关于三维图像切片交互提取（回调函数、观察者-命令模式）运行后只显示一张切片图像，并没有鼠标滑动的交互效果的解决办法

原程序基于《VTK图形图像开发进阶》第五章，用于鼠标实时进行三维图像的切面提取。由于我使用的版本是VS2022+VTK9，所以我对提供的程序进行了一定的修改，加入了Update()函数，代码为：

#include 
VTK_MODULE_INIT(vtkRenderingOpenGL2);

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#include  //建立“观察者/命令”模式监听鼠标消息 完成交互
#include 
#include 
#include 

class vtkImageInteractionCallback : public vtkCommand
{
public:
	static vtkImageInteractionCallback* New() //回调函数初始化函数
	{
		return new vtkImageInteractionCallback;
	}
	vtkImageInteractionCallback()
	{
		this->Slicing = 0;
		this->ImageReslice = 0;
		this->Interactor = 0;
	}
	void SetImageReslice(vtkImageReslice* reslice)
	{
		this->ImageReslice = reslice;
	}
	vtkImageReslice* GetImageReslice()
	{
		return this->ImageReslice;
	}
	void SetInteractor(vtkRenderWindowInteractor* interactor)
	{
		this->Interactor = interactor;
	}
	vtkRenderWindowInteractor* GetInteractor()
	{
		return  this->Interactor;
	}
	virtual void Execute(vtkObject*, unsigned long event, void*)
	{
		vtkRenderWindowInteractor* interactor = GetInteractor();
		int lastPos[2];
		interactor->GetLastEventPosition(lastPos);
		int currPos[2];
		interactor->GetEventPosition(currPos);

		if (event == vtkCommand::LeftButtonPressEvent)
		{
			this->Slicing = 1; //标志位 
		}
		else if (event == vtkCommand::LeftButtonReleaseEvent)
		{
			this->Slicing = 0; //标志位 
		}
		else if (event == vtkCommand::MouseMoveEvent)
		{
			if (this->Slicing)//检验鼠标左键已经按下 正在执行操作
			{	
				vtkImageReslice* reslice = this->ImageReslice;
				//记下鼠标Y向变化的幅值大小
				int deltaY = lastPos[1] - currPos[1];

				reslice->Update();
				double sliceSpacing = reslice->GetOutput()->GetSpacing()[2];
				vtkMatrix4x4* matrix = reslice->GetResliceAxes();
				//重新定位切片需要经过的中心点
				double point[4];
				double center[4];
				point[0] = 0;
				point[1] = 0;
				point[2] = sliceSpacing * deltaY;
				point[3] = 1.0;
				matrix->MultiplyPoint(point, center);
				matrix->SetElement(0, 3, center[0]);
				matrix->SetElement(1, 3, center[1]);
				matrix->SetElement(2, 3, center[2]);

				interactor->Render();
			}
			else
			{
				vtkInteractorStyle* style = vtkInteractorStyle::SafeDownCast(
					interactor->GetInteractorStyle());
				if (style)
				{
					style->OnMouseMove();
				}
			}
		}
	}
private:
	int Slicing;
	vtkImageReslice* ImageReslice;
	vtkRenderWindowInteractor* Interactor;
};
//**********************************************************************************//
int main()
{
	vtkSmartPointer reader =
		vtkSmartPointer::New();
	reader->SetFileName("brain.mhd");
	reader->Update();

	int extent[6];
	double spacing[3];
	double origin[3];

	reader->GetOutput()->GetExtent(extent);
	reader->GetOutput()->GetSpacing(spacing);
	reader->GetOutput()->GetOrigin(origin);

	double center[3];
	center[0] = origin[0] + spacing[0] * 0.5 * (extent[0] + extent[1]);
	center[1] = origin[1] + spacing[1] * 0.5 * (extent[2] + extent[3]);
	center[2] = origin[2] + spacing[2] * 0.5 * (extent[4] + extent[5]);

