page:** 1

<div class="post-metadata">

### Author: ![marlon.ma](https://discourse.vtk.org/user_avatar/discourse.vtk.org/marlon.ma/32/6091_2.png) [@marlon.ma](https://discourse.vtk.org/u/marlon.ma)
#### Post date: [February 28, 2023, 9:43am UTC](https://discourse.vtk.org/t/does-vtk-not-allow-changing-display-images/10831/1 "2023-02-28T09:43:26Z")

</div>

#include “vtkSmartPointer.h”

#include\<vtkRenderer.h\>  
#include \<vtkRenderWindowInteractor.h\>  
#include “vtkAutoInit.h”  
#include\<vtkImageData.h\>  
#include \<vtkDICOMImageReader.h\>  
#include \<vtkImageViewer2.h\>  
#include \<vtkRenderWindowInteractor.h\>  
#include \<vtkCallbackCommand.h\>

VTK\_MODULE\_INIT(vtkRenderingOpenGL2);

VTK\_MODULE\_INIT(vtkInteractionStyle);  
#include \<vtkDICOMImageReader.h\>  
#include \<vtkImageViewer2.h\>  
#include \<vtkRenderWindowInteractor.h\>

// 定义全局变量  
vtkSmartPointer reader1;  
vtkSmartPointer reader2;  
vtkSmartPointer viewer;

// 按键事件回调函数  
void KeyPressCallback(vtkObject\* caller, long unsigned int vtkNotUsed(eventId), void\* vtkNotUsed(clientData), void\* vtkNotUsed(callData))  
{  
vtkRenderWindowInteractor\* interactor = static\_cast\<vtkRenderWindowInteractor\*\>(caller);  
std::string key = interactor-\>GetKeySym();

```
if (key == "1")
{
    viewer->SetInputConnection(reader1->GetOutputPort());
    viewer->SetColorLevel(reader1->GetOutput()->GetScalarRange()[0] + reader1->GetOutput()->GetScalarRange()[1]);
    viewer->SetColorWindow(reader1->GetOutput()->GetScalarRange()[1] - reader1->GetOutput()->GetScalarRange()[0]);
    viewer->GetRenderer()->ResetCamera();
    viewer->Render();
}
else if (key == "2")
{

    viewer->SetInputConnection(reader2->GetOutputPort());
    viewer->SetColorLevel(reader2->GetOutput()->GetScalarRange()[0] + reader2->GetOutput()->GetScalarRange()[1]);
    viewer->SetColorWindow(reader2->GetOutput()->GetScalarRange()[1] - reader2->GetOutput()->GetScalarRange()[0]);
    
    viewer->Render();
}

```

}

int main(int argc, char\* argv[])  
{  
// 创建 DICOM 文件读取器  
reader1 = vtkSmartPointer::New();  
reader1-\>SetFileName(“1.dcm”);  
reader1-\>Update();

```
reader2 = vtkSmartPointer<vtkDICOMImageReader>::New();
reader2->SetFileName("2.dcm");
reader2->Update();

// 创建图像显示器
viewer = vtkSmartPointer<vtkImageViewer2>::New();
viewer->SetInputConnection(reader1->GetOutputPort());
viewer->SetupInteractor(nullptr);
viewer->SetColorLevel(reader1->GetOutput()->GetScalarRange()[0] + reader1->GetOutput()->GetScalarRange()[1]);
viewer->SetColorWindow(reader1->GetOutput()->GetScalarRange()[1] - reader1->GetOutput()->GetScalarRange()[0]);
viewer->SetSize(400,400);
viewer->Render();

// 创建交互器
vtkSmartPointer<vtkRenderWindowInteractor> interactor = vtkSmartPointer<vtkRenderWindowInteractor>::New();
interactor->SetRenderWindow(viewer->GetRenderWindow());

// 添加按键事件处理器
vtkSmartPointer<vtkCallbackCommand> keypressCallback = vtkSmartPointer<vtkCallbackCommand>::New();
keypressCallback->SetCallback(KeyPressCallback);
interactor->AddObserver(vtkCommand::KeyPressEvent, keypressCallback);

// 开始交互循环
interactor->Initialize();
interactor->Start();

return 0;

```

}

---

<div class="post-metadata">

### Author: ![marlon.ma](https://discourse.vtk.org/user_avatar/discourse.vtk.org/marlon.ma/32/6091_2.png) [@marlon.ma](https://discourse.vtk.org/u/marlon.ma)
#### Post date: [February 28, 2023, 9:44am UTC](https://discourse.vtk.org/t/does-vtk-not-allow-changing-display-images/10831/2 "2023-02-28T09:44:51Z")

</div>

This is my code. Why can’t I switch images correctly？