# How to Rendering the vtkImageData correctyly

**URL:** https://discourse.vtk.org/t/how-to-rendering-the-vtkimagedata-correctyly/13204
**Category:** Support
**Tags:** code
**Created:** [January 31, 2024, 8:37am UTC](https://discourse.vtk.org/t/how-to-rendering-the-vtkimagedata-correctyly/13204 "2024-01-31T08:37:39Z")
**Posts on this page:** 2
**Page:** 1

<div class="post-metadata">

### Author: ![lukeqiang9521](https://discourse.vtk.org/user_avatar/discourse.vtk.org/lukeqiang9521/32/8390_2.png) [@lukeqiang9521](https://discourse.vtk.org/u/lukeqiang9521)
#### Post date: [January 31, 2024, 8:37am UTC](https://discourse.vtk.org/t/how-to-rendering-the-vtkimagedata-correctyly/13204/1 "2024-01-31T08:37:39Z")

</div>

hello ,everyone! i have code like that :  
vtkSmartPointer ImageFillActor;  
vtkSmartPointer Reslice;  
vtkSmartPointer SliceToImageTransform;  
vtkSmartPointer LookupTableFill;  
vtkSmartPointer ImageThreshold;  
{

```
			//	this->ImageOutlineActor = vtkSmartPointer<vtkActor2D>::New();
			ImageFillActor = vtkSmartPointer<vtkActor2D>::New();
			Reslice = vtkSmartPointer<vtkImageReslice>::New();
			Reslice->SetOutputSpacing(1, 1, 1);
			Reslice->SetOutputDimensionality(2);
			Reslice->SetOutputOrigin(pDataLayer->GetAxialImageData()->GetOrigin()[0],
			pDataLayer->GetAxialImageData()->GetOrigin()[1],
			pDataLayer->GetAxialImageData()->GetOrigin()[2]);
			Reslice->GenerateStencilOutputOn();
			Reslice->SetBackgroundColor(0.0, 0.0, 0.0, 0.0);
			Reslice->AutoCropOutputOff();
			Reslice->SetOptimization(1);

			SliceToImageTransform = vtkSmartPointer<vtkGeneralTransform>::New();
			vtkNew<vtkMatrix4x4> matrix;
			ConstructWorldToImageMatrix(TestBrushImage, matrix);
			SliceToImageTransform->PostMultiply();
			
			{
				SliceToImageTransform->Translate(0, 0, 0);
				// SliceToImageTransform
			}

			Reslice->SetResliceTransform(SliceToImageTransform);

			Reslice->SetInputData(TestBrushImage);
			int* extent = pDataLayer->GetAxialImageData()->GetExtent();
			double* spacing = pDataLayer->GetAxialImageData()->GetSpacing();
			int extent2[6] = { 0,0,0,0,0,0 };
			extent2[1] = std::round(extent[1] * spacing[0]);
			extent2[3] = std::round(extent[3] * spacing[1]);
			extent2[5] = std::round(extent[5] * spacing[2]);
			Reslice->SetOutputExtent(extent2);
		//	Reslice->SetOutputExtent(extent);

			//vtkSmartPointer<vtkMatrix4x4> worldToImageMatrix = vtkSmartPointer<vtkMatrix4x4>::New();
			LookupTableFill = vtkSmartPointer<vtkLookupTable>::New();
			

			LookupTableFill->SetNumberOfTableValues(2);
			LookupTableFill->SetRange(0, 1);
			LookupTableFill->IndexedLookupOff();
			LookupTableFill->Build();

			int index = LookupTableFill->GetIndex(1.0);
			LookupTableFill->SetTableValue(index, 255, 0, 0, 0);
			// Image fill
			vtkSmartPointer<vtkImageMapToRGBA> fillColorMapper = vtkSmartPointer<vtkImageMapToRGBA>::New();
			fillColorMapper->SetInputConnection(Reslice->GetOutputPort());
			fillColorMapper->SetOutputFormatToRGBA();
			fillColorMapper->SetLookupTable(LookupTableFill);
			fillColorMapper->Update();

			vtkSmartPointer<vtkImageMapper> imageFillMapper = vtkSmartPointer<vtkImageMapper>::New();
			imageFillMapper->SetInputConnection(fillColorMapper->GetOutputPort());
			imageFillMapper->SetColorWindow(255);
			imageFillMapper->SetColorLevel(127.5);
			//imageFillMapper->Update();

		
			ImageFillActor->SetMapper(imageFillMapper);
			this->CurrentRenderer->DisplayToWorld();
			this->CurrentRenderer->AddActor2D(ImageFillActor);
			ImageFillActor->SetPosition(0, 0);
			this->CurrentRenderer->ResetCamera();
			this->Interactor->Render();

```

![image](https://discourse.vtk.org/uploads/default/original/2X/2/2792718c84fca8c30ab4d6e6a0d4640d60ed04c2.png)

---

<div class="post-metadata">

### Author: ![lukeqiang9521](https://discourse.vtk.org/user_avatar/discourse.vtk.org/lukeqiang9521/32/8390_2.png) [@lukeqiang9521](https://discourse.vtk.org/u/lukeqiang9521)
#### Post date: [January 31, 2024, 8:39am UTC](https://discourse.vtk.org/t/how-to-rendering-the-vtkimagedata-correctyly/13204/2 "2024-01-31T08:39:39Z")

</div>

the redimag don’t overlay the ct image.i need to do that the path image overlay the ct image,and when i scale or shift the ct image,the path image also do that way