	static double axialElements[16] = {
		1, 0, 0, 0,
		0, 1, 0, 0,
		0, 0, 1, 0,
		0, 0, 0, 1
	};

	vtkSmartPointer resliceAxes =
		vtkSmartPointer::New();
	resliceAxes->DeepCopy(axialElements);

	resliceAxes->SetElement(0, 3, center[0]);
	resliceAxes->SetElement(1, 3, center[1]);
	resliceAxes->SetElement(2, 3, center[2]);

	vtkSmartPointer reslice =
		vtkSmartPointer::New();
	reslice->SetInputConnection(reader->GetOutputPort());
	reslice->SetOutputDimensionality(2);
	reslice->SetResliceAxes(resliceAxes);
	reslice->SetInterpolationModeToLinear();
	reslice->Update();

	vtkSmartPointer colorTable =
		vtkSmartPointer::New();
	colorTable->SetRange(0, 1000);
	colorTable->SetValueRange(0.0, 1.0);
	colorTable->SetSaturationRange(0.0, 0.0);
	colorTable->SetRampToLinear();
	colorTable->Build();

	vtkSmartPointer colorMap =
		vtkSmartPointer::New();
	colorMap->SetLookupTable(colorTable);
	colorMap->SetInputConnection(reslice->GetOutputPort());
	colorMap->Update();

	vtkSmartPointer imgActor =
		vtkSmartPointer::New();
	imgActor->SetInputData(colorMap->GetOutput());

	vtkSmartPointer renderer =
		vtkSmartPointer::New();
	renderer->AddActor(imgActor);
	renderer->SetBackground(.4, .5, .6);

	vtkSmartPointer renderWindow =
		vtkSmartPointer::New();
	renderWindow->SetSize(500, 500);
	renderWindow->AddRenderer(renderer);

	vtkSmartPointer renderWindowInteractor =
		vtkSmartPointer::New();
	vtkSmartPointer imagestyle =
		vtkSmartPointer::New();

	renderWindowInteractor->SetInteractorStyle(imagestyle);
	renderWindowInteractor->SetRenderWindow(renderWindow);
	renderWindowInteractor->Initialize();
	//****************建立 观察者-命令 模式****************//
	vtkSmartPointer callback =
		vtkSmartPointer::New();
	callback->SetImageReslice(reslice);
	callback->SetInteractor(renderWindowInteractor);

	imagestyle->AddObserver(vtkCommand::MouseMoveEvent, callback);
	imagestyle->AddObserver(vtkCommand::LeftButtonPressEvent, callback);
	imagestyle->AddObserver(vtkCommand::LeftButtonReleaseEvent, callback);

	renderWindowInteractor->Start();

	return 0;
}

运行结果如下，只能显示一张切面图，无法使用鼠标进行交互。

出现这种情况的原因是：新版vtk需要在vtkImageInteractionCallback类的定义里增加vtkImageMapToColors的更新的相关函数才可以正常切换切片。

所以我们需要在原来的代码里增加以下部分：

void SetImageResliceColorMap(vtkImageMapToColors* colorMap)
{
	this->colorMap = colorMap;
}
vtkImageMapToColors* GetImageResliceColorMap()
{
	return this->colorMap;

callback->SetImageReslice(reslice);
callback->SetInteractor(renderWindowInteractor);
callback->SetImageResliceColorMap(colorMap);

这样就可以实现鼠标滑动改变切面了。

三维图像切片交互提取（回调函数、观察者-命令模式）

如果需要这段代码更加详细的解析，可以参考我的另一篇博文：6.VTK二维三维图像显示以及二维三维图像切面交互提取（回调函数、观察者-命令模式）_vtk怎么提取切面-CSDN博客另外如果想给这段代码用Qt界面展示出来，我的这篇博文可以用来参考：VS2022联合Qt5开发学习5（QT5.12.3联合VTK在VS2022上开发医学图像项目）-CSDN博客